Dr. Vinh Nguyen
Queensland Brain Institute, The University of Queensland, Brisbane, Qld.
Title: Fusing concurrent EEG-fMRI data: Application to correlation and connectivity during face perception
Date: Thursday 11th April 2013, 12-1pm in Keats Reading Room (AVLG17) (video streaming to AV3 in the Ourimbah library)
If you would like to meet with Dr. Nguyen, please contact A/Prof Frini Karayanidis (firstname.lastname@example.org).
Abstract: Despite the wealth of research on face perception, the interactions between core regions in the face-sensitive network of the visual cortex are not well understood. In particular, the link between neural activity measured by fMRI and EEG is not well established. I will present studies using a trial-by-trial correlation and dynamic causal modelling (DCM) as a data fusion approach to integrate concurrently acquired EEG and fMRI signals during the perception of faces. First, we introduce a method for single-trial estimation of N170 amplitudes and correlation of the trial-by-trial variation in N170 neural responses with fMRI. For upright faces, BOLD responses in the right superior temporal sulcus (STS) were negatively correlated with N170 amplitudes. For inverted faces, a medial region of the medial fusiform gyrus (mFG) was positively correlated with N170 amplitudes. Second, the DCM analysis suggests that the occipital face area (OFA) acted as a central gatekeeper directing visual information to the superior temporal sulcus, the fusiform face area (FFA) and to the mFG. The connection from the OFA and the STS was enhanced on trials in which N170 amplitudes to upright faces were large. In contrast, the connection from the OFA to the mFG was enhanced for inverted faces, and the enhancement was even stronger in trials in which the N170 amplitudes were small. The FFA, on the other hand, provides feedback connection to the OFA, and integrates connection from both the OFA and STS for holistic face processing. Together, these results suggest that trial-by-trial variation in neural activity at around 170 ms, reflected in the N170 component, reflects the relative engagement of the OFA to STS/FFA network over the OFA to mFG object processing network for face perception
Bio: Vinh is a PhD student of the Cunnington lab at the Queensland Brain Institute. Before joining QBI, Vinh did his computer science undergraduate degree at the University of Newcastle from 2004 to 2008. During his undergraduate program, Vinh worked as a research assistant for the ASRB project, then did his Honours project with A/Prof Frans Henskens on the development of an automatic MRI segmentation method. He graduated the computer science degree with first class honours and won a University medal. Vinh moved QBI in 2009 to pursue his PhD under the supervision of A/Prof Ross Cunnington and Prof Michael Breakspear. His project is looking at combining EEG and fMRI techniques to correlate the high temporal information of EEG signals with high spatial resolution of fMRI signals.