Chapter 9 - Mechanism of Memory Formation

Question 1

What is neural plasticity?

Answer 1

When a new memory is formed

Question 2

What is Acetycholine?

Answer 2

Neurotransmitter

• memory & learning
• muscle movement
• controls REM sleep

Question 3

What is dopamine?

Answer 3

Neurotransmitter

• Facilitates movement, attention and learning reinforcement

Question 4

What is serotonin?

Answer 4

Neurotransmitter

• Regulates mood
• controls eating, sleep and pain

Question 5

What is the role of neurons in memory formation?

Answer 5

Memories are formed through biochemical changes in synapses in response to different neurotransmitters (chemicals)

Neural connections are constantly removed and re-made (neural plasticity)

Question 6

What is alzheimers disease?

Answer 6

Low levels of acetylcholine due to the progressive destruction of neurons in the brain that cause memory loss

• Amyloid Plaques (proteins that form among axon terminals and interfere with communication between neurons)
• Neurofibrillary Tangles (an abnormal build-up of protein inside neurons)
• Hippocampus shrinks
• Brain Shrinks (atrophy)

Question 7

What is korasakoffs syndrome?

Answer 7

Levels of serotonin are disrupted by excessive alcohol abuse over time. Affects formation of new memories.

The hippocampus and temporal lobes are unaffected but the frontal lobes deteriorate.

Caused by deficiency in the vitamin thiamine (B1)

Question 8

Function of neurons

Answer 8

Neurons recieve, transmit & process information

Question 9

Explain the structure of a neuron

Answer 9

• Dendrite’s: tree-like extension that receive information from other neurons
• Soma: cell body that controls metabolism and maintenance of cell
• Axon: nerve fibre which carries information (neural impulse/action potential) away from the cell.

Question 10

Explain communication between neurons

Answer 10

Within the terminal buttons - synaptic vesicles contain neurotransmitters

Question 11

Work of Eric Kandel

Answer 11

• Conditioning = extra serotonin released causing new proteins and thus new memories are formed
• new synapses formed and remained
• repeated stimulation of synapses formed new dendrites

Question 12

What is LTP?

Answer 12

Long Term Potentiation (LTP) refers to:

• repeated stimulation of a particular neural pathway tends to strengthen the likelihood of it firing again

With LTP:

• increased neurotransmitter release
• increased receptor sensitivity
• structural changes in synapses

LTP leads to heightened activation of the receptor of the neurotransmitter glutamate & improved efficiency of the connection between cells

LTP is THEORETICAL (for humans as only tested in animals)

Question 13

What is glutamate?

Answer 13

Neurotransmitter

• Necessary for changes in synapses that occur with memory formation

Question 14

What is cortisol?

Answer 14

Hormone

• Repairs the body

Question 15

Explain the case of H.M.?

Answer 15

H.M. (1957)

• HM patient with severe temporal lobe epilepsy
• Had an operation to remove portions of both temporal lobes
• Couldn’t learn new declarative memories but could learn new procedural memories thus;

Explicit (declarative) & Implicit (procedural) memories are stored in different parts of the brain

Question 16

Brain structure and memory

Answer 16

• Hippocampus
  
  • ​Process of consolidation & retrieval of long-term declarative memories
• Cerebral Cortex
  
  • ​​STM & aspects of declarative memory
• Frontal Lobes
  
  • ​​Working memory, procedural memory, episodic memory
• Amygdala
  
  • ​​Long-term declarative memories. Regulates emotions
• Basal Ganglia
  
  • ​​LTM (procedural)
• Cerebellum
  
  • ​​Classically conditioned responses

Question 17

What is the consolidation theory?

Answer 17

• Memory is permanetly stored through processes where there are physical changes to neurons
• Memories strengthen overtime

3 Steps Necessary:

1. Physical Neural Change
2. No Disruption
3. Time - takes approximately 30 mins to set (24 hours/good sleep makes permanent)

Question 18

Explain memory decline

Answer 18

If memory decline does occur, there are several reasons;

• reduced number of synapses in hippocampus
• reduced insulation of axons of neurons
• changes in the functioning of the pre-frontal cortex

Decline in;

• Working Memory
• Episodic Memory
• Ability to form new memories
• Memory as measured by free recall

No decline in;

• Well learned semantic memories
• procedural memories
• memory as measured by recognition

Question 19

What is Anterograde Amnesia?

Answer 19

Unable to form new memories but can remember before trauma

Question 20

What is Retrograde Amnesia?

Answer 20

Unable to remember the past

Question 21

What is Infantile Amnesia?

Answer 21

Minimal declarative memories from early childhood

Question 22

List forms of Brain Trauma

Answer 22

• Head Injuries
• Stroke (due to lack of oxygen to the brain)
• Concussion
• Post Traumatic Amnesia

Question 23

What is the function of the Hippocampus in memory formation?

Answer 23

The hippocampus is a finger-sized curved structure that lies in the interior of each of the temporal lobes and is located close to the amygdala.

Hippocampus cells are special because they are able to reproduce, and therefore, enable new learning to take place and new memories to form.

The hippocampus is important for forming explicit memory and for difficult tasks that draw upon declarative memory.

Question 24

The function of the Amygdala in memory formation

Answer 24

In each hemisphere, the amygdala is located almost directly behind the temple and beneath the cortex of the temporal lobe. It regulates emotions such as fear and aggression, and plays a more general role in the formation of emotional memory.

• role in the memory of emotions shown on faces
• enhances memorability of an event that is stated as declarative memory

Question 25

What is dementia?

Answer 25

Dementia is a disorder affecting higher mental functions. It can have various forms and may be caused by disease or brain damage.

e.g. Alzheimer’s disease