Theta moments, completion of a composition, & cortical fasciculi

Following up from last post: Ah, theta moments, specifically hippocampal theta moments when the apprehension of something new instigates the mental response composing a new situation. I have written about this several times before. Theta waves manifest during key behaviors, simple ones like the chicken’s head bob (yes, almost everything is new because so little is old) or a rat’s step (yes, safety demands almost constant appraisal and memory for location to gain food or avoid danger) or more complex ones like a cat’s orienting response (of what interest is that and should I bother the cat must ask) or a chimpanzee’s expression of bewilderment when an expected treat does not materialize (now what does this mean and what should I do?). Theta is named for the slower waves which accompany these behaviors and signals that diverse areas are focused on the salient event. As the animal processes incoming information the theta disappears as faster, more irregular waves in diverse areas indicate specific information is being processed to help delineate the contextual situation.


The hippocampus is old, deeply embedded cortex. Cortical input flows into the thicker end and the output from the narrower part.

The important thing here is that the hippocampus receives highly processed perceptual information (forms, movement, id of conspecifics, predators, etc. are more automatically recognized) that it processes and then sends the results on upward to the frontal areas engaged in planning and implementing actions and downward as it contributes to the emotional processing carried on by the limbic system. As I have noted before, the hippocampus is way cool. Consider, then, that a theta moment is when the animal formulates a new situational gestalt, a governing form or proto-narrative structure developed from ambient information as discussed in my last post, and then other processes fill in the details, i.e., they finish the composition with perceptual analyses and emotional streams. Of course, these theta moments are actually completed when the animal initiates its next action, e.g., fight or flight, eating, exploration, retreat, or social behaviors.

We humans have a strong network of cortical fasciculi or fiber connections between and among perceptual areas and frontal action areas. These fibers connect the same areas which contribute to hippocampal input and receive its output to initiate the plans and structure of behaviors but they bypass the hippocampus and its situational construct of the immediate ambient and the pressure to act accordingly as well as with the emotional dynamics governing the animal’s responses. By doing so, bypassing this involvement through lower channels, these cortical fasciculi would seem to permit the processing of information apart or displaced from ambient and emotional conditions. What happens to our theta moments there?


Hippocampal theta, remember, first marks something as new or salient and then holds that as a gestalt for the brain to fill in needed information. In this some information, even as it is noticed as new, is held as invariant or as old, so that it can operate as an anchor for further processing of variant information. With the systems connected by the cortical fasciculi, old and new are not contingent upon perceptual notice but upon, at least for us, the gestalts and composition of symbolic information, e.g., the syntax for a linguistic utterance, the intuitive form for aesthetic pieces. So theta moments may be relegated to eurekas, epiphanies, ‘sudden’ insights, realizations, or coming to your senses, etc., the function of generating an invariant form as an anchor for further composition may now continue independently of hippocampal circuits.

I do not want to go into the sleepy land of complicated thinking here about propositional forms based upon the invariance of the verb case frames or how the arcuate fasciculus of the dorsal loop

arcuate fasciculus

helps to maintain the invariant relationship between phonemes and articulatory movements (see recent post on dual loop model) or the invariance of memes as cultural constructs or the invariant memories held in place by guilt or joy, etc. I do want to say that artistic inspiration, that theta moment, major or minor of ‘aha’ or ‘ummm’, when the artist intuits the commanding form and begins to add newly variant elements to compose his or her artistic piece, is one of the most important moments in terran biology and that when we evolved to do this, the universe, well, as it were, sort of, changed for the better. Life began to create new out of the old on its own intentionally without relying on the universal flux of the environment that is slowly, entropically degrading to ‘om’ and that creation was based upon our feelings of fitness, aesthetics, or our sense of beauty.

Now last post I said that Daniel Stern’s understanding of the ‘proto-narrative envelope’ [commanding form) and vitality affects [vital feelings abstracted from experience] from his studies of infants was important. Consider that state of an infant known as the quiet alert state that occurs after feeding. Then the child is most available for social interaction, most readily engaged in rhythmic social exchange and in playful affect modulation. Then the parent helps the child develop the capability for positive affect through engagement. And then it seems to me, the infant sees its whole life as a theta moment as he or she begins to accrue the schemas needed to interpret experience and live a human life. Artistic inspiration and effort has often been compared to these child-like energies and for good reasons. We can see this clearly in the quiet alert state now open for reflection, inspiration and beginning a composition. Artistic creation is clearly related to such youthful joy and we sense this in many artistically talented people (though perhaps cloudily in the tormented geniuses of historical stature). And this has biological roots. I will travel on now to work simply in the garden.

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