9 - animal cognition Flashcards
why is prefrontal cortex special?
- associated with core cognition and executive function
- damage to prefrontal cortex associated with deficits in executive function
- open questions - dissociating between executive functions, localisation of lesions in patient studies
how are action potentials measured?
- inserting electrodes into brain
- electrodes measure voltage changes in extracellular space around neurons
- very precise timing of action potentials
how was the neural basis for working memory studied in mammals?
Niki presented monkey with a WM task, electrodes in PFC
cue causes initial spike in neuronal activity
sustained ‘spike trains’ during delay (delay activity), neurons sustaining memory of which light was active
drops off after choice is made
delay in activity bridges the time gap between stimulus and choice
limitations of the delay activity study?
the delay activity of the neurons may be because they are anticipating a reward since the monkeys had to be conditioned with rewards
could be testing STM not WM
do birds have a cortex?
not in the same way as mammals, no neocortex
subcortical structures - basal ganglia, globus pallidus
bird brains previously thought to have been made up of same tissue as subcortical structures
reconsidered bird brains to have a large palatial area - analogous to human cortex
how is the avian nidopallium caudolaterale (NCL) analogue to the mammal PFC?
both can perform working memory very well, functionally analogue
despite structural and organisational differences
study observing WM in pigeons
WM task in pigeons
directed forgetting procedure
remember trials - increase in neuronal activity, sustained activity during delay
forget trials - increase in neuronal activity when stimulus is provided, then drops off after cue
evidence that NCL has delay activity that bridges gap between stimulus and choice- participating in WM
what is the directed forgetting procedure?
- pigeon presented with sample
- played an audio remember cue, indicated they need to remember cue
- 3 second delay
- compared to another sample, must identify correct sample
- compared to forget trial were pigeons are played a forget cue
- animals should discern whether to remember or forget
limitations with the directed forgetting procedure?
abolished delay activity could be linked with reward prediction rather than WM
could also be due to preparation of motor response required, forget cue requires no motor response
disentangles WM with motor preparation and reward anticipation
what is a match-to-sample task (MTS)
presented with sample, time delay, and then presented with same stimulus among other stimuli and pick same one out
evidence of WM in crows?
perform match-to-sample task at very high level
neurons in NCL active during selection period
sample-selective neurons shows they are engaging in identifying the stimulus
delay-selective neurons, response of neuron is selective during delay period
what are advantages of using animal studies?
allow direct, single cell recordings of action potentials
invasive - not possible in humans
spatial and temporal accuracy can’t get from EEG, fMRI
provides insight into basis of intelligence, analogues of cognition in different species
what are disadvantages of using animal studies?
invasive - can be stressful for animals
animals cannot self-report, have to be trained on tasks
tasks do not reflect ‘typical’ behaviour
features of the bee brain
small ~ 0.5mm
only ~1,000,000 neurons
how is WM in bees studies?
bee enters tunnel, presented with sample, distance to fly is delay period, bee needs to select tunnel with the correct sample for a reward
delayed match-to-sample task
bees have high performance levels for short delays but gets worse with longer delays
performance indicates WM of up to ~6.5s
