Memory Deficiency & Memory 3.6 Explain how biological factors affect ONE cognitive process (memory). Alzheimer’s Disease Alzheimer Brain

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Anatomy of Memory Damage to the hippocampus results in anterograde amnesia

Anatomy of Memory Amygdala: emotional memory and memory consolidation Hippocampus: memory recognition, spatial, episodic memory, laying down new declarative long-term memories Thalamus, formation of new memories and working memories Cortical Areas: encoding of factual memories, storage of episodic and semantic memories, skill learning, priming.

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Alzheimer’s Disease (AD) Degenerative brain disease Symptoms are gradual Progression is continuous and irreversible Symptoms (2 cognitive symptoms) Main: memory impairment Attentions, language (speaking/understanding) impaired movement, altered personality Progression Depression, hallucinations, delusions, loss of sleep and appetite

What memory is impacted? Episodic memory! Less impact: Memory from distant pass Procedural memory less impacted through most of the course of the disease

Schwindt and Black, 2009 Hypothesis: The Medial Temporal Lobe (MTL) is responsible for the memory deficiencies in AD Meta-Analysis Collected fMRI scans from AD patients Results Compared to controls, AD patients showed a decrease activation in the MTSL

The Brain and AD Temporal Lobe Stages in Brain change Main responsibility  Why? fMRI shows a decrease in activity Important to episodic memory Stages in Brain change Temporal Lobe + hippocampus Parietal lobes Other regions

Stages of Alzheimer’s http://www.youtube.com/watch?v=7-P9lbTJ9Hw

Abnormal Levels Lead to Atrophy Amyloid-B Protein Damages axons and dendrites. Neurofibrillary tangles Structural support of neuron collapses Results  Cerebral Cortex Shrinks

Scoville and Milner, 1957 Hippocampus and Amnesia Method: Case Study with HM Scoville performed experimental surgery to stop seizures Results Anterograde amnesia Couldn’t form new semantic and episodic memories (explicit) Could form new implicit memory

What have we learned from HM? Memory is a specialized and complex system Hippocampus is critical in moving information from ST to LT Memory Hippocampus is necessary for the storage of memory but does not store memories Why? HM was able to remember events before the surgery Cortical areas store long-term memory Similarities are found in other people with amnesia

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Cortisol and Memory Deficits Chronic over-secretion of cortisol Hinder ability to form NEW memories or ACCESS already existing memories Example Prolonged stress damages the hippocampus Restore cortisol levels, restore hippocampus activity Long-term  irreversible damage

(Review) Newcomer et al. 1999 Aim: investigate how cortisol levels impact memory Method: double-blind experiment Procedure: 3 Groups High, Medium, Placebo injection Verbal, declarative memory task Results: high level preformed the worst after 1 day Implications: Too much cortisol limits the formation of new memories Evaluation: Clear cause and effect (randomized and blind) Informed consent No long term exposure to cortisol

Lupien et al., 1998 Method: Longitudinal study, correlational, MRI Participants: elderly people over 5 years Results 30% has high levels of cortisol Memory impairment Shrinking of hippocampus Memory impairment can be reversed IF the damage had not gone beyond “a point of no return” Implications Relationship between high levels of stress, high levels of cortisol and hippocampus damage

Lupien et al., 2002 Follow-up to 1998 research Method: experiment AIM: investigate if it is possible to reverse memory problems with drugs (metyrapone) Method: experiment Participants: elderly from original 5-year study 3 groups (placebo, high and moderate levels of cortisol) Procedure: Drug  prevent cortisol (metyrapone) Memory test Drug  restore original cortisol level (hydrocortisone) Results Moderate  no problem restoring memory High  no memory improvement, did worse on hydrocortisol

Exam Tip Explain how biological factors affect ONE cognitive process (memory). Be clear about which behavior you are focusing on (MEMORY) Discuss at least two biological factors Brain injury/surgery Alzheimer's Disease Cortisol