Abstract
Spatial and temporal expectations act synergistically to facilitate visual perception. In the current study, we sought to investigate the anticipatory oscillatory markers of combined spatial-temporal orienting and to test whether these decline with ageing. We examined anticipatory neural dynamics associated with joint spatial-temporal orienting of attention using magnetoencephalography (MEG) in both younger and older adults. Participants performed a cued covert spatial-temporal orienting task requiring the discrimination of a visual target. Cues indicated both where and when targets would appear. In both age groups, valid spatial-temporal cues significantly enhanced perceptual sensitivity and reduced reaction times. In the MEG data, the main effect of spatial orienting was the lateralised anticipatory modulation of posterior alpha and beta oscillations. In contrast to previous reports, this modulation was not attenuated in older adults; instead it was even more pronounced. The main effect of temporal orienting was a bilateral suppression of posterior alpha and beta oscillations. This effect was restricted to younger adults. Our results also revealed a striking interaction between anticipatory spatial and temporal orienting in the gamma-band (60–75 Hz). When considering both age groups separately, this effect was only clearly evident and only survived statistical evaluation in the older adults. Together, these observations provide several new insights into the neural dynamics supporting separate as well as combined effects of spatial and temporal orienting of attention, and suggest that different neural dynamics associated with attentional orienting appear differentially sensitive to ageing.
Highlights
IntroductionOur interactions with the world are adaptively shaped by our ability to anticipate relevant sensory events and orient our attention towards them
Our interactions with the world are adaptively shaped by our ability to anticipate relevant sensory events and orient our attention towards them. While such attentional orienting is classically studied with regard to how we orient our attention in space (i.e. “spatial orienting”; Posner et al, 1980), the question of how we orient our attention in time (i.e. “temporal orienting”) is relevant (Coull and Nobre, 1998; Nobre and Heideman, 2015; Nobre and van Ede, 2018)
Studies point to a synergistic interaction between spatial and temporal orienting in vision, whereby the influence of temporal expectations is pronounced when combined with spatial expectations (Doherty et al, 2005; Rohenkohl et al, 2014)
Summary
Our interactions with the world are adaptively shaped by our ability to anticipate relevant sensory events and orient our attention towards them. Most previous studies investigating anticipatory neural dynamics in humans have focused on oscillations below 30 Hz. One study in non-human primates showed that temporal orienting of attention may amplify higher-frequency gamma-band oscillations in visual cortex (Lima et al, 2011), which are suggested to reflect enhanced feedforward communication (Fries, 2015). One study in non-human primates showed that temporal orienting of attention may amplify higher-frequency gamma-band oscillations in visual cortex (Lima et al, 2011), which are suggested to reflect enhanced feedforward communication (Fries, 2015) It remains unclear whether visual gamma-band amplification can be observed during temporal orienting in humans and, if so, whether such anticipatory gamma modulations interact with spatial orienting
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