Social Cognitive and Affective Neuroscience
April 13, 2016
Mick Lehmann, Erich Seifritz, A Henning et al.
58 citations
Distraction and rumination are distinct ways people respond to negative thoughts and feelings. Rumination involves elevated self-focus, linked to increased resting state functional connectivity and decreased reactivity within the default mode network. The NMDA receptor antagonist ketamine reduces functional connectivity in this network, but its effects on brain responses during stimulus perception were unknown. In healthy subjects given a single ketamine dose, blood oxygenation level-dependent (BOLD) reactivity to negative emotional pictures increased specifically in the pregenual anterior cingulate cortex, not in a posterior control region. The increase was greater in subjects with low ability to use distraction during negative experiences. Ketamine may attenuate pathological increased self-focus during negative experiences.
Pharmacopsychiatry
September 1, 2011
Simone Grimm, Milan Scheidegger, A Henning et al.
Ketamine, a glutamatergic NMDA receptor antagonist with rapid antidepressant properties, was used to investigate the neurobiology of major depressive disorder. In a multimodal imaging study of 23 healthy subjects, a single ketamine infusion increased negative BOLD responses in brain regions involved in emotional processing, particularly limbic areas linked to emotional information and higher-order mental functions. During cognitive processing, ketamine affected negative BOLD responses in anterior but not posterior regions of the default-mode network. Strong correlations were found between glutamate, glutamine, GABA, and glutamine/glutamate ratios and these brain responses after ketamine administration, suggesting a link to glutamatergic neurotransmission.
Pharmacopsychiatry
September 1, 2011
Milan Scheidegger, A Henning, Martin Walter et al.
A subanaesthetic dose of ketamine alters brain activity during emotional processing and increases glutamate-glutamine cycling in the pregenual anterior cingulate cortex, a region linked to mood regulation. In 23 healthy subjects, ketamine infusion changed fMRI responses to emotional pictures, and these changes correlated with shifts in glutamine-to-glutamate ratios measured by spectroscopy. The findings suggest ketamine's rapid antidepressant effect may stem from enhanced glutamatergic neurotransmission.