CONTEXT: Neural plasticity in the human cortex involves a reorganization of synaptic connections in an effort to adapt to a changing environment. In schizophrenia, dysfunctional neural plasticity has been proposed as a key pathophysiological mechanism. OBJECTIVE: To evaluate neural plasticity in unmedicated and medicated patients with schizophrenia compared with healthy subjects. DESIGN: Neural plasticity can be evaluated from the motor cortex in healthy subjects using transcranial magnetic stimulation through a paradigm known as use-dependent plasticity. This paradigm involves several steps: (1) measuring the spontaneous direction of transcranial magnetic stimulation-induced thumb movements; (2) training subjects to practice thumb movements opposite to this baseline direction for 30 minutes; and (3) measuring the direction of transcranial magnetic stimulation-induced thumb movement after training. Previous experiments have shown that in healthy subjects, posttraining transcranial magnetic stimulation-induced movements occur in a vector commensurate with the practiced movements, which may be associated with time-limited reorganization of motor circuits. SETTING: All of the participants were recruited and evaluated at the Centre for Addiction and Mental Health. PARTICIPANTS: Fourteen medicated and 6 unmedicated patients with schizophrenia and 20 healthy subjects were recruited. MAIN OUTCOME MEASURE: It was anticipated that patients with schizophrenia would demonstrate attenuated motor reorganization in the direction of training. RESULTS: Both medicated and unmedicated patients with schizophrenia demonstrated significantly reduced motor reorganization compared with healthy subjects. CONCLUSIONS: It is possible that in schizophrenia, these deficits in neural plasticity are related to disturbances of gamma-aminobutyric acid, N-methyl-D-aspartate neurotransmission, or dopamine that may potentially account for the aberrant motor performance of these patients.
CONTEXT: Neural plasticity in the human cortex involves a reorganization of synaptic connections in an effort to adapt to a changing environment. In schizophrenia, dysfunctional neural plasticity has been proposed as a key pathophysiological mechanism. OBJECTIVE: To evaluate neural plasticity in unmedicated and medicated patients with schizophrenia compared with healthy subjects. DESIGN: Neural plasticity can be evaluated from the motor cortex in healthy subjects using transcranial magnetic stimulation through a paradigm known as use-dependent plasticity. This paradigm involves several steps: (1) measuring the spontaneous direction of transcranial magnetic stimulation-induced thumb movements; (2) training subjects to practice thumb movements opposite to this baseline direction for 30 minutes; and (3) measuring the direction of transcranial magnetic stimulation-induced thumb movement after training. Previous experiments have shown that in healthy subjects, posttraining transcranial magnetic stimulation-induced movements occur in a vector commensurate with the practiced movements, which may be associated with time-limited reorganization of motor circuits. SETTING: All of the participants were recruited and evaluated at the Centre for Addiction and Mental Health. PARTICIPANTS: Fourteen medicated and 6 unmedicated patients with schizophrenia and 20 healthy subjects were recruited. MAIN OUTCOME MEASURE: It was anticipated that patients with schizophrenia would demonstrate attenuated motor reorganization in the direction of training. RESULTS: Both medicated and unmedicated patients with schizophrenia demonstrated significantly reduced motor reorganization compared with healthy subjects. CONCLUSIONS: It is possible that in schizophrenia, these deficits in neural plasticity are related to disturbances of gamma-aminobutyric acid, N-methyl-D-aspartate neurotransmission, or dopamine that may potentially account for the aberrant motor performance of these patients.
Authors: Andrew Zalesky; Alex Fornito; Marc L Seal; Luca Cocchi; Carl-Fredrik Westin; Edward T Bullmore; Gary F Egan; Christos Pantelis Journal: Biol Psychiatry Date: 2010-10-29 Impact factor: 13.382
Authors: Idil Cavuş; Robert M G Reinhart; Brian J Roach; Ralitza Gueorguieva; Timothy J Teyler; Wesley C Clapp; Judith M Ford; John H Krystal; Daniel H Mathalon Journal: Biol Psychiatry Date: 2012-03-15 Impact factor: 13.382