adsense code

Saturday, March 21, 2020

The Electrical Nature of Conscious Memory Formation and Retrieval


When you memorize something, the brain creates a nerve-impulse code to create a representation of the information represented in brain, and this code can get stored in memory. Upon retrieval, the code is replayed, and thus what the code represents becomes consciously available again as a simulation. At least that’s the theory. Until now, the evidence for this explanation has been derived mostly from rodents. But now rather direct evidence is available from humans.
In one new study, human subjects created memory associations between word pairs, while experimenters simultaneously recorded single-neuron impulses and their associated field potentials from an implanted microelectrode array in the medial temporal cortex, which is known to participate in memory formation. The EEG was also recorded from subdural electrodes implanted over the temporal cortex immediately above the microelectrode array. This allowed simultaneous observation of the local nerve impulse discharges, their associated local field potentials, and the EEG during memory formation and retrieval after a brief distraction period.
Recordings revealed the well-known relationship that EEG signals often have superimposed low-voltage high-frequency waves, which are called ripples. As expected, the ripples appeared at the same time of the impulse discharges from the microelectrodes, indicating that the impulses actually cause the small field potential changes of ripples.

In the top signal, we have the sum of a fast and slow oscillations, where the power of fast oscillation's envelope changes with the phase of the slower oscillation. The bottom signal shows only the filtered fast oscillation and the variation in its power. As it is obvious from comparison of two signals, the fast rhythm's power is always maximum at a certain coupled phase of slower oscillation (From Samiee et al.).
In the experiment, impulse burst clusters occurred throughout the presentation of word pairs while subjects were encoding the pairs. Trial-specific spike sequences observed during encoding were replayed during correct recall. As expected, ripples during recall appeared at the same time as the impulse sequences.
Not mentioned by the authors is that their findings have implications for neural correlates of consciousness. After all, forming the word-pair associations was a conscious operation. In the field of consciousness research, neural correlates are clearly evident in the EEG in that the frequency of voltage shifts predictably as the brain progresses from large slow waves during anesthesia or sleep to increasingly faster and smaller waves during alert arousal.  Relatively high frequencies (40-200 waves per second) appear more prominently when the brain is working on difficult tasks. Moreover, hard tasks are associated with more phase-locking of the EEG oscillations at different locations of the cortex.
Conscious perceptions seem to involve short- and long-range oscillations in the vertically oriented network columns in the cortex. Each column contains a local network that processes input locally in oscillatory activity that is gated at certain frequencies by inhibitory neurons in the circuit.  
At the same time, local oscillations from large pyramidal cell firings spread to distant columns both within and between the cortical hemispheres. The frequencies of this long-range activity may be slower because of the longer impulse conduction and synaptic delays. Collectively, local and distant networks interact and may likely be the basis for consciousness. The electrographic correlate is that of fast frequencies from local processing being nested within more globally generated slow frequencies. The timing phase relationships would clearly influence how much integration of local and distant processing occurs and the likelihood that the processing could be consciously perceived.
Many experiments have shown that selective attention is needed for conscious perception. Such attention activates local processing (and ripples in the local field potential). Bear in mind, however, that the ripples are not the source of processing but rather an associated manifestation of the processing that is actually occurring via the impulse timing in the local circuitry.
Two basic kinds of coupling can be seen in brainwave activity: 1) the phase of the slower frequency modulates the faster frequency, and (2) the phase coupling between two overlapping frequencies occurs when one frequency is a harmonic multiple of the other.
Conscious processing seems to be crucially dependent on the cross-frequency coherence of neural activity that can be seen at the local circuit level in multiple local sites of neocortex, hippocampus, and basal ganglia. There are different varieties of cross-frequency coupling (phase-phase, amplitude-amplitude, and phase-amplitude coupling), each of which may reflect distinctive processing. Such coherence differs across brain areas in a task-relevant manner, and changes quickly in response to sensory, motor, and cognitive events, and correlates with performance in learning tasks. Moreover, cross-frequency coherence increases with level of task demand. For example, continuous EEG recordings obtained during an arithmetic task, rest and breath focus revealed that cross-frequency alpha and theta peak-frequency coherence significantly higher when cognitive demands increased (Rodriguez-Larios and Alaerts, (2019). What is likely to remain enigmatic is how such cross-frequency coupling yields a conscious perception.
The most significant neural correlation of consciousness may prove to be time locking of nested oscillation of different frequencies whose underlying impulse patterns carry different aspects of information. The time locking of nested high- and low-frequency activity likely increases information throughput in the local circuits participating in selective attention, occludes noisy disruption from other inputs, and improves the signal-to-noise ratio of neural activity that is processing the target of attention. Parsimonious as this view might be, it still does not fully explain how a conscious percept emerges.

Sources:

Rodriguez_Larios, Julio and Alaerts, Kaat (2019). Tracking transient changes in the neural frequency architecture: harmonic relations between theta and alpha peaks facilitate cognitive performance. J. Neurosci. 7 August, 39 (32) 6291-6298; DOI: https://doi.org/10.1523/JNEUROSCI.2919-18.2019

Samiee, Sohelila et al. (2019) Phase-amplitude coupling. Nov. https://neuroimage.usc.edu/brainstorm/Tutorials/TutPac

Vaz, Alex P. et al. (2020). Replay of cortical spiking sequences during human memory retrieval. Science. 367,1131-1134.

Sunday, March 01, 2020

On Becoming More Human: The Two Human Distinctions


To become more human, it seems we must first recognize what is distinctive about being human. Basic biology is about the same in all higher animals and humans. So for distinctiveness we must look to mental and behavioral functions. It seems that only two mental characteristics are distinctively human. These are commonly referred to as constructed imagined scenarios and deliberate practice.

The clarification of human scenario building became evident from the research of Thomas Suddendorf at the University of Queensland. He challenged the usual claim that humans are distinct because of their capacity for “speech, fire, agriculture, writing, tools, and large-scale cooperation.” Actually, certain animal species can perform one or more of these activities in their own way. As examples, Suddendorf reminds us that "If you set the bar low, you can conclude that parrots can speak, ants have agriculture, crows make tools, and bees cooperate on a large scale." What sets people apart from others in the animal kingdom is that humans have imagination that enables them to develop scenarios and link other scenario-building minds. Such use of creative imagination, he says, allows humans to turn animal communication ”into open-ended human language, memory into mental time travel, social cognition into theory of mind, problem solving into abstract reasoning, social traditions into cumulative culture, and empathy into morality."

Suddendorf concedes that some animals, like great apes, seem to have some scenario-building capability. But human capability explodes after about age 2, while this does not happen in great apes. Age 2 is about when humans show signs of conscious self-awareness, which may be the key determinate for scenario-building capability.

We should not overlook the creativity element of scenario-building. Creativity has certainly been central to cultural advancement. Animal cultures, if they evolve at all, mostly seem to arise from trial-and-error learning.

A second uniquely human feature is captured in the term "deliberate practice." This term was apparently first coined in 1993 by Florida State University professor, K. Anders Ericsson and colleagues, as a result of observing the development of expertise by budding musicians. Their report has been cited an astounding 10,000 times according to Google Scholar. Key principles include the importance of purposeful learning involving individualized instruction and a focus on identifying goals and methods for achieving musical mastery. The phenomenon has since been named "structured practice" to capture the essential feature of systematic growth of expertise. I take the liberty of adding to the original ideas about deliberate practice by identifying several central elements for success of deliberate practice:

·       Motivation to develop expertise,
·       A specific learning regimen,
·       Learner control,
·       Knowledge on how to improve,
·       Time on task,
·       Repetition that features explicit awareness of how well mastery develops,
·       Immediate performance feedback,
·       Analysis of corrective feedback needed,
·       Successive approximations of feedback correction and attendant positive reinforcement of improvement,
·       Repetition that incorporates corrections.

Though Erickson originally claimed that a challenging expert teacher or coach is needed, the learner need not have direct supervision of a teacher, as long as there is an external source of information on the nature of the expertise, advice on how to develop it, and an objective metric for the extent of growth in expertise. Obviously, deliberate practice is more efficient when performed under the guidance of an expert coach or teacher.

Obviously, deliberate practice is most needed for development of specific skills, as in sports, music, and competitive games like chess. My own experience with use of mnemonics suggests a role for deliberate practice in the ability to memorize. Also relevant to the effectiveness of deliberate practice are the memory principles of focused attention, conditions supporting memory consolidation, and spacing of practice session. Other aspects of learning experience can be a kind of deliberate practice that promotes learning sets and a learning-how-to-learn expertise.

So, if we want to become more human, it seems necessary to develop our capacity for creativity and scenario building and for deliberate practice. Numerous writings, including my own, suggest ways to become more creative. Deliberate practice is achieved by doing it, especially in a way that promotes remembering what the practice is teaching you. As described on my web site (WRKlemm.com), my four books on memory seem to cover the breadth of memory theory and application.

Sources:

Ericsson, K. A., Krampe, R. T., and Tesch-Römer, C. (1993). The role of deliberate practice in the acquisition of expert performance. Psychol. Rev. 100, 363–406. doi: 10.1037/0033-295X.87.3.215

Ericsson, K. Anders, and Harwell, Kyle W. (2019), Deliberate practice and proposed limits on the effects of practice on the acquisition of expert performance: Why the original definition matters and recommendations for future research. Front. Psychol., 25 October 2019, https://doi.org/10.3389/fpsyg.2019.02396

Klemm, W. R. (2018). Developing a strategic and systematic idea creation and management system. International Journal of Creativity and Problem Solving. 28(1), 7-26.

Klemm, W. R. (2017). Leadership and creativity, p. 263-296. In Leadership Today, edited by Joan Marques and Satinder Dhiman. New York: Springer.

Klemm, W. R. (2017). Reason and creativity require free will. Chapter 2, in Free Will: Interpretations, Implementations and Assessments  In Hauppauge, NY: Nova Science.

Klemm, W. R. (1990). Leadership: creativity and innovation, p. 426-439. Concepts for Air Force Leadership, 2nd Ed. Air University, Maxwell AFB, Ala. Available on-line at the Air War College website, http://www.au.af.mil/AU/AWC/AWCGATE/au-24/au24-401.htm. (Used as a text in several military academies for multiple years).

Suddendorf, Thomas (2013). The Gap: The Science of What Separates Us from Other Animals. New York, NY, United States: Basic Books).

Monday, February 17, 2020

New Research on How Learning Changes the Brain


Learning programs the brain. It is nature’s way to create simultaneously both “hardware” and “software” for the brain. Neuroscientists have long known that learning experiences change the functional circuitry that is used to process and remember a given learning event. The circuit change is anatomical: electron microscope photographs reveal that the synaptic changes take the form of little blebs located on dendrites. These blebs are called “dendritic spines,” and their size and number change in response to learning and memory formation. You might think of the induced change as a physical location for information storage. What is stored at any given spine is an increase in the probability that the spine will participate in activations that generate recall of the stored memory from all the spines that were enhanced in creating the memory.
Functionally, the change operates as a template that resides more or less permanently that is available not only to recall the original learning event but to respond to similar events in the future. Of course, no one synapse accounts for these recall and programming effects. However, the learning and memory results from the collective enhancement of all the enhanced dendritic spines in the participating circuitry. The templates thus created provide a way for the brain to program itself for future capabilities. Learning how to solve one kind of task makes it easier to learn new tasks that are similar. This is the basis for the so-called “learning-set,” a concept introduced many decades ago by Harry Harlow.
We tend to think about such matters in the education of children. However, the principle applies at all ages, including seniors. The aging brain responds to learning the same way a child’s brain does: it grows new task-specific synapses that can be recruited for other uses.
The learning effect is manifest in the growth of existing synapses and the formation of new synapses. In the absence of mental stimulation, the spines degenerate. Indeed, a typical effect of aging is that the brain actually shrinks as a consequence of the cumulative shrinkage of spines. Many neurological diseases are characterized by reduced synaptic density: schizophrenia, autism, and dementia. An opposite problem occurs with drug addiction, where certain synaptic connections are strengthened by the drug, essentially creating a way to store a memory for the addiction.
Until now, we have not learned as much about the chemical changes that occur with learning. A recent study from Thomas Jefferson University reveals that new patterns of molecular organization develop as connections between neurons strengthen during learning. The researchers basically asked the question, “What does learning look like at the molecular level? Using super-resolution live-cell microscopy, the researchers confirmed the enlargement of synapses previously reported by others. But they also saw that that during a learning experience the molecules involved in sending and receiving the signals between neurons appeared to be organized in clumps or "nanomodules" that both dance and multiply when stimulated by learning-like signals.
The researchers developed a novel technique wherein they could visualize the chemical involved in transmitting signal from one neuron to another. Chemicals on the pre-synaptic side appeared green and those on the receiving postsynaptic sign appeared as red. Then while observing the colors, they observed live neurons in real time as they sent signals to each other via their neurotransmitter chemical systems. The color changes indicated that during signaling activity, the presynaptic chemicals clumped together and bound to clumped molecules on the postsynaptic side. The clumps appeared to have a uniform size. When the presynaptic neurons were stimulated in a way that promoted spine enlargement, they saw that the number of chemical clumps increased. Such stimulation caused non-moving clump to jiggle and move around the synaptic spine, with pre- and post-synaptic chemicals moving in lock-step. Maybe this jiggling helps to trigger the biochemical cascade that neurotransmission causes to change activity in the post-synaptic neuron.
Perhaps we don’t think enough about the movement of molecules in living tissue. All chemicals in solution bounce around randomly. Clumping together and jiggling in lock-step creates new ways for chemicals to produce their effects. Apparently, the clumping is the triggering event for the enlargement of dendritic spines that creates a structural basis for memory.
This kind of chemical interaction is not only relevant to learning. It also applies in unknown ways to the altered function in addictions and other neurological diseases in which strong interneuronal connections become too strong. Research on neurotransmitter clumping in disease states has not yet begun, but here we may find clues on how to treat some of these conditions. Clearly, disrupting the clumping would disrupt the ability to strengthen synapses. While we want our synapses strengthened to promote normal learning, we don’t want this to happen for example, for opiate pain relievers, which create addiction. At the molecular level, addiction is a learned condition.

Sources
Hruska, M. et al., "Synaptic nanomodules underlie the organization and plasticity of spine synapses," Nature Neuroscience, DOI: 10.1038/s41593-018-0138-9, 2018.
Klemm, W. R. Core Ideas in Neuroscience. https://www.smashwords.com/books/view/390780

Monday, February 03, 2020

Lifestyles that Promote Living Longer and Better



People in many parts of the world are living longer, due largely to improvements in medicine and healthier lifestyle afforded by less poverty. The downside is that the longer one lives the more likely a debilitating disease will emerge, such as cardiovascular disease, cancer, diabetes, or Alzheimer's Disease. For many people, the important thing is not how long they live, but how long they can live without serious physical suffering.

Many studies have established that the incidence of the common debilitating diseases can be reduced or delayed by modifiable lifestyle factors. While genes can obviously affect one’s vulnerability to disease, genes may not be the primary factor in how long or how well one lives. This is suggested, for example, by one study of over 110,000 healthcare professionals (about 1/3 male, 2/3 female) that clearly showed the value of healthy lifestyles.

The investigators queried these subjects and categorized them according to five lifestyle criteria:

    Diet, as assessed using the Alternate Healthy Eating Index, with a score in the upper 40% indicating a healthy diet;
    Smoking (never vs ever);
    Moderate to vigorous physical activity (≥ 30 minutes/day);
    No alcohol consumption above 15 g/day for women, 30 g/day for men;
    Body mass index (18.5-24.9 kg/m2).

Women who met four of the five low-risk lifestyle factors lived 10 more years free of cancer, cardiovascular disease, and type 2 diabetes at 50 years than women who followed none of the low-risk factors. In men, the gain in disease-free life expectancy was near 8 years. In terms of total life expectancy, women in the low-risk group at age 50 showed an increase from 31.7 years to 41.1 and men increased their life span from 31.3 years to 39.4 years.

This large-scale study confirms what has been indicated by a host of earlier studies that healthy lifestyles involve proper diet, absence of smoking, low consumption of alcohol, substantial exercise, and a BMI in the range of 18.5-24.9 kg/m.2  Moreover, both women and men who have a healthy lifestyle have significantly more years in which they avoid crippling heart disease, cancer, and type 2 diabetes.

The largest impact was on reduced incidence of cardiovascular disease and diabetes in both women and men. The lifestyles that were most likely to increase the three major diseases were smoking and obesity, in both women and men. Perhaps beneficial effects would be magnified by more stringent healthy lifestyle criteria (for example, upper 10% of healthy diet or level of exercise).

Other posts on lifestyle and aging research have clearly identified other healthy factors, such as  the value of emotional well-being and reduced psychological stress. Anecdotes suggest that living a life of worthy purpose may also promote aging well and living longer, though apparently there is not much formal research on this possibility.

Though we have no direct control over our genes, most of us can largely control how we live our lives. The beneficial effects of healthy lifestyle on aging well and longevity surely include direct enhancement of organ function and indirect effects on gene expression. Healthy lifestyles will help you, as we say in Texas, "Go out with your boots on."

Source

Li, Yanping, et al. (2020). Healthy lifestyle and life expectancy free of cancer, cardiovascular disease, and type 2 diabetes: prospective cohort study, January 8, BMJ 2020; 368 doi: https://doi.org/10.1136/bmj.l6669

Monday, January 27, 2020

Engram Neurons: A New Take on Memory Consolidation

As far back as Plato and Aristotle, people believed that our memories had to be physical somethings that were stored somewhere in the brain. But only in modern times have we learned much about what this something is. First, the something was given a name: memory engram. Then, as knowledge accumulated about what happens in neurons and their synapses as they become active in learning and remembering, it became clear that learning events that could be remembered were causing chemical and physical changes in the junctions (synapses) between neurons that participate in the learning experience. Participating neurons grow new dendritic branches (called spines) and the synapses on those spines enlarge and their neurotransmitter systems become enhanced. These changes constitute the engram. Post-learning reactivation of the synapses holding such an engram can produce recall of the original learning that created the engram.

In the early days of neuroscience, scientists believed that learning experiences assigned or recruited certain parts of the brain to hold the memory. An experimenter, Karl Lashley, taught certain tasks to lab animals, and then under anesthesia, destroyed different parts of the neocortex in the hopes of finding where the memory was stored. He couldn’t find any particular storage location. What he did find was that the more extensive he made the cortical lesions, the more likely he could erase the memory. In other words, memory of a given experience seemed to be deconstructed and parceled out into different regions.

Then came quantitative EEG studies by E. Roy John, in which he tracked the location of brain electrical evoked responses in different parts of the cortex during learning experiences. He saw that a given learning experience would produce electrical responses in several parts of the cortex, again suggesting a deconstruction and distribution of memory engrams. This led him to famously proclaim, “Memory is not a thing in a place, but a process in a population.”  Well, we know that this is a bit of over-statement. There is such a thing as a memory engram that is stored in specific places. Nonetheless, there is a distribution process for creating the engram in multiple locations and for orchestrating them into simultaneous and coordinated activity during recall of the memory.

Modern genetic engineering and neuron staining technology provide powerful new tools to examine neurons that participate in joining the neural circuits involved engrams. There are now ways to image and manipulate engrams at the level of neuronal ensembles.  Several lines of evidence show that engram neurons can be seen histologically and evaluated under various experimental approaches. For example, histological stains revealing neurons that are activated by a learning experience show that they are also active during memory retrieval of that experience. Second, loss-of-function studies show that impairing engram neuron function after an experience impairs subsequent memory retrieval. Third, studies show that memory retrieval can be triggered by optogenic stimulation of engram neurons in the absence of any natural sensory retrieval cues.

The basic approach used by investigators in the lab of Susumu Tonegawa was to teach mice to avoid walking into a chamber in which they would receive a mild electric shock. Neurons that are activated by this fear conditioning fluoresce in immunohistological stains of brain slices in mice that are sacrificed at various times after learning reveal a memory engram that resides in selected neurons in the amgydala (which processes fear information), in the hippocampus (which converts short-term memory to longer-term memory), and in multiple regions of neocortex (which holds long-term memory in the form of enhanced synaptic capability). Some of these cells still fluoresce when examined many days later, indicating that they have become part of an ensemble of engram neurons that hold a relatively lasting representation of the original learned experience.

Other mice were genetically engineered so that engram cells would fluoresce and be activated when exposed to light delivered via micro-fiber optic cables surgically implanted in various regions of neocortex. Such light stimulation of engram cells confirmed their engram status, because light stimulation alone triggered the previously learned behavior (freezing in place, rather than entering the shock chamber). A key finding was that engram neurons in the prefrontal cortex were “silent” soon after learning — they could initiate freezing behavior when artificially activated by light delivered via surgically implanted fiber optic filaments, but they did not fire during natural memory recall. In other words, the memory engram was formed right away in all three places (amygdala, hippocampus, and neocortex), but the engram cells in the neocortex had to mature over time to become fully functional.

Over the next two weeks, the engram neurons in the neocortex gradually matured, as reflected by changes in their anatomy and physiological activity. By the end of that same period, the hippocampal engram cells became silent and were no longer used for natural recall. At this point, the mice could recall the event naturally, without activation of neocortical cells by fiber-optic light. However, traces of the memory remained in the hippocampus, because reactivating those hippocampal neurons with light prompted the animals to freeze.

The past prevailing view was that learning experiences are temporarily held in circuits in the hippocampus and then later exported out to other parts of brain for final storage. Both in the past and now, all the evidence indicates that the hippocampus is crucial for forming lasting memories of experiences that do not involve motor learning, but the mechanisms had been uncertain. 
Neuroscientists did know that long-term memories were stored outside of the hippocampus, because people with hippocampal damage can lose the ability to form new long-term memories, but they are still able to recall old memories.

Now, the new research suggests that memory engrams are not transported from hippocampus to neocortex but are present in both places at the outset of learning. The memory engram in the neocortex just requires maturation for the memory to become more permanent. Moreover, the hippocampus cannot, and need not, hold long-lasting engrams.

Though this is a new way to think about the mechanisms of how temporary memories consolidate into longer-lasting ones, the conventional idea of consolidation remains confirmed. That is, the memory engram must mature over time in the form of biochemical and anatomical changes in the engram cells. Obviously, such maturation process would be disrupted if those same engram cells are recruited to serve other learning purposes before they have finished their maturation as a specific memory engram. This also helps to explain why subsequent rehearsals help make memories last longer, because each rehearsal re-engages engram neurons into the same kind of activity they performed during learning, thus strengthening the relevant synapses.

Once memories were formed in the fear-conditioned mice, the engram cells in the amygdala remained unchanged throughout the course of the experiment. Those cells, which are necessary to evoke the emotions linked with specific memories, like fear of entering the shock chamber in this case, communicate with engram cells in both the hippocampus and the prefrontal cortex.

We don’t know what happens to memory-specific engram cells in the hippocampus. Maybe as they gradually lose their engram status, they become available for processing new kinds of learning experience. Perhaps some traces of engram remain in hippocampus and are accessible for reactivation if highly relevant inputs are received, as could be the case with strong memory cues. Perhaps the important point is that these new techniques for labeling engram cells open the door for new ways to study of memory retrieval, the long-neglected aspect of memory mechanisms.

Another potentially relevant finding of this kind of research is that memory engrams may become damaged but may still exist in a form that cannot be retrieved by natural means. The fact that such “silent” engrams can be retrieved with direct optogenetic stimulation indicates that failures to recall do not necessarily indicate that the memory is lost. The problem may lie in an inadequacy of the natural memory cues used to triggger memory retrieval.

The door is also now open for experiments that might advance our understanding of the maturation of engram neurons in the neocortex. What is known so far is that maturation requires initial communication with engram cells in the hippocampus. Disrupting hippocampal connections between hippocampus and frontal cortex prevents the maturation of neocortical engram cells.

Sources

Takashi Kitamura, Takashi, et al., (2017). Engrams and circuits crucial for systems consolidation of a memory,” Science, 356(6333), 73-78; DOI: 10.1126/science.aam6808

Josselyn, Sheena A., and Tonegawa, Susumu (2020). Memory engrams: Recalling the past and imagining the future. Science. 367 (6473), eaaw4325. Doi: 10.1126science.aaw4325. https://science.sciencemag.org/content/367/6473/eaaw4325

Tuesday, January 07, 2020

How Does Learning Change the Brain?


Learning programs the brain. It is nature’s way to create simultaneously both “hardware” and “software” for the brain. Neuroscientists have long known that learning experiences change the functional circuitry that is used to process and remember a given learning event. The circuit change is anatomical: electron microscope photographs reveal that the synaptic changes take the form of little blebs located on dendrites. These blebs are called “dendritic spines,” and their size and number change in response to learning and memory formation. You might think of the induced change as a physical location for information storage. What is stored at any given spine is an increase in the probability that the spine will participate in activations that generate recall of the stored memory from all the spines that were enhanced in creating the memory.
Functionally, the change operates as a template that resides more or less permanently that is available not only to recall the original learning event but to respond to similar events in the future. Of course, no one synapse accounts for these recall and programming effects. However, the learning and memory results from the collective enhancement of all the enhanced dendritic spines in the participating circuitry. The templates thus created provide a way for the brain to program itself for future capabilities. Learning how to solve one kind of task makes it easier to learn new tasks that are similar. This is the basis for the so-called “learning-set,” a concept introduced many decades ago by Harry Harlow.
We tend to think about such matters in the education of children. However, the principle applies at all ages, including seniors. The aging brain responds to learning the same way a child’s brain does: it grows new task-specific synapses that can be recruited for other uses.
The learning effect is manifest in the growth of existing synapses and the formation of new synapses. In the absence of mental stimulation, the spines degenerate. Indeed, a typical effect of aging is that the brain actually shrinks as a consequence of the cumulative shrinkage of spines. Many neurological diseases are characterized by reduced synaptic density: schizophrenia, autism, and dementia. An opposite problem occurs with drug addiction, where certain synaptic connections are strengthened by the drug, essentially creating a way to store a memory for the addiction.
Until now, we have not learned as much about the chemical changes that occur with learning. A recent study from Thomas Jefferson University reveals that new patterns of molecular organization develop as connections between neurons strengthen during learning. The researchers basically asked the question, “What does learning look like at the molecular level? Using super-resolution live-cell microscopy, the researchers confirmed the enlargement of synapses previously reported by others. But they also saw that that during a learning experience the molecules involved in sending and receiving the signals between neurons appeared to be organized in clumps or "nanomodules" that both dance and multiply when stimulated by learning-like signals.
The researchers developed a novel technique wherein they could visualize the chemical involved in transmitting signal from one neuron to another. Chemicals on the pre-synaptic side appeared green and those on the receiving postsynaptic sign appeared as red. Then while observing the colors, they observed live neurons in real time as they sent signals to each other via their neurotransmitter chemical systems. The color changes indicated that during signaling activity, the presynaptic chemicals clumped together and bound to clumped molecules on the postsynaptic side. The clumps appeared to have a uniform size. When the presynaptic neurons were stimulated in a way that promoted spine enlargement, they saw that the number of chemical clumps increased. Such stimulation caused non-moving clump to jiggle and move around the synaptic spine, with pre- and post-synaptic chemicals moving in lock-step. Maybe this jiggling helps to trigger the biochemical cascade that neurotransmission causes to change activity in the post-synaptic neuron.
Perhaps we don’t think enough about the movement of molecules in living tissue. All chemicals in solution bounce around randomly. Clumping together and jiggling in lock-step creates new ways for chemicals to produce their effects. Apparently, the clumping is the triggering event for the enlargement of dendritic spines that creates a structural basis for memory.
This kind of chemical interaction is not only relevant to learning. It also applies in unknown ways to the altered function in addictions and other neurological diseases in which strong interneuronal connections become too strong. Research on neurotransmitter clumping in disease states has not yet begun, but here we may find clues on how to treat some of these conditions. Clearly, disrupting the clumping would disrupt the ability to strengthen synapses. While we want our synapses strengthened to promote normal learning, we don’t want this to happen for example, for opiate pain relievers, which create addiction. At the molecular level, addiction is a learned condition.

Sources

Hruska, M. et al., "Synaptic nanomodules underlie the organization and plasticity of spine synapses," Nature Neuroscience, DOI: 10.1038/s41593-018-0138-9, 2018.
Klemm, W. R. Core Ideas in Neuroscience. https://www.smashwords.com/books/view/390780

Tuesday, December 24, 2019

The Role of Learning in Religion, Part II


(Excerpted from the new book, Triune Brain, Triune Mind, Triune Worldview (Brighton Publishing)(available at Amazon and Barnes and Noble).
In part 1 of this series, I explained that what one is taught and chooses to learn about religion changes the biology of the brain. Changing brain biology creates a change in who and what you are as a person. This principle applies to everyone, religious or irreligious.


Here, I will explore specific ways in which we program our brains to accept and live religious ideas. Relevant learning principles include the self-programming by brains and neural plasticity. There are important implications of religious learning in child rearing and adult maturation. Religious instruction matters to who you have become and how you will be in the future.

The Self-programming Brain


Brains self-programfor better or worse. Much of this programming can occur unconsciously. Freud made his mark in history by showing how the unconscious mind is a reservoir of feelings, thoughts, and memories that we may not easily access. Freud called this mind “subconscious,” a term that has fallen out of favor, perhaps because so much happens during unconscious processing that this should not be considered as inferior function. After Freud, numerous scientific findings confirmed that a great deal of information processing occurs in the unconscious brain, even during anesthesia. I led one such study on visual processing in anesthetized monkeys.[1] Since then, numerous studies have shown in humans that the brain is quite active during sleep in consolidating the experiences of the preceding day into memory. The dream stages of sleep obviously reflect intense brain activity, much of which would likely exert programming influences. When we are awake, we deliberately program our brain by the choices we make of what to read or hear, who to hang out with, what environments we prefer, and what we do.
Even while still in the womb, the brain of a late-stage fetus is programming itself to recognize sounds of the mother's pulse and visceral gurgles and external sounds from voices and music. Pressure changes in the womb are registered. Fetal brain continually programs recognition of limbs and the ability to move limbs. At birth, the process accelerates. I remember how astonished I was to watch my month-old great granddaughter program herself. When awake, her eyes were open and constantly scanning the environment. You could just imagine her brain going click, click, click, as it detected and stored input.
All mental experience can have programming effects. These may create a bias. In some sense, what you have learned can hold you hostage. However, humans also have the ability to change how they have been programmed. All this applies to religion.

Neural Plasticity        


Minds can change, and when they do, brains can change. We know that brain structure and function change in young people as they mature through childhood into adults. Even adult brains change in response to sensory and cognitive experiences. Your brain cannot form memories without changing the synaptic structure and biochemistry needed to store the memory. Learning experiences stimulate growth of microscopically measurable dendritic spines that enable new synapse formation. The information learned at the synapse level exists in the form of a stored propensity to regenerate the nerve impulse pattern representation of the learned information. The changes in the synapse in response to new information are enzyme systems that synthesize and degrade neurotransmitters, storage of neurotransmitters in presynaptic vesicles, up-regulation of postsynaptic molecular receptors, and biochemical cascades triggered by the receptor binding.
The brain’s greatest capacity for change occurs in childhood. As the learning of childhood progresses, many synaptic connections form to help store the new learning. In fact, in the fetus, far more neurons and connections form than needed, and the development process dismantles the surplus. This seems to be a competitive selection process, called “neural Darwinism.” Neurons and connections that survive are the ones that seem most useful to the brain.
Adults generally seem to be constrained by their earlier learning, as described in the old saw, “You can’t teach old dogs new tricks.” Actually, you can. It is just harder and may take longer to develop the new connections.
Because of the hard wiring that occurs in childhood, an “inner-child” persists as a memory throughout life. This fact formed the basis for the ideas in the famous book, I’m O.K. Your O.K., which emphasized that adults may be held hostage to their inner childhood. That is a burden if the childhood experiences were troubling.
The religious teachings of children likewise can have a powerful lasting effect. For example, a study of ministers revealed that what they learned as children markedly affected their adult perceptions of God. If they had vague or limited teaching about God as a child, they tended as adults to view God as remote. If they had in-depth exposure to God ideas as a child, their adult view was of a more personal God.[2]
The brain’s ability to change itself allows it to be responsive to outside influence aimed at alleviating mental health problems such as anxiety, depression, obsessions, and distorted self-image. One clinical method of treatment, known as cognitive behavioral therapy (CBT), attempts to change undesired thinking patterns into more positive ones and preserve them as new memories. Studies involving religiously oriented CBT use scripture, prayer, and other religious practices to overcome negative thoughts and perceptions. One study improved patient coping skills by both religious and secular CBT approaches, but quicker results resulted from the religious approach.[3]

Child Rearing


Religious upbringing helps children develop value systems, thinking styles, emotional development, and pro-social behaviors.[4] In all religions, education about the faith focuses on children, and the effects tend to be lasting. Religious parents often go to great expense to have their children educated in religious schools, because this ensures proper religious instruction, inculcation of moral values, and presumably fewer sinful temptations. In modern American culture, where perhaps a majority of children grows up without a father in the home, religious education might help compensate for the absence of a normal family environment. Government education has fewer mechanisms than religion for compensating for absentee fathers.
The more religious parents are, the more creative and persistent their children are in schoolwork. These children tend to be more motivated to learn and more attentive. Religious conflict between parents or within the family may produce negative effects on children. The common lament about poor academic performance by U.S. schoolchildren might be due at least in part to the general decline of religious commitment by the parents and by school policies that keep religion out of the curriculum.
A problem with religious education of children is that a child's brain is not yet developed, and certain limitations of emotion, language, and intellect limit what you can teach a child about religion or anything else. Typically, most religions teach their doctrines differently to children than to adults. Moreover, all religions recognize that children usually are unable to have an adult understanding of religious faith. Saint Paul explained this in the famous quote, "When I was a child, I spoke as a child, I felt as a child, I thought as a child. Now that I have become a man, I have put away childish things" (1 Corinthians 13:11).
Whatever one's religion, religion tends to create a partially closed mindset that prevents learning positive things about another religion. This is a special problem with young people. A study of fourth-, fifth-, and sixth-grade students (half Catholic, half Jewish) revealed strong cultural bias. The middle- to upper-class students lived in the same city. Teachers judged them to be average or above average in reading ability. Yet, when the students read a straightforward passage about the religion to which they did not belong, their cultural bias frequently caused them to misunderstand the reading and make memory errors. This was religion-specific in that they showed no such confusion or memory errors when asked to read non-religious passages at the same fourth-grade level.[5] Why the confusion and memory errors? I suspect they were less motivated to be sufficiently attentive to reading about a religion they did not believe in.
Age 13 (12 for girls) is often considered the transition point, as is expressed in Jewish tradition of Bar Mitzvah, where children are expected to be able to follow religious commandments. Christian groups also often set 12 or 13 as ages when children become sufficiently adult, as expressed in "confirmation" ceremonies.
Such age markers fail to accommodate what neuroscience has revealed about the biology of childhood maturation. A child’s brain is poorly developed, even at 13. Multiple ways of measuring maturation indicate that the brain does not reach biological maturity until the mid-twenties. Moreover, beyond that, we can all mature still further through learning and life experience.
A variety of evidence confirms that many teenagers are rebellious and pursue high-risk, ill-advised behaviors. Scientific experiments support the conclusion that the teenage brain is not "normal"no surprise to parents. For example, teenagers and adults have spatiotemporal differences in brain electrical activity in the prefrontal cortex. Teenagers are less able to use their prefrontal cortex to control behavior, especially to inhibit a desired action.[6] The real-world consequence is often poor judgment and self-defeating behavior. These limitations of brain function surely affect how a teenager deals with religious beliefs and behavior.
Parents and teachers try to prevent and correct bad behavior in one of two ways: reward or punishment, carrot or stick. An interesting comparison of these options for young children revealed that reward for proper behavior is usually more effective. In particular, food rewards seem to be the most effective in children.[7] There may also be an effect of religious outlook. If a child thinks of God as harsh and punishing over sin, their sense of self-worth may be threatened, and their motive for repentance is mind-crippling fear, guilt, or shame. However, if they think of God as loving and forgiving, they may be more likely to respect themselves enough to want to become a better person.

Neural Development and Aging Influences


The best markers for brain maturation seem to be age-related changes in amounts of cortical white matter (fiber tracts) and grey matter (cells and their processes). One kind of MRI (diffusion tensor imaging) noninvasively measures the amounts of both white and gray matter. An extensive study of 387 subjects from age 3 to 27 reveal that male brains are up to 10% larger than females. That may simply reflect that males usually have larger bodies than females. Total brain volume peaks earlier in females (10.5 years) than in males (14.5 years). White matter increases progressively over the years, but with a steeper rate of increase in males. At all ages, males have more white matter than females. However, females have more white matter in the fiber tracts that connect the two hemispheres. Grey matter increases early on in both sexes, and then decreases,[8] presumably reflecting the pruning of neural processes and synapses that normally occurs with learning.
Brain size usually shrinks in the elderly. Most of this shrinkage probably occurs from shriveling the extent of dendritic trees. Staying mentally active in old age seems to arrest this shrinkage. Mental activity, especially learning, promotes the proliferation of dendritic trees even in the elderly. A negative factor is likely the cumulative effects of a lifetime of stress. Stress releases cortisol, which in continuous large amounts disrupts synaptogenesis and formation of dendritic proliferation. All these factors affect all aspects of our lives, no doubt including religiosity.

Religious Instruction


Teaching of religious doctrines may be explicit or presented less obviously in the form of environmental conditioning. There are two kinds of conditioning, “classical,” as with Pavlov’s salivating dogs, and “operant,” a positive reinforcement technique used to train animals.
As a religious example of classical conditioning, kneeling is a natural reaction of submission, but when coupled with a cue of "let us pray," can trigger the impulse to kneel. Church bells or well-known hymns make you think of God and church.
 Such cues are not involved in operant conditioning, where repeated reward for a given action causes a person to repeat that behavior. A religious example is that churchgoers attend faithfully because past participation was rewarding for them. If you believe that confessed sins are forgiven, then it is positively reinforcing to confess sin.
In typical religious environments, conditioning tends to be informal, and perhaps thereby less effective than it would be with the more systematic formal methods of conditioning. Religions do repeat their doctrines of heaven and hell, and, when paired with religious ritual, constitutes a kind of classical conditioning. Operant conditioning might be involved in the positive reinforcement that comes from thinking repeatedly about the joys of heaven, while negative reinforcement comes from thinking about the horrors of hell.
Operant conditioning occurs when people participating in worship service perceive a net positive.[9] C. S. Lewis, the famous Christian advocate, made it a point upon his religious conversion to attend worship service regularly because he found spiritual support, even though he did not like most of the hymns, and the preaching was done by intellectual inferiors.[10] In order to sustain attendance at worship service, a believer may need to gain increasing amounts of positive reinforcement. Akin to drug addiction, one can develop a tolerance to the same dose of positive reinforcement. If worship does not provide the reinforcement of growing spirituality, the religion may eventually be abandoned. The current state of decline of Christianity in Europe and the U.S. may testify to this phenomenon,
At what point does teaching morph into "brainwashing?" We might say that teaching becomes brainwashing when it occurs in a closed environment that does not include alternative views. Learning, and certainly brainwashing, creates measurable changes in brain, and the differences vary by gender. For example, memory of emotionally charged information caused distinctive brain-scan changes in the right amygdala of males, while in women the changes occur in the left amygdala.[11]
Some believers deliberately place themselves in environments designed for brainwashing, where there is minimal exposure to secular matters and maximal exposure to religious thinking and practice. Examples include Catholic monasteries and nunneries or Muslim madrassas. People who commit to such environments may do so for different reasons, but a common denominator may be the desire to reduce secular temptations and gain some measure of "insurance" for God's favor. However, that insurance may be jeopardized if those people remain cloistered and do not reach out to the suffering masses.
The best way to avoid sin is to avoid the temptation in the first place. As a child, I remember my uncle Bob, who chose never to drink alcohol. When I asked him why, he said, "I am afraid I might become an alcoholic, and the one sure way to avoid that is to not start drinking in the first place." Many people today, knowing that cigarette smoking is highly addictive and unhealthy, pledge to avoid the addiction by never taking that first smoke.
If our positive reinforcement system promotes sinful behavior, why do we have such a system? Religious people might answer that God gave us such a system to test our faith, an idea as old as Adam and Eve. Other religious people might say we have the system because we can learn to avoid the negative reinforcers that are bad for us and seek out the happiness that positive reinforcers can produce.
Another advantage of the reinforcement systems comes from the motivation those systems provide. The reward system drives the brain to do beneficial things rather than reside as a passive recipient of whatever comes its way.
People tend to avoid religious practices or experiences that they find negatively reinforcing and seek to repeat those that are positively reinforcing. Thus, religion hooks everyone in the sense that the experiences compel a reaction. Atheists wiggle off the hook by rejecting spirituality. Believers find that the hook drags them into a positively reinforcing world. They may become hooked on religion.
Motivation is central to learning, and motivation is affected by personality type: people may fall into categories of those who “see the glass as half empty” and those who “see the glass as half full.” Each of us has an inherent predilection to be pessimistic or optimistic. The psychologist Martin Seligman pioneered the concept of learned optimism and learned pessimism. He argued that learning could adjust where a person is on this scale. In the case of learned pessimism, a person adds to a pessimistic mind set with every instance of bad life experiences if they are viewed as pervasive, personal, and permanent. Thus, a bad situation becomes much worse in the mind’s evaluation if it goes beyond the immediately obvious, is demeaning to one’s sense of confidence and self-worth, and will be long lasting. So, for example, if your religion teaches that you are fatally flawed by “original sin,” you are learning to be pessimistic and that there is nothing you can do to prevent more of the same in the future. Learned optimism is the attitude of mind that sin need not be typical of what you usually do, and that with God’s help you can prevent it from occurring again.
Religious implications have been explored in a study that compared fundamentalists (Orthodox Jews, Muslims, and Calvinists), moderates (Catholics, Conservative Jews, Lutherans, and Methodists), and liberals (Reform Jews and Unitarians).[12] Surveys reflected their degree of optimism vs. pessimism. The religious conservatives were the most optimistic, whereas the least optimistic were liberals. Variables such as income, sex, and education were irrelevant.
More optimistic people have more control over their emotions. Even a brain structure difference may account for this. Brain scans show that more optimistic people have larger volumes of the parahippocampus gyrus, a key structure in the limbic system of structures that controls emotions.[13]
Scripture calls for an optimistic outlook. The Christian Bible reads, “We know that for those who love God all things work together for good, for those who are called according to his purpose” (Romans 8:28). The Hindi teaching of Swami Vivekananda asserts that the essential features of Hinduism are its universality, its impersonality, its rationality, catholicity―and optimism.[14] The Qur’an states, “Hoping for good is also an act of worship of Allah.”[15] All these religions try to promote optimism in the form of hope.
Adolescence is a time of special responsivity to memories of religious experience. Church camps and mission trips can have life-long impact. Similar effects result from certain ceremonies, like confirmation in Christian churches or Jewish bar mitzvahs. In adolescents, brain scans indicate that the nucleus accumbens reward center is more sensitive to positive reinforcements.[16] This could have the effect of augmenting emotional responses to religious experience at the expense of reasoned examination of the implications and ramifications.
Repeatedly participating in positive religious experiences should strengthen religious memories, including all associated emotions. Self-control and discipline is at issue here, a fact long understood by ascetic religious groups such as monks and nuns.[17]  In the brain, one study using transcranial magnetic stimulation to disrupt function in the left, but not right, lateral prefrontal cortex, lessened self-control, in that immediate reward became more preferred over delayed rewards.[18]
It is one thing to forget, and quite another to remember falsely. In the context of religion, we may have false memories about our transgressions or those who transgressed against us. We may misremember scripture. In the face of temptation, we may forget our moral standards.
We should also consider a possible role for false memory in the creation of scripture, especially the oldest of scripture that was handed down from generation to generation by oral tradition. We have all perhaps seen this first hand in the parlor game where one person tells a story secretly to another, who then repeats the story privately to another, who in turn does likewise. After going through a chain of five to 10 people, for example, the story told by the last person in the chain is quite different from the original. Because most scripture originated and was repeated orally for centuries, this kind of corruption seems likely.
All religions expect the believers to remember the tenets of the faith. This is commonly manifest in the expectation to memorize significant portions of the scripture. Certain Islamic sects require children to memorize all 6,236 ayats (verses) of the Qur’an. The memory encoding stage involves a small group setting where the student memorizes half a page and recites it to the other students before reciting again to the teacher. The procedure repeats for the second half of the page and finally learners recite the whole page. The consolidation stage, involves five rehearsals of the previous memorized pages within 30 days so that the verses stay in the mind.[19]
"Memory athletes" use powerful mnemonic techniques, but these are not appropriate for the word-for-word memorization required of the Qur’an.[20] Here, the youngsters must use the tedious and inefficient rote method, where they repeat sections repeatedly and then move on to memorize the next section. They use chanting and rhythmic rocking movements to make the memorization easier.
Muslims and fundamentalist Christians regard their scripture as the literal "word of God," but Christians don’t require memorization of the entire Bible. The emphasis on memorizing scripture has two main problems. First, it reduces the necessity for thinking about the underlying truths and implications of scripture. Second, memorization keeps one from thinking about discrepancies in scripture, which are obvious upon analysis of both the Qur’an and the Bible. Fundamentalists often fail to recognize the possibility that they have confused worshiping scripture with worshiping God.
Memories shape who we have become. Long-term memory storage resides in the synaptic junctions among neurons. Repeated memory recall can cause changes in brain anatomy and chemistry that outlast the memory itself. Depending on experiences and on our health, new synapses may increase or decrease in number, and existing ones grow or shrivel. Thus memories of religious experience can make us more spiritual, even when we forget certain specific religious memories.
What we have become can predict our future. Our past religious experiences, good or bad, create yearnings, attitudes, beliefs, and hopes about religion that affect how we act and react to religious ideas and experiences in the future.



[1] Klemm, W. R., Goodson, R. A., and Allen, R. G. 1984. Steady‑state visual evoked responses in anesthetized monkeys. Brain Res. Bull. 13, 287‑292p
[2]Worsley, H. (2002). The impact of the inner-child on adult believing. Journal of Beliefs & Values, 23(2), 191-202. doi:10.1080/1361767022000010842
[3]Koenig, H. G., et al. (2015). Effects of religious vs. standard cognitive behavioral therapy on therapeutic alliance: A randomized clinical trial. Psychotherapy Research, 26(3), 365-376.
[4] Bartkowski J.P., Xu X., Levin M.L. (2008) Religion and child development: Evidence from the Early Childhood Longitudinal Study, Social Science Research 37(1), 8-36. http://dx.doi.org/10.1016/j.ssresearch.2007.02.001.
[5] Lipson, M. (1983). The influence of religious affiliation on children's memory for text information. JSTOR, 18(4), 448. http://dx.doi.org/10.2307/747379
[6] Julie Vidal, Julie, et al. (2012). Response inhibition in adults and teenagers: Spatiotemporal differences in the prefrontal cortex, Brain and Cognition, 79(1), 49-59.
[7] Slocum S.K. and Vollmer T.R. A. (2015).Comparison of positive and negative reinforcement for compliance to treat problem behavior maintained by escape. Journal of Applied Behavior Analysis, 48, 563-574.
[8] Lenroot, Rhoshel K. et al. (2007). Sexual dimorphism of rain developmental trajectories during childhood and adolescence. NeuroImage. 36(4), 1065-1073. doi.org/10.1016/j.neuroimage.2007.03.053.
[9] Crapps, R. W. (1986). An Introduction to Psychology of Religion. Macon, Georgia: Mercer University Press.
[10] Lewis, C. S. (1955).  Surprised by Joy. New York: Harcourt.
[11] Barweger, L (2013). Neuroscience and education: The importance of a Christian understanding  of human persons. ICCTE Journal. Retrieved from http://icctejournal.org/issues/v4i1/v4i1-neuroscience/   Complete ref.
[12] Sheena, Sethi, and Seligman, Martin E. P. (1993). Optimism and fundamentalism. Psychological Science 4(4), 256-259.
[13] Yanga, J., Wei, D., Wang, K., & Qui, J. (2013). Gray matter correlates of dispositional optimism: A voxel-based morphometry study. Neuroscience Letters, 553, 201-205.
[14] Aiyar, R. (1965). An introduction to Hinduism. Retrieved October 19, 2016, from http://www.staff.uni-giessen.de/~gk1415/hinduism.htm
[15] Ghayyur, T. (n.d.). 12 Sayings of the prophet to inspire optimism. http://www.soundvision.com/article/12-sayings-of-the-prophet-to-inspire-optimism. Retrieved October 19, 2016,
[16] Galvan, A., Hare, T. A., Parra, C. E., Penn, J., Voss, K., Glover, G., et al. (2006). Earlier development of the accumbens relative to orbitofrontal cortex might underlie risk-taking behavior in adolescents. Journal of Neuroscience, 26, 6885–6892.
[17] Rounding, K., Lee, A., Jacobson, J.A., & Ji, L.J.  (2012).  Religion replenishes self-control.  Psychological Science, 23(6), 635-642.
[18] Figner, Bernd, et al. (2010). Lateral prefrontal cortex and self-=control in intertemporal choice. Nature Neuroscience. 13, 538-539.
[19] Bhutto, Saifullah (2015). Traditional and modern methods used for memorization of Qur’an in Turkey. Ma’arif Research Journal, July-Dec. http://mrjpk.com/wp-content/uploads/Issue%2010/eng/10-Traditional%20and%20Modern%20Methods%20Used%20for.pdf. Retrieved Aug. 29, 2018.
[20] Saat, R.m., et al. (2011). Memorization activity and use of reinforcement in learning. Content analysis from neuroscience and Islamic perspectives. J. Applied Sciences 11(7), 1113-120.