Briana Cassetta

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.

Background

Psychopathy• Personality disorder• 1% of general population, 15-25% of

incarcerated offenders• Characterized by:

○ Superficiality○ Persuasiveness○ Lack of empathy○ Lack of guilt, remorse

Introduction

Prior research using behavioural methods• Criminal psychopaths fail to experience

emotional significance of stimuli• Fail to show normal differentiated responses

between emotional and neutral words• Require more cognitive resources to

process and evaluate affective stimuli

Introduction Purpose:

• Use whole brain fMRI to examine neural systems of emotional processing during an affective memory task

Hypothesis: • Psychopaths will show less activation than

healthy controls and criminal nonpsychopaths when processing affective words compared with neutrals

Methods

Subjects:• 8 criminal psychopaths and 8 criminal

nonpsychopaths from prison in Abbotsford○ Escorted to UBC Hospital’s MRI Unit○ Hare Psychopathy Checklist-Revised

• 8 healthy controls from general population

Methods

Materials and Procedure:• 8 trials with 3 sequential phases:

○ Encoding: memorize list of 12 words○ Rehearsal: mentally rehearse words○ Recognition: 6 correct words and 6 incorrect

words (indicate yes or no)

Methods

Procedure:• 25s rest between trials• Half of trials neutral words, half negative• Words similar in length, imagery,

concreteness• 2 practice runs prior• fMRI done during task

Results

No differences: neutral vs. rest Less affect-related activity in:

Amygdala/hippocampal formationParahippocampal gyrusVentral striatumAnterior and postior cingulate gyri

Greater activation for affective stimuli in:Bilateral fronto-temporal cortex

Results

Discussion

Support hypothesis: abnormalities in limbic system and frontal cortex

Amygdala, ventral striatum, hippocampal formation: emotion and memory

Inferior lateral frontal cortex: semantic and decision-making processes

Discussion

Strengths:fMRI to identify specific structuresNo group differences

Limitations:Small sample size for groups (sample

specific effects?)Substance abuseOther disorders in criminal psychopaths

Discussion

Future studies:Different affective stimuli

○ Faces○ Pictures

Identification of other possible disorders○ Depression / Mood

Bigger sample size