Spontaneous recovery of effects of contrast adaptation without awareness

Abstract

Prolonged exposure to a high contrast stimulus reduces the neural sensitivity to subsequent similar patterns. Recent work has disclosed that contrast adaptation is controlled by multiple mechanisms operating over differing timescales. Adaptation to high contrast for a relatively longer period can be rapidly eliminated by adaptation to a lower contrast (or meanfield in the present study). Such rapid deadaptation presumably causes a short-term mechanism to signal for a sensitivity increase, canceling ongoing signals from long-term mechanisms. Once deadaptation ends, the short-term mechanism rapidly returns to baseline, and the slowly decaying effects in the long-term mechanisms reemerge, allowing the perceptual aftereffects to recover during continued testing. Although this spontaneous recovery effect is considered strong evidence supporting the multiple mechanisms theory, it remains controversial whether the effect is mainly driven by visual memory established during the initial longer-term adaptation period. To resolve this debate, we used a modified Continuous Flash Suppression (CFS) and visual crowding paradigms to render the adapting stimuli invisible, but still observed the spontaneous recovery phenomenon. These results exclude the possibility that spontaneous recovery found in the previous work was merely the consequence of explicit visual memory. Our findings also demonstrate that contrast adaptation, even at the unconscious processing levels, is controlled by multiple mechanisms.

The Role of Bottom-Up and Top-Down Cortical Interactions in Adaptation to Natural Scene Statistics

“…The human visual system optimally adapts to the changes in the natural environment which span different timescales. As suggested by previous studies, multiple adaptive mechanisms potentially underlie adaptation at different timescales (Bao and Engel, 2012; Bao et al, 2013; Mei et al, 2015). However, if these multiple adaptive mechanisms correspond to the dynamic synapses in the recurrent FF-FB streams of the cortical circuitry has not been previously assessed.…”

Repeated Contrast Adaptation Does Not Cause Habituation of the Adapter

“…Thus, the account of habituation of adaptation mechanism can be tested in future work where, for example, SSVEP amplitudes for stimuli in different contrasts are measured prior to and following adaptation. Furthermore, visual adaptation has been found to operate at different timescales and processing stages (Vul et al, 2008 ; Bao and Engel, 2012 ; Mei et al, 2017 ). Neural recordings at different sites on the visual pathway may also provide more insight into the origin of habituation of visual adaptation.…”

Augmented Reality as a Tool for Studying Visual Plasticity: 2009 to 2018

“…One prediction of this multiple-mechanism theory is that residual effects of long-term adaptation will spontaneously reemerge following a short-term deadaptation that cancels the long-term effects. Such “spontaneous recovery” of long-term aftereffects has been observed in a number of studies covering many different types of visual adaptation (Bao & Engel, 2012; Bao, Fast, Mesik, & Engel, 2013; Haak et al, 2014; Mei, Dong, Dong, & Bao, 2015; Mei, Yuan, Liu, Pan, & Bao, 2018; Mesik, Bao, & Engel, 2013). It appears to be a general rule in the visual system that multiple distinct mechanisms control visual adaptation over different time scales that can range from milliseconds to days.…”