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Simen Hagen, James Tanaka; Exploring expert object recognition by the means of fast periodic visual stimulation. Journal of Vision 2015;15(12):617. doi: 10.1167/15.12.617.
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© ARVO (1962-2015); The Authors (2016-present)
Expert category domains are thought to be instantiated within the human ventral visual pathway. For instance, differential responses to expert domains (e.g., faces, birds, cars, novel objects) have been shown in spatially localized areas using functional magnetic resonance imaging. In the current study we used fast periodic visual stimulation (FPVS) to explore the neural sensitivity to expert categories. Electroencephalogram was recorded from bird experts and bird novices, each presented with two trials of 60s sequences containing a base-bird (A, e.g., american robin) sinusoidally contrast-modulated at a presentation rate of 6 images per second (F=6Hz) with size varying every cycle to control for low-level adaptation effects. At every 5th cycle (F/5=1.2Hz), a different oddball-bird (e.g., northern cardinal, anna’s hummingbird…) (B, C…) substituted the repeating base-bird (i.e., AAAABAAAACAAAAD…). The results showed that despite changes in low-level information (i.e., image size), the experts showed an adaptation in the right occipito-temporal channels (PO8, P8) in response to the base-bird within the first 18s of the 60s sequence, whereas the novices showed a sustained signal-to-noise ratio (SNR) throughout the entire sequence. For the oddball-birds, both experts and novices showed a significant SNR at the fundamental 1.2 Hz frequency and its harmonics that remained sustained across the entire 60s sequence and that peaked at the right occipito-temporal channels (PO8, P8). In summary, the experts but not the novices showed an adaption to the base-birds, however, within the same sequence, both the experts and novices showed a sustained response to the oddball-birds. These results indicate that the response to the base-bird and oddball-birds are dissociated in experts, but not the novices.
Meeting abstract presented at VSS 2015
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