PSY100H1 Lecture Notes - Lecture 4: Cortical Blindness, Oliver Sacks, Visual Cortex
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February 1st, 2011
PSY100- Lecture 4
Gambling study and PFC
- Non conscious biases, in the form of visceral signals, “gut feelings,” can serve
as guides to wise/intelligent behaviour
- Our non-conscious implicit system can achieve insight BEFORE conscious
- These visceral feelings, our biases, are crucial for motivation; without
emotional KICK, knowledge alone does not motivate behaviour change.
The Split Brain
- The two hemispheres of the brain are actually two mini-brains connected by a
bundle of fibers, the corpus collosum
- In the 1930s – 1950s, cutting the corpus collosum became all the rage, to
help people with epileptic seizures and other disorders
- Amazingly, these people seemed pretty normal, but clever psychologists (like
Gazzaniga, your textbook author) discovered ways of communicating
separately with the now-independent hemispheres.
Split- Brain experiments
- When asked to point to the item that was seen, the left hand (RG) pointed to
the image seen by the right hemisphere. (figure 4.7 in textbook)
Similarly to blind sight, in which some brain areas know things that other brain
areas do not, a patient can have emotional reactions to stimuli that the left brain
doesn’t know it’s seen other experiment where left brain makes up incorrect
rationalization for actions, person believes it….(slide)
Left hemisphere is speech.
- The brain changes continuously
- “Our brains; connections are refined and returned with every experience of
- Only recently have we begun to appreciate our brains’ incredible “plasticity”
– or ability to change.
- Plasticity is amazing, but the limits are unknown.
- Certainly, age is a factor: ex. Very young children with severe epilepsy >
radical hemispherectomy – mostly normal functioning!
- Brain areas can even recruit systems normally devoted to other tasks.
oEx. Cut off a finger > that part of the sensory cortex will start to
receive signals from the other fingers > enhanced sensitivity
oEx. If blind > the sensory cortex corresponding to the Braille-reading
finger expands ; sense of touch starts to get processed by the visual
- In essence, this is how our sensorimotor cortices evolved in the first place.
The Mind is what the Brain does?