Evidence of Serial Dependence from Decoding of Visual Evoked Potentials

Abstract

It is well known that recent sensory experience influences perception, recently demonstrated by a phenomenon termed “serial dependence.” However, its underlying neural mechanisms are poorly understood. We measured ERP responses to pairs of stimuli presented randomly to the left or right hemifield. Seventeen male and female adults judged whether the upper or lower half of the grating had higher spatial frequency, independent of the horizontal position of the grating. This design allowed us to trace the memory signal modulating task performance and also the implicit memory signal associated with hemispheric position. Using classification techniques, we decoded the position of the current and previous stimuli and the response from voltage scalp distributions of the current trial. Classification of previous responses reached full significance only 700 ms after presentation of the current stimulus, consistent with retrieval of an activity-silent memory trace. Cross-condition classification accuracy of past responses (trained on current responses) correlated with the strength of serial dependence effects of individual participants. Overall, our data provide evidence for a silent memory signal that can be decoded from the EEG potential, which interacts with the neural processing of the current stimulus. This silent memory signal could be the physiological substrate subserving at least one type of serial dependence.SIGNIFICANCE STATEMENTThe neurophysiological underpinnings of how past perceptual experience affects current perception are poorly understood. Here, we show that recent experience is reactivated when a new stimulus is presented and that the strength of this reactivation correlates with serial biases in individual participants, suggesting that serial dependence is established on the basis of a silent memory signal.

Feature-specific reactivations of past information shift current neural encoding thereby mediating serial bias behaviors

“…A recent interesting study revealed brief reactivation of past spatial information during the intertrial interval (ITI) [33], while here we observed the concurrent emergence of past reactivation and present information after the stimulus, as also revealed in other EEG findings [30][31][32]. Both findings support past reactivation from an activity-silent to an activity-based state for serial bias to occur, but at different time points, i.e., prestimulus versus poststimulus.…”

“…Additionally, we aimed to find the neural signature of multiple features, so focusing on broad-band signals rather than specific neural rhythms would be a more conservative choice. In fact, broad-band decoding has been widely used in a series of WM studies (e.g., [ 22 , 27 , 56 , 57 ]) and serial dependence works [ 30 – 32 ].…”

“…Interestingly, recent WM studies suggest that although information could be retained in an "activity-silent" state [21][22][23][24][25][26][27], memory operations still rely on the activation of neural representations [28,29]. Accordingly, previous studies have demonstrated that past-trial information is reactivated when processing new inputs, a process that potentially contributes to serial bias [30][31][32]. Moreover, a recent study observed that previous information remained in activity-silent traces reappeared before the stimulus, and the reactivation strength correlates with the strength of serial bias [33].…”

Spatial correspondence in relative space regulates serial dependence

“…However, there are also good reasons to expect that the alternative scenario is at work. From a bottom-up, mechanistic perspective, the influence of preceding stimuli on ensuing stimuli may reflect the sensory-level carry-over effects induced by the lingering or reactivated traces of neural activity associated with the previous stimuli [34][35][36] . If such sensorylevel mechanisms mediate serial dependence, then the spatial specificity of serial dependence will be better accounted for in retinotopic coordinates, as previously observed in a single-target situation 5,14 .…”

Serial Dependence in face-gender classification revealed in low-beta frequency EEG

“…Beta oscillations (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) have been linked to several perceptual, motor and cognitive processes [8][9][10][11][12]. Especially the lower range (up to ~18 Hz) of beta oscillations may play a fundamental role in maintenance of working memory [13][14][15].…”