Cortex, countercurrent context, and dimensional integration of lifetime memory

The correlation between relative neocortex size and longevity in mammals encourages a search for a cortical function specifically related to the life-span. A candidate in the domain of permanent and cumulative memory storage is proposed and explored in relation to basic aspects of cortical organization. The pattern of cortico-cortical connectivity between functionally specialized areas and the laminar organization of that connectivity converges on a globally coherent representational space in which contextual embedding of information emerges as an obligatory feature of cortical function. This brings a powerful mode of inductive knowledge within reach of mammalian adaptations, a mode which combines item specificity with classificatory generality. Its neural implementation is proposed to depend on an obligatory interaction between the oppositely directed feedforward and feedback currents of cortical activity, in countercurrent fashion. Direct interaction of the two streams along their cortex-wide local interface supports a scheme of "contextual capture" for information storage responsible for the lifelong cumulative growth of a uniquely cortical form of memory termed "personal history." This approach to cortical function helps elucidate key features of cortical organization as well as cognitive aspects of mammalian life history strategies

Nested ontology and causal options: A paradigm for consciousness

A brain charged with guiding its body through a complex and lively world from a position of solitary confinement inside its opaque skull faces a set of functional problems whose solution may account for the existence and nature of consciousness. An analysis of the more general and basic of these problems, sensory as well as motor, suggests the utility of implementing a high-level mutual interface between sensory target selection, motor action selection, and motivational ranking of needs at a late stage in the run-up to the brain’s decision about the very next action to take. The three selection processes are subject to a number of mutual dependencies such that a regimen of constraint satisfaction among them would yield gains in behavioral efficiency. The logistics of implementing such a regimen can be simplified by casting the interface in a particular nested, analog format. It would host a running synthetic summary of the rest of the brain’s interpretive labors, reflecting best estimates of the veridical current state of world, body, and needs for purposes of real-time decision making. Detailed scrutiny of the design requirements for such a mechanism discloses that it would be functionally partitioned in a way that defines a conscious mode of operation. Moreover, the design of the mechanism mandates a specific departure from veridicality at a point that makes its functional format match the assumptions of naive realism. Consciousness itself thus introduces a significant, though not insuperable, psychological obstacle to the development of a veridical account of its nature