Memory and Cognition Flashcards
what is cognition?
Cognition describes the integration of all sensory information to make sense of a situation.
Cognition relates to the highest order of brain function and relates to behaviour that deals with thought processing
whats the function of association areas?
integrate information from multiple sources, rather than being concerned with one specific function
The brain can therefore be thought of as multiple parallel processing units
what are the 3 components of learning and memory?
Hippocampus – formation of memories
Cortex – storage of memories
Thalamus – searches and accesses memories
function of the limbic system?
gives events emotional significance – essential for memory.
what is the most primitive part of the cortex?
limbic system
what are the 4 distinct areas of the limbic system?
hypothalamus (assoc. with ANS responses), hippocampus (assoc. with memory), cingulate gyrus and the amygdala (assoc. with emotion).
what happens when there is an electric stimulation of certain areas in the limbic system?
intense feelings of well being, euphoria and sexual arousal = reward areas
what are punishment areas?
Other nearby areas elicit fear/terror, anger or pain
what forms the “affective components” of sensory experiences?
Reward and punishment
what does almost all sensory information go through?
the hippocampus
what happens to people with bilateral hippocampal damage?
have immediate (sensory) memory (seconds in length) and intact long-term memory (from time before damage), but are unable to form new long-term memories.
Their reflexive memory (motor skills) remains intact.
The effect is totally devastating.
what can memory be divided into?
Immediate or Sensory memory
Short-term memory
Intermediate long-term memory
Long-term memory
what is Immediate or Sensory memory
a few seconds. Describes the ability to hold experiences in the mind for a few seconds. Based on different sensory modalities. Visual memories decay fastest (<1s), auditory ones slowest (<4s).
what is Short-term memory
seconds - hours. Often called Working Memory. Brain’s “post-it note”. Used for short term tasks such as dialling a phone number, mental arithmetic, reading a sentence. Associated with reverberating circuits.
what is Intermediate long-term memory
hours to weeks e.g. what you did last weekend. Associated with chemical adaptation at the presynaptic terminal.
what is Long-term memory
can be lifelong. e.g. where you grew up and your childhood friends. Associated with structural changes in synaptic connections.
short-termed memory is an electrical phenomenon, what does it depend on?
depends on maintained excitation from reverberating circuits
what keeps the brief short term memory alive?
the reverberating circuit
what happens when the reverberation is disrupted e.g. following a head injury or infection?
memory loss normally results – amnesia
what are the two types of amnesia?
Anterograde
Retrograde
what is the difference between anterograde and retrograde?
Anterograde – cannot form new memories
Retrograde – cannot access (more recent) old memories
what is anterograde amnesia?
inability to recall events that happen after the injury. Depending on the severity of the injury this can be short lived or permanent. Destruction of the hippocampus (as with Clive Wearing) results in permanent inability to form new memories.
what is retrograde amnesia?
can’t remember events leading up to the injury, although recall of events that happened a long time ago is usually unaffected, probably because they are better rehearsed and more deeply imbedded.
Retrograde amnesia often presents with anterograde amnesia. However, interestingly, if only the thalamus is damaged, and the hippocampus spared, only retrograde amnesia is seen. Suggests thalamus is required for “searching” our existing memory bank.
the intermediate long term memory involves chemical changes in….
presynaptic neurons
increaseing calcium entry to presynaptic terminals ….. neurotransmitter release
increases
what structural changes at synapse does long-term memory involve?
Increase in NT release sites on presynaptic membrane.
Increase in number of NT vesicles stored and released.
Increase in number of presynaptic terminals
what is long-term potentiation?
increased amplitude in graded membrane potential (EPSP) in the post-synaptic cell is often observed. This “strengthens the synapse”, is called Long Term Potentiation
what does the long term potentiation form the basis of?
basis of much learning and memory
what is the name of a well established, well rehearsed pattern of neuronal firing unique to that particular memory
long term potentiation
whatare the two main types of long term memory?
Declarative or Explicit Memory:
Procedural/ Reflexive/Implicit Memory:
what is Declarative or Explicit Memory?
Abstract memory for events (episodic memory) and for words, rules and language (semantic memory).
Relies heavily on the hippocampus
what is Procedural/ Reflexive/Implicit Memory
Acquired slowly through repetition. Includes motor memory for acquired motor skills such as playing tennis, and rules based learning such as, in the UK, always driving on the left.
Thinking about these skills (“memories”) often impairs performance!
Is based mainly in the cerebellum.
Is independent of hippocampus (remember Clive Wearing).
how is short term memory converted to long term memory?
through consolidation
what does consolidation involve?
selective strengthening of synaptic connections through repetition
what is the papez circuit?
hippocampus–> mamillary bodies–> anterior thalamus—> cingulate gyrus—-> hippocampus
what is the association with the olfactory system and limbic system?
Olfactory stimuli are relayed via the olfactory tract to the primary olfactory cortex where substantial connections to the amygdala and hippocampus are found.
This association with the limbic system, and hippocampus in particular, explains why smells are especially powerful in evoking long term memories.
what is korsakoffs syndrome?
there is Vitamin B1 deficiency which leads to damage of limbic system structures. The ability to consolidate memory is impaired.
