Effect of Dorsomedial Prefrontal GABA Levels on Brain Perfusion in People at Ultra High Risk for Psychosis

Presentation First Author: 
Gemma Modinos

Background: Altered cortical _-aminobutyric acid (GABA)ergic function has been proposed to play a critical role in the dopamine elevations classically observed in psychosis. In addition, increased levels of brain perfusion have been largely documented in patients with psychosis, thought to arise from such neurochemical alterations. Whether GABAergic function is related to brain perfusion before the onset of psychotic disorder is unknown. Methods: We assessed GABA levels in the dorsomedial prefrontal cortex (dMPFC) in 18 individuals who met criteria for an Ultra High Risk of psychosis (UHR) using proton magnetic resonance (MR) spectroscopy at 3.0 Tesla. All spectra were analysed using LCModel. Brain perfusion was measured with arterial spin labeling (ASL) perfusion MRI. ASL images were preprocessed with SPM8. Correlations between whole-brain perfusion levels and GABA concentrations in the dMPFC were assessed with multiple regression in SPM8, including age and gender as covariates of no interest. Effects were considered significant at p<.05 after="" family-wise="" error="" correction="" for="" multiple="multiple" comparisons="" at="" the="" cluster="" level.="" results:="" dmpfc="" gaba="" levels="" were="" negatively="" correlated="" with="" brain="" perfusion="" in="" inferior="" and="" medial="" frontal="" gyrus.="" a="" positive="" correlation="" was="" observed="" between="" right="" amygdala="" left="" posterior="" cingulate="" gyrus="" cerebellum.="" conclusions:="" our="" findings="" indicate="" an="" effect="" of="" concentrations="" on="" limbic="" subcortical="" regions.="" this="" is="" consistent="" notion="" that="" gabaergic="" abnormalities="" are="" associated="" changes="" function="" these="" interactions="" involved="" increasing="" vulnerability="" to="" psychosis.="">

Conference Name: 
Presentation Date: 
January, 2015
Additional Authors: 
Fatma Simsek - Matthijs Bossong - Carly Samson - Matilda Azis - Beverly Quinn - Ilaria Bonoldi - Oliver Howes - James Stone - Paul Allen - Philip McGuire
See other presentations in this session: