Different Electrophysiological Correlates of Visual Awareness for Detection and Identification.
Mika Koivisto, Simone Grassini, Niina Salminen-Vaparanta, Antti Revonsuo
Journal of cognitive neuroscience September 1, 2017 DOI: 10.1162/jocn_a_01149 via PubMed
Summary
AI-generated from the abstractConscious detection of an object and conscious identification of that object rely on different neural processes. In an experiment measuring event-related potentials (ERPs), participants performed tasks requiring either detection or identification of a visual stimulus. Behaviorally, a stimulus could be consciously detected without being identified. A posterior electrophysiological signature occurring 200-300 milliseconds after stimulus onset was sensitive to conscious detection but not to identification, which correlated with later widespread brain activity. These findings provide behavioral and neural evidence for elementary visual experiences that are not yet enriched with higher-level knowledge, suggesting that research on consciousness should focus on early phenomenal experiences to avoid confounding effects of higher-level processes.
Study at a glance
| Characteristics | Experimental study Peer reviewed |
|---|---|
| Key finding | Conscious detection and conscious identification of a visual stimulus have distinct neural correlates: a posterior ERP signature 200-300 ms after stimulus onset is specific to detection, while identification correlates with later widespread activity. |
Abstract
Detecting the presence of an object is a different process than identifying the object as a particular object. This difference has not been taken into account in designing experiments on the neural correlates of consciousness. We compared the electrophysiological correlates of conscious detection and identification directly by measuring ERPs while participants performed either a task only requiring the conscious detection of the stimulus or a higher-level task requiring its conscious identification. Behavioral results showed that, even if the stimulus was consciously detected, it was not necessarily identified. A posterior electrophysiological signature 200-300 msec after stimulus onset was sensitive for conscious detection but not for conscious identification, which correlated with a later widespread activity. Thus, we found behavioral and neural evidence for elementary visual experiences, which are not yet enriched with higher-level knowledge. The search for the mechanisms of consciousness should focus on the early elementary phenomenal experiences to avoid the confounding effects of higher-level processes.