4: normal aging 1

Question 1

learning vs. memory (def)

Answer 1

learning = acquisition of knowledge (environment modifies behavioural expression). memory = maintenance

Question 2

3 rat models for hippocampal dependent (spatial) memory

Answer 2

barnes circular maze. 8 arm radial maze. morris water maze.

Question 3

in rodents: what is an important function of hippocampus? damage causes?

Answer 3

spatial memory. rats with hippocampal damage perform poorly on circular maze, radial maze, water maze tests

Question 4

how do aged rats do on barnes circular maze?

Answer 4

impaired in learning excape location, remembering learned location, learning new escape location

Question 5

aged rats in 8 arm radial maze?

Answer 5

make more errors, impaired in remember locations of arms visited. no deficits in the non-spatial, tactile version

Question 6

aged rats in morris water maze?

Answer 6

impaired in learning platform location, but no deficits in the non-spatial cued version

Question 7

aging: effects on anatomy of hippocampus (2)?

Answer 7

loss of volume (35%) and reduction of cholinergic inputs

Question 8

loss of volume in hippocampi due to? not

Answer 8

not due to loss of neurons: due to loss of connections between cells like anatomical synapses and synaptic markers

Question 9

effects of aging on physiology: basic intrinsic neuronal properties?

Answer 9

unchanged: RMP, input resistance, time constant, spike threshold, firing rates

Question 10

effects of aging on physiology: calcium regulation? ACh? interconnectivity?

Answer 10

increase in Ca currents and density of high threshold L type calcium channels. reduced influence of ACh. mixed evidence in impairments in functional interconnectivity

Question 11

Aged dentate gyrus vs. CA1: presynpatic fiber potential and field EPSP?

Answer 11

DG: decreased presynpatic potential, decreased field EPSP. CA1: same presynpatic, decreased field EPSP. so overall ratio of field EPSP to presynpatic fiber potential: increased for aged DG, decreased for ca1

Question 12

aged DG vs. CA1: AMPA? NMDA?

Answer 12

DG: same AMPA sensitivity, decrased NMDA EPSP. CA1: decreased AMPA sensitivity, decreased NMDA EPSP

Question 13

summary of effects of aging on dentate gyrus (4)

Answer 13

reduction of input fibers, decrease in number of synapses, increased in synaptic strength of remaining synapses, decrease in relative NMDA component

Question 14

summary of aging effects on CA1 (4)

Answer 14

no chage in input fibers, decreased in synapse number. no change in synaptic strength or NMDA compoenent

Question 15

brain is the organ of? so changes?

Answer 15

behaviour. changes in behaviour must involve changes in the brain - environmental influences that modify behaviour/thought must reflect functional/structural changes in NS

Question 16

how can functioning of brain be changed (2)?

Answer 16

modify properties or responsiveness of neurons. modify connections and interactions between neurons

Question 17

modify properties/responsiveness of neurons: characteristics? ex?

Answer 17

intrinsic, non-specific, fast, short term alterations. ex: state changes like arousal vs. sleepy

Question 18

modify connections/interactions b/w neurons: characteristics? ex?

Answer 18

synaptic, specific, slower, longer term alterations. ex: reflex strengthening with practice

Question 19

LTP: definition?

Answer 19

enduring increase in synaptic efficacy resulting from an activity dependent (Hebbian) process

Question 20

LTP requires? 3 properties?

Answer 20

requires presynaptic and post synaptic activity. specific, cooperative, associative

Question 21

where does LTP happen

Answer 21

exists at most if not all glutamatergic synapses

Question 22

3 phases of LTP

Answer 22

early = induction. medium = expression. late = maintenance.

Question 23

what happens during early/induction LTP? depends on?

Answer 23

NMDA receptors activation, dependent on calcium

Question 24

medium/expression LTP: what happens (2)

Answer 24

changes to receptors and release machinery, local protein synthesis

Question 25

late/maintenance LTP: 2 things happen? dependent on?

Answer 25

genomic involvement, translation dependent, anatomical changes