Memory and cognition

Question 1

What is cognition

Answer 1

Cognition describes the integration of all sensory information to make sense of a situation.

Thought processing - making sense of something requires an ability to remember events and learn from them

Question 2

Most of the cerebrum is Association areas. What does this mean?

Answer 2

association areas make sense of things - they integrate information from multiple sources rather than being concerned with one specific function.

Example - when you put your hand in to your pocket to find your keys - you can’t see them but you can feel the shape, temperature, size of them and compare this with other things in the pocket in order to pull out your keys correctly etc and all this info is assessed (association)

this processing is required for cognition and relies on an ability to learn and remember

Question 3

what are 3 key components/ parts of the brain associated with learning and memory?

Answer 3

Hippocampus
Cortex
Thalamus

we require all 3 for normal memory to take place

Question 4

What is the purpose of the hippocampus

Answer 4

formation of memories

Question 5

What is the purpose of the cortex

Answer 5

storage of memories

Almost all sensory information goes through the hippocampus, which in turn relays information to other limbic system structures

Question 6

What is the purpose of the thalamus

Answer 6

searches and accesses memories

Question 7

Which system is involved in forming memories?

Answer 7

Limbic system - this gives events emotional significance - essential for memory

Question 8

What is the limbic system

Answer 8

Most primitive part of the cortex

Consists of four distinct areas – hypothalamus (assoc. with ANS responses), hippocampus (assoc. with memory), cingulate gyrus and the amygdala (assoc. with emotion). These areas are also responsible for instinctive behaviour - thirst, sex, hunger etc

It seems as though the limbic system is responsible for selecting what experiences are stored in memory, with a small number of significant experiences being stored but most experiences being ignored and never remembered.

Question 9

Electrical stimulation of certain areas in the limbic system in conscious patients causes what?

Answer 9

intense feelings of well being, euphoria and sexual arousal = reward areas

Question 10

What feelings do punishment areas near limbic system elicit?

Answer 10

fear/terror, anger or pain

Question 11

What gives a task significance? ie what motivates you to study for an exam?

Answer 11

reward and punishment - drives almost every conscious thing we do

Motivation to learn comes from gaining a reward (passing an exam) or avoiding a “punishment” (resitting an exam).

Question 12

Bilateral hippocampal damage

Answer 12

immediate (sensory) memory (seconds in length) and intact long-term memory (from time before damage), but are unable to form new long-term memories.

Their reflexive memory (motor skills) remains intact.

Question 13

What 4 categories can memory be divided into?

Answer 13

Immediate or Sensory memory

short-term memory

Intermediate long-term memory

Long-term memory

Question 14

Describe Immediate or Sensory memory

Answer 14

Describes the ability to hold experiences in the mind for a few seconds.

Based on different sensory modalities.

Visual memories decay fastest (<1s), auditory ones slowest (<4s).

Question 15

Describe Short-term memory

Answer 15

seconds - hours. Often called Working Memory.

Used for short term tasks such as dialling a phone number, mental arithmetic, reading a sentence.

Associated with maintained excitation from reverberating circuits (ie continue to excite all the neurons in the pathway from A-B - keep memory alive) It is an electrical phenomenon. If deemed significant eventually results in consolidation into long term storage

if insignificant - reverberation fades - no consolidation

Question 16

Describe Intermediate long-term memory

Answer 16

hours to weeks e.g. what you did last weekend.

Associated with chemical adaptation at the presynaptic terminal. Increasing Ca2+ entry to presynaptic terminals increases neurotransmitter release

Question 17

Describe long-term memory

Answer 17

can be lifelong. e.g. where you grew up and your childhood friends.

Associated with structural changes in synaptic connections

LTM is basically a well established, well rehearsed pattern of neuronal firing unique to that particular memory.

Question 18

What is anterograde amnesia

Answer 18

cannot form new memories after the event that caused amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact.

Depending on the severity of the injury this can be short lived or permanent

Question 19

what is retrograde amnesia

Answer 19

A loss of memory-access to events that occurred, or information that was learned in the past. It is caused by an injury or the onset of a disease.

Amnesia often presents with anterograde amnesia. However, interestingly, if only the thalamus is damaged, and the hippocampus spared, only retrograde amnesia is seen

Illustrates that memory requires ability to form (hippocampus), store (cerebrum) AND search (thalamus) our memories.

Question 20

Name 3 structural changes at synpases that can occur with long-term memory

Answer 20

1. Increase in NT release sites on presynaptic membrane.
2. Increase in number of NT vesicles stored and released.
3. Increase in number of presynaptic terminals

Question 21

Two main types of long term memory

Answer 21

Declarative or Explicit Memory

Procedural/ Reflexive/Implicit Memory

Question 22

What is Procedural/ Reflexive/Implicit Memory?

Answer 22

Acquired and used unconsciously, and can affect thoughts and behaviours

Acquired slowly through repetition.
Includes motor memory for acquired motor skills such as playing tennis, and rules based learning such as, in the UK, always driving on the left.

Helps people performing certain tasks without conscious awareness of these previous experiences

Is based mainly in the cerebellum.

Is independent of hippocampus

Question 23

What is Declarative or Explicit Memory?

Answer 23

The conscious, intentional recollection of factual information, previous experiences, and concepts

Episodic - specific personal experiences
Semantic - Factual information

Relies heavily on the hippocampus

Question 24

How is short-term memory converted to long-term memory?

Answer 24

through consolidation - involves selective strengthening of synaptic connections through repetition (for minutes to hours)

Consolidation takes time (hours/days)

During the consolidation process, memory simply exists as electrical activity and is vulnerable to being wiped out.

Consolidation requires attention, hence learning is harder when you are tired.

Question 25

What assesses the significance of events?

Answer 25

The frontal cortex and its association with the reward/punishment centres in the limbic system assess the significance of an event in STM

Question 26

What is the Papez circuit

Answer 26

neural circuit for the control of emotional expression

hippocampus - mamillary bodies - anterior thalamus - cingulate gyrus - hippocampus

Question 27

What is Korsakoff’s syndrome

Answer 27

(chronic alcoholism)

There is Vitamin B1 deficiency which leads to damage of limbic system structures.

The ability to consolidate memory is impaired.

Question 28

Alzheimer’s disease

Answer 28

There is a severe loss of cholinergic neurons throughout the brain, including the hippocampus.

Gross impairment of memory.

Some improvement in Alzheimer’s may be seen with anti-cholinesterases, but underlying degeneration continues.

Cause unknown.

Have greatly reduced REM sleep

Question 29

Why is sleep important for memory?

Answer 29

REM sleep is important for memory.

Subjects deprived of REM sleep show significant impairment of memory consolidation for complex cognitive tasks.

Dreaming may enable memory consolidation, reinforce weak circuits.