Transcript TEN PHILOSOPHIES OF MIND

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
intention
value
internal
mind
culture
society
-
object
mechanism
fact
external
body
nature
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
SYNCHRONISATION
DESYNCHRONISATION
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)