Lecture 37: Memory Beyond the Hippocampus Flashcards
What are the different types of temporal learning?
- Short-term memory
- Long-term memory (new memories)
- Remote memory
What is short-term memory?
Working and immediate memory
Ability to hold info across an undistracted delay
You lose it as soon as you are distracted
Example: when someone ask you to remember a phone number for 20 minutes
What is long-term memory (new memories)?
Memory of thing not lost by distraction
Example: what you remember for a test lol
What is remote memory?
Memory of events many months to years ago
Example: your birthday
Where are remote memories distributed in cortex?
-represented in a MODALITY-specific (sight, smell, etc) fashion in the cortex
What is working memory? How much can working/short-term memory can you remember?
Mental manipulation and online holding of information over relatively short periods of time
7 +/- 2 pieces of information; chunking is possible
What is Chunking?
Ability to remember information in “chunks” rather than discrete units
For instance, we can only remember 7 pieces of information, +/- 2
So we can either remember a phone number as 7 digits or phone number as 3 visual parts
Where does working memory localize in brain?
- phonological WM deficits = more LEFT
- phonological = words like dog, cat, chat
- visuospatial WM deficits = more Right
- pictures and objects
- dorsolateral prefrontal cortex (DLPFC) is implicated in almost all WM tasks (because it is the central executive)
What part of the brain is most important for working memory? (Hint: since this is a “beyond the hippocampus lecture” it is prob not the MTL lol)
Dorsolateral prefrontal cortex (DLPFC)
The connection among prefrontal cortex and parietal lobes/subcortical areas mediate working memory
What are the symptoms of working memory impairment?
Anything that involves short-term memory is impaired
Difficulty following multistep commands
Trouble multitasking
Inefficient learning (because you can’t remember)
Impaired verbal fluency
What types of pathology lead to working memory?
-focal: infarcts, tumors
-multi-focal: MS
-neurodegenerative, AD, PD, HD
Pyschiatric: ADHD (lol)
What is consolidation? How does it work?
The process by which memories are solidified into long-term stores
Involves gradual transfer of info from hippocampal circuits to neocortical ones
What is the mnemonic for where new memories are formed?
The hippo and rhino made NEW memories together lmaooo
Hippocampus/parahippocampus and perirhinal/entrorhinal cortex
Consolidation
: process by which memories are solidified into long-term stores
-involves gradual transfer of information from hippocampal circuits neocortical ones
What types of long-term memory is mediated by the hippocampus?
Explicit (declarative)
Can be articulated
-episodic (biographical events)
-semantic (words, ideas, concepts)
What type of long-term memory is NOT mediated by hippocampus?
Implicit (non-declarative). Can’t be articulated -procedural -classical/operant/emotional conditioning -nonassociative -priming
What is Habituation?
Decreased response to stimuli
Nonassociative (non-declarative) learning
What is Sensitization?
Increased response to various stimuli after a noxious stimulus
Nonassociative (non-declarative) learning
Do nonassociative learning require conscious awareness? Where do they occur?
No awareness required
Spinal reflexes mediated
How does Aplysia Californica demonstrate habituation?
When repeated stimulation of the gill siphon reflex results in diminished gill withdrawal reflex
(when you touch siphon, and the sea slug is like OK man I guess you’re not touching my gill lmao)
Mediated by excitatory/inhibitory interneurons
After repeated stimulation, sensory neuron releases fewer synaptic vesicles; decreased neurotransmitter response in interneurons/motor neurons…thereby decreasing force of gill withdrawal
How does Aplysia Californica demonstrate sensitization? MOA?
If you provide a noxious sensitizing stimuli to Aplysia tail, the withdrawal of the gill is quicker and more forceful
Mediated via SEROTENERGIC axoaxonal synapse
-sensory neuron 2 increases the EPSP in the motor neuron without increasing response of sensory neuron 1
-the key is a greater motor response and the same type of sensory response
What is classic conditioning? What is MOA?
The phenomenon in which one learns a relationship between two stimuli
Example: Pavlov’s dog, food = salivation for dog, but bell = time for food…at the end of some weeks, the bell by itself = salivation
Mediated by CEREBELLUM (but a number of areas are implicated)
What is Emotional conditioning? What is it mediated by?
The learned association between a stimulus and an emotional response
Example: your learned association with ice cream vs. a roach
AMYGDALA plays a critical role in emotion
Kluver-Bucy syndrome:
MOA: lesions in amygdala Symptoms -Blunted emotionality -Lack of fear response -Altered sexual behavior -Hyperorality -Visual agnosia
What is operant conditioning? Mediated by?
Learning of cause and effect…REWARD LEARNING
Example: Mouse learns that if you press lever it gets grub
Mediated by:
1. dopaminergic projections from ventral tegmental area (SNr)
2. nucleus accumbens (caudate and putamen together)
3. Dorsomedial frontal crotex
What is Procedural learning? Mediated by?
Shit you learn by doing them Sports, musicianship, video games -description is typically inadequate to transfer ability Mediated by 1. supplementary motor area 2. basal ganglia 3. Cerebellum NOT MEDIATED BY 1. MTL because the famous patient “HM” could still learn beside the a bilateral MTLobectomy
What is Serial reaction time task (SRTT)?
demonstrates learning is separate from awareness
when you press numbers in accordance to a sequence of numbers
Where is this localized?
- supplementary motor area
- basal ganglia (caudate, putamen, globus pallidus, substantia nigra
- Cerebellum
What happens to types of learning when you have Parkinson’s?
Loss of procedural learning because basal ganglia is iinvolved
What is Priming? Mediated by?
A benefit in the ability to detect or identify words or objects after recent experience with them
-Ability to be primed to stimuli is UNRELATED to explicit recall of stimuli
-Occurs robustly in patients with anterograde amnesia
Mediated by Modality-specific cortices (touch, sight, vision, hearing, smell)
