Alpha-band sensory entrainment alters the duration of temporal windows in visual perception

Abstract

The phase and frequency of neural oscillations in the alpha band (8–12 Hz) have been recently proposed as key parameters for the temporal resolution of visual perception. Here, we tested the possible causal links between these oscillatory features and temporal integration/segregation. The individual alpha frequency (IAF) peak as obtained from resting-state electroencephalography was used to set the frequency of sensory (audio-visual) entrainment for the lower (IAF − 2 Hz) and upper (IAF + 2 Hz) alpha. Entrainment at IAF ± 2 Hz was administered in the prestimulus interval to align oscillations to a faster or slower rhythm. We densely sampled in time the accuracy for integration/segregation by using identical stimuli with different instructions. The spectral peaks of performance fluctuations over time were found in the upper or lower alpha band for the IAF + 2 and IAF − 2 Hz entrainment, respectively, implying that faster entrainment resulted in faster behavioral fluctuations. Moreover, the entrainment frequency had opposite effects on temporal resolution: faster entrainment improved segregation while slower entrainment improved integration. Performance fluctuations were almost in anti-phase between the two tasks, such that highest integration performance coincided with lowest segregation performance. These findings provide evidence for a direct link between changes in the alpha band and the temporal resolution of perception.

Oscillatory Properties of Functional Connections Between Sensory Areas Mediate Cross-Modal Illusory Perception

“…In this respect, there is ample evidence that, in isolation, visual and auditory sensory processing are governed by oscillatory activity in the alpha band (Ergenoglu et al, 2004;Hanslmayr et al, 2007;Romei et al, 2008aRomei et al, ,b, 2010Van Dijk et al, 2008;Dugué et al, 2011;Weisz et al, 2011;Frey et al, 2014), while somatosensory processing typically occurs within the beta band (Salenius and Hari, 2003;Foffani et al, 2005;Engel and Fries, 2010;Baumgarten et al, 2015). While there is abundant documentation of the relationship of visual processing with alpha oscillations, and with the speed of alpha frequency (Samaha and Postle, 2015;Wutz et al, 2016Wutz et al, , 2018Gulbinaite et al, 2017;Minami and Amano, 2017;Ronconi et al, 2018), there is little empirical evidence highlighting the specific oscillatory nature of the interaction between multiple senses. We and other groups have shown that the impact of simple auditory stimulation on visual processing seems to be governed by the way sounds phase align alpha oscillatory activity in the occipital cortex (Teplan et al, 2003;Romei et al, 2012;Mercier et al, 2013;Frey et al, 2014;Gleiss and Kayser, 2014).…”

Visual Entrainment at 10 Hz causes periodic modulation of the Flash Lag Illusion

“…The idea of a discrete sampling mechanism in vision affecting temporal perception has enjoyed a recent upswing in interest. Most recently it was shown that audio-visual entrainment at a participant’s individual alpha frequency influences performance in a visual integration/segregation task (Ronconi et al, 2018). Similarly, the phase of alpha oscillations can predict performance in a synchronous/asynchronous task (Milton & Pleydell-Pearce, 2016; Valera et al, 1981).…”

“…To our knowledge only one study has succeeded in this so far. In a recent publication by Ronconi et al (Ronconi, Busch, & Melcher, 2018) it was shown that visuo-auditory entrainment at the individuals alpha frequency + or – 2 Hz was able to modulate the integration or segregation of two stimuli in close temporal proximity. In this study we seek to provide an important addition to these findings by demonstrating a causal influence of alpha on the perception of time, using a well investigated visual illusion, the flash lag effect (FLE).…”

Anomalous Perception of Biological Motion in Autism: A Conceptual Review and Meta-Analysis

“…TBWs can shrink or expand also as a result of synchronization of brain rhythms (i.e. entrainment) (Ronconi, Busch, & Melcher, 2018;Ronconi & Melcher, 2017), or after few days of perceptual learning trainings (Powers, Hevey, & Wallace, 2012;Powers, Hillock, & Wallace, 2009;Stevenson, Wilson, Powers, & Wallace, 2013). Intriguingly, the hypothesis of a temporal processing anomaly as one of the key aspects responsible for BM deficits observed in ASD would be consistent with the involvement of the cerebellum and its bidirectional connectivity with the right posterior superior temporal sulcus (STS), which represent an important part of the network involved in the processing of BM (Jack, Keifer, & Pelphrey, 2017;Sokolov et al, 2012Sokolov et al, , 2014Sokolov, Gharabaghi, Tatagiba, & Pavlova, 2010;Sokolov et al, 2018) as we will discuss in the next subsection.…”