title: Trait- and state-dependent cortical inhibitory deficits in bipolar disorder.
abstract: Euthymic patients with bipolar disorder (BD) have deficits in cortical inhibition. However, whether cortical inhibitory deficits are trait- or state-dependent impairments is not yet known and their relationship with psychiatric symptoms is not yet understood. In the present study, we examined trait- and state-dependent cortical inhibitory deficits and evaluated the potential clinical significance of these deficits.
  
  
  
  Nineteen patients with bipolar I disorder were evaluated using the paired-pulse transcranial stimulation protocol, which assessed cortical inhibition during an acute manic episode. Cortical inhibition measures were compared with those obtained in 28 demographically matched healthy controls. A follow-up assessment was performed in 15 of these patients three months later, when there was remission from their mood and psychotic symptoms. The association between cortical inhibitory measures and severity of psychiatric symptoms was also studied.
  
  
  
  During mania, patients showed decreased short-interval intracortical and transcallosal inhibition, as well as a normal cortical silent period and long-interval cortical inhibition. These findings were the same during euthymia. Symptoms associated with motor hyperactivity were correlated negatively with the degree of cortical inhibition. These correlations were not significant when a Bonferroni correction was applied.
  
  
  
  The present longitudinal study showed cortical inhibitory deficits in patients with BD, and supports the hypothesis that cortical inhibitory deficits in BD are trait dependent. Further research is necessary to confirm the clinical significance of these deficits.
authors.affiliation: Grupo Neurodesarrollo y Psicosis, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla/UGC Salud Mental HVR, Seville, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Ruiz-Veguilla
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: Martín-Rodríguez
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Palomar
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Paolo
authors.initials: P
authors.lastname: Porcacchia
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Paloma
authors.initials: P
authors.lastname: Álvarez de Toledo
authors.affiliation: Grupo Neurodesarrollo y Psicosis, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla/UGC Salud Mental HVR, Seville, Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Perona-Garcelán
authors.affiliation: Grupo Neurodesarrollo y Psicosis, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla/UGC Salud Mental HVR, Seville, Spain.|Departamento de Personalidad, Evaluación y Tratamientos Psicológicos, Facultad de Psicología, Universidad de Sevilla, Seville, Spain.
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: Rodríguez-Testal
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Ismael
authors.initials: I
authors.lastname: Huertas-Fernández
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Seville, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Mir
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D002605:Character; D003337:Corpus Callosum / Q000503:physiopathology; D005260:Female; D006801:Humans; D007395:Interneurons / Q000502:physiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000502:physiology
chemical_list: D005680:gamma-Aminobutyric Acid
keywords: GABA receptors; cortical inhibition; longitudinal study; motor cortex; short-interval intracortical inhibition; transcallosal inhibition