The Entangled Brain by Luiz Pessoa

Author:Luiz Pessoa
Language: eng
Format: epub
Publisher: MIT Press

From Sensation to Cognition, One Step at a Time

How are cognitive mechanisms built? In this section, I’ll discuss a view that was popular for many decades, until at least the late 1980s. Although researchers currently don’t subscribe to stronger incarnations of this model, the main idea lies dormant in the background, and current thinking is still influenced by it. It goes roughly like this.

Parts of the cortex are sensory, others are motor. In the former, cell responses are tied to stimulus and perceptual properties; in the latter, they are linked to movements and actions in a fairly direct manner. We can think of the prefrontal cortex as the part of the brain that’s decoupled from immediate sensory and motor variables. In a nutshell, it deals with the abstract. On the sensory end, researchers think of the cortex in terms of information flowing from early sensory regions (for instance, visual, auditory) to parts of the prefrontal cortex (figure 7.5). Along the way, intermediate regions have cells whose responses are progressively more independent from sensory variables. Sensory signals provide a steady stream of signals that progress through a cortical hierarchy until reaching the prefrontal cortex. At each junction, responses become more refined—namely, less about physical properties. In the prefrontal cortex, they are sufficiently abstract that they can support “symbolic processing” of the type that possibly distinguishes humans from other apes, or maybe apes from other primates.

Figure 7.5

Flow of information processing in the brain. In the scheme favored by neuroscientists until at least the late 1980s, sequential processing steps move from the early visual cortex to the prefrontal cortex, where “abstract processing” is assumed to take place.

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