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Who are Psychopaths?

Limbic abnormalities in affective processing by criminal psychopaths as revealed by functional magnetic resonance imaging. By: Kent A Kiehl , Andra M Smith, Robert D Hare, Adrianna Mendrek , Bruce B Forster, Johann Brink, Peter F Liddle . Presented by: Richard Rigby.

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Who are Psychopaths?

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  1. Limbic abnormalities in affective processing by criminal psychopaths as revealed by functional magnetic resonance imaging. By: Kent A Kiehl, Andra M Smith, Robert D Hare, Adrianna Mendrek, Bruce B Forster, Johann Brink, Peter F Liddle. Presented by: Richard Rigby

  2. Who are Psychopaths? -Psychopaths are characterized by a deficit in processing affective material* which can lead to symptoms such as: -superficiality -lack of empathy, guilt, or remorse -failure to experience or appreciate the significance of emotional stimulus *Affective material: something that elicits an emotional response.

  3. Previous Research • -1% of the general population are psychopaths • -15-25% of the prison population are psychopaths • -Using SPECT it was found that psychopaths show greater bilateral activation for affective stimuli in the temporofrontal cortex. • -This suggests psychopaths require more activation in areas outside the limbic system to evaluate effective stimuli • -Many other structures have been suggested to cause psychopathy, yet little was known about their involvement

  4. Purpose Using an fMRI(1.5 T) to measure emotional processes in the brain activated by an affective memory task.

  5. Participants Participants: -Criminals from a maximum security prison in Abbotsford BC -Criminal psychopaths (n=8) -Criminal non-psychopaths (n=8) -Healthy participants from general population (n=8) -All participants were controlled to have no significant difference in: -Years of substance abuse -Age -Parental socioeconomic status -IQ -The Hare Psychopathy Checklist-Revised assessed psychopathy

  6. PCL-R 4 Dimensions: -Affective (lack of empathy) -Interpersonal (manipulative) -Antisocial (keep going back to jail) -Lifestyle (craves high stimulation, unreasonable goals)

  7. Procedure - Encoding: subjects memorized 12 words shown on a screen one at a time (0.5s to view word, 1.5 in between) toaster chair fish car

  8. Procedure - Rehearsal: participants were told to rehearse words rehearse

  9. Procedure - Recognition: 12 words presented, participants were asked if the word was present in the first sequence (2s to view word, 0.5s in between) . toaster chair box cat

  10. Procedure -Repeated 8 times -On half the trials all words were neutral (Ex. Chair) -The other half were negative words (Ex. Hate) which were used as an affective stimuli punch hate cry kill

  11. Results -Psychopaths showed less activation than non-psychopaths in response to the affective stimuli in: -rostral and cuadal anterior cingulate -posterior colingulate -left inferior frontal gyrus -right and left amygdala -ventral striatum -parahippocampalgyrus -bilateral anterior superior temporal gyrus

  12. Results -Psychopaths showed less activation than non-psychopaths in response to the affective stimuli in: -All are areas of the Limbic System or Frontal Lobe

  13. Results -Psychopaths showed greater activation outside the limbic system in response to affective stimuli: -left anterior superior temporal gyrus -left anterior inferior frontal gyrus -right inferior frontal gyrus

  14. Discussion -Psycopathy is a result of limbic system and frontal lobe abnormalities, which affect: -The ability to process emotions (amygdala, ventral striatum, and hippocampal formation) -Memories (amygdala, ventral striatum, and hippocampalformation) -Fear of punishment (amygdala) -Psychopaths use non-limbic regions more than non-psychopaths to process affective stimuli.

  15. Discussion -Limitations: -Small sample size -Substance abuse could have altered results Future experiments: -Different affected stimuli (faces)

  16. My Opinion Pros -Lots of previous research -They controlled confounds very well in their participants -They included brain images -Thorough explanation of results Cons -The images weren’t great -Lots of complicated jargon about random effects analysis -Complicated large tables

  17. References Kiehl, K. A., et al (2001). Limbic abnormalities in affective processing by criminal psychopaths as revealed by functional magnetic resonance imaging. Bio Psychiatry, 50, 677-684. Recommended by Psych prof

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