Memory and Cognitive Thinking Flashcards
What is cognition?
Relates to highest order of brain function and relates to behaviour that deals with though processing
Is the integration of all sensory information to make sense of a situation
What does making sense require?
Remembering events and learning from them which requires motivation
Describe the association areas of the brain
Integrate information from multiple sources, rather than being concerned with one specific subject
Multiple parallel processing units
Processing required for cognition
What are the main association areas of the brain?
Motor
Prefrontal
Sensory
Visual
Auditory
What are the 3 components of learning and memory?
Hippocampus - formation of memories
Cortex - storage of memories
Thalamus - searches and assesses memories
Where are memories formed?
In the limbic system
Has important connection with neo cortex, in temporal and frontal lobes - makes situations of info through learning
What is the main function of the limbic system?
Gives emotional significance to events - essential for memory
What are the 4 distinct areas of the limbic system?
Hypothalamus - ANS responses
Hippocampus - memory
Cingulate gyrus
Amygdala - emotion
What are the areas of limbic system responsible for?
Instinctive behaviour - thirst, sex, hunger and emotional behaviours are driven by seeking reward or avoiding punishment
What are the 2 areas of the limbic system?
Reward areas - intense feelings of well being, euphoria and sexual arousal
Punishment areas - fear/terror, anger or pain
These are central aspects for learning
What happens to experiences that are neither rewarding or punishing?
They are barely remembered as insignificant - forgotten
Frontal cortex of brain assesses the significance of the event
Describe the hippocampus
All sensory info comes through here
In turn it relays the info to other limbic system structures
Is essential for formation of memories
What happens if you have bilateral hippocampal damage?
Have immediate sensory memory and intact long term memory from before damage but unable to form new long term memories
Reflective memory remains intact
What can memory be divided into?
Immediate or sensory memory
Short term memory
Immediate long term memory
Long term memory
What is immediate or sensory memory?
A few seconds
Ability to hold experiences in mind for a few seconds based on different sensory modalities
Visual memories delay fast and auditory is slowest
What is short term memory?
Seconds to hours - called working memory
Used for short term tasks - phone numbers, mental arithmetic, sentence
Associated with reverberating circuits
What is immediate long term memory?
Hours to weeks
Associated with chemical adaption at the presynaptic terminal
What is long term memory?
Can be life long
Associated with structural changes in synaptic connections
Describe short term memory and reverberating circuits
Each synapse in a reverberating circuit is excitatory and hence a brief excitatory stimulus causing long lasting neuronal activity in all neurons of pathway
What is the short term memory is deemed significant?
Reverberation results in consolidation of the memory into long term memory storage
What if reverberation is disrupted?
Memory loss - amnesia
Usually if effect to hippocampus or thalamus
What are the 2 types of amnesia?
Anterograde - cannot form new memories
Retrograde - cannot access old memories
Describe anterograde amnesia
Inability to recall events that happen after the injury
Can be short lived or permanent
Destruction of hippocampus - permanent inability to form new memories
Describe retrograde amnesia
Cant remember events leading up to the injury but events that happened a long time ago can be recalled - as more deeply imbedded
What happens if hippocampus is spared but thalamus damaged?
Retrograde amnesia seen
Describe the chemical changes in presynaptic terminal in intermediate long term memory
Increasing Ca entry to presynaptic terminals which increases neurotransmitter release
What structural changes at synapses are involved in long term memory?
Increases in NT release sites on presynaptic membrane
Increase in number of NT vesicles stored and released
Increase in number of presynaptic terminals
Describe long term potentiation
Increased amplitude in graded membrane potential in post synaptic cell - strengthens the synapse
Forms basis of much learning and memory
What are the 2 main types of long term memory?
Declarative or explicit memory
Procedural/ reflective/ implicit memory
Describe declarative or explicit memory
Abstract memory for events and for words, rules and languages
Relies heavily on hippocampus
Describe procedural/ reflective/ implicit memory
Acquired slowly through repetition
Includes motor memory for acquired motor skills
Biased mainly in cerebellum and is independent of hippocampus
Describe consolidation
How short term memory is converted to long term memory
Involves selective strengthening of synaptic connection through repetition - during this period memory is vulnerable of being wiped out
What is memory recall dependant on?
Significance of events - brain gives attention to significant events
Where are new memories stored?
Coded then stored in sensory and association areas of cortex
Coding results in new memories being stored by others that seem similar
What happens if experience is considered useful?
The frontal cortex gates the papez circuit - which includes hippocampus, mammillary bodies, anterior thalamus and cingulate gyrus in circle
Where does reverberating activity continue between?
Papez circuit, frontal cortex, sensory and association areas until consolidation process is complete
Where is each component of memory stored?
In different relevant parts of cortex
Describe Korsakoff’s syndrome
Chronic alcoholism - there is a vitamin B1 deficiency which leads to damage of limbic system structures so ability to consolidate memory is impaired
Describe Alzheimer’s disease
Severe loss of cholinergic neurons through out the brain including the hippocampus
Gross impairment on memory
Anti-cholinesterase can help
Describe REM sleep and memory
Is important for memory - dreaming may enable memory consolidation and reinforce weak circuits
