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Brain slow potential changes elicited by missing stimuli and by externally paced voluntary responses
Biological Psychology
|August 1, 1980
Summary
Missing auditory stimuli can trigger slow potential shifts, known as contingent negative variations (CNVs), in the brain. These findings highlight the role of internal brain processes over external stimuli in cognitive tasks.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Electrophysiology
Background:
- Contingent Negative Variation (CNV) is a slow negative potential shift observed in electroencephalography (EEG) during warned reaction time tasks.
- Previous research has primarily focused on the role of external stimuli in eliciting CNVs.
Purpose of the Study:
- To investigate the generation of slow potential shifts, specifically CNVs, in response to omitted auditory stimuli.
- To explore the cortical origins and endogenous determinants of missing stimulus potentials.
- To characterize slow potential shifts preceding self-initiated responses.
Main Methods:
- Recorded brain evoked potentials from the scalp of 22 normal subjects and the cortex of two patients.
- Utilized a warned foreperiod response task with conditions involving expected auditory stimuli omissions.
- Analyzed slow potential shifts preceding self-initiated, externally paced responses to auditory clicks.
Main Results:
- Stimulus omissions were found to reliably initiate contingent negative variations (CNVs).
- Slow potential shifts exceeding 3 seconds preceded self-initiated responses, containing elements of both CNV and Bereitschaftspotential.
- The negative component of missing stimulus potentials closely matched the N1 component of click-evoked potentials in latency and amplitude, contrary to prior reports.
- Experiments confirmed the cortical origin of missing stimulus potentials and their dependence on endogenous factors.
Conclusions:
- Missing stimulus potentials, including CNVs, are significantly influenced by endogenous factors rather than solely by external stimulus properties.
- The findings suggest that slow potential shifts reflect increasing cortical involvement during response preparation, particularly in self-initiated actions.
- The study provides evidence for the cortical generation of responses to omitted stimuli and clarifies their relationship with other event-related potentials.