neural substrates of attention Flashcards
attention - james (1890)
“everyone knows what attention is. Attention is taking possession of the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of though. Focalisations, concentration of consciousness are of its essence. It implies withdrawal from some things in order to deal effectively with others”
ability to narrow down on one main thing
attention - colman (2015)
sustained conc on a specific stim, sensation, idea, thought or activity, enabling one to use info-processing systems with limited capacity to handle vast amounts of info available from the sense organs & mem stores
sometimes we need to deal with other info
sustained (and focused) attention
- ability to attend (focus) on a stim for a long period of time
- wont look at this in lecture
- measure using 5 choice serial reaction time task
- 5 little holes in chamber which have lights
- one will briefly flash, rat needs to poke nose in correct
- if correct turn around and get pellet, return for next trial
selective attention
- ability to attend on a stim in presence of distractors
- some learning theories have emphasised that selective att can be learned: Mackintosh (1975) att to stim which predict reinforcement, blocking effect, LI
- other theories can also provide an explanation for these phenomena, so it is unclear that these provide an explanation for these phenomena, so it is unclear that these provide unequivocal ev for attentional mechanisms
intradimensional and extradimensional shifts
mackintosh & little (1969)
- stage 1 - IDS
- stage 1 - EDS
- stage 2 - discrimination
intradimensional shift group
mackintosh & little (1969)
- stim are compound of 2 dimensions (colour and orientation)
- orientation is irrelevant (red always +)
- attend to colour, ignore orientation
- data from this stage are not important in demonstrating attentional set
extradimensional shift group
mackintosh & little (1969)
- orientation is relevant (vertical is always +)
- attend to orientation, ignore colour
- data from this stage are not important in demonstrating attentional set
stage 2 discrimination
mackintosh & little (1969)
- colour is relevant, orientation irrelevant
- IDS > EDS as they have leaned to pay attention to colour
- EDS group has to learn to shift their attention to colours
multiple stage designs
brown & tait (2015)
- overcome the drawbacks associated with previous designs
- within-subjects - overcomes some issues with multiple stages
- multiple stages in ID/ED allow to parse out diff cog processes: reversal learning, ID/ED, new learning
- stages can be added or removed depending on experimenter’s needs/expectations/predictions
- computerised CANTAB (sim to WCST
total change designs - humans and monkeys
- learn shape discrimination between 2 shapes
- reversal learning - 2 shapes get switched
- compound discrimination - lines on top of shapes
- ID acquisition - new shapes and lines but shape is still relevant dimension
- ED acquisition - new shapes and lines but lines is not relevant
total change designs - rodents
- dont have visual acuity so use tactile and odour discrimination
- follow basics of compound discrimination, ID acquisition and ED acquisition
birrell & brown (2000)
- began with simple discrimination with odours
- moved to compound discrimination - odours, medium irrelevant
- then did reversal learning
- switch which odour paired with the reward
- IDS - new odours
- EDS - medium becomes the relevant
also reversed both IDS & EDS
strengths of total change designs
- measure diff psychological processes in same ppts (within-subjects comparison)
- can be used in diff species (not just humans)
limitations of total change designs
- requires multiple stim for each dimension
- ID/ED compares performance in 2 discriminations learned at diff times
- simple discrimination given at start of training means one dimension is more familiar than the other
optional-shift design
rodents - duffaud et al. (2007)
- conditional instrumental discrimination task: 2 levers
- 4 visual stim (V1, V2, V3, and V4)
- 4 auditory stim (A1, A2, A3, and A4)
- first stage either auditory or visual stim relevant
- auditory relevant: A1 always paired with L1, A2 always paired with L2
- visual relevant: V1 always paired with L1, V2 always paired with L2
- once learned, moved to new stim: A3, A4, V3, V4
- A3V3–>L1 and A4V4 –> L2
- tested on a mixture of a mix of 3 and 4
- trained on auditory, pay attention to whether it is A3 or A4
- trained on visual, pay attention to whether it is V3 or V4
ID/ED shifts
- humans, monkeys, pigeons and rodents can learn these
- superiority of ID over ED shift is the main finding, suggesting that all these species show ev for “attentional” mechanisms
- always easier to learn about stim dimension you have already learned about, even if it is not the exact same stim (IDS better performance that EDS)
- these findings are problematic for standard (non-attentional - R-W) theories of learning
cognitive flexibility
- attentional set-shifting
- rule or strategy-shifting
- reveral learning
attentional shifting & reversal learning
- we can measure these with the tasks described before so we can look into the neural basis of cog flexibility
- can measure these two at the same time
owen et al. (1991) - patients with brain lesions
- ID/EDS task with total change design
- EDS takes more trials to reach criterion across all
- deficit in learning & being able to switch in older ppl and those with damage to frontal lobe
- selectively impaired going from ID to ED
- slower - temporal lobe group and amygdalo-hippocampectomy group
ev from non-human animals
- although capturing att in animals is less straightforward, it can be done
- by using normal animals, rather than clinical human populations, we are more likely to be gaining general info about att
- moreover, excitotoxic brain lesions can be directed very accurately, causing little collateral damage to the brain regions that are adjacent to the target brain area
- remember that the primate’s dlPFC is the analogue of the rodent medial PFC
locus specificity
damage to non-frontal structures affects attentional set
pathology specificity
- parkinson’s disease isnt only disorder associated with alterations of attentional set
- e.g. SZ, depression, mania, OCD
- Rogers (2003) cites human ev of WCST deficits with non-frontal damage ppts & absence of WCST deficits in known frontal patients
counterbalancing
- many attentional-set experiments cant have been adequately counterbalanced; –> may show effects of stim generalisation (rather then attentional-set effects
- Mackintosh & Little had 4 main experimental groups
- takes a lot of money and time to do to be able to counterbalance this experiment
oswald et al. (2001)
locus specificity
- rats trained with multiple “configural” discriminations but using logic of Mackintosh & Little (1969) between subject design
- walls relevant to tone/click discrimination - env placed in tells them whether the tone or the clicker was the relevant stim
- floors either bumpy or smooth - irrelevant to solve discrimination
- for other rats, walls irrelevant, floors relevant
- next stage, some of rats received an IDS where walls continued to inform discrimination - diff patterns of the walls, floors warm or cool
- entorhinal lesions right outside hippocampus - didnt show effect
comparison of ID/ED trandfer at diff times in ‘complete-change design’
- se of ‘complete-change design’ requires comparison of ID v ED at diff times; perhaps ID > ED is really due to time-related artefact
- ID discrimination occurs before ED
- –> may be collateral diffs between rats’ performance
- ED poor because of attention set shift or satiation, boredom…
- ID/ED & optional shift designs ensure that attentional comparisons are made at same time point, solving this potential problem
