title: Neural correlates of tactile prepulse inhibition: a functional MRI study in normal and schizophrenic subjects.
abstract: Prepulse inhibition (PPI) of the startle reflex refers to the ability of a weak prestimulus, the prepulse, to inhibit the response to a closely following strong sensory stimulus, the pulse. PPI is found to be deficient in a number of psychiatric and neurological disorders associated with abnormalities at some level in the limbic and cortico-pallido-striato-thalamic circuitry. We applied whole-brain functional magnetic resonance imaging to elucidate the neural correlates of PPI using airpuff stimuli as both the prepulse and the pulse in groups of (i) healthy subjects and (ii) schizophrenic patients. Cerebral activation during prepulse-plus-pulse stimuli with stimulus-onset asynchronies of 120 ms was contrasted with activation during pulse-alone stimuli. In healthy subjects, PPI was associated with increased activation bilaterally in the striatum extending to hippocampus and thalamus, right inferior frontal gyrus and bilateral inferior parietal lobe/supramarginal gyrus, and with decreased activation in the right cerebellum and left medial occipital lobe. All activated regions showed significantly greater response in healthy subjects than schizophrenic patients, who also showed a trend for lower PPI. The findings demonstrate involvement of the striatum, hippocampus, thalamus, and frontal and parietal cortical regions in PPI. Dysfunctions in any of these regions may underlie observations of reduced PPI in schizophrenia.
authors.affiliation: Section of Cognitive Psychopharmacology, Institute of Psychiatry, King's College, De Crespigny Park, London SE5 8AF, UK. v.kumari@iop.kcl.ac.uk
authors.forename: Veena
authors.initials: V
authors.lastname: Kumari
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Gray
authors.forename: Mark A
authors.initials: MA
authors.lastname: Geyer
authors.forename: Dominic
authors.initials: D
authors.lastname: ffytche
authors.forename: William
authors.initials: W
authors.lastname: Soni
authors.forename: Martina T
authors.initials: MT
authors.lastname: Mitterschiffthaler
authors.forename: Goparlen N
authors.initials: GN
authors.lastname: Vythelingum
authors.forename: Andrew
authors.initials: A
authors.lastname: Simmons
authors.forename: Steve C R
authors.initials: SC
authors.lastname: Williams
authors.forename: Tonmoy
authors.initials: T
authors.lastname: Sharma
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D003342:Corpus Striatum / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000503:physiopathology; D009433:Neural Inhibition / Q000502:physiology*; D009434:Neural Pathways / Q000503:physiopathology; D010296:Parietal Lobe / Q000503:physiopathology; D012016:Reference Values; D013216:Reflex, Startle / Q000502:physiology*; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013788:Thalamus / Q000503:physiopathology; D014110:Touch / Q000502:physiology