Probing the Prerequisites for Motion Blindness

Abstract

Neurobiological studies of visual awareness usually focus on the neural events elicited by perceived or nonperceived stimuli but neglect the preexisting conditions that allow (or prevent) conscious perception. We have examined the conditions that lead to temporary motion blindness in a rapid serial visual presentation paradigm, in which subjects have to detect coherent motion in the peripheral stream after a cue (a red fixation point) in the central stream. The failure of awareness depends critically on the occurrence of similar coherent motion events (probes) before the cue. Event-related brain potentials (ERPs) were recorded to track the processing of motion distractors, which determine the prerequisites for this transient deficit. Analysis of motion-evoked responses revealed that there is no progressive reduction in sensitivity in early visual processing. There is, however, a progressive increase in amplitude of a negative wave over the frontal cortex at approximately 250 msec after motion onset and a corresponding reduction of a centro-parietal positivity at approximately 350 msec with an increasing number of distractors. We propose that these nonsensory ERP components reflect a postperceptual frontal gating mechanism that controls the access of visual stimuli to higher order evaluation and conscious detection.

A primer on motion visual evoked potentials

“…The study showed that both the motion N2 and the cognitive P300 component were reduced, but only the P300 showed a correlation with the psychophysical performance in individual trials, suggesting that sensory processing does not account for the impairment in coherence detection. This was confirmed by a second study, where Niedeggen et al [158] recorded VEPs to motion distractors to track sensory processing. In an experiment involving direction changes of two transparently moving surfaces, Rodríguez and Valdé s-Sosa [159] investigated how the occurrence of one stimulus affects the N2 recorded to a second stimulus that was presented shortly after the first one.…”

Closing the Gates to Consciousness: Distractors Activate a Central Inhibition Process

“…Using ERPs, we have been able to identify a neural correlate of this inhibitory mechanism. With increasing number of distractors, a frontal negativity (FN), peaking at about 250 msec after distractor onset, was found to be more expressed (Niedeggen, Hesselmann, Sahraie, Milders, & Blakemore, 2004). In a recent study on the attentional blink, a similar ERP component has been reported (Zhang, Zhou, & Martens, 2009).…”

Open and closed cortico-subcortical loops: A neuro-computational account of access to consciousness in the distractor-induced blindness paradigm

“…Our model is in line with existing empirical evidence and provides specific predictions for future experiments that will be outlined below. Niedeggen, Hesselmann, Sahraie, Milders, and Blakemore (2004) recorded ERPs during a distractor-induced blindness paradigm and concluded that the inhibition of target perception occurs at a post-sensory level. In a later study, moreover, they showed that the inhibition causes an ERP EEG negativity over frontal cortical areas (Niedeggen et al, 2012).…”

“…As a consequence, the model does not account for findings that the blindness effect increases in magnitude with increasing numbers of distractors (Hesselmann et al, 2006;Michael et al, 2011;Niedeggen et al, 2004Niedeggen et al, , 2012. Moreover, the current implementation of the reset pulse that terminates reverberation of activity in the closed frontal loop is of a rather abstract nature as it is evoked from outside the model rather than originating from model dynamics.…”