hemispheric differences
Research Papers
Exploring Hemispheric Differences in Infrared Brain Emissions
Background. Carmen (Toomim & Carmen, 1999) has shown that training to increase frontal lobe infrared emissions with neurofeedback techniques inhibits migraine pain, but nothing is known about the psychological correlates of the infrared signal. We assess if reading out loud would increase activation in the left hemisphere in comparison to the right. We also assessed test/retest reliability by repeating measures a week later. Methods. Measurements of infrared activity, while reading or not, were taken three times from the left, center, and right forehead of 24 persons who had signed Institutional Review Board approved consent forms. The order of reading and non-reading was varied systematically. Results. Significant differences in activation favoring the right rather than the left hemisphere were found, but only in those who read first. Both order-of-reading groups significantly declined in overall activity during the second session. Five of six Pearson correlations measuring test/retest reliabilities in the reading-first group and two of six in the reading-second group attained statistical significance. Only measurements taken at the left forehead site were reliable across all four conditions, which represent the combination of two orders and two types of stimulation. Conclusions. Test/retest correlations provide some support for the inference that the infrared measures reflect enduring traits, especially in the left hemisphere. Hemispheric difference data suggest that infrared emissions were sensitive to processes such as orientation, habituation and attention. There was no evidence of sensitivity to left hemisphere specialization for verbal processing.
View Full Paper →EEG Measures of Cerebral Asymmetry: Conceptual and Methodological Issues
An overview of the use of EEG to assess hemispheric differences in cognitive and affective processes is presented. Some of the advantages of using EEG to assess asymmetric hemispheric differences in the study of complex mental activity are described. Following this brief introduction, two conceptual issues which are central to studies of EEG asymmetries are introduced: (1) the distinction between hemispheric specialization and activation, and (2) the importance of rostral-caudal differences for the understanding of both specialization and activation. Three methodological issues in the use of EEG to assess hemispheric differences are then presented: (1) the use of asymmetry metrics, (2) muscle artifact, and (3) appropriate reference electrode location. Finally, some empirical examples of using EEG to assess affective and cognitive processes which illustrate these conceptual and methodological issues are described.
View Full Paper →Ready to Optimize Your Brain?
Schedule a free consultation to discuss hemispheric differences and how neurofeedback training can help
Or call us directly at 855-88-BRAIN
View Programs & Pricing →