yes, that's the key question. Maybe modeling after some type of dynamic control system incorporating various feedback.

Perhaps the limbic system is hierarchical and the outer brain is distributive ? A Hybrid..

It must be a combination of these two models: hierarchy and dynamic control system.

The brain definitely has hierarchical structure as a substantial organizing principle. Witness, for example, the increasing size and abstraction of receptive fields as one moves from V1 to V2 and beyond in the visual sytsem.

One can look at each cortical brain area as a bi-directional transducer that transforms signals coming from sensory areas into signals heading for the motor areas and visa versa. The feed-forward transformations (sensory-to-motor) drive perception and ultimately behavior. The feed-back transformations shape the interpretation of the environment and propagate predictive information.

As mentioned, there are those interconnected areas in the middle (e.g. the frontal association areas) which are more difficult to model in a hierarchical or chained configuration.

Ultimately, I think the unifying model of the brain will show it to be a dynamic system that seeks out stability and satiation through its interactions with the environment.

In this limbic-system-level model, the brain is an organ employing numerous strategies, implemented as transformations on information flows, to achieve stability in a dynamic environment. The brain as a system seeks pleasure of various sorts and avoids hunger, thirst, and other discomforts.

The most recently evolved strategy used by animals with a more developed neocortex is that of exploratory behavior.

The neocortex, I think we will discover, is a part of the brain whose job it is to seek out, discover, and exploit structural invariances in the environment. The neocortex does all of the heavy lifting at direction of mid-brain and lower brain areas. These lower areas are deciding when to sleep, when to be awake, when to be more active, when to be cautious, and when to be adventursome. I think these attitude stances toward the environment will turn out to be manifested as configurations of an internal pattern generator that drives the overall activity of the brain, including the flow of signals throughout the neocortex.

One of the jobs of the neocortex during exploratory behavior, I predict, is to filter and organize the relationships between motor activity (what are body is doing) and the flood of information coming in from the senses. The neocortex seeks to factor this information into statistically differentiated indicators, and to detect and discover structural invariances in the environment. An example of a structural invariance is the baby that passes an object in front of its face and realizes that the object moves while the background does not. And furthermore that the object is moving under the baby's control. In this way, we discover what parts of the world we are able to control through manipulation, and we factor the world into its constituent parts (self and environment, objects, people, situations, interactions, tools, ...)

The exteent to which our brain is hierarchically organized will turn out to be a manifestation of the extent to which the world is hierarchically organized.

interesting suggestion. Some would suggest the brain and neural processing reflect statistical regularities in the environment. Of course, defining exactly what we mean by statistical regularity and elucidating its structure proves more difficult. Also, I believe the brain and neural processing must be 'more' than just a reflection of statistical regularities in the environment since we do more than just mirror the environment in our consciousness, but rather seek to creatively and dynamically shape our environment (which in turn shapes us, etc..) and to enrich and realize ourselves.

We are not here to model the environment. We are here to survive within it. The model is just part of the survival strategy.

It would be more accurate to say that our brain is organized to conform to the hierarchical structure of the dynamic interface between our body and the environment.

The sensory side of this organization reflects the hierarchical structure of the physical environment in relation to our sensory apparatus (the 2D retina, the 2D somatic envelope, the 1D fourier decomposition of sound). It also includes the hierarchical structure of the environment independent of us but at our scale (modeling of spatial placement, connected pathways of navigation, spatial territory structure, abstract conceptions of the universe).

The motor side of this organization reflects the hierarchical structure of our body in relation to the environment (limb hierarchy, temporally planned engagement with objects in the environment).

A third aspect to the hierarchical organization are the abstraction levels of our survival strategies. The lower-level strategies are fast but not very clever (recoiling from pain, protecting our face). The higher-level strategies are historical, social, and contextual (learning from parents, adapting to the rules of society, performing useful work for reward).