These are excerpts and elaborations from my book "The Nature of Consciousness"
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Concentric Consciousness The British neuroscientist
Susan Greenfield derived a definition of consciousness from her studies of mental
infirmities: consciousness is the process of propagating a stimulus through a
network of connected neurons, the same way one perceives the widening ripples
created by an object falling in a pond. She believes that, while
there is no integrator of consciousness in the brain, nonetheless some type of
"temporary" localization must exist. There is no site of
consciousness, but consciousness originates from processes happening locally somewhere
sometime. She believes that different groups of neurons take over at different
times, a picture that resembles theories by Michael Gazzaniga and Daniel Dennett. Therefore, consciousness is multiple in space but unitary in time. These groups of neurons she
calls "gestalts": highly dynamic and transient, they are created by
some kind of "arousal" and they are localized around an
"epicenter". She calls them
"gestalts" because the dynamic properties of the brain
"emerge" in a gestalt fashion from the connectivity of such
neuronal assemblies. An arousal can be an
external (sensory) phenomenon or an internal (cognitive) phenomenon. The
arousal causes the formation of a "gestalt" around an epicenter. The
gestalt causes the "emergence" of a conscious event. Each instance of
consciousness arises from such a gestalt, caused by an arousal and localized
around an epicenter. Overall consciousness develops from epicenters spread
around the brain. The passage from one
conscious event to another conscious event, from one gestalt to another
gestalt, which is typical of our inner life, is due to a ripple effect: the
ripples of one gestalt's concentric action may act as an arousal and trigger
another gestalt. The size of a gestalt
depends, first of all, on the strength of the arousal. But it also depends on
the power of the epicenter to recruit neurons, a power that in turn depends on
rival gestalts that all compete for neurons. The size of the gestalt has a
direct meaning for us, because it corresponds to the depth of consciousness, to
the intensity of the feeling. During growth, epicenters
tend to shift from "outside" to "inside", from external
stimuli to internal associations. Mental life is a dual
process of searching for information and adaptation to information, the former
leading to more conscious access, the latter reducing conscious access (things
become habitual and automatic). Consciousness
"grows" as the brain does (from fetus to neonate to child to adult). Back to the beginning of the chapter "Consciousness: the Factory of Illusions" | Back to the index of all chapters |
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