The School of Psychology is proudly hosting a talk by:
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
(frini.karayanidis@newcastle.edu.au).
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.
