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Consciousness absent and present: a neurophysiological exploration
1University of Oxford, Department of Experimental Psychology, Oxford OX1 3UD, UK. edmund.rolls@psy.ox.ac.uk
Progress in Brain Research
|December 4, 2003
Summary
Neuronal activity in the visual cortex allows face discrimination even without conscious awareness. Higher neuronal firing and information are needed for conscious face identification, suggesting a threshold for conscious perception.
Area of Science:
- Neuroscience
- Cognitive Science
- Visual Perception
Background:
- Investigating the neural basis of conscious visual perception.
- Understanding the role of the inferior temporal visual cortex in face recognition.
Purpose of the Study:
- To quantify neuronal activity and information content during conscious and unconscious face perception.
- To determine the neural threshold for conscious visual identification.
Main Methods:
- Utilizing backward masking to disrupt visual processing in macaque monkeys.
- Measuring neuronal firing rates and information content in the inferior temporal cortex.
- Correlating neural data with human psychophysical performance and subjective reports.
Main Results:
- Neuronal activity can discriminate faces even when conscious identification is absent.
- Increased neuronal firing and information transfer correlate with conscious face recognition.
- A threshold exists for conscious perception, higher than that for basic stimulus discrimination.
Conclusions:
- Conscious visual perception requires a higher level of neuronal activity and information processing than unconscious discrimination.
- The brain may filter out less significant neural signals to prevent interruption of conscious thought processes.
- This study quantifies the neural correlates of conscious versus unconscious visual processing.