Thoughts on multiple pathways for sensory input into the neocortex

It seems to be a thing for connectome/cortex researchers to ignore the processing that goes on in the “lower” brain structures. These were/are sufficient to run lizards and amphibians. There is absolutely no reason to think that they re not performing much of their original functions inside of the functioning brain.

The lower brain receives a low-resolution image from the eye area “away” from the fovea and directs the eye to point at interesting areas to form identification of an object with a version of the old 20 questions game in the cortex. There the fovea image is constantly updated as the eyes dart around under the control of this primitive and unconscious scanning system. The cortex is presented with these views in a highly stereotyped fashion and parse out this spaciotemporal stream.

The executive control of attention and identification of primitives for emotional response is a well-preserved function in the lower structures. The hippocampus and related structures have a graduated spacial structure that performs a very effective scale invariant coding scheme. Place, direction, borders, and head position are widely touted but the hippocampus codes all kinds of maps and structures. There is ample research to say that all episodic memory is coded with this system. (patient HM for example) This is passed on to the amygdala for evaluation for recognition of what we chose to call emotional content. I might favor archetypal primitives and selection of basic programs with the resulting priming of chemical messengers. [1] This same coding is passed directly to the temporal lobe much the same way that the other more recognized sensory streams are passed to various locations around the occipital lobe.

The raw body sensors (hunger & thirst are prime examples) are also projected to the edges of a lobe - in this case - the frontal lobe. These are elaborated into motor planning including directed attention to bridge the gap between needs and the perceived and remembered environment.

My working model is a dumb boss/smart advisor with the cortex performing a “sharpening” of the perception and connections of various processing regions of the cortex that we describe as “attention and consciousness.” The lower brain is still the boss and incidentally - the source of the whole “unconsciousness” animal nature mystique.

Another way of looking at all this is that the lower brain structures “drags” the cortex along as it does what a lizard brain might do and the cortex responds by projecting back shaping influences to improve this behavior.

[1] Amygdala Response to Emotional Stimuli without Awareness: Facts and Interpretations - Matteo Diano, Alessia Celeghin, Arianna Bagnis and Marco Tamietto