BIPOLAR DISORDER AS FAILURE OF INTERHEMISPHERIC INHIBITION

This paper has three parts. In the first part we introduce G. Munévar’s hypothesis about the neuroscience of bipolar disorder. According to this hypothesis, bipolar disorder is a failure of interhemispheric inhibition in the frontal lobe. When the electrical activation of the left side overwhelms that of the right, the left frontal lobe dominates, thus leading to exaggerated states of ela- tion (or others that also constitute mania). Dominance in activation by the right side, in turn, leads to states of depression. The neuroscience literature already offers a large amount of support for this hypothesis, as we explain. The second part describes our own study using transcranial direct current stimulation (tDCS) to successfully decrease positive moods in 25 healthy individuals. This result was obtained by connecting the tDCS electrodes to the right hemisphere of the frontal lobe of participants while they viewed arousing pictures (from the International Affective Picture Scale), which accords with the hypothesis. The third part gives a working outline for a potential new study to establish the hypothesis of frontal lobe interhemispheric inhibition failure in bipolar disorder. This study would use a new functional brain imaging technology based on qEEG: standardized weighted low-resolution electromagnetic tomography (swLORETA). If successful, this study may lead to electrical-stimulation therapy for bipolar disorder patients.