Premium
Elevated mirror neuron system activity in bipolar mania: Evidence from a transcranial magnetic stimulation study
Author(s) -
Basavaraju Rakshathi,
Mehta Urvakhsh M.,
PascualLeone Alvaro,
Thirthalli Jagadisha
Publication year - 2019
Publication title -
bipolar disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.285
H-Index - 129
eISSN - 1399-5618
pISSN - 1398-5647
DOI - 10.1111/bdi.12723
Subject(s) - mania , psychology , disinhibition , transcranial magnetic stimulation , bipolar disorder , audiology , mood , empathy , mirror neuron , young mania rating scale , neuroscience , developmental psychology , clinical psychology , stimulation , psychiatry , medicine
Objectives The role of the “mirror neuron system” (MNS) in the pathophysiology of mood disorders is not well studied. Given its posited role in the often‐impaired socio‐emotional processes like intention detection, empathy, and imitation, we compared putative MNS‐activity in patients with bipolar mania and healthy comparison subjects. We also examined the association between putative MNS‐activity and hyper‐imitative behaviors in patients. Methods We studied 39 medication‐free individuals diagnosed with mania and 45 healthy comparison subjects. TMS‐evoked motor cortical reactivity was measured via single‐ and paired‐pulse stimuli (assessing SICI—short and LICI—long interval intracortical inhibition) while subjects viewed a static image and goal‐directed actions. Manic symptom severity and imitative behaviors were quantified using the Young's Mania Rating Scale and a modification of the Echolalia Questionnaire. Results Two‐way repeated measures analysis of variance demonstrated a significant group ×time interaction effect indicating greater facilitation of cortical reactivity during action‐observation (putative MNS‐activity) in the patient group as compared to the healthy group. While LICI‐mediated MNS‐activity had a significant association with manic symptom severity (r = 0.35, P = 0.038), SICI‐mediated MNS‐activity was significantly associated with incidental echolalia scores in a subgroup of 17 patients with incidental echolalia (r = 0.75, P < 0.001). Conclusions Our findings demonstrate that putative MNS‐activity is heightened in mania, possibly because of disinhibition, and associated with behavioral consequences (incidental echolalia).