RESUMO
OBJECTIVES: Clinical and electrophysiological studies suggest that panic disorder (PD) patients show disturbed response inhibition to sensory stimuli. Thus, habituation of neuronal activation after repeated sine tone stimulation was assessed by functional magnetic resonance imaging (fMRI) in patients with PD. METHODS: Twenty patients with PD and 20 age- and gender-matched healthy controls were assessed by 3T fMRI for auditory habituation. During three stimulation cycles of digitally generated pulsed (ν=5 Hz) 800-Hz sine tones alternating with silent periods, activation of the auditory cortex and other anxiety- or sensory integration-related regions was assessed. Brain activation was further analyzed dependent on functional serotonin transporter (5-HTT) gene variation (5-HTTLPR). RESULTS: PD patients demonstrated an extended brain activity in the first stimulation block, which normalized during the second stimulation cycle. A positive correlation with anxiety measures (HAMA) and an increased activity of distinct anxiety- or sensory integration-related areas (e.g., BA 22, BA 10) were seen during the third block of auditory stimulation. There was a significant interaction of left amygdala activation and the 5-HTTLPR S allele. CONCLUSIONS: Our results support the hypothesis of an aberrant processing of sensory information in PD patients. This phenomenon may underlie an enhanced responsiveness to anxiety-relevant or irrelevant stimuli possibly increasing PD vulnerability.
Assuntos
Atenção/fisiologia , Percepção Auditiva/fisiologia , Encéfalo/fisiopatologia , Aumento da Imagem , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Transtorno de Pânico/fisiopatologia , Estimulação Acústica , Adulto , Alelos , Tonsila do Cerebelo/fisiopatologia , Ansiedade/diagnóstico , Ansiedade/genética , Ansiedade/fisiopatologia , Ansiedade/psicologia , Nível de Alerta/fisiologia , Córtex Auditivo/fisiopatologia , Mapeamento Encefálico , Núcleo Caudado/fisiopatologia , Dominância Cerebral/fisiologia , Feminino , Lobo Frontal/fisiopatologia , Genótipo , Humanos , Masculino , Vias Neurais/fisiopatologia , Oxigênio/sangue , Transtorno de Pânico/diagnóstico , Transtorno de Pânico/genética , Transtorno de Pânico/psicologia , Projetos Piloto , Filtro Sensorial/fisiologia , Proteínas da Membrana Plasmática de Transporte de Serotonina/genéticaRESUMO
Previous studies on neuronal activation correlates of panic attacks were mostly based on challenge tests, sensory-related stimulation or fear conditioning in healthy subjects. In the present study, we report on a female patient with panic disorder experiencing a spontaneous panic attack under an auditory habituation paradigm in the last stimulation block with sine tones captured with fMRI at 3T. The panic attack was associated with a significantly increased activity in the right amygdala. This is the first report on neuronal activation correlates of a spontaneous panic attack in a patient with panic disorder as measured by fMRI, which lends further support to a pivotal role of the amygdala in the pathogenesis of the disease.