During auditory paired-stimulus paradigms, schizophrenia subjects have smaller differences between S1 and S2 amplitudes than normal. A series of reports indicate this effect results from smaller S1 amplitudes, not larger S2 amplitudes, among patients. These findings are consistent with reports from other studies of auditory information processing in schizophrenia, perhaps revealing a pattern that contains important clues about the neuropathological correlates of this illness. The proposed research will evaluate this possibility by studying the cognitive and sensory correlates of auditory evoked responses (AERs) using 143-channel MEG and dense array EEG. We will use steady-state stimulation and auditory oddball and paradigms to help clarify (1) The limits on cortical neuronal response rates and the associated ability to integrate information over time during auditory processing in schizophrenia, (2) whether group processing of simple auditory stimuli can be normalized among schizophrenia patients by entrainment of neuronal activity at a 'manageable' rate (which will have implications for understanding the relationship between background brain states and auditory processing in schizophrenia), and (3) whether auditory processing abnormalities in schizophrenia is primarily associated with left hemisphere dysfunction and is a predictor of presence of auditory hallucinations, and (4) whether interhemispheric communication secondary to dysfunction of left auditory cortex is a cause of auditory recognition abnormalities among schizophrenia patients. Analyses will rely on current distributed source reconstructions, measures of spectral coherence in source and sensor space, measures of spectral power, and dipole modeling using realistic head models. It is hypothesized that schizophrenia patients have a limited ability to integrate information over time secondary to a low ceiling on neuronal response rates and that this effect is primarily due to left auditory cortex dysfunction. Indeed, right auditory cortex will be found to function normally among schizophrenia patients. Because of a low sampling rate on schizophrenia patients' auditory information processing systems, they have difficulty recovering the initial stimulus information, an abnormality that could facilitate the development of hallucinatory phenomena. In addition, dysfunction of left auditory cortex impedes proper inter-hemispheric communication, which interferes with the ability to generate normal recognition-type responses measured during oddball-type paradigms.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH057886-05
Application #
7012818
Study Section
Neural Basis of Psychopathology, Addictions and Sleep Disorders Study Section (NPAS)
Program Officer
Meinecke, Douglas L
Project Start
2000-03-15
Project End
2008-01-31
Budget Start
2006-02-01
Budget End
2007-01-31
Support Year
5
Fiscal Year
2006
Total Cost
$244,359
Indirect Cost
Name
University of Georgia
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
004315578
City
Athens
State
GA
Country
United States
Zip Code
30602
Hamm, Jordan P; Bobilev, Anastasia M; Hayrynen, Lauren K et al. (2015) Stimulus train duration but not attention moderates ?-band entrainment abnormalities in schizophrenia. Schizophr Res 165:97-102
Hamm, Jordan P; Ethridge, Lauren E; Shapiro, John R et al. (2013) Family history of psychosis moderates early auditory cortical response abnormalities in non-psychotic bipolar disorder. Bipolar Disord 15:774-86
Wang, Jun; Dobkins, Karen R; McDowell, Jennifer E et al. (2012) Neural response to the second stimulus associated with poor speed discrimination performance in schizophrenia. Psychophysiology 49:198-206
Hamm, Jordan P; Gilmore, Casey S; Clementz, Brett A (2012) Augmented gamma band auditory steady-state responses: support for NMDA hypofunction in schizophrenia. Schizophr Res 138:1-7
Ethridge, Lauren; Moratti, Stephan; Gao, Yuan et al. (2011) Sustained versus transient brain responses in schizophrenia: the role of intrinsic neural activity. Schizophr Res 133:106-11
Hamm, Jordan P; Gilmore, Casey S; Picchetti, Natalie A M et al. (2011) Abnormalities of neuronal oscillations and temporal integration to low- and high-frequency auditory stimulation in schizophrenia. Biol Psychiatry 69:989-96
Hamm, Jordan P; Dyckman, Kara A; Ethridge, Lauren E et al. (2010) Preparatory activations across a distributed cortical network determine production of express saccades in humans. J Neurosci 30:7350-7
Wang, Jun; Brown, Ryan; Dobkins, Karen R et al. (2010) Diminished parietal cortex activity associated with poor motion direction discrimination performance in schizophrenia. Cereb Cortex 20:1749-55
Ethridge, Lauren E; Brahmbhatt, Shefali; Gao, Yuan et al. (2009) Consider the context: blocked versus interleaved presentation of antisaccade trials. Psychophysiology 46:1100-7
Gilmore, Casey S; Clementz, Brett A; Berg, Patrick (2009) Hemispheric differences in auditory oddball responses during monaural versus binaural stimulation. Int J Psychophysiol 73:326-33

Showing the most recent 10 out of 25 publications