Spontaneous slow cortical potentials and brain oscillations independently influence conscious visual perception.

Perceptual awareness results from an intricate interaction between external sensory input and the brain's spontaneous activity. Pre-stimulus ongoing activity influencing conscious perception includes both brain oscillations in the alpha (7 to 14 Hz) and beta (14 to 30 Hz) frequency ranges and aperiodic activity in the slow cortical potential (SCP, <5 Hz) range. However, whether brain oscillations and SCPs independently influence conscious perception or do so through shared mechanisms remains unknown.

Memory representations during slow change blindness.

Classic change blindness is the phenomenon where seemingly obvious changes that coincide with visual disruptions (such as blinks or brief blanks) go unnoticed by an attentive observer. Some early work into the causes of classic change blindness suggested that any pre-change stimulus representation is overwritten by a representation of the altered post-change stimulus, preventing change detection. However, recent work revealed that, even when observers do maintain memory representations of both the pre- and post-change stimulus states, they can still miss the change, suggesting that change blindness can also arise from a failure to compare the stored representations.

A novel, semi-automatic procedure for generating slow change blindness stimuli.

Change blindness is the phenomenon that occurs when an observer fails to notice what would seem to be obvious changes in the features of a visual stimulus. Researchers can induce this experimentally by including visual disruptions (such as brief blanks) that coincide with the changes in question. However, change blindness can also occur in the absence of these disruptions if a change occurs sufficiently slowly.

Unconscious Touch Perception After Disruption of the Primary Somatosensory Cortex.

Brain damage or disruption to the primary visual cortex sometimes produces blindsight, a striking condition in which patients lose the ability to consciously detect visual information yet retain the ability to discriminate some attributes without awareness. Although there have been few demonstrations of somatosensory equivalents of blindsight, the lesions that produce "numbsense," in which patients can make accurate guesses about tactile information without awareness, have been rare and localized to different regions of the brain. Despite transient loss of tactile awareness in the contralateral hand after transcranial magnetic stimulation (TMS) of the primary somatosensory cortex but not TMS of a control site, 12 participants (six female) reliably performed at above-chance levels on a localization task.

Dissociations of conscious and unconscious perception in TMS-induced blindsight.

As with some patients with primary visual cortex (V1) damage, transcranial magnetic stimulation (TMS) over V1 reliably induces blindsight, whereby observers can correctly discriminate the attributes of visual stimuli despite being unable to detect them. This TMS-induced blindsight has been demonstrated to reflect a form of unconscious vision that relies upon different neural pathways than with conscious vision. However, the timing of the neural processes mediating TMS-induced blindsight has been unclear, especially when considering suggestions that TMS interferes with feedback processes to V1 that mediate conscious visual perception.