Elevated mirror neuron system activity in bipolar mania: Evidence from a transcranial magnetic stimulation study

Abstract

| INTRODUC TI ONBipolar disorder (BD) is a chronic psychiatric disorder with high rates of relapses and recurrences and is among the leading causes of disability worldwide. 1 A sound understanding of its biological substrates will not only help device better treatments but also facilitate identifying a neuroscience-informed and psychopathologydependent set of biomarkers. The current understanding of brain network disturbances in BD is centered on the theory of diminished prefrontal regulation of anterior limbic emotion processing structures. 2,3 In bipolar mania, this is supported by the observations of a diminished functional connectivity between the prefrontal cortex/ anterior cingulate and the amygdala, 3,4 along with an increased functional connectivity of the amygdala with the inferior frontal gyrus 5 and the supplementary motor area. 4 Interestingly, both the inferior frontal gyrus 6 and the supplementary motor area 7 have "mirroring"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 socioemotional 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 hyperimitative 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). K E Y W O R D Sbipolar disorder, corticospinal facilitation, echolalia, mirror neurons, motor resonance

A Systematic Review of Long-Interval Intracortical Inhibition as a Biomarker in Neuropsychiatric Disorders

“…Enhanced MNA assessed with LICI was detected in the medication naïve symptomatic BD patients (p = 0.033). LICI mediated putative MNA was significantly correlated with symptom severity (p = 0.038)(37).The studies examining BD patients had varied results demonstrating both normal LICI and enhanced LICI relative to HC. These results are interesting as studies with other neurophysiological paradigms have shown inhibitory deficits in BD…”

Understanding the Neuropathophysiology of Psychiatry Disorder Using Transcranial Magnetic Stimulation

“…In contrast, patients with mania demonstrate an elevated MNS response, perhaps reflecting disinhibition of the regulatory prefrontal brain regions. Higher MNS activity in mania was associated with higher manic symptom severity [32].…”

Mirror Neuron dalam Proses Empati Manusia kerusakan / Disfungsi yang Terjadi pada Mirror Neuron

“…16 No. 4 (2023) 340-346 341 menonton perlombaan, seseorang bisa merasakan jantung berdebar kencang saat para pelari bersaing mencapai garis akhir terlebih dahulu [5]. Ketika melihat orang lain berbahagia, mirror neuron akan aktif dan mencerminkan keadaan emosional serupa sehingga pelihat juga dapat merasakan kebahagiaan tersebut [6].…”