Lecture 12

Question 1

Charles Sherrington thought alterations in ________ was basis for learning

Answer 1

Synapses

Question 2

Synaptic changes that may store memories include

Answer 2

• increased NT release, increased amount of receptors, both
• formation of new synapses
• rearrangement of synaptic input
• changes w/ interneuron modulation

Question 3

Animals living in enriched conditions had:

Answer 3

• thicker, heavier cortex
• enhanced cholinergic (Ach) pathways
• more basal dendritic branching, more dendritic spines

Question 4

Hebb’s Law

Answer 4

Neurons that fire together, wire together
- cell assemblies, liked via Hebbian synapses, could store memory traces

Question 5

Sensitization (chemically)

Answer 5

• serotonin on facilitating neuron blocks K+ channels on presynaptic neuron

Question 6

Aplysia advantages

Answer 6

large neurons, little individual variation, fewer nerve cells, detailed circuit maps

Question 7

Aplysia Habituation

Answer 7

After repeated squirts of water on siphon, gill is retracted less.
- less NT released from sensory neuron to motor neuron

Question 8

Aplysia Long-term Habituation

Answer 8

over several days it habituates faster
- number of synapses between sensory and motor neuron is reduced

Question 9

Long Term Potentiation (LTP)

Answer 9

Stable and enduring increase in effectiveness of synapses
- Candidate for LTM
- Synapses behave like Hebbian synapses
- Leaves synapse “potentiated” for a period of time, makes neuron more responsive

Question 10

Bliss + Lomo (1973) LTP study

Answer 10

• with rabbits
• dorsal hippocampus
• glutamatergic synapses
• stimulation of perferant pathways to dentate gyrus –> increase in EPSP’s for days
• increase in receptors on postsynaptic neuron

Question 11

Facilitation

Answer 11

Amplitude of postsynaptic response increases when its activated several times in succession

Question 12

Tetanus

Answer 12

brief increase of electrical stimulation that triggers thousands of APs

Question 13

Properties that suggest LTP as a cellular basis for learning and memory

Answer 13

Specificity - only synapses onto the specific cell thats been activated become strengthened
Cooperatively - stimulus from two or more axons makes LTP much stronger
Associativity - pairing a weak stimulus with a strong one makes wear stronger

Question 14

Long-term Depression

Answer 14

prolonged decrease in response at a synapse where axons have been active at a low frequency
- opposite of LTP

Question 15

Mechanisms of LTP depend on changes in ______ synapses in ______ neuron. This occurs at the 2 ionotrophic receptors ______ and ______.

Answer 15

glutamate, postsynaptic, AMPA, NMDA

Question 16

_________ required for stable, LTM

Answer 16

transcription

Question 17

increased histone acetylation =

Answer 17

increased LTP, increased LTM

Question 18

_________ and ___________ work together to regulate plasticity and memory formation in the hippocampus

Answer 18

DNA methylation and Histone acetylation

Question 19

HDACI = ________ LTM

Answer 19

increased

Question 20

DNMTI = _________ LTM

Answer 20

decreased

Question 21

w/ age, impairment on memory tasks that:

Answer 21

require effort, rely on internal generation of memory

decrease in spatial memory, navigational skills

Question 22

nootropics

Answer 22

drugs that enhance cognitive function

Question 23

Yerkes-Dodson Law

Answer 23

Certain stimulants improve cognitive abilities in low doses, in high doses they cause cognitive deficits