Exam 2 Material Flashcards
Aplysia californica
A mollusk that feeds on algae in the shallows of
the Pacific ocean on the coast of the US &
Mexico
why are we talking about sea slugs in a
psychology/neuroscience class?
-Relatively small nervous system (~20,000 cells)
-Their neurons are identifiable
-Learning & memory in Aplysia’snervous system can
be fully understood
non-associative learning
when mere exposure to a stimulus alters the
magnitude or intensity of subsequent responses
Habituation
when a response to a stimulus decreases with repeated exposure. The process by which experience allows you to “get used to it”
Sensitization
when a response to a stimulus increases with repeated exposure, or with exposure to a different stimulus (cross-sensitization). The process by which experience makes you increasingly reactive
Gill withdrawal reflex
the siphon (thru which water
is expelled) receives a light manual stimulus,
triggering a reflex that causes the siphon & gill to
retract
Repeated light touch to the siphon causes the reflex
to become ____ intense (i.e. habituate)
less
Shock applied to the tail causes the response to
____ to its original intensity (i.e. dishabituate)
return
Habituation allows animals to _______, while sensitization and dishabituation reinstate and enhance ________ reactions
adjust; defensive
Gill Withdrawl Circuit
A simple circuit in the abdominal ganglion of Aplysiamediates gill withdrawal and encodes
the habituation and sensitization learning processes that alter this defensive reflex
Short Term Habituation (STH)
A decrease in the magnitude of a response that lasts for a relatively brief period, hours in the case of Aplysia’sgill withdrawal reflex
STH is mediated by __________ __________
Synaptic Depression
Synaptic depression is rapidly _______
in dishabituation
reversed
Long Term Habituation (LTH)
A long-lasting decrease in the magnitude of response, days-weeks in the case of Aplysia’s gill withdrawal reflex
What induces LTH?
Protein synthesis plays a crucial role
LTH is also mediated by __________ _________
synaptic depression
Short Term Sensitization (STS)
An increase in the magnitude of the response that for a relatively short period, minutes in the case of Aplysia’sgill withdrawal reflex
STS is mediated by ________ ________
synaptic facilitation
The facilitation is caused by
increased neurotransmitter release from the siphon
sensory neuron
What causes the increase in
neurotransmitter release?
-Serotonin release onto the terminal of the siphon sensory neuron causes an increase in the duration
of the action potential
-A longer action potential causes more calcium ions to enter the terminal, increasing neurotransmitter
release
-Neurotransmitter release is triggered by calcium, which enters the presynaptic terminal when the
action potential arrives
Long Term Sensitization (LTS)
An increase in the magnitude of a response that lasts for a long period, days-weeks in the case of Aplysia’sgill withdrawal reflex
LTS is a __________ process
multistage
STH & STS
brief synaptic depression or
facilitation mediated by changes in
neurotransmitter release
LTH & LTS
long-lasting synaptic depression or
facilitation mediated by addition or
subtraction of synapses
LTH & LTS require
protein synthesis-dependent
consolidation
Procedural Memory
Implicit/non-declarative, acquired through associative & non-associative mechanisms
Pavlovian Learning/Classical Conditioning
A form of associative learning about the relationship between otherwise neutral stimuli in
the environment and the motivationally salient stimuli & outcomes they predict
Conditioned Stimulus (CS)
a ‘neutral’ sensory cue that does not elicit a major response when presented alone
Unconditioned Stimulus (US):
a cue, event, or outcome that can elicit a behavioral response (known as the
unconditioned reaction or UR) when presented alone
Conditioned Reaction (CR)
the learned response elicited by the CS once it has become associated with
the US
Rescorla-Wagner model λ-ΣV=ΔV
New learning (ΔV) will result if the US you get (λ)
differs (-) from what you expect (ΣV)
Where Does Eye Blink Conditioning
Occur in the Brain?
The cerebellum
Cerebellum
Plays a key modulatory role in motion, contributing to
timing and precision
Lesions of the
rabbit cerebellum
prevent the __,
but not the __
CR, UR
Reflex
an involuntary motor reaction that occurs in response to a particular sensory stimulus
Parallel fibers
granule cell axons that
contact Purkinje cells
Purkinje cell
large inhibitory neuron
that is the primary out put of the cerebellar
cortex
Climbing fiber
axon that arises from
cells in the inferior olivary nucleus; carries
info about air puff (US) to the Purkinje cell
Mossy fiber
axon that arises from
cells in the pontine nucleus; carries info
about tone (CS) to the Purkinje cell via
granule cells (blue)
Presentation of the CS causes Purkinje cells to _____ the rate at which they fire
action potentials. The magnitude of the ______ correlates with the size of the eye blink CR
decrease
Purkinje cells _________ the eye blink CR
pathway
disinhibit
Both CS and US form excitatory (glutamate) synapses on Purkinje cells, yet experimental
manipulations of these projections that should produce associative LTP instead
produce ___
LTD
LTD is mediated by a decrease in AMPA receptor function at parallel fiber synapses on
Purkinje cells
*The flow of sodium ions through AMPA receptors is reduced
*AMPA receptors become less sensitive to glutamate
*Fewer AMPA receptors in the postsynaptic membrane
Emotion
A psychological state, triggered by external stimuli, that rapidly organizes and implements a complex, coordinated response that is appropriate/adaptive for a given situation
Once triggered, emotions organize a coordinated
response at multiple levels:
*Conscious: feelings
*Cognitive: decision making
*Behavioral
*Autnonomic/physiological
Constructionist Definition of Emotion
Emotions are a mix of other, more fundamental psychological components, and thus do not have
dedicated circuits underlying them.
The amygdala
A brain structure in the temporal
lobe that plays a key role in
emotional processing
Klüver-Bucy Syndrome
removal of the monkey amygdala causes a series
of bizarre emotional and motivational responses
Capgras Syndrome
The delusional belief that significant figures in your life
have been replaced with imposters
Capgras Syndrome damage location
Neurological damage impacts the ‘ventral stream’,
which carries visual information from the occipital
lobe to the temporal lobe and amygdala
a Capgras sufferer will remember
________ about a person (i.e. no amnesia), but still
believe that they have somehow been replaced
everything
Emotional memory
Stored information that triggers an emotional reaction
Fear conditioning
a form of Pavlovian learning in which a neutral cue (conditioned
stimulus) comes to predict an aversive outcome (unconditioned stimulus)
Freezing:
immobility with increased muscle tension
Freezing is a _________ behavior
respondent
Increased cardiovascular function
heart rate and blood pressure increase when the CS is
presented
Conditioned analgesia
the animal becomes less sensitive to pain when the CS is presented
Hormonal changes
the CS increases corticosterone concentrations in the blood
Galvanic skin response (GSR)
emotionally arousing stimuli cause you to sweat imperceptibly,
change the electrical conductance of your skin to change in measurable ways
Lateral Amygdala (LA)
contains multimodal cells that
respond to auditory CSs AND
shock USs, thought to be a
crucial ‘locus of association’ in
fear conditioning
Basal Amygdala (BA):
plays a role in routing information around the
amygdala and to other structures
Central amygdala (CeA)
a major output region of the amygdala that
contacts all the other structures involved in producing conditioned
reactions to the CS
the locus of association
the LA
____ in LA is necessary for fear learning
NMDA
Periaqueductal gray (PAG)
brainstem structure
crucial for freezing & conditioned analgesia
*PAG lesions prevent both effects
*Drugs that block opioid receptors injected into
PAG prevent conditioned analgesia
Dorsal vagal complex (DVC)
brainstem structure
involved in conditioned changes in heart rates
Lateral hypothalamus (LH)
brainstem structure
involved in conditioned hormonal responses
CeA works via a complex _______ microcircuit
inhibitory
Medial prefrontal cortex (mPFC)
Region of the brain crucial for
‘executive function’ – a broad
term for various forms of
cognitive control and self
regulation necessary to
facilitate complex tasks and the
attainment of long term goals
____ plays an
inhibitory role, regulating
emotional responses that might
interfere with other adaptive
behavior
mPFC
Intercalated Cells (ITC)
inhibitory neurons
between amygdalar nuclei that receive
mPFC input
mPFC lesion ________
conditioned
freezing
enhances
Extinction Learning
Repeated presentation of the CS absent the US reduces the expression of a Pavlovian fear
memory
Extinction produces a new ________ memory- the association between the CS and the absence of the US
inhibitory
Cognitive Map
stored information about the attributes and layout of the environment that is
used to navigate through space
The traditional behaviorist interpretation
animals learn behavioral
responses through reinforcement (an event or outcome that makes the
preceding response more likely)
Tolman’s Maze Experiment
Behaviorist hypothesis: food at the end gradually
reinforces efficient maze running trial by trial
Cognitive map hypothesis: using a variety of
sensory inputs, the subject generates a stored
representation of the maze that allows them to run
it more efficiently
Food ______ behavior, but, according to the
cognitive map hypothesis is not necessary for
spatial learning
motivates
latent learning
information that is acquired and stored but does not
necessarily impact behavior until the correct test is performed
Contextual fear memory
The chamber in which conditioning occurs can act as a CS, and becomes associated with the US through
Rescorla-Wagner learning rules. Later, the chamber itself will elicit conditioned reactions such as freezing
When does contextual fear memory occur?
Contextual fear conditioning
occurs when shock US is
unsignalled (no tone CS
presented)
immediate shock deficit (ISD)
if shock is delivered within 10-20 secs of the first time an animal is placed in a new
chamber, no contextual association is formed. Relatively weak conditioning will occur within the first 20-120 secs.
Does contextual fear memory require the
formation of a cognitive map?
Place cells begin to show location-specific firing over a period of seconds to minutes, paralleling the times needed in the chamber to produce a strong contextual association.
Do contextual fear memories require
NMDA?
no
The role of the amygdala is _____ required for contextual conditioning when only one or a few shocks are given during training
always
Hippocampus & amygdala are _______ at the time of learning to produce life-long contextual fear memory
needed
