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Abnormal bihemispheric responses in schizophrenia patients following cathodal transcranial direct stimulation.

Hasan A, Aborowa R, Nitsche MA, Marshall L, Schmitt A, Gruber O, Falkai P, Wobrock T - Eur Arch Psychiatry Clin Neurosci (2012)

Bottom Line: On the non-stimulated hemisphere, RMTs were increased and MEPs were decreased only in the healthy control group.Dysfunctional N-methyl D-aspartate receptors or modulation of dopaminergic transmission can explain these findings.Nevertheless, the effects of antipsychotic medication still need to be considered.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry and Psychotherapy, Georg-August University, Göttingen, Germany. ahasan@gwdg.de

ABSTRACT
Post-mortem and in vivo studies provide evidence for a link between reduced plasticity and dysconnectivity in schizophrenia patients. It has been suggested that the association between plasticity and connectivity contributes to the pathophysiology and symptomatology of schizophrenia. However, little is known about the impact of glutamate-dependent long-term depression (LTD)-like cortical plasticity on inter-hemispheric connectivity in schizophrenia patients. The aim of the present study was to investigate LTD-like cortical plasticity following excitability-diminishing cathodal transcranial direct current stimulation (tDCS) of the left primary motor cortex (M1) and its effects on the non-stimulated right M1. Eighteen schizophrenia patients and 18 matched (age, gender, handedness, and smoking status) control subjects were investigated in this study. Corticospinal excitability changes following tDCS and intra-cortical inhibitory circuits were monitored with transcranial magnetic stimulation. On the stimulated hemisphere, cathodal tDCS increased resting motor thresholds (RMT) in both groups and decreased motor-evoked potential (MEP) sizes in healthy controls to a greater extent compared to schizophrenia patients. On the non-stimulated hemisphere, RMTs were increased and MEPs were decreased only in the healthy control group. Our results confirm previous findings of reduced LTD-like plasticity in schizophrenia patients and offer hypothetical and indirect in vivo evidence for an association between LTD-like cortical plasticity and inter-hemispheric connectivity in schizophrenia patients. Moreover, our findings highlight the impact of plasticity on connectivity. Dysfunctional N-methyl D-aspartate receptors or modulation of dopaminergic transmission can explain these findings. Nevertheless, the effects of antipsychotic medication still need to be considered.

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Related in: MedlinePlus

Absolute change of MEP size pre- and post-tDCS stimulation in healthy controls and schizophrenia patients. Baselines did not differ between groups on the left hemisphere (p > 0.05) and on the right hemisphere (p > 0.05). Cathodal tDCS reduced the MEP sizes on the stimulated left hemisphere in healthy controls (p < 0.001) and in the schizophrenia group (p = 0.001), whereas the decrease in MEP size was greater in the control group (p = 0.049). On the non-stimulated hemisphere, cathodal tDCS reduced MEP size in the control group (p = 0.026), but not in the schizophrenia group (p = 0.376). Therefore, MEP sizes were smaller in the control group (p = 0.031). Short horizontal line: significant differences before and after stimulation (paired-sample t test). Long horizontal line: significant “time × group” interaction (ANOVA)
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Fig1: Absolute change of MEP size pre- and post-tDCS stimulation in healthy controls and schizophrenia patients. Baselines did not differ between groups on the left hemisphere (p > 0.05) and on the right hemisphere (p > 0.05). Cathodal tDCS reduced the MEP sizes on the stimulated left hemisphere in healthy controls (p < 0.001) and in the schizophrenia group (p = 0.001), whereas the decrease in MEP size was greater in the control group (p = 0.049). On the non-stimulated hemisphere, cathodal tDCS reduced MEP size in the control group (p = 0.026), but not in the schizophrenia group (p = 0.376). Therefore, MEP sizes were smaller in the control group (p = 0.031). Short horizontal line: significant differences before and after stimulation (paired-sample t test). Long horizontal line: significant “time × group” interaction (ANOVA)

Mentions: PANSS Positive and Negative Syndrome Scale, GAF global assessment of functioning, CGI clinical global impression, CPZ chlorpromazine equivalent dose


Abnormal bihemispheric responses in schizophrenia patients following cathodal transcranial direct stimulation.

Hasan A, Aborowa R, Nitsche MA, Marshall L, Schmitt A, Gruber O, Falkai P, Wobrock T - Eur Arch Psychiatry Clin Neurosci (2012)

Absolute change of MEP size pre- and post-tDCS stimulation in healthy controls and schizophrenia patients. Baselines did not differ between groups on the left hemisphere (p > 0.05) and on the right hemisphere (p > 0.05). Cathodal tDCS reduced the MEP sizes on the stimulated left hemisphere in healthy controls (p < 0.001) and in the schizophrenia group (p = 0.001), whereas the decrease in MEP size was greater in the control group (p = 0.049). On the non-stimulated hemisphere, cathodal tDCS reduced MEP size in the control group (p = 0.026), but not in the schizophrenia group (p = 0.376). Therefore, MEP sizes were smaller in the control group (p = 0.031). Short horizontal line: significant differences before and after stimulation (paired-sample t test). Long horizontal line: significant “time × group” interaction (ANOVA)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3412954&req=5

Fig1: Absolute change of MEP size pre- and post-tDCS stimulation in healthy controls and schizophrenia patients. Baselines did not differ between groups on the left hemisphere (p > 0.05) and on the right hemisphere (p > 0.05). Cathodal tDCS reduced the MEP sizes on the stimulated left hemisphere in healthy controls (p < 0.001) and in the schizophrenia group (p = 0.001), whereas the decrease in MEP size was greater in the control group (p = 0.049). On the non-stimulated hemisphere, cathodal tDCS reduced MEP size in the control group (p = 0.026), but not in the schizophrenia group (p = 0.376). Therefore, MEP sizes were smaller in the control group (p = 0.031). Short horizontal line: significant differences before and after stimulation (paired-sample t test). Long horizontal line: significant “time × group” interaction (ANOVA)
Mentions: PANSS Positive and Negative Syndrome Scale, GAF global assessment of functioning, CGI clinical global impression, CPZ chlorpromazine equivalent dose

Bottom Line: On the non-stimulated hemisphere, RMTs were increased and MEPs were decreased only in the healthy control group.Dysfunctional N-methyl D-aspartate receptors or modulation of dopaminergic transmission can explain these findings.Nevertheless, the effects of antipsychotic medication still need to be considered.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry and Psychotherapy, Georg-August University, Göttingen, Germany. ahasan@gwdg.de

ABSTRACT
Post-mortem and in vivo studies provide evidence for a link between reduced plasticity and dysconnectivity in schizophrenia patients. It has been suggested that the association between plasticity and connectivity contributes to the pathophysiology and symptomatology of schizophrenia. However, little is known about the impact of glutamate-dependent long-term depression (LTD)-like cortical plasticity on inter-hemispheric connectivity in schizophrenia patients. The aim of the present study was to investigate LTD-like cortical plasticity following excitability-diminishing cathodal transcranial direct current stimulation (tDCS) of the left primary motor cortex (M1) and its effects on the non-stimulated right M1. Eighteen schizophrenia patients and 18 matched (age, gender, handedness, and smoking status) control subjects were investigated in this study. Corticospinal excitability changes following tDCS and intra-cortical inhibitory circuits were monitored with transcranial magnetic stimulation. On the stimulated hemisphere, cathodal tDCS increased resting motor thresholds (RMT) in both groups and decreased motor-evoked potential (MEP) sizes in healthy controls to a greater extent compared to schizophrenia patients. On the non-stimulated hemisphere, RMTs were increased and MEPs were decreased only in the healthy control group. Our results confirm previous findings of reduced LTD-like plasticity in schizophrenia patients and offer hypothetical and indirect in vivo evidence for an association between LTD-like cortical plasticity and inter-hemispheric connectivity in schizophrenia patients. Moreover, our findings highlight the impact of plasticity on connectivity. Dysfunctional N-methyl D-aspartate receptors or modulation of dopaminergic transmission can explain these findings. Nevertheless, the effects of antipsychotic medication still need to be considered.

Show MeSH
Related in: MedlinePlus