Consciousness as Afterthought

I get a lot of questions in Quora about neuroscience, because neuroscience is what I do. A recent question prompts this post. The question was: "Does all thinking originate in subconscious thinking?" This is a provocative question. It gets to the heart of the matter: What is the default mode of brain operation, conscious or subconscious?

Semantic Confusion

Much of the confusion about consciousness arises because words fail us. We have poor definitions for the usual words: conscious, unconscious, subconscious, non-conscious. Before I attempt an answer to my Quora question, let me establish some background about terminology. First, the currency of thought is patterns of nerve impulse activity constrained by flowing in and through defined circuits of linked neurons. The impulse thought patterns that occur in primitive circuitry, like spinal  segments and neuroendocrine circuits are considered nonconscious thoughts because we can never be consciously aware of what those circuits are doing. We can, for example, use instruments to measure our blood pressure, but on its own, the brain can never detect that consciously.

Perhaps the most common kind of thought is that which occurs all the time, even when asleep, that we are not aware of. These days, scholars like to call this "unconscious" thinking.  But coma is clearly an unconscious state, and there often is little electrical activity that reflects thought. That is why a more useful term in this context is "subconscious," a term popularized by Freud. That is probably why the term has fallen into disuse. Too many of Freud's ideas have been discredited. But not his idea of subconsciousness.

Consciousness Is Not the Same as Being Awake

Reflect on your own perceptual experiences. Every time you are consciously aware of something you were attending to it. True, you can be awake without being conscious (see Selective Attention below). This means that we have to make a careful distinction between wakefulness and consciousness. They are not synonymous. You can't be conscious if you are not awake, but being awake does not assure consciousness of non-attended objects.  Wakefulness is generated out of excitatory activity of the brainstem reticular formation acting on neocortex, as I explain in my book, Mental Biology. The mechanisms of consciousness have not been established, but they likely involve coherent nerve impulse activity in distributed circuitry.

The phylogenetic perspective argues for unconsciousness as the default mode of thinking, inasmuch as lower animals are not likely to have conscious thought, yet their behavior clearly indicates that they are awake and their brains are "thinking." Also, we know from studies of infants that behavioral signs of consciousness are rare and only emerge as the brain matures. It is clear that much human thinking occurs below the level of conscious awareness.

The many scholars who claim that humans have no free will use the assumption of subconscious thinking to defend their stance against free will. They came to this conclusion from experiments that say indicate that all willed action is generated subconsciously and only recognized later in consciousness. The experiments and the interpretation are flawed, as I explain in my book on free will. To help defend the stance that free will is an illusion, the proponents go further to argue that consciousness is just an observer, like a movie patron in a theatre. You can just watch what is happening but can't do anything about it. Thus, they construct the specious circular argument that you can’t have free will because free will requires consciousness by definition, and consciousness can’t do anything. How convenient! This absurd notion, held by academics who are not as smart as they think they are, assume that all our consciousness thinking is basically irrelevant. They assume that the neural activity of conscious thought cannot influence neural activity in other parts of the brain, even though they have to admit that the neurons that mediate conscious thought are functionally connected with the other parts of brain. By these connections, conscious thought can, for example, explicitly evaluate the meaning of stimuli, or order certain muscles to contract, or force mental  effort to memorize, or change our emotional state and visceral functions in light of reason or mindfulness meditation, and so on. The circuitry of consciousness is not in a pickle jar outside the brain. It is inextricably bound to other brain circuits.

I certainly don't mean to dignify the anti-free-will position by describing it. However, debunking that position opens the door to reconsider the possible relationship between subconscious and conscious thought. Suppose conscious thought is an afterthought, but not in the restricted sense prescribed by the anti-free-will crowd. Just because subconscious thought can lead to conscious thought does not mean that conscious thought has no action of its own. When we consciously think about what we have recognized in consciousness, all that thinking is, by definition, conscious.  Conscious thought can consider options explicitly. It can reason. It can set goals, plan, command action, evaluate consequences of action, and adjust programming as needed. Subconscious thinking can do that too. Most likely the two modes of thinking work in potentially synergistic ways, though it seems clear that conscious thought can veto subconscious impulses and bad ideas.

Consciousness as Selective Attention

Have you seen the U tube video of a pickup basketball game? The video instructs viewers to count how many times one of the teams pass the ball. Viewers are so focused on the task that many of them fail to see a man in a gorilla suite walk into the game, do a little chest pounding, and then walk off the court. The point is that the eyes and subconscious mind saw the gorilla, but not the conscious mind. The same phenomena has been confirmed in another context. The phenomenon is labeled by psychologists as "inattentional blindness." In other words, we are only conscious of targets of our attention.

Like all biological systems, brains are stimulus-response systems. Humans have unique ways to respond to stimuli and experience, in that their brains selectively identify the information content, evaluate it in terms of available optional responses, and then determines an appropriate response. Both subconscious and conscious thought can be involved, but conscious thought only operates on attended targets.

Scanning for Meaningful Impulse Patterns

While it is clear that conscious brains think, it may be useful to consider that consciousness is also a scanning mechanism. We don't know how such scanning is enabled by wakefulness, but we do know that the awake brain generates more regular oscillations of impulse activity. These oscillations arise in many localized subnetworks throughout the cortex, occurring at varying frequencies and extent of synchrony among other generators. Intracellular recordings of neurons reveal that one or a few spikes are generated each time the membrane depolarizes. Oscillation is a built-in feature of neural circuits which commonly oscillate because impulse output re-enters the circuitry that generates it.  Increasing the frequency of oscillation increases the total impulse discharge because there are more depolarizations per unit of time. This increases the informational throughput in the network. Likewise, the degree to which multiple oscillators synchronize to share data modulates impulse throughput throughout linked circuits.

Perhaps the oscillation itself is the scanning mechanism. As novel or particularly relevant input enters an oscillating circuit, that circuit’s own impulse firing pattern may be disrupted, re-set, change frequency, or alter its time locking to other subnetworks. Enhanced time-locking among circuits could have the magnifying intensity effect that seems to be required in selective conscious attention. The carrying capacity for information is limited, because only subsets of networks in the global workspace synchronously engage at any one moment. This is one way to improve the signal-to-noise ratio of neural circuit processing.

Perhaps conscious thought is the afterthought of this scanning once it latches onto a subconscious thought that compels attention. Such a mechanism has great biological advantage in that it is a way for brain to scan through a noisy stimulus- and thought-world to identify signals that are salient for appropriate and selective processing and response. Once the target is captured in consciousness, conscious neural activity evaluates the salient signals and determines what to do about it and directs useful action. Taken in this light, I answer a tentative yes to my Quora questioner who wanted to know if all thinking originates in subconscious thinking.

Sources

Klemm, W. R. (2014). Mental Biology: The New Science of How the Brain and Mind Relate. New York: Prometheus.

Klemm, W. R. (2016). Making a Scientific Case for Conscious Agency and Free Will. New York: Academic Press.

https://www.youtube.com/watch?v=vJG698U2Mvo   The original basketball game example of the invisible gorilla.

https://www.youtube.com/watch?v=UtKt8YF7dgQ  A confirmation of the invisible gorilla in another context.

Consciousness Explanation. Part II

In an earlier post, “Where Neuroscience Stands in Understanding Consciousness,” I presented a summary of the progress occurring in neuroscientific understanding of consciousness (https://www.psychologytoday.com/us/blog/memory-medic/201804/where-neuroscience-stands-in-understanding-consciousness).

Now a recent report in the May issue of Science adds to a growing understanding of how the brain generates conscious recognition. The study examined neural impulse discharge responses of monkey brain to visual stimuli. Electrodes were implanted in the four visual cortex areas that are sequentially activated by visual stimuli. The stimulus was a circular spot of varying contrast in the lower left area of the visual field. Monkeys were cued when a stimulus was delivered, though whether they saw it or not varied with the spot’s contrast against the visual background. Monkeys were trained to report when they knew they saw the spot by shifting  their gaze from a central fixation point to the spot’s prior location some 450 msecs earlier. Monkeys reported unrecognized spots by shifting the gaze to the right of the default fixation point. Investigators imposed the delay for reporting to eliminate the response being a simple reflex saccade. A longer delay would have been more convincing, but it might have taxed the monkey’s working memory and easy distractibility.

As expected, spots of sufficient contrast evoked impulse discharge in each of the four visual cortex regions. Whether or not the monkey reported actually seeing the spot depended on whether there was also increased impulse discharge in the region of frontal cortex that had implanted electrodes. No doubt, other non-monitored frontal areas might also have been activated under conditions where recognition was reported. The point is that conscious recognition requires activation of widely separated brain areas at the same time.

Not demonstrated here is how the frontal activity is interacting with activity in the visual cortex areas, but that certainly could be predicted from studies in my lab, reported in 2000. We showed that conscious realization of alternate perceptions of ambiguous figures in humans occurred when brain electrical activity (EEG) over the visual areas of scalp became highly synchronized, over a wide range of frequencies with multiple frontal areas, both in the same and even opposite hemisphere. Figure 1 shows the topography of coherence change at the moment of realization for the upper frequency band of 25-50Hz.

Figure 1. Topographic summary of p<0.01-level coherence increases across all 10 ambiguous figures, all subjects, in the 25-50 Hz band. Each square matches a given electrode and shows how activity at that location became more coherent with activity at other locations at the instant the subject consciously realized the alternate perception in any of 10 ambiguous figures. From Klemm et al. (2000). Widespread coherence increases were also seen in the band below 25 Hz.

Thus, it seems that a meaningful detectable signal, which need not be limited to vision, not only activates its immediate neural targets, but those target cells can trigger feed-forward to trigger activity in more frontal areas. Feedback from those frontal areas can set up time-locked oscillatory coupling across wide expanses of cortex that is apparently necessary for conscious recognition. The time locking probably amplifies the signals to the threshold for conscious realization.

The distributed signal processing does not necessarily mean consciousness requires huge expanses of neural tissue. Recall from the split-brain studies in Roger Sperry’s lab that even half a brain can be fully conscious of the stimuli it can receive. The magic of consciousness seems to lie in the qualitative nature of data sharing, not in the volume of tissue involved.

Thus, the major issue is how oscillatory coupling of otherwise isolated circuitry amplifies signals to become consciously recognized. “Amplify” may be a misleading word, inasmuch as there is no compelling evidence as yet that consciousness is related to having more nerve impulses per unit of time. The impulses certainly don’t get bigger, because their voltage magnitude is constrained by concentration and electrostatic gradients. Rather, the secret may lay in the controlled timing of impulses. A likely form of amplification results from the reverberation of activity among coherent neuronal ensembles, which could have the effect of sustaining the stimulus long enough to be consciously detected, that is, for the brain to “see” what the eyes were looking at.

Consciousness may also simply be a matter of improving the signal-to-noise ratio. Time-locked, reverberating activity should be more isolated and protected from random activity which is unreliably associated with a given stimulus. Intuitively, that is what we sense in daily experiences. When we look at a tree, the cognitive noise of the multitude of tree signals may obscure our seeing the bird in the tree until, by accident or intent, we are able to see the bird.

This still leaves us with an incomplete answer. What is it about amplifying or reducing background noise that makes stimuli consciously recognizable? Where is the “who” in the brain that does the realizing? When my brain sees or hears something, it is “I” who consciously see or hear it. How does my brain create my “I” and where in my brain is my “I?” One possibility is that the unconscious brain can release a set of unique network activity that operates much like an avatar, giving brain a functionality it otherwise would not have. I elaborated this idea in my post, “The Avatar Theory of Consciousness” (https://www.psychologytoday.com/us/blog/memory-medic/201506/the-avatar-theory-consciousness).

How does this avatar “I” find a stimulus that it recognizes? Is it searching for it, like a searchlight scanning across the cortex for stimulus-induced activity? Or maybe it is not “looking for” sensation but rather is triggered into temporary existence when a stimulus acquires the needed threshold to launch consciousness. The monkey experiments support the latter option. However a stimulus becomes recognized, the awareness may outlast the triggering. We often consciously think about the meaning of a momentary stimulus, integrate it with memories, and develop beliefs, intentions, and responses, either cognitive or behavioral or both.

One more thing needs mention. In the monkey experiments, it was clear that the monkeys were continuously awake, even when they were not detecting presented stimuli. Thus, being awake is not the same as being conscious. We know this also from human experiments on inattentional blindness, which reveal that consciousness depends on selective attention. Wakefulness is a necessary condition for consciousness but not, by itself, sufficient.

For more explanation of brain function, see my book:

Mental Biology. The New Science of How Brain and Mind Relate.

Sources

Van Vugt, Bram, et al. (2018). The threshold for conscious report: signal loss and response bias in visual and frontal cortex. Science. 360 (6388), 537-542.

Klemm, W. R., Li, T. H., and Hernandez, J. L. (2000). Coherent EEG indicators of cognitive binding during ambiguous figure tasks. Consciousness & Cognition. 9, 66-85.