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Short- and long-term stability of alpha asymmetry in infants: Baseline and affective measures
Rebecca J Brooker1, Mara J Canen1, Richard J Davidson2
1Department of Psychology, Montana State University, Bozeman, Montana.
Insights
Cortical activity asymmetry in infants shows moderate short-term stability during neutral and fear states. Long-term stability of hemispheric asymmetry is evident by 12 months of age.
Area of Science:
- Neuroscience
- Developmental Psychology
- Infant Brain Development
Background:
- Cortical activity asymmetry is a key indicator of brain function.
- Understanding its stability in infancy is crucial for developmental research.
- Previous studies have yielded mixed results on infant asymmetry stability.
Purpose of the Study:
- To assess the short- and long-term stability of cortical activity asymmetry in infants.
- To examine stability across different conditions (baseline, negative, positive emotions).
- To investigate stability at frontal and parietal electrode sites.
Main Methods:
- Longitudinal study with 129 infants across four lab visits at 6 and 12 months.
- Electroencephalography (EEG) recorded during neutral baselines and emotion-eliciting tasks.
- Analysis of hemispheric asymmetry at midfrontal (F3/4, F7/8) and parietal (P3/4) sites.
Main Results:
- Moderate short-term stability of asymmetry observed during baseline and fear-eliciting tasks.
- Significant long-term stability of asymmetry demonstrated when data from 6 and 12 months were combined.
- Frontal asymmetry exceeded parietal asymmetry during baseline recordings.
- Minimal stability of asymmetry was found during positive emotion tasks.
Conclusions:
- Cortical activity asymmetry exhibits moderate short-term and good long-term stability in infants.
- Findings support the reliability of alpha asymmetry measures in infancy, particularly for baseline and negative emotional states.
- Further research is needed to understand asymmetry during positive emotional experiences in infants.
Abstract:
Asymmetry in cortical activity was tested for short- and long-term stability during the first year of life. Infants (N = 129) completed a total of four laboratory visits: two visits occurred about 1 week apart when infants were 6 months old, and two visits occurred about 1 week apart when infants were 12 months of age. At each laboratory visit, EEG readings were taken during five 1-min, neutral baselines as well as during a negative and a positive emotion-eliciting task. The stability of hemispheric asymmetry was assessed at midfrontal (F3/4, F7/8) and parietal (P3/4) electrode sites. Asymmetry in baseline and fear-eliciting episodes showed moderate short-term stability. Long-term stability was apparent when assessments were composited at 6 months and 12 months. Frontal asymmetry was greater than parietal asymmetry for baseline recordings. There was minimal evidence for stability in asymmetry during positive emotion tasks. Results are discussed with regard to the collection and interpretation of alpha asymmetry measures during infancy.