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.
medRxiv Preprint Server
December 1, 2023
Brandon Taraku, Joana R. Loureiro, Ashish K. Sahib et al.
1 citation
preprint
In major depressive disorder, ketamine infusions alter brain connectivity in networks involving the habenula and nucleus accumbens, regions central to reward processing. After four subanesthetic ketamine infusions given to 58 adults with depression, resting-state fMRI scans showed specific changes in static and dynamic functional connectivity between these regions and visual, parietal, and cerebellar areas. Decreased variability in connectivity between the left habenula and right precuneus and visual cortex, and between the right nucleus accumbens and right visual cortex, correlated with reduced depression severity. Reduced connectivity between the left habenula and visual/parietal cortices, and increased connectivity between the left nucleus accumbens and visual/parietal cortices, correlated with improvements in anhedonia. Ketamine appears to modulate overlapping habenula and nucleus accumbens functional pathways related to therapeutic response.
Journal of neuroscience research
January 1, 2026
Stephanie Njau, Artemis Zavaliangos-Petropulu, Shantanu Joshi et al.
In people with treatment-resistant depression, a single low-dose ketamine infusion increased glutamate levels in the dorsal anterior cingulate cortex only in those who responded to treatment, and lower pre-treatment glutamate levels predicted greater improvement in depression scores. GABA levels did not change after treatment. Other brain metabolites linked to neuronal health and metabolism also increased. These findings suggest that ketamine's antidepressant effect involves sustained enhancement of glutamate-related neurotransmission and that baseline glutamate levels may help predict who will benefit from ketamine.
Imaging neuroscience (Cambridge, Mass.)
January 1, 2025
Brandon Taraku, Jason S Nomi, Artemis Zavaliangos-Petropulu et al.
Ketamine treatment alters how brain networks dynamically interact in people with treatment-resistant depression. After four ketamine infusions over two weeks, patients spent less time in a visual-network brain state and more time in a central-executive-network state. Transitions between the salience network and central executive network increased, while salience-to-visual transitions decreased. Reduced time in the salience-network state was linked to less rumination. Before treatment, depressed patients differed from healthy controls in these same dynamic patterns, suggesting ketamine may shift network dynamics toward a healthier profile.