Exploring Hemispheric Differences in Infrared Brain Emissions

Résumé

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.