lecture 28: how does the brain think Flashcards
the nature of thought
psychological constructs:
- idea that some mental ability exists as an entity
- thought, attention, emotion and motivation
diffficult to localize constructs in brain
language in humans
gives humans an edge, a way to categorize info and organize time
- syntax or rules unique to humans
sequencing events in time
language might be byproduct of brain organized to string together events ex. motor movements for hunting
frontal lobes role
new movement and thought sequencing
- organize both behavior and thinking
- damge can cause difficulty generating novel solutions to problems
neural unit of thought
cell assembly: set of neurons that become functionally connected via common sensory inputs
- organized into systems and subsets
- basis of perception, memory and thought (Hebb)
newsome and colleagues
trained monkeys in apparent motion paradigm and made single cell recordings
- found that perception of apparent motion was influecned by individual neurons
consensus
cell assembly represents sensory event that activity of individual neurons detect
- assemblies converge inputs from individual neurons to arrive at consensus
basis for cognition
cell assemblies come together like words in language to produce coherent thoughts
- combination of individual neurons into novel neural networks produce complex mental representations
association cortex
neocortex outside the primary sensory and motor corticies produce cognition
- receives info that is more highly processed than information in primary corticies
3 parts of association cortex
temporal: related to visual and auditory
parietaL: somatosensation and movement guidance
frontal: parietal/temporal association and subcortical regions
ventral visual stream
knowledge about what objects are is in temporal association cortex
dorsal stream
knowledge of how to grasp the object
visual agnosia
temporal association cortex is destroyed
- lose visual knowledge about objects (what they are and what they are used for)
2 types of visual agnosia
apperceptive: unable to perceive an object in its entirety
associative: able to perceive, but cant recognize and cant connect it to semantic representations in memory
spatial cognition
range of mental functions related to transversing space or manipulating objects in space
- test using 3D object rotation
navigation
moving body from point A to B
- creation of mental map in hippocampus (allocentric)
- memorizing sequences of landmarks in basal ganglia and parietal cortex (egocentric)
deficits in spatial cognition
damage to parietal association regions causes deficits in processing complex spatial information
- right posterior parietal cortex
ex. topographical disorientation
damage to hippocampus and surrounding areas of MTL cause deficits in cognitive mapping
topographical disorientation
difficulty perceiving relative locations of objects with respect to the self
- right posterior parietal lobe
inability to set a course between current location and nearby targets
attention
selective narrowing/focusing of awareness to part of sensory environment or class of stimuli - inward or outward Moran and desimone show V4 neuorns can be trained to respond selectively to info in receptive field
selective attention (moran and desimone)
trained animal to attent to stimuli in one area of visual field and ignore other areas
rewarded vs unrewarded locations to train
neurons only fire when correct stimulus was present in correct location
conclusion: same stimulus can activate a neuron at one time but not another depending on learned focus of attention property of single neurons
deficits of attention
frontal: overly focused on environmental stimuli and cannot direct attention to an excessive degree or shift attention
parietal: contralateral neglect
- right hemisphere damage
extinction (contralateral neglect)
neglect of information on one side of body when presented simultaneoulsy with information from other side of the body
- exhibit as they recover
