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Craig Arnold, Matthew Belmonte, Christina Howard; Individual differences in position tracking are related to peak occipital alpha frequency . Journal of Vision 2016;16(12):1258. doi: 10.1167/16.12.1258.
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© 2017 Association for Research in Vision and Ophthalmology.
Although position tracking has been well studied, its underlying neurophysiological mechanisms remain poorly understood. Individual differences in temporal and spatial aspects of position tracking can be exploited to elucidate such mechanisms. Individual differences in peak alpha frequency (PAF) have been linked to several cognitive tasks. Because the phase of alpha oscillations appears to predict perception of stimuli (e.g. Busch et al., 2009) it has been suggested to be the cause of periodic updating of perception. How neural oscillations contribute to sustaining attention to moving targets has not, to our knowledge, been investigated. If rhythmic processes do play a role in position updating during tracking, this may have implications for parallel/serial tracking mechanisms. We asked observers to attempt to track the position of either one or both of two discs. After a period of semi-random motion, both discs disappeared and observers indicated the final position of one target. We calculated spatial errors: the distance between the final position and the reported final positions of queried objects. We found poorer spatial precision for monitoring two targets than a single target, consistent with a resource model of position perception. On average, people tended to report slightly out of date positions, that is to say that reports exhibited perceptual lags (e.g. Howard & Holcombe, 2008). In a separate recording block we recorded observers' resting alpha activity. We assessed individuals' PAF as the greatest mode of the occipital EEG power spectrum between 8-12 Hz. We did not observe a strong relationship between PAF and perceptual lags as may be predicted from oscillation-based explanations of lags. However individuals' PAF was correlated with position report precision such that slower peak alpha was associated with greater spatial precision. We suggest a possible role for the period of alpha oscillations in determining the accumulation of spatially precise position information.
Meeting abstract presented at VSS 2016
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