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Impairment in frontal but not temporal components of mismatch negativity in schizophrenia
Torsten Baldeweg1, Anthony Klugman, John H Gruzelier
1Institute of Child Health and Great Ormond Street Hospital, Wolfson Centre, Mecklenburgh Square, WC1N 2AP, London, UK. t.baldeweg@ich.ucl.ac.uk
Abstract:
Impairment in mismatch negativity (MMN) potentials is a robust finding in schizophrenia. While previous studies suggested that MMN in man is generated by a single dipole source bilaterally in the primary auditory cortex, more recent data modified this assumption by showing differential modulation of MMN components over the frontal and temporal scalp. Here we used a roving standard experiment to record mismatch potentials to tone duration deviants with the aim to detect robust temporal and frontal mismatch components. Fourteen schizophrenic patients with normal intelligence and without overt cognitive deficits and age- and sex-matched controls were studied. In agreement with previous findings MMN recorded from the frontal scalp was markedly attenuated in patients. However, in contrast to previous reports, positive mismatch potentials of normal magnitude were recorded from temporal (mastoid) electrodes. This finding raises the possibility of a selective impairment in multiple mismatch generators in schizophrenia and may lend support for the notion of impaired cortico-cortical connectivity in schizophrenia.
Insights
Mismatch negativity (MMN) potentials, an auditory event-related potential, are impaired in schizophrenia. This study found frontal MMN deficits but preserved temporal MMN, suggesting selective generator impairment and potential cortico-cortical connectivity issues.
Area of Science:
- Neuroscience
- Psychiatry
- Auditory Processing
Background:
- Impairment in mismatch negativity (MMN) potentials is a consistent finding in schizophrenia.
- Previous research suggested MMN originates from bilateral auditory cortex, but recent data indicate differential frontal and temporal MMN components.
Purpose of the Study:
- To investigate temporal and frontal mismatch components using a roving standard paradigm in schizophrenia.
- To examine auditory processing deficits in schizophrenia by analyzing MMN responses to tone duration deviants.
Main Methods:
- A roving standard experiment was conducted to record mismatch potentials (MMN).
- Participants included fourteen schizophrenia patients (normal intelligence, no overt cognitive deficits) and age/sex-matched controls.
- Tone duration deviants were used to elicit MMN responses.
Main Results:
- MMN recorded from frontal scalp electrodes was significantly attenuated in schizophrenia patients.
- In contrast to frontal findings, positive mismatch potentials of normal magnitude were observed at temporal (mastoid) electrodes in patients.
- These results differ from previous reports suggesting a generalized MMN impairment.
Conclusions:
- The findings suggest a selective impairment in multiple MMN generators in schizophrenia.
- Preserved temporal MMN alongside frontal deficits may indicate specific disruptions in cortico-cortical connectivity.
- This research contributes to understanding the neural basis of auditory processing deficits in schizophrenia.