Research Area #1: Cerebellar-dependent associative learning dysfunction in schizophrenia spectrum disorders
The Hetrick Lab has made significant contributions to the understanding of dysfunction of cerebellar-dependent associative learning deficits in schizophrenia spectrum disorders. They have found striking empirical evidence in schizophrenia of behavioral dysfunction of associative learning as measured by the highly translational eyeblink classical conditioning procedure. Moreover, they have found that 1st-degree relatives of schizophrenia patients and individuals with schizotypal personality disorder also exhibit associative learning deficits. They have produced evidence that the deficit may be ameliorated in schizophrenia with a novel pharmacological intervention. Finally, correlations between performance on cerebellar-dependent tasks and cognitive functioning support contemporary models of the role of the cerebellum in cognition. Taken together, their findings of associative learning deficits dovetail elegantly with emerging evidence of structural and functional cerebellar abnormalities in schizophrenia.
- *Forsyth, J.K., *Bolbecker, A.R., *Mehta, C.S., *Klaunig, M.J., Steinmetz, J.E., O'Donnell, B.F., & Hetrick W.P. (2012). Cerebellar dependent Eyeblink Conditioning Deficits in Schizophrenia Spectrum Disorders. American Journal of Psychiatry, 166, 460 466.
- *Bolbecker, A.R., Hetrick, W.P.,*Johannesen, J.K., O'Donnell, B.F., Steinmetz, J.E., and Shekhar, A. (2009). Secretin effects on cerebellar dependent motor learning in schizophrenia.Schizophrenia Bulletin, 38 (4), 751-759. doi: 10.1093/schbul/sbq148
- Bolbecker A.R., Kent, J.S., Petersen, I.T., Klaunig, M.J., Forsyth, J.K., Howell, J.M., Westfall, D.R., O'Donnell, B.F., & Hetrick, W.P. (2013). Impaired Cerebellar Dependent Eyeblink Conditioning in First Degree Relatives of Individuals With Schizophrenia. Schizophrenia Bulletin, http://www.ncbi.nlm.nih.gov/pubmed/23962891
- Kim, D.J., *Kent, J.S., Bolbecker, A.R., Sporns, O., Cheng, H., Newman, S.D., Puce, A., O’Donnell, B.F., Hetrick, W.P. (In Press). Disrupted Modular Architecture of Cerebellum in Schizophrenia: A Graph Theoretic Analysis. Schizophrenia Bulletin, 38 (4), 751-759. doi: 10.1093/schbul/sbq148
*Asterisks indicate advisees.
Research Area #2: Temporal processing dysfunction in schizophrenia
There is accumulating theoretical and empirical support for the hypothesis that schizophrenia is associated with a fundamental disturbance in the timing of neural processes. Deficits in the temporal coordination of information processing in the brain may lead to disturbances of consciousness as well as poor coordination of perceptual, affective, cognitive, and motor processes similar to classic symptoms of schizophrenia such as thought disorder and disorganized and contextually inappropriate behavior. Support for these conceptualizations is emerging with evidence that brain structures (e.g., cerebellum & basal ganglia) and neurotransmitter systems (e.g., dopamine & glutamate) that are directly linked to neural timing processes are also impaired in schizophrenia. Professor Hetrick’s group has made significant contributions to the understanding of temporal processing dysfunction using two well-established timing tasks: time estimation (e.g., temporal bisection task) and time production and reproduction (e.g., free and paced finger tapping).
- *Carroll, C.A., *Boggs, J., O'Donnell, B.F., Shekhar, A., Hetrick W.P. (2008). Temporal Processing Dysfunction in Schizophrenia.Brain and Cognition, 67, 150-161.
- *Carroll, C.A., O’Donnell, B.F., Shekhar, A., & Hetrick W.P. (2009). Timing dysfunctions in schizophrenia span from millisecond to several second durations. Brain & Cognition, , 70, 181 90.
- *Carroll, C.A., O’Donnell, B.F., Shekhar, A., Hetrick W.P. (2009). Timing dysfunctions in schizophrenia as measured by a repetitive finger tapping task. Brain & Cognition, 71, 345 353.
- *Forsyth, J.K., *Bolbecker, A.R., *Mehta, C.S., *Klaunig, M.J., Steinmetz, J.E., O'Donnell, B.F., & Hetrick W.P. (2012). Cerebellar dependent Eyeblink Conditioning Deficits in Schizophrenia Spectrum Disorders. Schizophrenia Bulletin, 38 (4), 751-759. doi: 10.1093/schbul/sbq148
Research Area #3: Sensory gating deficits in schizophrenia
The Hetrick Lab has made significant contributions to understanding the origins and correlates of perceptual aberrations in schizophrenia. Specifically, sensory gating hypotheses assert that perceptual and cognitive aberrations arise from deficits in gating, or filtering, of exteroceptive input by the central nervous system. It is speculated that this inability to gate or filter sensory inputs underlies information processing deficits—such as hyper-vigilance and poor selective attention—and might contribute to a psychotic state in which patients with schizophrenia are disorganized by an overabundance of irrelevant sensory stimulation. The Hetrick Lab has examined sensory gating across levels of analysis, including both neurophysiological and phenomenological/symptom levels.
- *Johannesen, J.K., *Kieffaber, P.D., O'Donnell, B.F., Shekhar, A., Evans, J.D., Hetrick W.P. (2005). Contributions of subtype and spectral frequency analyses to the study of P50 ERP amplitude and suppression in schizophrenia. Schizophrenia Research, 78, 269-284.
- *Johannesen, J.K., *Bodkins, M., O'Donnell, B.F., Shekhar, A., Hetrick W.P. (2008). Perceptual Anomalies in Schizophrenia Co occur with Selective Impairments in the Gamma Frequency Component of Mid latency Auditory ERPs. Journal of Abnormal Psychology, 117, 106-118.
- *Brenner, C.A., *Kieffaber, P.D., Clementz, B.A. *Johannesen, J.K., Shekhar, A., O'Donnell, B.F., & Hetrick W.P. (2009). Early Event related Potential Abnormalities in Schizophrenia: A Failure to "Gate In" Salient Information? Schizophrenia Research, 113, 332 338.
- Hetrick W.P., *Erickson, M.A., & Smith, D.A. (2012). Phenomenological Dimensions of Sensory Gating. Schizophrenia Bulletin, 38, 178 191.