lecture 18 Flashcards
what is a memory?
process of storage and retrieval that starts with a stimulus and progresses through stages
describe the stages of memory
(1) input (stimulus)
(2) sensory memory (lasts miliseconds), encoded into:
(3) short term/working memory (seconds), consolidated into:
(4) long-term memory (minutes-years)
what are the processes of memory?
- encoding
- rehearsal
- forgetting
- consolidation
- retrieval
describe encoding
conversion of perceived stimuli for storage (as sensory memory)
describe rehearsal
attention is given to a stimulus, or there is repetition of a single stimulus
describe forgetting
entrance of a new stimulus into working memory, whereby the old stimulus is replaced
describe consolidation
movement of a memory from working memory to long-term storage
describe retrieval
movement of a stored memory back to working memory for usage
short term memory is a component of:
working memory
wokring memory involves both ____ & ____ information
encoded information and retrieval of information
short term memory refers to only ____ information
newly encoded information
short term memory involves ____ storage of information
temporary
short term memory has a ____ capacity and a ___ duration, meaning it can only handle ____ items for ____
small capacity
short duration
7 +/-2 items for 15-30 seconds
what does the capacity and duration of short term memeory depend on?
attention and decay
describe the transfer of information from sensory memory to short term memory
- many stimuli enter sensory memory
- only stimuli that pass the filter will enter working memory
what does it mean for a stimuli to bypass the filter?
stimuli is given attention
what is short term potentiation?
strenghtening of a synapse due to increased neurotransmitter release
what is short term depression?
- depletion of neurotransmitter stores
- auto-receptor activation
what are 3 ways to improve short term memory?
- chunking
- mneumonic devices
- say it out loud
describe chunking as a method of improving short term memory
breaking information into groups that make sense
describe mneumonic devices as a method of improving short term memory
use of phrases, peoms, or songs to remember information
describe saying it outloud as a method of improving short term memory
method of dual encoding - processing happens in two different cortical areas and can thus happen simultaneously
describe the cortical areas involved in dual encoding
vision - parietooccipital cortex
speech - wenicke’s and broca’s areas
long term memory involves
the storage of information
describe the storage of information for long term memory
- information is initially stored in the hippocampus
- information is then moved to areas of the neocortex
long term memory has a _____ capacity and a ____ duration
unlimited capacity
long duration
describe long term potentiation with respect to protein synthesis
increased protein synthesis over time results in new neurotransmitters new ionotrpic channels
list the ionoptropic channels involved in long term potentiation
- ligand gated channels
- AMPA channel
- NMDA channel
what activates ligand gated ion channels for long term potentiation?
glutamate
what do AMPA channels allow for?
the movement of Na/K into the cell
what do NMDA channels allow for?
the movement of Na, K and Ca into the cell
describe the process of long term potentiation
- calcium travels through the NMDA receptor
- AMPA receptors move to post synaptic membrane
- AMPA receptors increase in post synaptic cleft w increased sensitivity to NTs
- AMPA signals the presynaptic neuron to release more NTs
long term memory formation depends on:
- emotional state
- rehearsal
- schemas
- automatic memory
what are schemas?
pre-existing file folders for information in the brain
what is automatic memory responsible for?
encoding information about time, space, and frequency
what is consolidation with respect to systems?
redistribution and relocation of information as follows:
hippocampus ---> cingulate gyrus ---> neocortex
what is consolidation with respect to synapses?
synaptic remodelling (long term potentiation)
what are the types of long term memory?
explicit and implicit
is explicit long term memory a concious or unconcious process?
concious
there are multiple types of explicit long term memory, what are they and what are they used for?
semantic (for facts) and episodic (for events)
is implicit long term memory a concious or unconcious process?
unconcious
there are multiple types of implicit long term memory, what are they and what are they used for?
- procedural (skills/habits)
- emotional association (emotional reaction to a stimulus)
- conditioning (learned response to a stimulus)
describe conditioning in more detail
two types:
1) classical (pavlov’s dog
(2) operant (reward and punishment)
describe how the dorsolateral prefrontal cortex is involved in memory
involved in working memory
describe how the ventromedial prefrontal cortex is involved in memory
- recieves input from the amygdala
- involved in fear and risk
where is hippocampal memory information found?
in the parahippocampal gyrus
what are the 3 components of the hippocampus?
- dentate gyrus
- hippocampal proper
- subiculum
describe the dentate gyrus
- toothed structure due to penetration by subarachnoid vessels
- 3 layers of granule cells
- a component of the perforant path
describe the hippocampal proper
- mostly 3 layers of pyramidal cells
- has 4 divisions: CA 1, CA 2, CA 3, CA 4
- includes alveus
- includes fimbria
describe CA 1
receives input from CA 3, sends output to subiculum
describe CA 2
often not mentioned or not included in diagrams
describe CA 3
receives input from the dentate gyrus
describe CA 4
only division tha has granule cells
aka hilum
what is the alveus?
- lines the superior surface
- contains myelinated efferents and afferents (fibers that are in the alvear pathway)
what is the fimbria?
connector btwn the hippocampus and the fornix
describe the subiculum
- 3-5 layers of pyramidal cells
- adjacent to the hippocampal proper
- origin of the alvear pathway
what are the 2 hippocampal pathways
preforant path and the alvear path
describe the preforant path
entorhinal cortex –> dentate gyrus –> CA3 –> CA1 –> subiculum –> entorhinal cortex
describe the alvear path
subiculim –> alveus –> fimbria
the amygdala contains:
basolateral nucleus and central nucleus
the basolateral nucleus of the amygdala is responsible for:
activation of the central nucleus
the central nucleus of the amygdala is responsible for:
the emotional response
what is the general function of the amygdala?
fear and anger
what is the function of the fornix?
connects the fimbria to the mammillary body
what are the component parts of the fornix?
crus, body, columns
describe the role of the mammillary body
- part of hypothalamus
- sends info to the anterior nucleus of the thalamus
describe the role of the anterior nucleus of the thalamus
- borders intraventricular foramen
- sends information to the cingulate gyrus
what is the function of the anterior cingulate gyrus?
associated with emotion
what is the function of the posterior cingulate gyrus?
- merges with parahippocampal gyrus
- associated with memory
describe the role of the basal forebrain
- not much is known
- thought to have functions related to memory & sleep
describe the basal nucleus of Meynert
cholinergic endings cover the cortex, thalamus, hypothalamus and limbic structures
what is the Papez circut associated with?
- introduced by james papez in 1937
- recognized to be associated with the formation of declarative memories
what are declarative memories?
names, dates, places, facts, etc. (things we know to be “true”)
e.g. moms bday is, zebras are animals, london is the capital of england
what is the pathway for the Papez circut?
hippocampus –> fimbria –> fornix –> mammillary body –> anterior thalamic nucleus –> cingulate gyrus*/parahippocampal gyrus –> hippocampus
*information can leave cingulate gyrus and be sent to association areas of the neocortex
describe anterograde amnesia with respect to hippocampal damage
inability to form new declarative memories
describe anterograde amnesia with respect to amygdala damage
inability to form new emotional non-declarative memories
what is retrograde amnesia?
inability to form retrieve long term memories
what is anterograde amnesia?
inability to form new memories
describe retrograde amnesia with respect to hippocampal damage
inability to recall recently stored long term memories
describe the result of damage to the corpus striatum with respect to memory
- just the caudate and putamen = motor planning affected
- caudate, putamen and nucleus acumbens = motor movements that acompany emotions are also affected
describe the result of damage to the medial cerebellum, vermis, and flocculus
conditioning affected
describe the result of damage to the lateral cerebellum
procedural memories affected
does emotion involve the same or different structures of the limbic system when compared to memory?
the same, except amygdala has greater impact
what are the 4 pathways of emotion?
- stria terminalis
- amygdalofugal
- lateral olfactory tract
- direct interactions with the medial temporal lobe
describe the stria terminalis pathway
sends information to the hypothalamus and septal nuclei
describe the amygdalofugal pathway
sends information to the thalamus and hypothalamus more directly
describe the lateral olfactory tract pathway
information is sent between the amygdala and the olfactory bulb
the interaction of structures determines function, describe the function of limbic cortical areas
expressing emotions
the interaction of structures determines function, describe the function of sensory cortical areas
perceiving emotions
the interaction of structures determines function, describe the collective function of the ventromedial prefrontal cortex and the hypothalamus
autonomic and visceral reactions that accompany emotion