CLOA - Explain how biological factors affect a cognitive process

Question 1

Alzheimer’s Disease

Answer 1

• a serious degenerative brain disease

- symptoms include memory impairment, difficulty speaking, attention problems, altered personality

Question 2

what causes Alzheimer’s?

Answer 2

• abnormal protein fragments that kill brain cells
• begins at the hippocampus
• amyloid plaques
• neurofibrillary tangles
• reduced metabolism in the hippocampus (Mosconi, 2005)

Question 3

amyloid plaques

Answer 3

• caused by sticky deposits of amyloid-ß proteins that accumulate in the brain
• they damage axon and dendrite membranes
• plaques are formed from the degenerating axons and dendrites

Question 4

neurofibrillary tangles

Answer 4

• accumulation of an abnormal form of tau protein
• structural support of neurons collapses
• tangles occur in the microtubules

Question 5

tau protein

Answer 5

a component of the support structure of neurons

Question 6

how does AD impair cognitive functions?

Answer 6

• degradation of the neurons in the brain

- leading to widespread atrophy (shrinking)

Question 7

episodic memory

Answer 7

memory for events/personal experiences

Question 8

semantic memory

Answer 8

general knowledge about the world, concepts, language

Question 9

procedural memory

Answer 9

memory for the performance of particular actions

Question 10

effect of AD on various types of memory

Answer 10

• Salthouse and Becker (1998): analyzed data from 180 AD patients and over 1000 normal elderly individuals, and found that AD primarily impaired episodic memory
• Hodges et al. (1994) measured semantic memory in AD patients with tasks (e.g. naming pictures of objects or animals) and found a steady decline in semantic
  memory
• procedural memory is also affected but to a lesser extent

Question 11

Mosconi (2005) - Aim

Answer 11

To investigate early detection of Alzheimer’s

Question 12

role of hippocampus

Answer 12

encoding and transferral of STM to LTM

Question 13

Mosconi (2005) - Process

Answer 13

• Longitudinal study following a sample of 53 normal and healthy participants between 9 years and 24 years
• PET scans were used together with a computer program to measure hippocampus metabolism

Question 14

Mosconi (2005) - Findings

Answer 14

participants showing early signs of reduced metabolism in the hippocampus associated with later development of AD

Question 15

Mosconi (2005) - Conclusion

Answer 15

The hippocampus is a central part of memory processes and reduced metabolism may be a sign of AD

Question 16

lesions

Answer 16

damage to brain tissue

Question 17

how do lesions affect memory?

Answer 17

• manifests as memory loss
• demonstrates that different memories are stored in different areas of the brain

Main study: Scoville and Milner (1957)

Question 18

Scoville and Milner (1957)

Answer 18

case study on Henry Molaison

• epileptic who had parts of his brain (including the hippocampus) removed
• his epilepsy was cured but he developed severe anterograde amnesia and partial retrograde amnesia
• intact STM but couldn’t transfer semantic or episodic memories to the LTM
• his ability to store procedural memory in the LTM remains intact
• his memory prior to the surgery appears largely intact
• he has some capacity for working memory (could maintain short conversations)

Question 19

what can be learned from HM’s case?

Answer 19

• memory systems are highly specialized and complex
• hippocampus plays a critical role in transferral between STM and LTM
• however the hippocampus doesn’t appear to be the site of permanent storage itself
• the fact that HM has deficits in some types of memories but not in other suggests that the brain has multiple memory systems located in different regions

Question 20

relationship between HM’s brain damage and his memory deficits

Answer 20

Corkin (1997)

• scanned HM’s brain using MRI
• parts of the temporal lobes (including the hippocampus) was missing
• these parts are theorized to play an important role in the transferral of memories from STM to LTM
• as they are involved in specific neurotransmitter pathways (e.g. acetylcholine, which is associated with semantic and episodic memory)

Question 21

what to write when asked: “Explain how 1 biological factor may affect 1 cognitive process”

Answer 21

• biological factor: Alzheimer’s Disease; cognitive process: memory
• describe functions of the hippocampus
• explain hippocampus’ role in memory formation and recall
• describe symptoms and effects of AD
• explain the causes of neurofibrillary tangles and amyloid plaques and their biological effects
• refer to Salthouse and Becker (1988) and Hodges et al (1994) for cognitive effects of AD