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Early SPECT Studies. David Ingvar and Niels Lassen Daniel Weinberger and Karen Berman . Ingvar and Lassen. Normals. Patients (Hypofrontality). Frontal Functions. Fluency of thought and speech Emotional attachments Social and moral judgment Volition and drive
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Early SPECT Studies David Ingvar and Niels Lassen Daniel Weinberger and Karen Berman
Ingvar and Lassen Normals Patients (Hypofrontality)
Frontal Functions • Fluency of thought and speech • Emotional attachments • Social and moral judgment • Volition and drive • Planning and identifying goals • Formulating abstract concepts
Weinberger and Berman Normals Patients Number WCS
Normals: Remembering Words • Increased blood flow in frontal operculum, thalamus, cerebellum
Patients: Remembering Words • Failure to activate regions used by normals • Decreased frontal flow
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 processing—attribution—which is the interface between cognition and emotion
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
“Unpleasant” Activations • Extrastriate and visual cortex • Cerebellum • Amygdala
“Pleasant” Activations: • Medial, orbital, and dorsolateral prefrontal cortex
Interpretation:Emotion 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
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?)
Unpleasant Pictures: Areas of Decreased Flow • Thalamus • Extrastriate visual cortex • Hippocampus
Unpleasant Pictures: Areas of Increased Flow • Insula • Putamen/ accumbens • Superior frontal