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Eyeblink conditioning in unmedicated schizophrenia patients: a positron emission tomography study
Journal article   Peer reviewed

Eyeblink conditioning in unmedicated schizophrenia patients: a positron emission tomography study

Krystal L Parker, Nancy C Andreasen, Dawei Liu, John H Freeman and Daniel S O'Leary
Psychiatry research, Vol.214(3), pp.402-409
12/30/2013
DOI: 10.1016/j.pscychresns.2013.07.006
PMCID: PMC3980571
PMID: 24090512

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Abstract

Previous studies suggest that patients with schizophrenia exhibit dysfunctions in a widely distributed circuit-the cortico-cerebellar-thalamic-cortical circuit, or CCTCC-and that this may explain the multiple cognitive deficits observed in the disorder. This study uses positron emission tomography (PET) with O(15) H₂O to measure regional cerebral blood flow (rCBF) in response to a classic test of cerebellar function, the associative learning that occurs during eyeblink conditioning, in a sample of 20 unmedicated schizophrenia patients and 20 closely matched healthy controls. The PET paradigm examined three phases of acquisition and extinction (early, middle and late). The patients displayed impaired behavioral performance during both acquisition and extinction. The imaging data indicate that, compared to the control subjects, the patients displayed decreases in rCBF in all three components of the CCTCC during both acquisition and extinction. Specifically, patients had less rCBF in the middle and medial frontal lobes, anterior cerebellar lobules I/V and VI, as well as the thalamus during acquisition and although similar areas were found in the frontal lobe, ipsilateral cerebellar lobule IX showed consistently less activity in patients during extinction. Thus this study provides additional support for the hypothesis that patients with schizophrenia have a cognitive dysmetria--an inability to smoothly coordinate many different types of mental activity--that affects even a very basic cognitive task that taps into associative learning.
Frontal Lobe - physiopathology Humans Middle Aged Male Thalamus - blood supply Cerebellum - physiopathology Cerebrovascular Circulation Cognition Positron-Emission Tomography Conditioning, Classical - physiology Blinking - physiology Cerebellum - blood supply Young Adult Thalamus - physiopathology Extinction, Psychological Schizophrenia - physiopathology Adolescent Adult Female Frontal Lobe - blood supply

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