Basic system level diagram of the brain


HTM seeks to model and understand what is going on in your head.

I tossed this drawing together from memory so it is sure to be missing some connections. I skipped the thalamic connections all together as this was already a very complicated drawing. Also not shown are the connections between the limbic system and the stream passing through the brain stem and the cerebellum. These are important but not necessary to illustrate the basic cortical/limbic data flows. The blue maps are cortex composed of HTM processing modules. The orange modules are some of the key sub-cortical structures.

The blue connections in the various sensory streams are essentially in parallel form.
The broad green hub connections connecting the various highest levels in each lobe are also parallel.
We can quibble about details but it is clear that as data course from area to area it stays in a mostly parallel form. The maps of the various sensory fields, while “crazy quilted,” are preserved in the hierarchical processing.

So where does this all this parallel data come together?

First - I coded the data transformation connections in orange; these may not be what you could consider parallel. When you consider the limbic system the connections look different.

The EC/HC complex has some scaling where representations in multiple scales exist, but each maintains topography. The rest of the limbic system does not look anything like the cortex. The processing models look more like the classic Boltzmann network. Or perhaps a Hopfield Network? What is presented to the lower brain “wraps around” the complexes, transforming the topographic representation into a “spherical input” form. The limbic clusters don’t work the like the cortex so it should not be surprising that the topological format is transformed as the data is conveyed. The connections between the inputs to the limbic system and outputs to the prefrontal cortex all do some data rearrangement to make the data formats compatible.

The cortex prepossesses the senses into a form compatible with the older brain structures and after the lizard brain does it’s processing it projects commands to the prefrontal cortex to be elaborated into actions. These actions could be directed to further internal or external data gathering or into motor drives that move the body.

You can think of the level of processing of these lower brain structures somewhat like what a moth does in flying up to the light in response to all the cues that signal mating time. In the moth genetics have tuned it to fly up to the moon to mate; genetics did not plan for porch lights. With our big brains these old senses and drives are vastly enhanced. These senses should be better at processing sensory cues and turning those drives into suitable action plans. I call this my dumb boss/smart advisor model.

At the lowest levels to the forebrain, the output fibers don’t project to the body, they project to the temporal lobes to be experienced as “thinking” and “recall.” This is really the same thing as the lower brain structures pointing the eyes thought the FEF (frontal Eye Fields) to look at things of interest, but this part is all internal to the brain. These recalled memories are then experienced by the temporal lobe, hippocampus, and related structures in a loop of experience we call consciousness. The blue parts are available to consciousness, the workings of the limbic system are not.

Some of these forebrain activities may result in the selection and production of motor activity - words and actions. These are all stored motor programs that are being called into play, customized by the recalled memories and drives from the limbic system/forebrain. The networks in the various areas settle into states where there is the least “conflict” between the competing activation patterns. Experienced AI researchers will recognize this as a relaxation computing process mediated locally using attractor networks.

This basic layout or something similar should be a path to AI that has what looks like intelligent behavior.