Lecture 13 - Attention and impulsivity

The Social Brain: Critical Perspectives on Science, Society and Neurodiversity

Richard Ramsey

Today


Part 1

  • Attention and impulsivity


Part 2

  • Read articles and discuss



Overview


  • Background & ADHD
  • Performance on executive function tasks
    • Behavioural evidence
    • Neurobiological evidence

Background & ADHD

Living with ADHD


http://www.youtube.com/watch?v=mjmiWkB1TKw

ADHD

  • Attention Deficit/Hyperactivity Disorder (ADHD) is defined by a combination of symptoms of
    • Inattention
    • Hyperactivity/impulsivity
  • 3 types:

Diagnosis

  • Six (or more) of the following symptoms of inattention or hyperactivity-impulsivity have persisted for at least 6 months to a degree that is maladaptive and inconsistent with developmental level. Some examples as follows:

  • Inattention

    • Often does not give close attention to details or makes careless mistakes in schoolwork.
    • Often has trouble keeping attention on tasks or play activities.
    • Often does not seem to listen when spoken to directly.

  • Hyperactivity-impulsivity

    • Often fidgets with hands or feet or squirms in seat.
    • Often gets up from seat when remaining in seat is expected.
    • Often runs about or climbs when and where it is not appropriate.

Features

  • Peak onset between the age of 3 and 4
  • Affects 3%-5% children, prevalence higher in areas of socio-economic disadvantage
  • Male/Female ratio
    • 4:1 for the hyperactivity/impulsivity type
    • 2:1 for the inattention type
  • Co-morbidity: 50% of the children also show another psychiatric disorder:
    • Learning difficulties, Oppositional Defiant Disorder and Conduct Disorder, Anxiety and mood disorders, Substance abuse, Tic disorders
  • Medical/Physical characteristics:
    • More accident prone, Sleep problems
    • Persists in adolescence for around 50-80% of individuals and in adulthood for around 30-50% of individuals

Genetics

  • Disorder clusters in families
    • Increased risk for 1st and 2nd order degree relatives (Faraone et al. 1995)
    • Siblings are 3 to 5 times more at risk (Biederman et al., 1992, Faraone et al., 1993)
    • Concordance is higher in monozygotic twins (50%-80%) than dizygotic twins (33%) (Bradley & Golden, 2001)

Several candidate genes (Durston & Konrad, 2007), some linked to dopaminergic system and others to the serotonergic system. Likely to have a complex genetic origin

Cold vs hot executive tasks


  • “Cold” executive functions tasks are associated with working memory, inhibition and planning.

  • “Hot” executive function tasks are associated with reward and reinforcement mechanisms

Stroop task


Stroop task processes


Delay aversion


  • Greater preference for smaller-immediate over larger-delayed rewards (choice impulsivity)

  • 1CHF now or 100 CHF in a year?

    • At which point do you shift your choice?

  • Marshmallow test for kids. One now or two later?

Performance on executive function tasks

  • Behavioural evidence
  • fMRI evidence

Behavioural evidence


  • Review of 8 meta-analyses:

    • Large effect: >0.50
    • Medium effect: 0.50-0.30
    • Small effect: <0.30

(Nigg, 2005)

Nigg 2005 results

(Nigg, 2005)

Nigg 2005 results

(Nigg, 2005)

Neurobiological evidence

  • Functional MRI studies reveal atypical activity in
    • Prefrontal cortex (esp. right inferior frontal)
    • Basal ganglia (esp. putamen)
    • Cerebellum
    • Parietal areas

(Casey & Durston, 2006)

Response suppression task

(Rubia et al., 2005; Rubia, 2018)

Response suppression results

(Rubia et al., 2005; Rubia, 2018)

“Cold” task summary


Individuals with ADHD show:

  • Atypical performance in EF tasks

  • Atypical neural responses compared to controls in “cold” EF tasks

  • What about “hot” tasks?

Reward task

(Ströhle et al., 2008)

Reward results

(Ströhle et al., 2008)

Reward results

(Ströhle et al., 2008)

Summary


Individuals with ADHD show:

  • Atypical performance in EF tasks

  • Atypical neural responses compared to controls in “cold” and “hot” EF tasks

However…

Individual differences

(Nigg, 2005)

Individual differences

When ADHD children tested on both inhibition and delay aversion and looking at individual performances rather than group performance:

  • 23% deficit on both
  • 23% inhibition deficit only
  • 15% delay aversion deficit only
  • 39% no apparent deficit on any of the two

So what does this mean?

(Nigg, 2005)

Single cognitive mechanism?



Inhibition

Reward

Future research

  • Is there good evidence for a single cognitive deficit hypothesis?

  • How well does a deficit in inhibition or motivation/reward processing explain the clinical symptoms associated with ADHD?

  • Is it plausible to assume a single core deficit? What is the alternative?

(Castellanos et al., 2006; Rubia, 2018; Sonuga-Barke, 2005)

Take a break

Part 2 - Read and discuss

Discussion material


  • break into small groups (~ 5 per group)

  • discuss aspects of the lecture

  • discuss aspects of the journal article: Rubia, 2018

  • There is no need to read all of the paper. Pick a section of the paper that interests you and focus on that for the discussion.

References

Casey, B. j., & Durston, Ph. d., Sarah. (2006). From Behavior to Cognition to the Brain and Back: What Have We Learned From Functional Imaging Studies of Attention Deficit Hyperactivity Disorder? American Journal of Psychiatry, 163(6), 957–960. https://doi.org/10.1176/ajp.2006.163.6.957
Castellanos, F. X., Sonuga-Barke, E. J. S., Milham, M. P., & Tannock, R. (2006). Characterizing cognition in ADHD: Beyond executive dysfunction. Trends in Cognitive Sciences, 10(3), 117–123. https://doi.org/10.1016/j.tics.2006.01.011
Nigg, J. T. (2005). Neuropsychologic Theory and Findings in Attention-Deficit/Hyperactivity Disorder: The State of the Field and Salient Challenges for the Coming Decade. Biological Psychiatry, 57(11), 1424–1435. https://doi.org/10.1016/j.biopsych.2004.11.011
Rubia, K. (2018). Cognitive Neuroscience of Attention Deficit Hyperactivity Disorder (ADHD) and Its Clinical Translation. Frontiers in Human Neuroscience, 12. https://doi.org/10.3389/fnhum.2018.00100
Rubia, K., Smith, A. B., Brammer, M. J., Toone, B., & Taylor, E. (2005). Abnormal Brain Activation During Inhibition and Error Detection in Medication-Naive Adolescents With ADHD. American Journal of Psychiatry. https://doi.org/10.1176/appi.ajp.162.6.1067
Sonuga-Barke, E. J. S. (2005). Causal Models of Attention-Deficit/Hyperactivity Disorder: From Common Simple Deficits to Multiple Developmental Pathways. Biological Psychiatry, 57(11), 1231–1238. https://doi.org/10.1016/j.biopsych.2004.09.008
Ströhle, A., Stoy, M., Wrase, J., Schwarzer, S., Schlagenhauf, F., Huss, M., Hein, J., Nedderhut, A., Neumann, B., Gregor, A., Juckel, G., Knutson, B., Lehmkuhl, U., Bauer, M., & Heinz, A. (2008). Reward anticipation and outcomes in adult males with attention-deficit/hyperactivity disorder. NeuroImage, 39(3), 966–972. https://doi.org/10.1016/j.neuroimage.2007.09.044

Acknowledgements