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Chuan Hou, Kim Yee-Joon, Preeti Preeti Verghese; Attentional modulation is weak in V1 in human amblyopia. Journal of Vision 2014;14(10):702. doi: 10.1167/14.10.702.
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© ARVO (1962-2015); The Authors (2016-present)
It is well known that attention affects perception and selects informative neural populations as early as V1. However, it is not clear whether attentional modulation is affected by amblyopia. Here we used source-imaged steady-state visual evoked potentials (SSVEPs), to determine whether this is the case. Our stimulus design is essentially identical to the one used by Lauritzen et al (2010). We presented two 8 deg gratings, flickering at 12.5 and 16.7, with centers 7 deg to the left and right of fixation, respectively. Amblyopic observers fixated centrally and viewed the display monocularly while targets were presented bilaterally. A cue indicated that the observer should attend to left or right to detect a contrast increment on the cued grating. We recorded evoked responses at the second harmonic of the driving frequencies. Our data show that the modulation of the evoked response due to attention is different in amblyopic observers compared to observers with normal vision. Both eyes of amblyopic observers showed no attentional modulation in area hMT+, where previous studies showed strong attentional modulation in normal vision observers (Lauritzen et al., 2010). Morevoer, the pattern of attentional modulation was different between amblyopic and non-amblyopic eyes. The non-amblyopic eye showed attentional modulation in areas V1 and V4, while the amblyopic eye only showed attentional modulation in area V4, but not in V1. These findings indicate that the attentional modulation in V1 is strongly affected by amblyopia, even though the non-amblyopic eye shows clear attentional modulation in early visual areas.
Meeting abstract presented at VSS 2014
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