Synopsis:
- The human genome alone cannot specify the whole complex structure of the brain
- Individual brains are wildly diverse
- "Neural Darwinism": application of Jerne's "selectional" theory of the immune system to the brain
- The brain develops categories by selectively strengthening or weakening connections between neural groups
- Neural groups "compete" to respond to environmental stimuli
- Each brain is different because its ultimate configuration depends on the stimuli that it encounters during its development
- Adhesion molecules determine the initial structure of neural groups, the "primary repertory"
- Experience determines the secondary repertory
- Repertories are organized in "maps", each map having a specific neural function
- A map is a set of neurons in the brain that has a number of links to a set of receptor cells or to other maps
- Maps communicate through parallel bidirectional pathways, i.e. through "reentrant" signaling
- Reentry is more than feedback: there can be many parallel pathways operating simultaneously
- The process of reentrant signaling allows a perceptual categorization of the world
- Categorization is a process of establishing a relation between neural maps
- Categories (perceptual categories, such as "red" or "tall") do not exist phisically, they are not located anywhere in the brain: they are a (on-going) process.
- A further level of organization leads to (pre-linguistic) conceptualization
- Conceptualization consists in constructing maps of the brain's own activity, or maps of maps
- A concept is not a thing, it is a process
- The meaning of something is an on-going, ever-changing process
- Brain processes aredynamic and stochastic
- The brain is not an "instructional" system but a "selectional" system
- The brain is not a direct product of the information contained in the genome, it uses much more information that is available in the genome, i.e. information derived from experience, i.e. from the environment
- Primary consciousness (being aware of the world)
- Two kinds of nervous system...
- 1. Memory continuously reorganizes ("recategorizes")
- 2. Learning as ranking of stimuli ("value-laden" memory, instinctive behavior)
- Intelligent behavior + "instinctive" behavior
- Primary consciousness arises from "reentrant loops" that interconnect "perceptual categorization" and "value-laden" memory ("instincts")
- Higher-order consciousness (language and self-awareness)
- Distinction between the self and the rest of the world
- Social interaction_ anatomical changes _phonology_ _permanent categories...Semantics...Syntax
- Unique to humans
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