BACKGROUND: Recent advances have highlighted the hypothesis of schizophrenia as a disorder causing defective connectivity among distinct cortical regions. Neurophysiological evidence supporting this hypothesis, however, is still lacking. METHODS: In the present study, we used a novel twin-coil transcranial magnetic stimulation (tcTMS) approach to investigate ipsilateral parieto-motor connectivity in 20 schizophrenic patients (14 medicated, 6 unmedicated) and in 15 healthy age-matched volunteers. RESULTS: In healthy subjects, a conditioning TMS pulse applied over the ipsilateral posterior parietal cortex (PPC) at 90% of resting motor threshold (RMT) intensity was able to increase the excitability of the hand area of the right primary motor cortex, with peaks at interstimulus intervals (ISIs) of 4 and 15 msec. This paradigm of stimulation failed to reveal any facilitatory parieto-motor interaction in medicated and unmedicated schizophrenic patients. The between-group difference in paired-pulse facilitation was not ISI-specific. In following analyses, we found that the effects across ISIs induced by PPC conditioning at 90% RMT correlated with the Global Assessment Functioning score and with the negative subscale of the Positive and Negative Syndrome Scale, showing that patients with a better global functioning and lower negative symptoms had less impaired connectivity. Moreover the same parameter correlated with illness duration. CONCLUSIONS: Parieto-motor connectivity is impaired in schizophrenia. Cortico-cortical disconnection might be a core feature of schizophrenia.
BACKGROUND: Recent advances have highlighted the hypothesis of schizophrenia as a disorder causing defective connectivity among distinct cortical regions. Neurophysiological evidence supporting this hypothesis, however, is still lacking. METHODS: In the present study, we used a novel twin-coil transcranial magnetic stimulation (tcTMS) approach to investigate ipsilateral parieto-motor connectivity in 20 schizophrenicpatients (14 medicated, 6 unmedicated) and in 15 healthy age-matched volunteers. RESULTS: In healthy subjects, a conditioning TMS pulse applied over the ipsilateral posterior parietal cortex (PPC) at 90% of resting motor threshold (RMT) intensity was able to increase the excitability of the hand area of the right primary motor cortex, with peaks at interstimulus intervals (ISIs) of 4 and 15 msec. This paradigm of stimulation failed to reveal any facilitatory parieto-motor interaction in medicated and unmedicated schizophrenicpatients. The between-group difference in paired-pulse facilitation was not ISI-specific. In following analyses, we found that the effects across ISIs induced by PPC conditioning at 90% RMT correlated with the Global Assessment Functioning score and with the negative subscale of the Positive and Negative Syndrome Scale, showing that patients with a better global functioning and lower negative symptoms had less impaired connectivity. Moreover the same parameter correlated with illness duration. CONCLUSIONS: Parieto-motor connectivity is impaired in schizophrenia. Cortico-cortical disconnection might be a core feature of schizophrenia.
Authors: Giacomo Koch; Diane Ruge; Binith Cheeran; Miguel Fernandez Del Olmo; Cristiano Pecchioli; Barbara Marconi; Viviana Versace; Emanuele Lo Gerfo; Sara Torriero; Massimiliano Oliveri; Carlo Caltagirone; John C Rothwell Journal: J Physiol Date: 2009-07-21 Impact factor: 5.182
Authors: Thomas Wobrock; Alkomiet Hasan; Berend Malchow; Claus Wolff-Menzler; Birgit Guse; Nicolas Lang; Thomas Schneider-Axmann; Ullrich K H Ecker; Peter Falkai Journal: Psychopharmacology (Berl) Date: 2009-12-09 Impact factor: 4.530
Authors: Renaud Jardri; Kenneth Hugdahl; Matthew Hughes; Jérôme Brunelin; Flavie Waters; Ben Alderson-Day; Dave Smailes; Philipp Sterzer; Philip R Corlett; Pantelis Leptourgos; Martin Debbané; Arnaud Cachia; Sophie Denève Journal: Schizophr Bull Date: 2016-06-03 Impact factor: 9.306