Regulating the Access to Awareness: Brain Activity Related to Probe-related and Spontaneous Reversals in Binocular Rivalry

The Role of Momentary Dissociation in the Sensory Cortex: A Neurophysiological Review and its Implications for Maladaptive Daydreaming

Daydreaming, a form of spontaneous and self-generated mental process, may lead to the disintegration of attention from the immediate external environment. In extreme cases, patients may develop maladaptive daydreaming comorbid with dissociation. The examination of dissociative alterations frequently occurs within the framework of complex cognitive processes. While dissociation may be a neurological and psychological dysfunction of integration, transient dissociative occurrences, i.e., momentary dissociation may signify a dynamic interplay between attentional division and orientation within the sensory cortex. Furthermore, previous studies have recorded the interactivity of attention by stimuli onset with P3 event-related potentials and the active suppression of distractor positivity. In this context, during auditory and visual mismatch negativity, the sensory cortex may interact with attentional orientation. Additionally, distractor positivity during task-relevant stimuli may play a crucial role in predicting momentary dissociation since sensory cortices share cerebral correlates with attentional fluctuations during mental imagery. Thus, this theoretical review investigated the cerebral activities associated with attentional orientation and may be extended to mindfulness. By integrating these findings, we aim to provide a comprehensive understanding of dissociative states which may lead to a resolution for dissociative psychopathology.

Bistability of prefrontal states gates access to consciousness

Access of sensory information to consciousness has been linked to the ignition of content-specific representations in association cortices. How does ignition interact with intrinsic cortical state fluctuations to give rise to conscious perception? We addressed this question in the prefrontal cortex (PFC) by combining multi-electrode recordings with a binocular rivalry (BR) paradigm inducing spontaneously driven changes in the content of consciousness, inferred from the reflexive optokinetic nystagmus (OKN) pattern. We find that fluctuations between low-frequency (LF, 1-9 Hz) and beta (∼20-40 Hz) local field potentials (LFPs) reflect competition between spontaneous updates and stability of conscious contents, respectively. Both LF and beta events were locally modulated. The phase of the former locked differentially to the competing populations just before a spontaneous transition while the latter synchronized the neuronal ensemble coding the consciously perceived content. These results suggest that prefrontal state fluctuations gate conscious perception by mediating internal states that facilitate perceptual update and stability.

Probing the mechanisms of probe-mediated binocular rivalry

Binocular rivalry occurs when incompatible images are presented simultaneously but separately to each eye. Perceptual dominance reverses over time such that one image temporarily dominates perception, while the other image is suppressed. Prior research has shown that briefly-presented probes modulate perception such that probes presented to the suppressed eye tend to produce shorter percept durations relative to when probes are presented to the dominant eye. This pattern suggests that probes strengthen the competitive strength of the image over which they appear. However, it remains unclear whether probe-modulated effects on binocular rivalry are equivalent across the visual field, in particular as a function of whether probes appear within the region of interocular conflict (i.e on-object) or outside the region of interocular conflict (i.e. off-object). We tested this by manipulating whether probes appeared on-object or off-object. We replicate prior work showing that suppressed-eye probes produce shorter percept durations relative to dominant-eye probes. Critically, however, we show that percept duration also varies as a function of whether probes appear on vs. off the rivalry objects; that is, differences in percept duration between suppressed-eye and dominant-eye probes were much larger for on-object than off-object probes. Importantly, however, the difference between suppressed-eye and dominant-eye probes was still significant for off-object probes. Together these results suggest dynamic mechanisms at work in probe-mediated rivalry, such that on-object probe effects are larger relative to smaller, yet reliable off-object effects.