Lecture 12 Memory Flashcards
Different definitions of Memory
General and
Psychological
- General definition: the ability to consciously recall events or facts.
- Psychology definition: Memory is the faculty of the brain by which information is encoded, stored, and retrieved when needed.
- Anything that goes through the brain goes through memory. NOT just the past, but all future behaviour is based on memory, social norms, tying shoelaces (low level), remembering people’s life stories as a therapist (higher level), etc.
- Process of maintaining information over time.
- This information takes many different forms, e.g. images, sounds or meaning.
How would life be without memory?
“Vital to experiences, it is the retention of information over time for the purpose of influencing future action. If we could not remember past events, we could not learn or develop language, relationships, or personal identity” (Eysenck, 2012).
•Without a memory of the past, we cannot operate in the present or think about the future. We would not be able to remember what we did yesterday, what we have done today or what we plan to do tomorrow. Without memory, we could not learn anything.
Similarities of memory and learning
•Two sides of the same coin – both are experience dependant behaviour.
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•Learning is a relatively permanent change in behaviour as a function of experience.
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•Memory and learning depend critically on each other.
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Cognitive Neuroscientists consider memory as the :
as the retention, reactivation, and reconstruction of the experience - independent internal representation.
Internal representation of memory contains two components:
- The expression of memory at the behavioural or conscious level.
- The underpinning physical neural changes.
- also called engram or memory traces.
What are engrams
•Engrams are theorized to be means by which memories are stored as biophysical or biochemical changes in the brain (and other neural tissue) in response to external stimuli.
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- The consensus view in neuroscience is that the sorts of memory involved in complex tasks are likely to be distributed among a variety of neural systems, yet certain types of knowledge may be processed and contained in specific regions of the brain.
- Long-term potentiation is the closest idea to this we have research for?
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Areas of memory localization
- Cerebellum: plays an important role in the processing of procedural memories.
- Prefrontal cortex, and plays an important part in processing short-term memories and retaining longer term memories which are not task-based.
- Temporal lobe key role in the formation of long-term memory.
- Medial temporal lobe: involved in declarative and episodic memory. Within this, the limbic system, which includes the hippocampus, the amygdala, the cingulate gyrus, the thalamus, the hypothalamus, the epithalamus, the mammillary body and other organs, many of which are of particular relevance to the processing of memory.
- Hippocampus: essential for memory function, particularly the transference from short- to long-term memory and control of spatial memory and behaviour. The hippocampus is one of the few areas of the brain capable actually growing new neurons.
- Amygdala: performs a primary role in the processing and memory of emotional reactions and social and sexual behaviour.
- Basal ganglia system: particularly the striatum which is important in the formation and retrieval of procedural memory.
Role of Cerebellum in memory
plays an important role processingof procedural memories.
Prefrontal Cortex in memory
•and plays an important part in processing short-term memories and retaining longer term memories which are not task-based.
Temporal lobe in memory
•key role in the formation of long-term memory.
Medial temporal lobe in memory
: involved in declarative and episodic memory. Within this, the limbic system, which includes the hippocampus, the amygdala, the cingulate gyrus, the thalamus, the hypothalamus, the epithalamus, the mammillary body and other organs, many of which are of particular relevance to the processing of memory.
Hippocampus in memory
essential for memory function, particularly the transference from short- to long-term memory and control of spatial memory and behaviour. The hippocampus is one of the few areas of the brain capable actually growing new neurons.
Amygdala in memory
•: performs a primary role in the processing and memory of emotional reactions and social and sexual behaviour.
Basal ganglia in memory
system: particularly the striatum which is important in the formation and retrieval of procedural memory.
For psychologists the term memory covers three important aspects of information processing:
•Encoding: attending to the information (learning).
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•Consolidation: storing it for later use (learning).
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•Retrieval: retrieving the information from where it was stored in the brain (memory).
five main ways in which information can be encoded:
- Visual (picture)
- Acoustic (sound) repeating a phone # in head or out loud, even writing repetitively is considered acoustic/verbal
- Semantic (meaning) acronyms etc.
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•4. Tactile (touch).
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•5. Elaborative (relating new meaning to old meaning).
What is the process of encoding?
Learning it, by perceiving it and relating it to past knowledge
(Encoding is a biological event that begins with perception)
- All sensations travel to the brain’s thalamus where they are combined into one single experience.
- Various threads of information are stored in various parts of the brain. However, the exact way in which these pieces are identified and recalled later remains unknown.
- The hippocampus is responsible for analyzing these inputs and ultimately deciding if they will be consolidated into long-termmemory.
Neuroscience of Encoding
•Encoding of working memory involves the spiking of individual neurons induced by sensory input, which persists evenafterthe sensory input disappears.
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•Encoding of episodic memory involves persistent changes in molecular structures that alter synaptic transmission between neurons.
Main differences b/w Short-term memory and Long-term memory (re: consolidation)
- Short-term memory (STM) is temporary and subject to disruption, while long-term memory (LTM), once consolidated, is persistent and stable. For something to be in long-term, it must be consolidated first.
- LU:waysmemory is consolidated (Ex., repetition, semantic meaning,
Methods of consolidating memory
- Conversion from short-term to long-term memory requires a concerted effort, the passage of time, and the absence of interference in memory consolidation.
- Takes place with repetition and review.
- In the process, the synapses become stronger between the two neurons as signals are more frequently passed between them.
- Improving one’s memory:
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improve processes of encoding
* __Good encoding techniques include relating new information to what one already knows, forming mental images, and creating associations among information that needs to be remembered.
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improve processes of encoding
- use techniques that guarantee effective retrieval.
* The key to good retrieval is developing effective cues that will lead the rememberer back to the encoded information. Classic mnemonic systems, known since the time of the ancient Greeks and still used by some today, can greatly improve one’s memory abilities.
- use techniques that guarantee effective retrieval.
Memory Consolidation and Sleep
•Strong evidence that at least one function of sleep is to “consolidate” memory traces into more permanent forms of long-term storage.
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•During all stages of sleep, the brain is working to process new memories, consolidating them into long-term storage and integrating recently acquired information with past experience.
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•Post-learning sleep, in particular, is known to be beneficial for human memory performance. (if you learn, then nap, etc)
Relationship b/w Memory, Sleep and Dreams
•Studies have shown a relationship between the “replay” of recent experience in dream content, and enhanced memory performance in humans.
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•Dream experiences bear a relationship to recently encoded information, and therefore are thought to be involved in consolidation of memory.
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•One stage of consolidation is thought to involve the integration of information with pre-existing knowledge and the linking of distant but related concepts.
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•We are thought to dream when we become aware of these activated traces, which are often fragmented images and sounds coupled with motor activity.
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Ideas of why we dream
•Memory fragments have been found in both REM and NREM dreams, but demonstrating that dream contents contain memory fragments not necessarily demonstrate a functional role for dreams in memory processing. (because every thought is from memory anyway….?)
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Neuralactivity in the primary sensory areas of the neocortex can produce the impression of sensory perception:
- This means that neurons firing in the primary visual cortex create the illusion of seeing things, neurons firing in the primary auditory area create the illusion of hearing things, and so forth.
- If that firing occurs at random, these perceptions can feel like crazy, randomly fragmented hallucinations.
Memory consolidation, synaptic consolidation, systems consolidation, reconsolidation
Memory consolidation is a category of processes that stabilize a memory trace after its initial acquisition. Consolidation is distinguished into two specific processes,
synaptic consolidation, which is synonymous with late-phase long-term potentiation and occurs within the first few hours after learning, and,
systems** **consolidation where hippocampus-dependent memories become independent of the hippocampus over a period of weeks to years.
Recently, a third process has become the focus of research, reconsolidation, in which previously-consolidated memories can be made labile (refers to something that is constantly undergoing change or something that is likely to undergo change) again through reactivation of the memory trace.
memory tree
What is the Multi-store memory model?
Multi-Store Model (Atkinson & Shiffrin, 1968):
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- This model suggested that information exists in one of 3 states of memory: the sensory, short-term and long-term stores.
- Information passes from one stage to the next the more we rehearse it in our minds but can fade away if we do not pay enough attention to it.
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Long Term Memory
- Long term memories are those that you can recall days, months, and even years after they were stored. Have to be salient in order to be encoded into longterm
- There seems to be no limitation on the capacity of long term memory.
- Even though some events are stored in long term memory, they are no longer retrievable.
- Some events also don’t make it into long term memory, eg. what you had for lunch last Tuesday.
- Pic: one is for more implicit, one important to remember>
What is the “Working Memory Model”?
Working Memory Model (Baddeley & Hitch, 1974):
(like an extension on the multi-store model, so came up with “Working Memory Model”)
4 Parts:
- Visuospatial sketchpad (the ‘inner eye’).
- Articulatory-phonological loop (the ‘inner ear’).
- Episodic buffer: the third member of these slave systems and is theorized to integrate the other two with a sense of time, so that things occur in a continuing sequence, like a story from a book or movie. Added to the model recently.
- Central executive: collects and processes information from the other components. Same concept as personality, but talking about memory now.
Why the difference between “mental imagery” and “spatial information” within the Visuospatial Sketchpad?
•Differences between these two different visual abilities are due in large part because of different pathways of each of the abilities in the brain.
Dorsal: spatial info;
Ventral: shape, objective, colour,
(double check)
