inhibition & sustained attention lecture--lab 4

8/2/2019 Inhibition & Sustained Attention Lecture--Lab 4

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Inhibition & Sustained Attention

Lab Experiment 4



What is inhibition?

• The act of withholding a prepotent response

• Sets up a race paradigm between the “Go”

process (tapping your desk) and the “NoGo”

process

• The time between the presentation of a beep

that coincides with an “←” or “→” results in a

“build-up” of the expectation to respond



What happened for you?

• Did you ever tap your desk when there was abeep?

– Commission error

•

Did you ever fail to press a key when an “←” or“→” appeared without a beep?

– Omission error

• How did the time between beeps function within

the activity? – Was it harder to stop yourself from pressing a key when

there was a longer delay between beeps?



What is sustained attention?

• Ability to maintain behavioral responses during

a repetitive and continuous activity



What have you noticed with your sustained attention

experiment?

• When was your optimal performance?

• Did you notice performance changing as you

continued the Stop Signal Task?



What is ADHD?

• Affects 4-10% of children (Barkley, 1998; Froehlich et al., 2007)

Higher ratio of males diagnosed

Children with ADHD may have an

80% chance of having

at least one other disorderex., Learning Disorder,

Oppositional defiant disorder,

Developmental CoordinationDisorder



ADHD: Pattern of symptoms

• Characterized by developmentally inappropriate

levels of:

– Inattention

– Hyperactivity/Impulsivity



Inattention

• Fails to give close attention to details/make careless mistakes.

• Difficulty sustaining attention.

• Does not seem to listen.

•

Lack of follow through.• Difficulty organizing tasks and activities.

• Avoids/dislikes tasks requiring sustained mental effort.

• Loses things.

• Easily distracted.

• Forgetful.



Hyperactivity

• Fidgets with hands or feet.

• Difficulty remaining seated.

• Runs about/climbs excessively.

• Difficulty playing quietly.• On the go. “Driven by a motor.”

• Talks excessively.

•Blurts out answers before questions are asked.

• Difficulty awaiting turn.

• Interrupts or intrudes on others.



Associated difficulties with ADHD

• Impaired academic performance

• Increased social rejection

• Increased family discord

• Poor achievement motivation

• Increased risk of substance abuse

•Increased risk of risky sexual activity



Which cognitive processes may be impaired for

individuals with ADHD?

• Sustained Attention

– Could be associated with inattentive symptoms

• Inhibition

– Could be associated with impulsivity/hyperactivitysymptoms

• Other cognitive processes?

–

Working Memory – Set-Shifting

– Planning



Inhibition & ADHD

• Children with ADHD have more difficulty than

comparison children based on:

– More commission errors

– More omission errors

– Greater inter-trial variability



Sustained attention & ADHD

• Cognitive performance

– Children with ADHD have worse cognitive

performance than comparison children as time on a

task increases (Houghton et al., 2004)

• Movement

– Children with ADHD move more than comparison

children only at the end of the school day (Tsuili etal., 2007)



Benefits of brain activity research

• EEG measures the background electrical activityin the brain

• Allows examination of neurofunctional

processes• Special interest in the amplitude of brain

activity

–

Peak of the wave – Indicates use of

cognitive resources



Brain activity:

Sustained attention & Inhibition

• Sustained attention is associated with a

waveform called the P100

• Inhibition is associated with a waveform called

the N200



Example of brain activity and

inhibition• Successful inhibition• Anterior region of the brain

Pink = Comparison childrenPurple = Children with ADHD

(Pliszka et al., 2007)



Example of brain activity &

inhibition• Failed inhibition• Posterior region of the brain

Pink = Comparison childrenPurple = Children with ADHD

(Pliszka et al., 2007)



What does the brain activity

indicate?• Findings suggest a primary deficit of inhibition

for children with ADHD

• Appears likely that deficits in sustained

attention may appear in relation to deficits in

other cognitive processes



Possible strengths of ADHD

• Multi-tasking

• Creativity

– Problems with inhibition may “allow” for:

• “outside the box“ thinking

• Unique displays of art

inhibition & sustained attention lecture--lab 4

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