Flashcards
Topic 9: Memory consolidation and storage
Cards in this deck (29)
- 1What is amnesia• Greek for ‘forgetfulness’
- 2Two different types of amnesiaRetrograde
• Retro - backward & gradi – to go
• Loss of memory prior to the event
Anterograde
• Antero – forward - 3Who is HM?• Arguably the most famous research subject in the history of brain science
• Henry Molaison started having epileptic seizures in late teens and by late 20’s they were out of control
Consequences
Positive
• Seizures reduced and controllable with medication
Negative
• Lost ability to form new memories
• Continued until his death, 50 years after operation
• Could retain a new fact only briefly
• After their death, didn’t know parents had died
• Couldn’t form lasting relationships with anyone new
• Regardless of previous experiences with someone, had to start anew when they met again - 43) Why did he need surgery and what was removed?Needed surgery for epileptic fits, cortex at both temporal removed, amygdala and most of hippocampus
- 5What impact did that have on his memory, what memories were impaired and what were not?Lost ability to form new memories but could remember everything before his accident
couldn’t consolidate LT declarative memories but could retrieve memories consolidated before his surgery - 6What studies implicate the hippocampus in encoding declarative long-term memories?• Other patients have had the amygdala removed, but less damage to the hippocampus, and showed no amnesia
• So hippocampus seems vital for consolidating declarative LTM - 7What findings indicate that the hippocampus is not involved in the storage of most memories?• Given that HM could retrieve old memories, the hippocampus can’t be the storage site
• Based upon clinical and animal lesion studies, appears that:
• Hippocampus is important for the consolidation of declarative memories
• Memories are stored in other cortical regions - 8What information do place and grid cells in hippocampus process?• Place cells
• encode selective spatial locations
• Become active when the rat is in/moving towards the location encoded by that place cell
• If placed in a new environment, these cells remap to that environment
• Grid cells
• fire when the animal crosses the intersection points of an abstract grid map of the local environment
• Akin to encoding latitude and longitude - 9What is a mirror task, and what were HR’s pattern of results on this task? What did it tell us about his memory ability?• Tested on a mirror-tracing task
• See a figure in a mirror and have to trace it
• Ten trials per day, over 3 successive days
• Episodic memory
- On days 2 & 3, did not remember doing the task
• Nondeclarative skill learning
- Improved considerably over repeated trials on day 1 and that improvement endured into days 2 and 3
HM not impaired in non-declarative learning - 10What cortical region is involved in learning skills?• All three are impaired in people with damage to the basal ganglia
• Damage to other regions, especially the motor cortex, also impairs performance
• Though with the motor cortex, would be impairing execution of the task - 11What are the three aspects of skill learning?• Sensorimotor
• e.g. mirror tracing
• Perceptual
• e.g. reading mirror-reversed text
• Cognitive
• e.g. playing puzzles - 12What is classical conditioning?• Learning that an initially neutral stimulus comes to predict an important event
- 13What is most common experimental task used to study it? What brain area is involved in establishing classical conditioning?Eye-blink reflex
• A form of classical conditioning
• A tone is associated to a puff of air to the eyes of rabbits
• The air causes an eye blink, so when conditioned, the tone results in an eye blink
• Cerebellum (and other structures) is important for this conditioning - 14What is instrumental or operant conditioning?• A stimulus and response learning
• The likelihood that an act (instrumental response) will be performed depends on the consequences (reinforcing stimuli) that follow it
• Reinforcement and/or punishments that the response elicits determine whether that behaviour continues - 15Why can aromas be so evocative?• Olfaction (sense of smell) is part of the limbic system and the olfactory bulb is next to and provides input to the amygdala
- 16What cortical region is involved in encoding emotive memories?• The amygdala is involved in forming these emotive memories
- 17What can strong emotions do in relation to memory?• Strong emotions can enhance memory formation and retrieval
- 18What disorder can occur due to over activation of amygdala when forming memories?PTSD
• Adrenal glands release a number of neuroTS that strengthen memory formation via amygdala - 19What are some treatments for PTSD aimed at reducing the emotive impact of the memories?• Injecting into the amygdala a blocker for the receptors of one of these neurots stops the memory-enhancing effects of stress
• If injected into people who have suffered from traumatic event, then their memory of the event is significantly reduced (compared to controls) when tested months later - 20What is an engram?- physical changes in the brain that underlie a LTM
- also called a memory trace - 21List the two main types of cellular changes that have been linked to the encoding of memories and given an example of each.• Current theories on the cellular basis of learning and memory focus on plasticity of the synapses
• Two types of changes
-- Structural
E.g. greater connection between cells (white matter)
-- Physiological
E.g. greater neurot release - 22Describe the rat study that showed that the richness of the environment could affect the structure of the brain.Rats placed in 3 different environments
• Standard condition (SC)
- small groups in standard cages
• Impoverished condition (IC)
-individually in standard cages
• Enriched condition (EC)
-Larger social groups in special cages
Findings: Compared to IC rats (and occasionally SC rats), EC rats have a heavier and thicker cortex with more dendritic branches - 2319) What is long term potentiation? When cells fire together, the strength of the connections between the cells increases
- 24What is the evidence that LTP can play a role in memory formation?• Time course of LTP very similar to the time course of memory formation i.e. both can be induced within seconds, can last for days or weeks, and shows an active consolidation period that lasts for minutes after induction
• Of course, correlational findings are not strong evidence, but a good starting point - 25What memory tasks reliably show an impairment with aging?• •Conscious recollection that rely primarily on internal generation of the memory
• •Working memory
• •Ability to form new episodic and declarative memories
• •Some decrease in spatial memory - 26What memory tasks are typically not affected by aging?• •Cued memory tasks
• •Existing memories like autobiographical and sematic - 27What neural changes are linked to memory impairments with aging?•Impairments in encoding and retrieval
• •Less cortical activity when encoding and self-initiated retrieval, e.g. faces (see Figure)
•Loss of neurons and/or connections
• •Brain gradually loses weight after age 30
•Problems with cholinergic neurotransmission
• •Two subcortical regions provide profuse cholinergic inputs to the hippocampus and cortex. Some memory loss (e.g. Alzheimer’s) linked to a loss of these inputs - 2824) What are the ways to minimise memory impairments with aging?•Favourable environmental circumstances
•e.g. above average education, demanding & rewarding job
•Engaging in complex and intellectually stimulating activities
•e.g. reading, travel, cultural events, continuing education - 29What are Nootropics?• •Drugs that aim to enhance cognitive function, including memory
problem: •Given how massively complex memory consolidation and storage is, and the vast number of different chemicals and neurotransmitters, my view, have to be ‘brave’ to take drugs to try to improve memory, unless you had a specific pathology
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- Flashcards on Topic 9: Memory consolidation and storage , created by Catrina Dorrell on 05/11/2018.
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