The Corticohippocampal Circuit: Order Flashcards
declarative memory
conscious, goal directed encoding and recall of information
semantic memory
encoding and recall of general facts (i.e. encyclopaedic knowledge)
episodic memory
encoding and recall of specific facts related to our unique experiences
STUDY: remember faces
encoding: learn name
distractor: odd/ even number task
recall: asking if correct name stem
what faces study showed about encoding
associated with activation of entire HF
what was point of distractor?
to make sure its not just in working memory
what did faces study show about recall?
HF activation
STUDY: visual one-to-one connections
(used depth electores in hippocampi and had participants look at visuals)
- “Jennifer Aniston neuron” spike in neuron when see picture of her
- “Halle Berry neuron” spike in different neuron, also responded to letter string of her name
long-term potentiation
increases strength of connection between neurons supporting memory (ex. begin to remember name with face, apartment they live in, etc.)
how does electical stimulation of the hippocampus impact memory consolidation?
variety of studies
- one shows greater memory of word pairs
- sometimes can hurt memory consolidation
semantic map in the human brain
stored in the cortex
relationship between memory stories and consolidation
hippocampus important for remembering and encoding but meaning is stored in the cortex
what stream
- encoding and recall
- PRC –> LEC (item) encoding and recall
- hippocampus (item in context)
where stream
- cortical areas encoding and recall
- PHC –> MEC (context) encoding and recall
- hippocampus (item in context)
emotional “flashbulb memories”
convergence of strong happiness and reward of fear and threat
where is object memory stored?
anterior hippocampus
where is spatial memory stored?
posterior hippocampus
what is a good metaphor for hippocampus?
card catalog, it stores where you can locate the book in the library, but does not store books itself
(ex. visual memories in visual cortices)
what is directed encoding with the PFC?
executive control (ex. learn names of these faces) (ex. mentally rehearsing material before an exam)
what is executive control?
capacity to generate and orchestrate complex plans and goal-directed behaviors through…
what is attention?
selectively concentrating on one aspect of stimulus
what is working memory?
briefly maintaining infornation in mind and manipulating it to achieve goals
what is response selection?
direct and redirect behavioral resources because of changing demands
STUDY: wisconsin card sorting test
(had to sort cards and then sort in different way until given positive feedback)
EXECUTIVE CONTROL
STUDY: CPT (Connor’s continuous performance task)
(information quickly on screen, have to press button when target letter appears) how long can you maintain attention?
ATTENTION & RESPONSE SELECTION
STUDY: N-back test
(press button when letter shown n-back from front) used fMRI
WORKING MEMORY
STUDY: stroop task
(showing color words in same/ different color ink, identify ink color) slower bc incongrunt trial, read word first
RESPONSE SELECTION
what activates when maintaining information in working memory?
dACC (negative error feedback), dlPFC, vlPFC, parietal cortex
what is TMS?
transcranial magnetic stimulation
can impair or inhibit activity useful for cortical circuits
STUDY: faces and spot
(show spot in 3 locations, show pic of spot and ask if saw location, then show face and ask if seen the face before)
RESULTS:
1. location impaired when TMS on dmPFC
2. faces impaired when TMS on vlPFC
3. both impaired when TMS on dlPFC
why faces impaired by vlPFC impaired?
why location impaired by dmPFC impaired?
dorsal(where) and ventral(what) stream
how do pyramidal and GABA neurons interact in stroop test?
when doing stroop test, pyramidal neurons processing ink color inhibit those processing word with GABA neurons
STUDY: understanding anatomy of stroop test
- afferent layers (IV) info change processing in dlPFC
- efferent layers (V + VI) dlPFC regulates subcortical regions
how can we reinforce inhibition of reading word in stroop test?
- release of dopamine, reward (increases cholinergic signaling)
- amygdala, can punish incorrect response (NBM, cholinergic tone)
what does the medial frontopolar cortex do?
undirected exploration
- monitors current goal for redistributing cognitive resources for another potential goal
what does the lateral frontopolar cortex do?
directed exploration
- monitoring a few alternative tasks/ goals for possibly re-engaging one as replacement of the current task/ goal
what does the posterior prefrontal cortex do?
exploitation
- recruiting and implementing cognitive control to optimize the performance of the current goal
what are the afferent layers of the dlPFC?
layers I-III
- mediate cholinergic potentiation of dlPFC through NBM (corticolimbic) or VP (corticostriatal)
what are the efferent layers of the dlPFC?
layers V & VI
- allow dlPFC to regulate VS and HF
