lecture 20

Question 1

What are types of memory?

Answer 1

Explicit

• memory of facts
• if short term, sometimes called Working Memory

Implicit

• usually long term
• includes
• • habituation (the ability to become desensitised to benign stimuli), sensitisation (almost the obliteration of habituation when there is an alarming stimulus - you become aware of everything you had become habituated to) (can be short term) entirely unconscious
• • classical conditioning (pavlov’s dog) (stimulus before behaviour)
• • operant conditioning (reward or punish a behaviour - behaviour before stimulus)
• • procedural (reflexive) (writing, typing, automatic, motor programmes, require continuous practise, unconscious)
• • with enough time explicit memories can become procedural memories

Question 2

What is working memory?

Answer 2

• psychological construct rather than a specific function
• stores newly acquired information and retrieved memories
• memory traces last seconds to minutes
• depends on prefrontal cortex– also lateral intraparietal cortex
• has several subdivisions:
• • central executive (prefrontal cortex, sets up timing and what you will attend to etc)
• • phonological loop (way of remembering words and sounds, keeping things in working memory requires looping information, can hold seven items on average) (sequences of numbers etc have to be stored by the loop itself, unless you store it and keep repeating it, it won’t go into long term memory, auditory cortex)
• • spatiotemporal sketchpad (what’s going on in visual space, how does it relate to time, sensory stimuli, visual cortex)
• each component of working memory is distributed across a different set of brain regions
• comparing the environment to what’s there already
• gives you the capacity to make decisions
• what you’re holding for long enough to be functional
• phineas gage: lost a component of working memory and ability to control emotionals when a pole thing went through his prefrontal cortex
• working memories are represented in the parts of the brain that detected the stimulus in the first place

Question 3

What is explicit memory?

Answer 3

• also called declarative memory
• • subdivided into semantic and episodic memory (stored slightly differently)
• • includes normal working memory
• requires hippocampal formation for transfer from working to long term memory (not where the memory is stored long term)
• primarily stored in the neocortex once consolidated
• long term
• the memory you can describe, state etc
• semantic = facts
• episodic = the order in which facts happened, what happened rather than the meaning

Question 4

Why can’t someone with severe alzheimer’s remember a conversation spoken minutes earlier?

Answer 4

• goes into working memory than lost because the hippocampal area where short term memories are turned into long term/explicit memories is lost

Question 5

What happened to the guy who had severe epilepsy?

Answer 5

guy who had intractable epilepsy, removed hippocampus bilaterally, dangerous surgery but he survived until mid-80s, however couldn’t remember anything

Question 6

What is semantic memory?

Answer 6

• content, meanings of words, sights, sounds etc

- facts

Question 7

What is episodic memory?

Answer 7

• spatial and temporal relationships between different semantic memories
• important for language
• uses different parts of the hippocampus to semantic memory in the initial parts of being stored

Question 8

How are memories stored?

Answer 8

• transfer if information into long term memory depends on repetition
• recall into working memory enhances the long term memory (use it or lose it)
• repetition alters strength of active synapses, thereby laying down an activity pattern that can be recalled (Hebb’s theory)
• also if a memory is repeated in more than one way e.g. writing and speaking you strengthen the storage of the memory
• frequently, sleep is required with both slow wave and rapid eye movement being implicated - sexual dimorphism
• males store this kind of memory differently from females
• females can create temporary forms of long term memory i.e. studying just before an exam

Question 9

What is the theoretical construct of how a memory is stored?

Answer 9

• stored as strength of connections between neurons in a network
• • individual neurons can participate in several memories
• • distributed, rather than depending on single neurons
• • theory applies to all networks of neuron-like elements
• usually located close to the region that responds to a specific modality
• one of the reasons why you can recognise someone even if they change their appearance in some way