Early SPECT Studies

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Early SPECT Studies

• David Ingvar and Niels Lassen
• Daniel Weinberger and Karen Berman

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Ingvar and Lassen
Normals
Patients (Hypofrontality)
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Frontal Functions

• Fluency of thought and speech
• Emotional attachments
• Social and moral judgment
• Volition and drive
• Planning and identifying goals
• Formulating abstract concepts

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Weinberger and Berman
Normals
Patients
Number
WCS
5
PET Studies
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Normals Remembering Words

• Increased blood flow in frontal operculum,
  thalamus, cerebellum

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Patients Remembering Words

• Failure to activate regions used by normals
• Decreased frontal flow

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Using PET to Study Anhedonia

• Examine changes in blood flow in response to
  visual emotional stimuli
• Comparison of pleasant vs unpleasant pictures
• Examine the final stage in emotional
  processingattributionwhich is the interface
  between cognition and emotion

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Unpleasant
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Pleasant
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Activations in Normals Visual Stimuli

• Subtraction images Unpleasant minus pleasant
• Unpleasant activations areas of increased flow
  are red
• Pleasant activations areas of increased flow
  are blue

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Unpleasant Activations

• Extrastriate and visual cortex
• Cerebellum
• Amygdala

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Pleasant Activations

• Medial, orbital, and dorsolateral prefrontal
  cortex

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InterpretationEmotion Attribution in Normals

• The system that assigns positive emotional
  valence to stimuli is primarily prefrontal
• Pleasure attribution in human beings activates
  phylogenetically younger higher cortical regions

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Randomization Analysis of PET Data

• A non-parametric statistical method that is
  robust to differences in variance
• Displays areas where patients differ from
  controls
• Blue flow is decreased in patients during
  unpleasant stimuli
• Red flow is increased during unpleasant stimuli
  (?compensatory?)

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Unpleasant Pictures Areas of Decreased Flow

• Thalamus
• Extrastriate visual cortex
• Hippocampus

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Unpleasant Pictures Areas of Increased Flow

• Insula
• Putamen/ accumbens
• Superior frontal

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Focusing Visual Attention
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Remembering Faces
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Recalling Complex Narratives