Poster No:
2069
Submission Type:
Abstract Submission
Authors:
Jessica Taubert1, Amanda Robinson2, Jason Mattingley3
Institutions:
1University of Queensland, Brisbane, Queensland, 2The University of Queensland, St Lucia, QLD, 3University of Queensland, St Lucia, Queensland
First Author:
Co-Author(s):
Introduction:
According to a prominent view in neuroscience, high-level visual stimuli are encoded by discrete areas located along the ventral visual cortex. Neurons in these areas respond preferentially to specific visual categories such as objects, scenes and faces. Although these areas are thought to contribute directly to conscious perception and recognition, activity has almost always been measured while stimuli were presented in isolation and behind a central fixation point, a situation atypical of the real world. How these areas respond under more naturalistic conditions remains largely unknown (Taubert et al., 2022). For example, we do not yet understand whether activity in the fusiform face area (FFA) is modulated by competition from nearby stimuli in cluttered visual environments. Here, we used high-field (7T) functional MRI to address this fundamental question.
Methods:
We scanned healthy adults (N=20) across two separate scan sessions using a 7-T Magnetom MRI scanner. In the first scan session we collected independent localiser data and used this to define the Fusiform Face Area (FFA) and the Parahippocampal Place Area (PPA) in both hemispheres. In the main experiment, participants were shown images of 45 faces and 45 objects at different horizontal locations (i.e., at fixation, left visual field and right visual field) in the presence or absence of competing visual inputs (i.e., scenes occupying the remaining screen locations). To maintain their attention in the centre of the screen, we asked participants to detect changes in the contrast of the central fixation point. We used a rapid event-related design whereby stimulus displays were shown for 200 ms, followed by a 300 ms inter-stimulus interval. The EPI sequence parameters reflected this experimental design (TR = 0.5, TE = 25.20, flip angle = 40 deg, voxel size = 1.8 mm ^ 3).
Results:
We found that the human FFA responds more to faces than objects, even when there are competing visual stimuli present. This represents a significant departure from what has been observed in the macaque brain. We also found that the adjacent PPA responds more to objects than faces, even when there are competing visual stimuli present. Thus, this immunity to competition is not unique to face-selective regions. Interestingly, we also found evidence that the left FFA has a preference for peripheral faces and shows a contralateral bias, whereas there was no such pattern for the right FFA. The PPA showed a preference for peripheral objects, with a contralateral bias in both hemispheres.
Conclusions:
Collectively, these findings provide important clues about how the ventral visual cortex responds to multiple, competing, stimuli present in the visual field.
Emotion, Motivation and Social Neuroscience:
Social Cognition
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI) 2
Novel Imaging Acquisition Methods:
BOLD fMRI
Perception, Attention and Motor Behavior:
Perception: Visual 1
Keywords:
Cognition
Cortex
FUNCTIONAL MRI
Perception
Vision
1|2Indicates the priority used for review
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Please indicate below if your study was a "resting state" or "task-activation” study.
Task-activation
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Healthy subjects
Was this research conducted in the United States?
No
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel?
NOTE: Any human subjects studies without IRB approval will be automatically rejected.
Yes
Were any animal research approved by the relevant IACUC or other animal research panel?
NOTE: Any animal studies without IACUC approval will be automatically rejected.
Not applicable
Please indicate which methods were used in your research:
Functional MRI
For human MRI, what field strength scanner do you use?
7T
Which processing packages did you use for your study?
AFNI
Provide references using APA citation style.
Taubert, J., et al., (2022). Clutter Substantially Reduces Selectivity for Peripheral Faces in the Macaque Brain. Journal of Neuroscience, 42(35), 6739-50.
No