Memory

Question 1

Define Memory

Answer 1

Memory can be classified by the time course of storage

Immediate memory: fractions of a second - seconds

Working memory: seconds - minutes

Long term memory: day - years

Question 2

Consolidation of memory

Answer 2

Short-term memory moves to Long-term memory by creating new protein synthesis

Question 3

8

Mammalian memory systems

Answer 3

1. Declarative:
   Facts, Events = Medial Temporal Lobe Diencephalon
2. Nondeclarative:
   a. Procedural (skills and habits), in the Striatum
   b. Priming and perceptual learning, in the Neocortex
   c. Simple classical conditional
   - - emotional responses, in the Amygdala
   - - skeletal responses, in the Cerebellum
   d. Nonassociative learning, in the reflex pathways

Question 4

9 H.M. and the types of amnesia

Answer 4

H.M.: Bilateral temporal lobe resection which led to anterograde amnesia

AMNESIA: pathological memory loss
ANTEROGRADE AMNESIA: an inability to establish new memories following onset of amnesia
RETROGRADE AMNESIA: difficulty retrieving memories established prior to the onset of amnesia

Question 5

13

Hippocampal lesions

Answer 5

Hippocampal lesions in rodents impair performance in spatial navigation tasks

Question 6

14

define Engram?

Answer 6

a hypothetical means by which memory traces are stored

Question 7

In search of the memory engram, Karl Lashley

Answer 7

Mass Action Principle:
any degradation in learning and memory depends on the amount of cortex destroyed and the more complex the learning task the more disruptive the lesion, therefore memory cannot be localized to a specific cortical area, but is instead distributed throughout the cortex

Equipotentiality Principle:
the brain has the ability to do what a damaged part of the brain no longer can do

Question 8

Conditioned learning

Answer 8

1. CLASSICAL conditioning:
   - An innate reflex is modified through association with an unrelated stimulus.
   - (Unconditioned Stimulus + Conditioned Stimulus)
   - Ex: Associative Fear Conditioning (see mouse in slide #19)
   
   • • Auditory: depends on amygdala
   • • Contextual: depends on hippocampus and amygdala
2. OPERANT conditioning:
   - Altered probability of a behavioral response caused by associating the response with a reward or punishment
   - Skinner box:
   - Rats learned to associate lever pressing with a food reward
   - Basal ganglia is involved

Question 9

21

CREB-Cre cells

Answer 9

CREB-Cre cells are dedicated to encode memory

Question 10

10-12 Lessons from H.M.

Lesson #1, 2, 3, 4

Answer 10

#1:  Short-term memories are biologically different from long-term memories because they do not require the hippocampus for formation
#2:  More than one type of long-term memory  (mirror drawing task)
#3:  Anatomical basis (medial temporal lobe) for declarative memory
#4:  Medial temporal lobe seems not required for remote long-term memory 

(Although suffering from retrograde amnesia and unable to recall memories during the years before the surgery, H.M. maintained vivid memories of his childhood)

Question 11

23

When both seeing and remembering an object…?

Answer 11

Similar brain regions are active while both seeing and remembering an object

First you perceive
Then you imagine what you perceived

see slide

Question 12

25

Which areas are important for declarative memory storage?

Answer 12

Hippocampus and cortex are both important for declarative memory storage

Question 13

26

Regions of the brain involved in memory acquisition and storage

Answer 13

Storage of DECLARATIVE memory:
Short period storage: hippocampus and related structures
Extended period storage
- a variety of cortical sites: Wernicke’s area for the meaning of words, temporal cortex for memories of objects and faces, etc.

Storage of NON-declarative memory:
Short period storage: sites unknown but presumably widespread
Extended period storage
- cerebellum, basal ganglia, premotor cortex, and other sites related to motor behavior

Question 14

27

Slow Memory Consolidation

Answer 14

“slow consolidation” process renders memory labile and vulnerable to manipulations during the “critical window” period shortly after learning

Memory strength peaks during short term, smaller peak with long term, gradual growth with long lasting

Question 15

Systems Consolidation

Answer 15

Systems consolidation describes a hypothetical process in which an experience-dependent internal representation is converted into a long-term form and reorganized over distributed brain circuits

1. For declarative memory, information is transferred from hippocampus to other MTL structures or neocortical regions.
2. One hypothesis is this process might happen during sleep.

Question 16

Memory and Aging

Answer 16

Brain mass decreases with age

Memory performance declines