The ongoing search for neural correlates of consciousness: does the P300 reflect conscious perception or its consequences?
Date
2015
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Tartu Ülikool
Abstract
A common scientific strategy towards understanding consciousness is to study neural
correlates of consciousness (NCC) for a particular conscious percept. It can be done by
contrasting conditions in which subjects are aware and unaware of a particular visual
stimulus. However, recent findings have been contradictory and this approach appears not to
reveal only the NCC, but also the prerequisites or consequences of consciousness. The goal
of the present study was to investigate whether the P300 component often claimed to be a key
signature of conscious access might actually rather reflect the consequences of conscious
perception. Twenty-one healthy subjects participated in the EEG experiment where most of
the stimuli were clearly perceived and only a quartile of trials was associated with not
perceiving the target. The visual masking paradigm used no discrimination task, always the
same stimulus was presented and the additional task was given together with the target
stimulus. Results indicate that trials where subjects reported to have seen the stimulus are
associated with a higher P300. Hence, the present data support the theories, which claim that P300 is a marker of conscious perception.