Schizophrenia research study: Daniel, Weinberger Jones et al

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Created by
Shekinah Obare

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  • a study into the effect of amphetamine on regional cerebral blood flow during cognitive activation in schizophrenia
  • Background
    studies shown low levels of activity in the pre-frontal cortex in people with SZ. This has been linked to activity of dopamine in the brain. Dopamine is important in suppressing random brain activity helping to focus on specific stimuli in the environment. 
  • Hypothesis
    if dysfunction was related to the prefrontal cortex was related to problems in dopamine-controlled synaptic transmission then a substance that stimulated dopamine activity (an agonist - amphetamines) should increase activity in that area during a cognitive task.
  • Design
    IV = whether participants had been given amphetamine or not. DV = performance on the Wisconsin card sorting test.
  • Procedure
    five participants did the BAR task first and five the WCST (counterbalancing). Each participant received either the dose of amphetamine or a placebo. Both tasks were carried out on a computer and required similar motor responses.
  • Materials:
    images of brain activity were recorded using SPECT technology, which was capable of collecting a full set of 80 projections in five seconds. They underwent 2 scans two to four days apart. Participants were seated in a comfortable chair, with their heads positioned in the scanner. Heads were kept still using foam-rubber inserts. Each scan involved a mock test to get the participants used to the set-up, test of sensori-motor control, the prefrontal activation test (WCST).
  • Conclusion
    Amphetamines significantly increased prefrontal cortex activity during performance of a cognitive task, despite it reducing blood flow in the brain. The results were in line with animal studies that had suggested the role of dopamine and other similar neurochemicals in modulating and enhancing cortical activity. This implies that some of the problems associated with SZ and prefrontal cortex dysfunction are in part reversible through drug treatment.