Prestimulus feedback connectivity biases the content of visual experiences

Abstract

Ongoing fluctuations in neural excitability and in networkwide activity patterns before stimulus onset have been proposed to underlie variability in near-threshold stimulus detection paradigms—that is, whether or not an object is perceived. Here, we investigated the impact of prestimulus neural fluctuations on the content of perception—that is, whether one or another object is perceived. We recorded neural activity with magnetoencephalography (MEG) before and while participants briefly viewed an ambiguous image, the Rubin face/vase illusion, and required them to report their perceived interpretation in each trial. Using multivariate pattern analysis, we showed robust decoding of the perceptual report during the poststimulus period. Applying source localization to the classifier weights suggested early recruitment of primary visual cortex (V1) and ∼160-ms recruitment of the category-sensitive fusiform face area (FFA). These poststimulus effects were accompanied by stronger oscillatory power in the gamma frequency band for face vs. vase reports. In prestimulus intervals, we found no differences in oscillatory power between face vs. vase reports in V1 or in FFA, indicating similar levels of neural excitability. Despite this, we found stronger connectivity between V1 and FFA before face reports for low-frequency oscillations. Specifically, the strength of prestimulus feedback connectivity (i.e., Granger causality) from FFA to V1 predicted not only the category of the upcoming percept but also the strength of poststimulus neural activity associated with the percept. Our work shows that prestimulus network states can help shape future processing in category-sensitive brain regions and in this way bias the content of visual experiences.

Connectomics of Human Electrophysiology

“…A number of perception studies in MEG/EEG sourcespace have taken a hypothesis-driven approach to selecting a small number of relevant regions activated by the task at hand. Among these task-related regions, prestimulus phase coupling affects perceptual decisions in various task settings and sensory modalities (Hanslmayr et al, 2007;Keil et al, 2014;Rassi et al, 2019). Further, beyond perception tasks, cognitive control processes such as top-down inhibition are affected by prestimulus connectivity states over and above the impact of prestimulus power (Hamm et al, 2012).…”

Response dependence of reversal‐related ERP components in perception of ambiguous figures

“…Before making firm conclusions, we set out to replicate the Experiment 1 results in an additional experiment using a different visual stimulus. Because it has been widely studied as an example of perceptual ambiguity (e.g., Hesselmann et al., 2008; Pitts et al., 2007; Rassi, Wutz, Müller‐Voggel, & Weisz, 2019), we chose Rubin's faces‐vase (Figure 1d) as the ambiguous stimulus for Experiment 2. Otherwise, the design of Experiment 2 was the same as that in Experiment 1.…”

Preparatory delta phase response is correlated with naturalistic speech comprehension performance

“…While this direct evidence has not been investigated in the speech domain, studies on general sensory processing have provided support for the existence of such a preparatory process. In the visual domain, the amplitude and phase of pre-stimulus oscillatory activities, especially in the alpha band, have been reported to have a significant impact on subsequent perceptual consequences, (Van Dijk et al 2008;Kok et al 2017;Harris et al 2018;Galindo-Leon et al 2019;Rassi et al 2019), such as threshold-level perception, attention orientation, visual search performance, etc.…”

“…Specifically, the TRF-based responses were further decomposed into amplitude and phase responses, as amplitude and phase have been proposed to play unique roles in networks underlying human cognition (Bonnefond and Jensen 2012;Engel et al 2013;Fries 2015). Following the studies on the perceptual influence of pre-stimulus neural activities (Smith et al 2006;Iemi et al 2019;Rassi et al 2019;Avramiea et al 2020), we were interested in whether the TRF-based responses at the preparatory stage could be correlated to speech comprehension performance, as measured by speech-content-related questionnaires, and how amplitude and phase responses contributed to speech preparation. With the employment of the cocktail party paradigm, we also addressed the issue about the attention-dependency of the to-beexplored performance-related preparatory activities.…”