cognitive control - inhibition

Question 1

define inhibiton

Answer 1

controlling ones attention, behaviour, thoughts, and/or emotions to override a strong internal predisposition or external lure

not simple stimulus-response driven, contextual response

Question 2

define flexibility

Answer 2

changing perspectives or approaches to a problem - flexibly adjusting to new demands, rules, priorities → switching between tasks

large range of behaviours applied to contexts flexibly → experiment participation where you respond to stimuli and follow and adapt to task rules

Question 3

define multi-tasking

Answer 3

some tasks can be done in parallel if they don’t “collide” → related to attention, can they be done on “auto-pilot”

related to working memory

Question 4

3 main features of cognitive control

Answer 4

inhibition
flexibility
multi-tasking (working memory)

Question 5

what is cognition

Answer 5

basis for intelligent behaviour

overrides reflexive, habitual responses in favour of complex often long-term goals

cognitive control of: sensory, memory, and motor system

in prefrontal cortex in mammals

Question 6

difference between cognitive control and executive function

Answer 6

executive functions = specific components e.g. working memory

cognitive control= less clear separation of distinct subcomponents

both are top-down mental processes (not stimulus-driven bottom-up ones)
requires effort or attention

Question 7

cognitive control – core/basic abilities and higher-order/insight-related abilities

Answer 7

core/basic abilities = working memory, inhibitory control, flexibility

higher-order/insight-related = object permanence, self-recognition, mental time travel, ToM, tool use, causal reasoning

Question 8

are different executive functions connected?
role and importance of EFs (7)?

Answer 8

questioned whether they can be entirely separated or work together
unknown if they are hierarchically structured

importance of EFs:
* impaired in mental disorders e.g. addiction, ADHD, OCD, depression, SZ etc
* poor EF associated with obesity, overeating, substance abuse
* idea that goof EF = better quality of life
* better school readiness and success
* job success
* marital harmony
* public safety

Question 9

multicomponent model of memory

Answer 9

central executive
VSSP, episodic buffer, phonological loop
LTM

Question 10

cognitive flexibility + task to test this

Answer 10

builds on other executive functions e.g. inhibition of previous perspective and loading new perspective into working memory

Wisconsin card sorting task
* task = draw a card and assign to a category to match colour, number, or symbol of another card
*given feedback on whether it was correct or not based on current rule (unknown to them)
* if correct, draw same category again
* if wrong, try another category
* “correct” category will change without warning so participant has to change behaviour in order to find correct category to match

people with some impairments struggle with this → e.g. frontal lobe damage, SZ, stroke, OCD

Question 11

challenges studying cognitive flexibility

Answer 11

neurological damage is unique to each patient

studied to identified localised involvement

solving task doesn’t only involve cognitive flexibility but also other aspects of EF

Question 12

inhibition – selecting appropriate thoughts and actions

Answer 12

strengthen appropriate response and inhibit other inappropriate ones

impulsivity related to deficient inhibitory processes

Question 13

role of frontal lobe in inhibition

Answer 13

inhibit automatic and habitual behaviour

also basal ganglia does this

shown by neurological studies on frontal lobe damage and utilisation behaviour (e.g. given glasses and see if they put them on correctly)

Question 14

directed vs competitive inhibition

Answer 14

directed = don’t do behaviour X e.g. stop driving at a red light

competitive = many actions competing and inhibition each other

Question 15

cognitive control stopping mechanisms

Answer 15

put a brake on inappropriate responses

to mediate goal-directed behaviour and self-control

Question 16

related constructs to inhibition (2)

Answer 16

self-control
* impaired common in many clinical disorders e.g. OCD, drug-addiction, gambling
* value-based decision making and delay discounting

attention
* similar to aspects of cognitive control → selecting/prioritising some processes over others
* often sensory → therefore more automatic than CC and EF
* other strategic forms may involve different mechanisms than sensory attention

Question 17

importance of inhibition in wider context (4)

Answer 17

• describes behaviour, decision-making, and cognitive processes
• measuring inhibition is important for some diagnoses
• related to clinical and developmental and neuroscience
• related to AI and robotics

Question 18

examples of inhibitory control (2)

Answer 18

driving in lots of traffic and phone rings/text message
* default = keep driving
* context = if you’re expecting an important call you are more likely to park or check the message

marshmallow test with kids
* long term or short term gain

Question 19

2 types of inhibition

Answer 19

behavioural inhibition = stopping actions
cognitive inhibition = stopping mental processes

overlapping brain processes from imaging studies for both of these processes

Question 20

3 types of behavioural inhibition

Answer 20

deferred gratification → impulsive choice → marshmallow test, linked to delayed gratification
* delay discounting, probability discounting, effort discounting

response inhibition → impulsive action → not answering phone whilst driving
* action postponing (waiting), action restraint/withholding, action cancellation (stopping)

reversal learning → inflexibility, compulsivity → stop understanding of one situation and think of new instead e.g. Wisconsin card sorting task
* discrimination reversal, rule/strategy reversal

Question 21

cognitive inhibition

Answer 21

difficult to understand and study

control of movement is similar to control of ideas

movements can be described and measured more precisely than ideas → can study principles and mechanisms of cognitive inhibition through studying motor response inhibition
* overriding planned or already initiated actions

Question 22

inhibition and EF

Answer 22

voluntary inhibition → is it a component of executive control?

current view = EFs require one another so combination or attention, inhibition, and flexibility allows complex behaviours

inhibition and attention together for selection of new goals, shifting of focus, performance monitoring and updating goals

impulsivity, compulsivity, and distractibility can inhibit parts of this process

Question 23

inhibition and impulsivity

Answer 23

acting quickly can be advantageous but doing this persistently can be risky and maladaptive

impulsivity = deficient inhibitory process
link to addiction, ADHD, mania etc.

response inhibition used to measure impulsivity in lab tasks

although response inhibition only corresponds to some types of impulsivity → not all types

use animal studies of response inhibition for neural mechanisms → quantifiable

Question 24

reaction time distribution

Answer 24

reaction time = time between onset of stimulus and response
contextual - depending on stimulus type

distribution = positive skew

Question 25

race model of reaction time

Answer 25

linear function used to represent a trial
faster = steeper line
x = time, y = position (activation of process)
horizontal threshold - faster response crosses this threshold first

slope of process and threshold = model parameters
choose parameter values to fit behavioural data from given participant

average out over many trials

(look at notion for graphs if needed)

Question 26

neurophysiology of reaction time variability

Answer 26

*recordings of frontal eye fields of monkeys performing reaction time task
* frontal cortex neurons indicate reaction times vary due to rate variability in slope of underlying process
* measuring single neuron in multiple trials

result shown in a line graph of average firing rate:
* time 0 = onset of movement (saccade)
* before onset = neuron sharply increases firing rate
* firing rate when movement begins = threshold for action

no difference in threshold for action
fast trails have difference in slope of firing rate increase to slow trials - fast = steeper slope

reflected in race model

Question 27

4 behavioural tasks to measure inhibition

Answer 27

stroop task
marshmallow test
go/nogo task
stop-signal task

Question 28

go/nogo task

Answer 28

participants must respond to a go signal and not to a nogo signal e.g. traffic lights where green is go and red is stop

assignment of go and nogo are arbitrary - depends on task instructions

measure reaction times and number of correct trials

Question 29

stop-signal tasks

Answer 29

2 trial types:
go → green = clap
stop → green followed by red = don’t clap

random order so stop signal cannot be predicted

different variants of a stop-signal task with different stimuli, responses, and trial types

Question 30

stop-signal delay

Answer 30

time between go and stop signals → shorter stop-signal delays make stopping easier

short delay (~200ms) = response not yet imminent = easier to inhibit

long delay (~800ms) = closer to action, harder to inhibit response = imminent responses are harder to inhibit

Question 31

SSRT

Answer 31

stop-signal reaction time

how quickly participant reacts to stop signal → reaction is the inhibition of behavioural response

cannot directly measure as you cannot measure not doing anything → but can estimate it using reaction time models and stop-signal tasks

Question 32

behavioural data in stop-signal tasks - basic and advanced measures

Answer 32

basic measure:
* reaction time in go trials and failed stop trials
* number of correct or error trials → % correct stops and % failed stops
issue of waiting strategies → never clap = 100% success rate on correct stops so need more info

advanced measures:
* inhibition functions = probability of motor response based on stop signal delay
* stop-signal reaction times

Question 33

intuition for stop-signal reaction time

Answer 33

cannot directly measure stop signal reaction time but can estimate SSRT:

if stop-signal reaction time is 100ms:
* 100ms is needed to make use of stop-signal
* response within 100ms of stop-signal cannot be stopped
* later than 100ms after signal can be stopped
know this based on reaction time distribution

failed stops
* reaction times in (empirical) failed stop trials are mostly fast → inline with consideration from stop-signal reaction times

Question 34

SSRT - 3 components of stopping

Answer 34

stimulus detection
action selection
inhibition

Question 35

SSRT - what type of inhibition do they measure

Answer 35

SSRT - describe how well you can inhibit response

reactive inhibition → speed of reacting to stop signal (not proactive inhibition)

common measure used in psychological studies on neurological and psychiatric conditions

Question 36

race model of stopping

Answer 36

same model as race model of reaction time - includes a stopping stimulus with the go stimulus

if go reaches threshold first, action is carried out
if not, it is inhibited

repeating across many trials to find average → sometimes go will win and sometimes stop will win

steepness of stop doesn’t changed much between trials but go does vary
* stop fails = steep go processes (fast reaction time)
* stop succeeds = flat go process (slow reaction time)

SSRT = time between stop signal and it crossing the threshold
GoRT = time between go signal and crossing the threshold
* analogous to each other

Question 37

using stop-signal tasks for modelling

Answer 37

• basis of computational models to provide estimate of SSRT from behavioural data
• mathematical - connects go and stop RTs, stop-signal delays, and stopping performance
• reaction times occur in go and failed stop trials
• SSRTs occur in stop trials, can’t be measured directly, estimated using behavioural data from many trials
• general model → describes behaviour and underlying cognitive and neurobiological processes
• application to different animals
• application to different types of stopping, stimuli, and tasks
• allows us to model inhibition functions – can be compared with patient populations or used in conjunction with imaging – fMRI, EEG

Question 38

proactive vs reactive inhibition

Answer 38

reactive = quick reaction to stop signal

proactive = adjust behaviour in anticipation of potentially having to inhibit a response - prepared to stop
* visible as a change in GoRT

Question 39

measure of proactive inhibition in stop-signal tasks

Answer 39

using explicit and implicit cues
explicit:
* given cue to indicate possibility of stop signal occurring or not occurring
* done trial by trial

implicit
* vary probability of stop signals across blocks
* e.g. block 1 has many stops, block 2 has very few stops
* needs to be randomised distribution of stop signals or it becomes predictable

Question 40

define:
* trial
* block
* session

Answer 40

trial = single presentation of a stimulus-response sequence

block = many trials with specific parameters e.g. more or less stops depending on block

session = consists of one or more block, sessions separated by longer time intervals e.g. days apart

Question 41

step by step measuring proactive inhibition with stop-signal

Answer 41

2 blocks studied

1. average reaction times from go trials in block #1
2. do the same for block #2
3. calculate proactive inhibition score -> mean(RTblock#2) - mean(RTblock#1)

comparing speed of response to go trials are when there are more or less stop trials present
* more stops = slower response to “go” due to proactive inhibition trying to predict stop signals

counterbalance order of block sequence to account for order effects

Question 42

proactive adjustment hypothesis

Answer 42

people adjust the response threshold when they predict stop signals – balance stopping and going

fast responses are harder to inhibit so they wait more to go in trials due to predicting potential stops

Question 43

impaired stopping - parkinsons

Answer 43

death of DAergic neurons → therefore levodopa for treatment to increase DA
severe motor and cognitive symptoms

stop-signal tasks compare reaction times in patients with Parkinson’s

longer SSRT in patients compared to control
* no significant differences between those on or not on levodopa medication - so not DA related?

Question 44

what causes impaired stopping - 3 examples

Answer 44

longer SSRTs than control for:
* alcohol dependence
* methamphetamine abuse
* cocaine abuse