PSY2002 W9 Animal Models 1 (L) Flashcards
Comparative models of working memory
What is cognition?
Basis for intelligent behaviour. Core vs Higher order cognitive abilities. Effort and attention required (on autopilot). Top-down mental processes (contrasting with stimulus driven bottom-up processes) Key structure in mammals (prefrontal cortex). Control sensory, memory and motor systems. Overriders reflective, habitual response in favour of complex long-term goals.
What is executive function?
Core/Basic: Inhibitory control, WM, cognitive flexibility.
Higher Order (insight related): Object permanence, self-recognition, theory of mind, tool use/causal reasoning, mental time travel.
Is there a ladder of being ?
Aristotle hierachical degree of perfection.
At some point animals stop being simply instinctual and become introspective.
Fish > Amphibians > Reptiles > Birds > Mammals
Do fish have a working memory?
Took fish, they got them to learn a pattern to get a food rewards, and they believed this was WM.
Do frogs have inhibition?
Frogs could inhibt a response to get something better.
Do lizards have inhibitory control?
Lizards can learn inhibitory control
Do crows have WM?
Yes they demonstrated working memory.
Time Go-stimulus/Pre-sample 500ms/[encoding/memory period] Sample 500ms/Delay 1000ms [encoding/memory period]/Choice 1800ms
Is a Cortex special?
The prefrontal cortex is especially special. Prefrontal lobe associated with core cognition and executive function. Damage to prefrontal regions associated with deficits in executive function. Open questions - dissociating between executive functions, localisation of lesions in patient studies.
What is a difference between birds and human?
Birds and mammals are quite distant from each other in evolutionary terms (“scala naturae” argument). Birds do not have a neocortex (“Cortex is special” argument).
What is working memory?
Miller 2000
The representation of items held in consciousness during experiences or after retrieval of memories. Short-lasting and associated with active rehearsal or manipulation of information
What is the neural structure mammalian prefrontal cortex (PFC)?
STM: passive store for brief retention of information
WM: storage and controlled processing of information in the present moment
What is an action potentials?
can be measured by inserting electrodes into brain. Contacting many neurons.
Electrodes measure voltage changes in extracellular space around neurons. Gives indication of many different neurons ‘spiking’. Can visualize these spile trains with dots/dashes. Very precise timing of action potentials, spatial accuracy.
What is the Delayed response task for monkeys (Niki, 1974)?
One fo two cue lights is illuminated for 1st (left or right). Then the cue illumination is turned off for 2-3s (delay period) Then the monkey has to choose between left and right. Delay activity in example units in the prefrontal cortex. Initial spike at presentation of cue. Sustained spike trains during delay - delay actiivty: persisitent firing rate change, bridges time gap of delay period. Neurons sustaining the memory of whihch light was active before selecction is made. Robust finding, delay activity in many studies.
Dopamine and Classical conditioning
Dopamine cells respond to sensory cues that predict reward. This signal could be used to tag sensory cues as relevant and facilitate their entrance into working memory.
So in the delayed response task: (1) cue-left and cue-right lead to a response in dopamine neurons; (2) this increases dopamine levels in the prefrontal cortex; (3) enables persistent delay activity in the PFC.
What bridges the time gap between stimulus and choice in monkeys?
Delay activity in PFC (monkey) bridges the time gap between stimulus and choice: could be a potential neural basis for working memory