No evidence that predictions and attention modulate the first feedforward sweep of cortical information processing

Abstract

Influential theories propose that sensory predictions based on regularities in the environment influence information processing across the cortical hierarchy, and that attention may regulate these effects. At present, it is unclear if predictions can modulate the first feedforward sweep of visual information processing, and how this depends on attention. To address this outstanding issue, we orthogonally manipulated visuospatial predictions and attention, and used EEG and a design optimized to measure activity generated by primary visual cortex. Evidence was only found for later (>80ms) top-down modulation of cortical activity. These results have important theoretical implications in that they suggest, together with previous attention studies, that the very first stage of cortical visual information processing may generally be impenetrable to top-down influences.2009). Crucially, as prediction and attention may have opposite effects on sensory processing, with predictions reducing sensory responses and attention boosting sensory responses, their effects on visual processing may cancel out when not properly controlled for in experimental designs, potentially explaining the absence of C1 modulations in previous studies. Thus, at present, it is unclear whether predictions and attention can modulate the first feedforward sweep of cortical visual information processing, and if so, how.Here, we orthogonally manipulated prediction (stimulus location predictability) and attention (relevance), and exploited the high temporal resolution of EEG, to test this issue. Next to examining modulations of the C1, we used multivariate pattern analysis (MVPA) to further investigate how early prediction and attention may modulate visual representations. Lastly, we also explored their effects on pre-stimulus activity, indicative of a top-down bias, and on several later ERP components that capture subsequent processing stages.

Learning What Is Irrelevant or Relevant: Expectations Facilitate Distractor Inhibition and Target Facilitation through Distinct Neural Mechanisms

“…It is possible that these modulations were masked by overlapping P1/N1 ERPs evoked by the other stimuli in the display. Alternatively, and in line with the longer-latency N2pc and Pd effects, findings from several recent studies also indicate that expectations may modulate only later stages of information processing (Rungratsameetaweemana et al, 2018;Alilović et al, 2019). Thus, effects of expectation seem to strongly depend on the extent to which the predicted features are relevant for performance, whether positively (as is the case for targets) or negatively (as is the case for distractors).…”

“…In addition to expectation, preparatory attention also induces stimulus templates in sensory cortex that facilitate target selection (Myers et al, 2015). Expectation and attention also interact, such that top-down biasing, as reflected in prestimulus alpha lateralization, is most pronounced when targets also most likely occur at the cued, task-relevant location (Alilović et al, 2019). Thus, taskrelevant expectations may bias corresponding visual regions in advance to facilitate goal-directed behavior.…”

Inhibition in selective attention

“…Synaptic memory traces provide a more efficient coding scheme than active suppression through inhibition, and could explain longer lasting effects of learning on distractor interference. The notion of synaptic plasticity as a mechanism underlying statistical learning can also be reconciled with proposals that expectations exert their influence only after the bottom-up stimulus has been initially processed, during later stages of sensory processing (84,119).…”

“…For example, a recent MEG study showed expectation-dependent sensory templates already before stimulus onset (83). Expectations (stimulus likelihood) and attention (stimulus relevance) also interact, such that top-down biasing, as reflected in pre-stimulus alpha-lateralization, is most pronounced when targets are also most likely occur at the cued, task-relevant location (84). Thus, expectations may modulate activity in corresponding sensory regions in advance to facilitate goal-directed behavior.…”

“…Thus, expectations may modulate activity in corresponding sensory regions in advance to facilitate goal-directed behavior. Nevertheless, it is still debated how early expectations modulate stimulus processing, with several recent EEG studies suggesting that expectations may primarily affect later stages of information processing (84,85). In addition, how distractor-specific expectations may help resolve interference at the neural level remains unclear, as very few neuroimaging studies have so far investigated how distractor learning helps to filter out visual distractions.…”