cog psy ch3

neuron

a nerve cell that receives, processes, and sends information through the nervous system

dendrites

Branch-like structures that receive signals from other neurons and carry them toward the cell body

cell body

main part of the neuron that contains the nucleus and maintains the cell

axon

A long structure that carries neural signals away from the cell body toward the terminal buttons

myelin sheath

layer surrounding the axon that speeds up the transmission of neural signals

terminal buttons

Structures at the end of an axon that release neurotransmitters to communicate with other neurons

synpase

the space between the terminal buttons of neurons

resting potential

at rest, more negative ions inside the cell, resting neuron has a charge of -70 millivolts

action potential

the electrical changes that take place when a neuron transmits info (all or none)

absolute refractory period

immediately after a neuron fires, it cannot fire again

relative refractory period

after the absolute refractory period, a stronger than normal signal is necessary in order for a neuron to fire

what pattern of chemical ion transfer into and outside of the neurons leads to the action potential?

At rest I'm negative, hit threshold, Na⁺ comes IN and makes me positive, K⁺ goes OUT and makes me negative, then I go too negative before resetting

divergence

each neuron synapses with anywhere from 100 to 15000+ other neurons

convergence

any given neuron receives chemical signals from as many other neurons

neurotransmitters

chemical messengers that allow neurons to communicate with each other

glutamate

main excitatory neurotransmitter

acetylcholine

excitatory and modulatory neurotransmitter involved with learning, memory, and attention; low levels are found in alzhemier’s

GABA

inhibitory neurotransmitter that weakens the connections between neurons

long term potentiation (LTP)

a long-lasting strengthening of the connection between neurons after they communicate with each other repeatedly

consolidation

process by which a new, fragile memory becomes more stable and long-lasting

how do LTP and consolidation relate to long term memory?

occurs over a long period of time, leads to multi-neuron complexes changes in connection strength (like LTP on a larger scale)

how is sleep related to consolidation?

consolidation happens best during stage 3 and 4 sleep

neurogenesis

new neuron formation, mostly occurs early in life but can still occur throughout life, new neurons are most likely to survive when learning new info

parallel distributed processing (PDP)

connectionist model that shows similarities and differences between pdp and network of neurons, ie. how to pronounce unknown words

similarities between PDP and network of neurons

• both are interconnected networks

• each unit receives input from many other units

• each unit provides an output to many other units

• units either are on (they fire) or off (they don’t)

• connections between units can be strengthened or weakened

differences between PDP and network of neurons

• NON is large and complex, PDP is small and simple

• neurons react differently to different neurotransmitters, this property is ignored in PDP models

thalamus

relay station

corpus callosum

bridge

amygdala

associated with emotional memory

hippocampus

involved with formation of memories

cerebral cortex

the thin outer layer of the brain made mostly of gray matter and is responsible for many complex functions, including perception, thinking, language, memory, and voluntary movement

frontal lobes

thinking, speaking, doing, broca’s

temporal lobes

hearing, language, memory, wernicke’s

parietal lobes

physical sensations

occipital lobes

vision

contralaterality (in general and specifically about visual processing)

left and right brains are “opposite” to what you’d think- left brain receives input from and controls right side of body, right brain receives input from and controls left side of body

optic chasm

sits just below hypothalamus, point where the optic nerves partially cross, causing information from the left visual field to be processed by the right hemisphere and vice versa

hemispheric specialization for language and spatial abilities

left hemisphere: language, right hemisphere: spatial abilities

broca’s aphasia

difficulty producing fluent speech caused by damage in the left frontal lobe

wernicke’s aphasia

difficulty understanding language, often accompanied by fluent but nonsensical speech

WADA test

estimates of LH language dominance within certain parts of population

split brain studies (sperry)

severed corpus callosum, found split brain patients could draw better with left hand (RH dominance in majority of pop.), spatial skills uses chimeric face to study differential processing across hemispheres

associations

two cognitive abilities are both impaired after the same brain injury

dissociations

brain damage affects one ability but not another

double dissociations

when damage to one brain area impairs Ability A but not B, while damage to another area impairs B but not A, providing strong evidence that the abilities rely on different brain systems