Human brain mapping
May 1, 2020
Joana R A Loureiro, Amber Leaver, Megha Vasavada et al.
65 citations
Both electroconvulsive therapy (ECT) and ketamine reduce amygdala reactivity to positive and negative emotional faces in people with treatment-resistant depression. In a naturalistic study of 44 patients (17 receiving ECT, 27 receiving ketamine), fMRI showed decreased amygdala response after both treatments. Subtle differences between treatments appeared in the dorsolateral prefrontal cortex and insula. Changes in brain activity in the inferior parietal cortex correlated with overall symptom improvement, while frontal region changes correlated with anxiety for negative faces and anhedonia for positive faces. The findings suggest common and distinct neural mechanisms underlying fast-acting antidepressant effects on emotion processing.
Translational psychiatry
July 30, 2020
Ashish K Sahib, Joana Ra Loureiro, Megha M Vasavada et al.
37 citations
Ketamine produces rapid antidepressant effects even in people with treatment-resistant depression, but how it alters brain function is not fully understood. In this study, 47 patients with treatment-resistant depression and 32 healthy controls performed a brain-imaging task measuring response inhibition. After one and then four intravenous ketamine infusions, 37 patients repeated the task. Brain activation decreased in regions involved in inhibitory control, including prefrontal and parietal areas and visual cortex, following repeated treatment. Patients who achieved remission had lower activation in the supplementary motor area before treatment, which then normalized toward control levels after ketamine. These changes in the supplementary motor area during response inhibition were linked to reduced depressive symptoms and may predict treatment outcome.
Psychological medicine
October 1, 2022
Ashish K Sahib, Joana R Loureiro, Megha Vasavada et al.
36 citations
Ketamine infusion therapy can rapidly relieve depression, but its effects on whole-brain functional connections are not well understood. In patients with major depressive disorder (MDD), baseline resting-state functional connectivity (FC) differed from healthy controls in the somatomotor network and between association and default mode networks. After one and four ketamine infusions, these disrupted FC patterns trended toward those of controls. Serial ketamine treatment significantly decreased FC between the cerebellum and the salience network. Patients who remitted showed higher pre-treatment FC between the cerebellum and striatum that decreased after treatment, while non-remitters showed the opposite pattern. Ketamine induces neurofunctional plasticity in cortico-striatal-cerebellar loops involving the salience network, which may serve as a biomarker for treatment response.
Brain and behavior
June 1, 2024
Brandon Taraku, Joana R Loureiro, Ashish K Sahib et al.
11 citations
Ketamine infusions alter brain connectivity in people with major depressive disorder, particularly in circuits involving the habenula and nucleus accumbens, which are linked to reward processing. After four infusions, changes in functional connections between these regions and visual, parietal, and cerebellar areas correlated with improvements in mood and anhedonia. For example, decreased variability in connectivity between the left habenula and right precuneus/visual cortex was associated with better mood, while altered connectivity between the left habenula and visual/parietal cortices and between the left nucleus accumbens and visual/parietal cortices correlated with reduced anhedonia. No such changes occurred in healthy controls.