Predictive Pursuit Association with Deficits in Working Memory in Psychosis

Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas. Electronic address: .
Biological psychiatry (Impact Factor: 10.26). 05/2012; 72(9):752-7. DOI: 10.1016/j.biopsych.2012.03.030
Source: PubMed


Deficits in smooth pursuit eye movements are an established phenotype for schizophrenia (SZ) and are being investigated as a potential liability marker for bipolar disorder. Although the molecular determinants of this deficit are still unclear, research has verified deficits in predictive pursuit mechanisms in SZ. Because predictive pursuit might depend on the working memory system, we have hypothesized a relationship between the two in healthy control subjects (HC) and SZ and here examine whether it extends to psychotic bipolar disorder (BDP).
Volunteers with SZ (n = 38), BDP (n = 31), and HC (n = 32) performed a novel eye movement task to assess predictive pursuit as well as a standard visuospatial measure of working memory.
Individuals with SZ and BDP both showed reduced predictive pursuit gain compared with HC (p < .05). Moreover, each patient group showed worse performance in visuospatial working memory compared with control subjects (p < .05). A strong correlation (r = .53, p = .007) was found between predictive pursuit gain and working memory in HC, a relationship that showed a trend correlation within the BDP group but not among SZ.
Individuals with SZ and BDP showed similar deficits in predictive pursuit, suggesting that this alteration could be a characteristic trait of the psychosis domain. The correlation between predictive pursuit and working memory in HC supports the assumption that working memory is related to predictive pursuit eye movements; however, the degradation of working memory in people with psychosis disrupts its association with eye-tracking behavior.

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    • "The results were found for a group of healthy control subjects, as well as for schizophrenic patients, although the eye velocities of the patients were slower. Hong et al. [58] and Moates et al. [59] reported similar findings using a related method involving retinally stabilized targets. They found that both the healthy control subjects and the schizophrenic patients pursued the stabilized targets in patterns that resembled the motion patterns of the unstabilized targets that were pursued in the immediately previous trials, as if the pursuit response reflected the prediction that the patterns of motion seen in the recent past would continue into the future. "
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