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
What is the avian (bird) brain?
birds do not have a crotex in the same way as mammals.
Smaller areas considered to be akin to cortex in mammals (neocortex). Birds brains previously thought to comprised of strucutres similar to basal ganglia (primitative structions).
Reconsidered areas to be consiered part of the pallial area, analogous to huma cortex. Neural activity: what ar these regions doing compared special in regard to behaviour.
What is the bidopallium caudolateral (NCL)?
Pallium: neuroanatomical term for the grey and white matter covering the cerebrum.
The nidopallium consists of many subregions, one of them is the caudolateral part, the NCL.
Do crows have WM?
Delayed match-to-sample task (MTS)
Disentangle working memory from motor preparation – location of stimulus changes randomly! Chance of reward was equal for all match items, randomised, reward expectation negated!
Crows perform task at very high level! Very good at cognitive tasks
Why do we need to be careful of delayed trail interpretation?
Abolished delay activity could be linked with reward prediction – food reward. Neurons could change firing rate in response to forget, because no reward.
Discern between confounds of WM and Reward prediction. Neuron could be involved in both! Could also be due to preparation of motor response required! Forget cue requires no motor response. Several interpretations possible
What is a sample selective neurons?
Response of neuron – active during selection period. This means that the neuron distinguishes the four different sample stimuli with its firing rate
Selective discrimination of stimuli – non-arbitrary
What is delay-selective neurons?
Delay-selective means that the response of the neuron is selective during the delay period
Note that during the sample period the neuron did not distinguish the stimuli
What are advantages of animal research?
- Animal studies allow direct recordings of action potentials – single cell recordings
- Invasive – not usually possible in humans
- Spatial and temporal accuracy can’t get from EEG, fMRI
- Provide great insights into the nature of cognition, analogues of cognition in different species – basis of intelligence
What are disadvantages of aniaml research?
- Invasive – can be stressful for animals
- Animals cannot self-report, have to be trained on tasks
- Tasks do not reflect ‘typical’ behaviour
- Difficult to design tasks to remove confounds – reward anticipation, motor preparation, STM vs WM?
What is a bee brain?
Small ~0.5mm3, only ~1,000,000 neurons but larged compared to fruit flieds. Not as simple with hard wired strucutre. Long tradition of noey-bee physiology, navigation and communication.
Can bees learn stimulus response associations?
Yes
Can bees retain relevant stimuli for several seconds?
STM
Yes approx. 6-7seconds
Can bee perform WM tasks?
May-bee , unclear if tasks are short term or working, but certainly some overlap!
Bees might have a “working memory” of several second
Can bees learn rules and abstract concepts (flexibility)?
To an extent! More on this next week
What task was used to evaluate honeybees working memory?
Dealyed match-to-sample task
Visual sample stimulus in the tunner. In decision chamber choice between the sample stimulus and a different incorrect pattern. High perforamnce levels for short delays (75% correct for 1.24s) Varying the distance d2 between sample and decision (= varying time interval - varying difficulty)
Performance indicates “working memory” of up to ~6.5s
How did they make the delayed match to sampel task more difficult for bees?
There is also the incorrect pattern somewhere in the tunnel. Now either IP1 or after IP2 the sampel stimulus the incorrect pattern is shown in the tunnel as well. The correct sample pattern is always presented at the same distance from the entrance.
Learning test 1: Baseline condition (without incorrect patterns)
Transfer test 1: Incorrect pattern (IP1) presented in front of the correct one
Transfer test 2: Incorrect pattern (IP2) presented after the correct one
Learning test 2: continuation of training
Transfer test 3: correct pattern suddenly at the IP1 position (ie 50cm) and incorrect pattern at IP2 (170cm)
Performance in all cases above chance level, except for the Transfer test 3 control
