title: Impaired inter-hemispheric facilitatory connectivity in schizophrenia.
abstract: OBJECTIVE
  To investigate the inter-hemispheric connections between the dorsal premotor cortex (dPM) and contralateral primary motor cortex (M1) in schizophrenia.
  
  
  METHODS
  Sixteen medicated, nine unmedicated schizophrenia patients and 20 healthy age-matched subjects were studied by twin-coil Transcranial Magnetic Stimulation. To activate distinct facilitatory and inhibitory transcallosal pathways between dPM and the contralateral M1, the intensity of dPM stimulation was adjusted to be either suprathreshold (110% of resting motor threshold) or subthreshold (80% of active motor threshold). Interstimulus intervals between conditioning stimulus and test stimulus were 6, 8 and 15 ms.
  
  
  RESULTS
  Schizophrenia patients had comparable efficacy of the inhibitory pathway. On the other hand, medicated patients showed less facilitation of contralateral M1 following dPM stimulation at 80% of active motor threshold, at interstimulus interval=8 ms. The individual amount of facilitation induced by dPM conditioning at 80% of active motor threshold at interstimulus interval=8 ms correlated negatively with negative symptoms.
  
  
  CONCLUSIONS
  Inter-hemispheric facilitatory dPM-M1 connectivity is selectively altered in schizophrenia.
  
  
  CONCLUSIONS
  This study produced evidence that dPM-M1 connectivity is dysfunctional and that correlates with negative symptoms. These results converge with previous studies which strongly hypothesize that inter- and intra-hemispheric connectivity disturbances may play a major role in schizophrenia.
authors.affiliation: Clinica Psichiatrica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy. Electronic address: michele.81@live.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Ribolsi
authors.affiliation: Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Mori
authors.affiliation: Clinica Psichiatrica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Magni
authors.affiliation: Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Codecà
authors.affiliation: Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy.
authors.forename: Hajime
authors.initials: H
authors.lastname: Kusayanagi
authors.affiliation: Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy.
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Monteleone
authors.affiliation: Clinica Psichiatrica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy.
authors.forename: Ivo Alex
authors.initials: IA
authors.lastname: Rubino
authors.affiliation: Clinica Psichiatrica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Siracusano
authors.affiliation: Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy; Centro Europeo per la Ricerca sul Cervello (CERC)/Fondazione Santa Lucia IRCCS, Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bernardi
authors.affiliation: Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy; Centro Europeo per la Ricerca sul Cervello (CERC)/Fondazione Santa Lucia IRCCS, Rome, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Centonze
authors.affiliation: Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy; Centro Europeo per la Ricerca sul Cervello (CERC)/Fondazione Santa Lucia IRCCS, Rome, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Koch
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology; D003337:Corpus Callosum / Q000503:physiopathology*; D003627:Data Interpretation, Statistical; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology; D009434:Neural Pathways / Q000502:physiology; D012559:Schizophrenia / Q000188:drug therapy / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents