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Cognitive Impairments in Schizophrenia as Assessed Through Activation and Connectivity Measures of Magnetoencephalography (MEG) Data.

Hinkley LB, Owen JP, Fisher M, Findlay AM, Vinogradov S, Nagarajan SS - Front Hum Neurosci (2010)

Bottom Line: Although studies utilizing electroencephalography (EEG), PET and fMRI have contributed significantly to our understanding of these mechanisms, magnetoencephalography (MEG) possesses great potential to answer long-standing questions linking brain interactions to cognitive operations in the disorder.Finally, both bivariate and multivariate functional connectivity metrics of MEG data are useful for understanding how these interactions in the brain are impaired in schizophrenia, and how cognitive and clinical outcomes are affected as a result.We also present here data from our own laboratory that illustrates how some of these novel functional connectivity measures, specifically imaginary coherence (IC), are quite powerful in relating disconnectivity in the brain to characteristic behavioral findings in the disorder.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Biomedical Imaging, University of California San Francisco, CA, USA.

ABSTRACT
The cognitive dysfunction present in patients with schizophrenia is thought to be driven in part by disorganized connections between higher-order cortical fields. Although studies utilizing electroencephalography (EEG), PET and fMRI have contributed significantly to our understanding of these mechanisms, magnetoencephalography (MEG) possesses great potential to answer long-standing questions linking brain interactions to cognitive operations in the disorder. Many experimental paradigms employed in EEG and fMRI are readily extendible to MEG and have expanded our understanding of the neurophysiological architecture present in schizophrenia. Source reconstruction techniques, such as adaptive spatial filtering, take advantage of the spatial localization abilities of MEG, allowing us to evaluate which specific structures contribute to atypical cognition in schizophrenia. Finally, both bivariate and multivariate functional connectivity metrics of MEG data are useful for understanding how these interactions in the brain are impaired in schizophrenia, and how cognitive and clinical outcomes are affected as a result. We also present here data from our own laboratory that illustrates how some of these novel functional connectivity measures, specifically imaginary coherence (IC), are quite powerful in relating disconnectivity in the brain to characteristic behavioral findings in the disorder.

No MeSH data available.


Related in: MedlinePlus

Mismatch negativity (MMN) in healthy control participants and in patients with schizophrenia. Changes in grand magnetic field power (mGFP) over auditory cortex in response to a deviant stimulus (phoneme change) are significantly reduced in patients with schizophrenia bilaterally. Reproduced, with permission, from Yamasue et al. (2004).
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Figure 2: Mismatch negativity (MMN) in healthy control participants and in patients with schizophrenia. Changes in grand magnetic field power (mGFP) over auditory cortex in response to a deviant stimulus (phoneme change) are significantly reduced in patients with schizophrenia bilaterally. Reproduced, with permission, from Yamasue et al. (2004).

Mentions: One cortical process extensively studied through MEG is the automatic response that is generated following a deviant stimulus in a train of auditory standards, or the mismatch negativity effect (MMN, or the magnetic equivalent, MMNm). This evoked response, which occurs 150–200 ms following a deviant stimulus, is thought to reflect, in healthy individuals, a pre-attentive process whose purpose is to reorient the individual towards a novel stimulus that has entered the environment (for a review, see Pulvermüller and Shtyrov, 2006). In patients with schizophrenia, the amplitude of the MMNm is generally reduced, across experimental designs and stimulus types (Figure 2, see Kasai et al., 2002; Kircher et al., 2004; Yamasue et al., 2004; Thönnessen et al., 2008). In schizophrenia, this deviation in MMNm is best produced in an optimum design paradigm (Näätänen et al., 2004), where the deviant occurs much more frequently in the stimulus train and is modified along one feature throughout stimulus presentation (either its frequency, intensity, duration, sound source or gap in tone, see Thönnessen et al., 2008). The MMNm is thought to be bilateral for categorical speech sound deviants (Kasai et al., 2002) and low MMNm amplitude may be due to, in part, reduced gray matter volume in the cortex along the planum temporale found in patients with schizophrenia (Yamasue et al., 2004). The demonstration of compromised gray matter density (and thus cortical function) in the temporal lobes of these patients are congruent with work in combined fMRI/MEG studies that examine MMNm in the patient and control group using both neuroimaging modalities (Kircher et al., 2004). In this study, reduced MMNm in patients with schizophrenia correlated with a decrease in BOLD signal in STG, along the planum temporale (secondary auditory cortex) but not in primary auditory cortex, along Heschl's gyrus (Kircher et al., 2004). Although a difference in MMN amplitude between patient and control groups is readily identifiable in averaged EEG sensor data, the sources that contribute to this deviation are likely to be far more complex than just reduced activity within secondary auditory areas. MMN represents a powerful and well-developed experimental paradigm used to assess auditory processing dysfunction in schizophrenia.


Cognitive Impairments in Schizophrenia as Assessed Through Activation and Connectivity Measures of Magnetoencephalography (MEG) Data.

Hinkley LB, Owen JP, Fisher M, Findlay AM, Vinogradov S, Nagarajan SS - Front Hum Neurosci (2010)

Mismatch negativity (MMN) in healthy control participants and in patients with schizophrenia. Changes in grand magnetic field power (mGFP) over auditory cortex in response to a deviant stimulus (phoneme change) are significantly reduced in patients with schizophrenia bilaterally. Reproduced, with permission, from Yamasue et al. (2004).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2991173&req=5

Figure 2: Mismatch negativity (MMN) in healthy control participants and in patients with schizophrenia. Changes in grand magnetic field power (mGFP) over auditory cortex in response to a deviant stimulus (phoneme change) are significantly reduced in patients with schizophrenia bilaterally. Reproduced, with permission, from Yamasue et al. (2004).
Mentions: One cortical process extensively studied through MEG is the automatic response that is generated following a deviant stimulus in a train of auditory standards, or the mismatch negativity effect (MMN, or the magnetic equivalent, MMNm). This evoked response, which occurs 150–200 ms following a deviant stimulus, is thought to reflect, in healthy individuals, a pre-attentive process whose purpose is to reorient the individual towards a novel stimulus that has entered the environment (for a review, see Pulvermüller and Shtyrov, 2006). In patients with schizophrenia, the amplitude of the MMNm is generally reduced, across experimental designs and stimulus types (Figure 2, see Kasai et al., 2002; Kircher et al., 2004; Yamasue et al., 2004; Thönnessen et al., 2008). In schizophrenia, this deviation in MMNm is best produced in an optimum design paradigm (Näätänen et al., 2004), where the deviant occurs much more frequently in the stimulus train and is modified along one feature throughout stimulus presentation (either its frequency, intensity, duration, sound source or gap in tone, see Thönnessen et al., 2008). The MMNm is thought to be bilateral for categorical speech sound deviants (Kasai et al., 2002) and low MMNm amplitude may be due to, in part, reduced gray matter volume in the cortex along the planum temporale found in patients with schizophrenia (Yamasue et al., 2004). The demonstration of compromised gray matter density (and thus cortical function) in the temporal lobes of these patients are congruent with work in combined fMRI/MEG studies that examine MMNm in the patient and control group using both neuroimaging modalities (Kircher et al., 2004). In this study, reduced MMNm in patients with schizophrenia correlated with a decrease in BOLD signal in STG, along the planum temporale (secondary auditory cortex) but not in primary auditory cortex, along Heschl's gyrus (Kircher et al., 2004). Although a difference in MMN amplitude between patient and control groups is readily identifiable in averaged EEG sensor data, the sources that contribute to this deviation are likely to be far more complex than just reduced activity within secondary auditory areas. MMN represents a powerful and well-developed experimental paradigm used to assess auditory processing dysfunction in schizophrenia.

Bottom Line: Although studies utilizing electroencephalography (EEG), PET and fMRI have contributed significantly to our understanding of these mechanisms, magnetoencephalography (MEG) possesses great potential to answer long-standing questions linking brain interactions to cognitive operations in the disorder.Finally, both bivariate and multivariate functional connectivity metrics of MEG data are useful for understanding how these interactions in the brain are impaired in schizophrenia, and how cognitive and clinical outcomes are affected as a result.We also present here data from our own laboratory that illustrates how some of these novel functional connectivity measures, specifically imaginary coherence (IC), are quite powerful in relating disconnectivity in the brain to characteristic behavioral findings in the disorder.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Biomedical Imaging, University of California San Francisco, CA, USA.

ABSTRACT
The cognitive dysfunction present in patients with schizophrenia is thought to be driven in part by disorganized connections between higher-order cortical fields. Although studies utilizing electroencephalography (EEG), PET and fMRI have contributed significantly to our understanding of these mechanisms, magnetoencephalography (MEG) possesses great potential to answer long-standing questions linking brain interactions to cognitive operations in the disorder. Many experimental paradigms employed in EEG and fMRI are readily extendible to MEG and have expanded our understanding of the neurophysiological architecture present in schizophrenia. Source reconstruction techniques, such as adaptive spatial filtering, take advantage of the spatial localization abilities of MEG, allowing us to evaluate which specific structures contribute to atypical cognition in schizophrenia. Finally, both bivariate and multivariate functional connectivity metrics of MEG data are useful for understanding how these interactions in the brain are impaired in schizophrenia, and how cognitive and clinical outcomes are affected as a result. We also present here data from our own laboratory that illustrates how some of these novel functional connectivity measures, specifically imaginary coherence (IC), are quite powerful in relating disconnectivity in the brain to characteristic behavioral findings in the disorder.

No MeSH data available.


Related in: MedlinePlus