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TEN PHILOSOPHIES OF MIND (Mario Bunge, 1991). 1. PSYCHONEURAL MONISM 1.1 Idealism (spiritualism) Everything is mental (Berkeley, Hegel) 1.2 Neutral - or double aspect monism Mental and physical are manifestations of an unknowable mental substance (Spinoza).
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TEN PHILOSOPHIES OF MIND(Mario Bunge, 1991) 1. PSYCHONEURAL MONISM 1.1 Idealism (spiritualism) Everything is mental (Berkeley, Hegel) 1.2 Neutral - or double aspect monism Mental and physical are manifestations of an unknowable mental substance (Spinoza)
1.3 Eliminative materialism - Nothing is mental (Watson, Skinner) 1.4 Physicalism Mental events are physical or physico-chemical (Hobbes, Pavlov, Churchland) 1.5 Emergentist materialism Mental processes are a subset of processes in brain of higher vertebrates (Hebb, Edelman, Mountcastle)
2. PSYCHONEURAL DUALISM 2.1 Autonomism - The mental and the neural are unrelated (Wittgenstein) 2.2 Psychophysical parallelism - Preestablished harmony mind-soma without interaction (Leibniz)
2.3 Epiphenomenalism - Mental events are caused by neural ones (Vogt) 2.4 Animism - Mental events cause neural ones (Plato, Augustine) 2.5 Interactivism - Causality goes both ways between mental and neural (Descartes, Penfield, Eccles, Chomsky)
TWO CATEGORIES OF REALITIES subject - object intention - mechanism value - fact internal - external mind - body culture - nature society - science Reductionism is an attempt to explain concepts and phenomena of the first category by those of the second, which are quantifiable
The specificity of neurobiology, compared to physico-chemical sciences is to be relational and historical. Ernst Mayr
HEBB ’S RULE If two neurons tend to be electrically active at the same time, they will automatically form a connection. If they are already weakly connected, the synapse between them will become strengthened. Circuit development is experience-dependent (use or lose).
SENSITIVE PERIOD OF PREFRONTAL CORTEX CIRCUITS DEVELOPMENT 6 months - 1 year: mutually responsive gaze, smiling, vocalization - Excitement modulated by mother’s responsiveness (Stern, 1985) - Increased dopamine release in prefrontal areas promotes a growth spurt of synapses and glial cells - Key in self-regulation of affects states
CEREBRAL INTERACTIONS The infant’s neuromodulatory system is modulated by maternal behavior, in particular the opioid system: affiliative reunion behavior is increased by opioid antagonists (naltrexone) that block the endogenous opiate production in both infant and mother. (Kalin, 1995; Hofer, 1996)
Environmental stimulation can increase the number of neurons in the hippocampus (Kempermann, 1997). If new cells are reared in a rich environment, they live longer.
Driven by a flood of sensory experiences, trillions of connections are established that cannot possibly be used. Use-dependent Darwinian competition eliminates synapses that are seldom used.
PERCEPTION Includes both ubiquitous, species-wide elements and personal, individual ones shaped by the past, the emotions and influences of which we are unaware. Separate cortical regions, linked by dendritic pathways, influence one another (reentry circuits, Edelman, 1982) contextual modification, e.g. in hypnotic, focalized consciousness.
The brain constantly interprets and constructs psychic reality, adding meaning to « factual » data Current perception is biased by previous experience (« good enough » match with a reorganized memory). (We tend to « see » what we have seen before). Repetition compulsion is neurobiological.
Quick and slower perception-reaction (LeDoux, 1995) Short route (emergency response): sensory and organ (e.g. retina) – thalamus-amygdala. Amygdala can initiate survival behavior (e.g. running). Cortex is bypassed: no awareness. Long route (simultaneous): sensory neuron – thalamus – sensory cortex – hippocampus – amygdala – orbitofrontal cortex. More detailed information is received, memory is involved, consciousness occurs, decision-making can inhibit the first emergency response.
The rhythmic firing of brain cells not only reflects their activity but actually changes the shape of the mind-brain, namely the patterns of wiring
SYNCHRONISATIONDESYNCHRONISATION Neurons oscillate at different frequencies. When they participate in the encoding of related “contents”, their connection leads frequencies to coordinate and their electrical discharges become synchronized. Conscious awareness may be related to synchrony. (Crick and Koch, 1990)