BIOL3050 Exam4

hyperthymestics

people who cannot forget

explicit, short-term memory

working memory

implicit, short-term memory

habituation/sensitization

explicit, long-term memory

fact and events; spatial memory

implicit, long-term memory

habits; motor skills

16 billion

how many neurons are in the human cortex?

synaptic matrix

what shows how memory is stored as strengths of synaptic connections in neural circuits?

long term potentiation (LTP)

a persistent increase in synaptic efficacy

synaptic efficacy

how much activating a synapse will affect the post-synaptic neuron

high

LTP can be induced by ___-frequency stimulation

fEPSP

the summed excitatory postsynaptic potentials of many neurons in a small volume of brain tissue

input specificity

the synapse which underwent high-frequency stimulation is the one that undergoes LTP

cooperativity

activating more than one axon is needed for LTP; pre and post-synaptic cell firing

associativity

a weak synapse will strengthen if activated simultaneously with a strong synapse nearby

CA3 → CA1

LTP at the hippocampal _______ synapse exhibits input specificity, cooperativity, and associativity

NMDA receptors

coincidence detectors that only open with both the binding of glutamate and the depolarization of the neuron’s membrane

coincidence detectors

only open when two simultaneous events occur

AMPA receptors

recruitment of ______ to the postsynaptic surface is a major mechanism of LTP expression

CaMKII

auto-phosphorylation of _____ creates a molecular memory that links LTP induction and expression

molecular memory

what is represented by the auto-phosphorylation of CaMKII continuing to be active, even after Ca²⁺ levels decrease

T286A

which mutation prevents phosphorylation/activation?

prevents more potentiation by CaMKII

what happens when you try to stimulate a synapse that has already undergone LTP?

weakens

long-term depression _____ synaptic efficacy

frequency of stimulation

what determines LTP vs. LTD?

determining amount of Ca²⁺ influx though NMDA receptors

how does frequency of stimulation impact potentiation?

long term depression (LTD)

low Ca²⁺ influx causes ____

long term potentiation (LTP)

high Ca²⁺ influx causes ____

phosphorylates

CaMKII _____ AMPA receptors

dephosphorylates

calcineurin _____ AMPA receptors

long term potentiation (LTP)

pre-synaptic neuron fires before post-synaptic neuron

long term depression (LTD)

post-synaptic neuron fires before pre-synaptic neuron

spike-timing-dependent platicity

what can adjust synaptic efficacy bidirectionally?

synapse strength

increasing or decreasing network activity causes compensatory changes in ______

miniature EPSC

spontaneous synaptic release

amplitude

the _____ of miniature EPSCs correlates with synaptic strength

TTX

blocks sodium channels and thus action potentials, decreasing network activity

bicuculline

blocks GABA receptors and thus increases firing rate, increasing network activity

homeostatic plasticity

visually depriving animals only transiently decreases the activity of neurons in their visual cortex (V1) is an example of _______

homeostatic plasticity

adjusts overall synaptic strengths according to overall activity levels

retrograde messengers

postsynaptic cells can produce ______ to regulate neurotransmitter release by their presynaptic partners

depolarization induced suppression of inhibition (DSI)

neurons can retrogradely signal with endocannabinoids to CB1 receptors on presynaptic partners, decreasing their inhibitory signaling

dendritic spines

LTP can induce the formation of ______

structural synaptic plasticity

LTP inducing the formation of dendritic spines

serotonin

what neurotransmitter is 5-HT?

longer

shocking the Aplysia tail over longer durations caused a _____ period of sensitization

anisomycin

inhibits protein synthesis

5-HT

serotonin that enhances post-synaptic potentials

5-HT

what is long-term facilitation dependent on?

cAMP production

what does activating 5-HT receptors promote?

adenylate cyclase

how do 5-HT receptors promote cAMP production

PKA

what does cAMP activate?

phosphorylates K⁺ channels

what does PKA do?

no

can each glomerulus be innervated by multiple olfactory receptor neurons (ORN)?

yes

can each olfactory receptor neuron (ORN) sense multiple odorants?

worse at finding hidden platform

how do hippocampal-lesioned rats perform in the morris water maze compared to control?

AP5

NMDA receptor antagonist

during training

when does injection of AP5 impair learning in the morris water maze?

impairs learning; longer time to find platform

how does a CaMKII mutant that prevents autophosphorylation impact mice in the morris water maze?

passive avoidance model

during training period, mice are electrically shocked while entering dark chamber

tTA

transcriptional activator of genes that have a TRE binding site upstream and is inhibited by doxycycline

Fos

gene that neural cells turn on when highly activated

prevents production of ChR2 in those phases, so it is only induced during fear conditioning

what does doxycycline do when given during habituation and testing phases? (neuron/memory re-activation)

dentate gyrus

highly active neurons during conditioning that turn on expression of ChR2 via the Fos-tTA/TRE-ChR2 genetic pathway

context/environment

what changes during the fear conditioning phase? (neuron/memory re-activation)

they are moved to a new context from fear conditioning

why should mice not exhibit fear during testing?

fMRI

functional magnetic resonance imaging

increases in oxygenated blood flow as a readout of neural activation

what does an fMRI measure?

more oxygen

highly active neural cells need _______

supplying highly active neural cells with oxygen

what are changes in blood flow for?

no

is the hippocampus important for long-term memories?

28 days

after how long of a delay did lesioning the hippocampus have little effect on retrieving memory?

neocortex

what contributes to long-term storage of explicit memory?

18-36 days

after how long of a delay did inactivating the neocortex impair memory retrieval?

no

does impairing the neocortex cause impairment in the short term?

sharp-wave ripples (SWRs)

occur during restful behavior and sleep; important for spatial memory formation in rats

amygdala

what part of the brain plays a central role in fear conditioning?

prevents it entirely

what effect does lesioning the amygdala have on fear conditioning?

prevents contextual, but not tonal, fear conditioning

what effect does lesioning the hippocampus have on fear conditioning?

extinction

repeating exposure to the CS without the US, decreasing the CR

valence (subjective good/bad)

the amygdala assigns ______ to experiences

spatial context, sensory cues, and pain experience

what signals does the amygdala integrate to control physiological responses to fear?

nose poke

optogenetic stimulation of dopamine neurons in the VTA (ventral tegmental area)

Alzheimer’s (AD)

disease involving brain deposition of numerous amyloid plaques and neurofilbrillary tangles

tangles

hyperphosphorylated tau forms toxic aggregates in cells

plaques

aggregates of proteolytic fragments of the amyloid precursor protein (APP)

B (beta) and Y (gamma)

which secretases produce the AB fragments that accumulate in AD?

secretase-cleavage

mutations near any ______ site can affect AD risk

swedish mutation (APP_SWE)

mutation in the APP gene that increases AB production; less p3

PS1 and PS2

genes that encode components of Y-secretase; mutations increase AB₄₂ levels

significantly worse by the age of 9-10 months

how did mice with the APP_SWE mutation perform in the morris water maze?

tauP301L

mutation that increases neurofibrillary tangles

tauP301L and APP_SWE

combination of mutations that greatly increases neurofibrillary tangles

ApoE (apolipoprotein E)

gene involved in lipid transport and metabolism with three main alleles

e4

which variant of the ApoE is a major risk factor of early-onset AD?

3 in the APP, 1 in the PS1, 1 in the PS2

which genes are the linked mutations in the 5xFAD mouse?

TREM2

gene that encodes a receptor expressed by immune cells, including microglia in the brain

R47H

which allele of TREM2 causes a higher risk of AD?

increased amyloid beta loads and decreased neuron density in the nerocortex

5xFAD mice lacking one or both copies of the TREM2 gene show what effects?

5xFAD mice lacking one or both copies of the TREM2 gene

what conditions cause increasingly more diffused amyloid plaques?

suppression

what effect does microglia have on phosphorylated tau formation?