Cited by 111Treatment of Major DepressionFunctional Brain Connectivity StudiesTranscranial Magnetic Stimulation Studies

Prefrontal Connectivity and Glutamate Transmission: Relevance to Depression Pathophysiology and Ketamine Treatment

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Abdallah, Chadi G., Averill, Christopher L., Salas, Ramiro, Averill, Lynnette A., Baldwin, Philip R., Krystal, John H., Mathew, Sanjay J., Mathalon, Daniel H.·2017·Biological Psychiatry: Cognitive Neuroscience and Neuroimaging

Abstract

Background Prefrontal global brain connectivity with global signal regression (GBCr) was proposed as a robust biomarker of depression, and was associated with ketamine's mechanism of action. Here, we investigated prefrontal GBCr in treatment-resistant depression (TRD) at baseline and following treatment. Then, we conducted a set of pharmacological challenges in healthy subjects to investigate the glutamate neurotransmission correlates of GBCr.Methods In study A, we used functional magnetic resonance imaging (f MRI) to compare GBCr between 22 TRD and 29 healthy control. Then, we examined the effects of ketamine and midazolam on GBCr in TRD patients 24h post-treatment. In study B, we acquired repeated f MRI in 18 healthy subjects to determine the effects of lamotrigine (a glutamate release inhibitor), ketamine, and lamotrigine-by-ketamine interaction.Results In study A, TRD patients showed significant reduction in dorsomedial and dorsolateral prefrontal GBCr compared to healthy control. In TRD patients, GBCr in the altered clusters significantly increased 24h following ketamine (effect size = 1.0 [0.3 1.8]), but not midazolam (effect size = 0.5 [-0.6 1.3]). In study B, oral lamotrigine reduced GBCr 2h post-administration, while ketamine increased medial prefrontal GBCr during infusion. Lamotrigine significantly reduced the ketamine-induced GBCr surge. Exploratory analyses showed elevated ventral prefrontal GBCr in TRD and significant reduction of ventral prefrontal GBCr during ketamine infusion in healthy subjects.Conclusions This study provides first replication of the ability of ketamine to normalize depression-related prefrontal dysconnectivity. It also provides indirect evidence that these effects may be triggered by the capacity of ketamine to enhance glutamate neurotransmission.

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Crossref · 10.1016/j.bpsc.2017.04.006

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  • Treatment-resistant depression was characterized by decreased global connectivity within the right dorsolateral prefrontal cortex and bilateral dorsomedial prefrontal cortex, including the dorsal anterior cingulate cortex.

    “Treatment-resistant depression (TRD) was characterized by decreased global connectivity within the right dlPFC and bilateral dmPFC (including the dACC) [76].”

    From Prefrontal cortex and depression (2022) · cites this paper as [76]

    The Results section (“GBCr in TRD & Post-ketamine”; page unavailable) reports significantly lower global brain connectivity in bilateral dorsomedial and right dorsolateral prefrontal clusters in TRD patients than in healthy controls. It does not identify the dorsal anterior cingulate cortex as part of those clusters, so the parenthetical detail is not established by our copy. (LLM, conf=0.86)

    Experimental — accuracy not yet measured
  • Ketamine infusion increased global connectivity in the right dorsolateral prefrontal cortex and bilateral dorsomedial prefrontal cortex, including the dorsal anterior cingulate cortex.

    “Notably, ketamine infusion increased global connectivity in all three regions.”

    From Prefrontal cortex and depression (2022) · cites this paper as [76]

    The Results section, “GBCr in TRD & Post-ketamine” (page unavailable), identifies three clusters in the bilateral dorsomedial and right dorsolateral prefrontal cortex, but reports a significant increase in their average connectivity 24 hours after treatment—not an increase in each cluster during infusion. The Results section, “GBCr & Glutamate Modulators” (page unavailable), reports increases during infusion in two clusters, in the bilateral dorsomedial and left frontolateral prefrontal cortex. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • In healthy subjects, a direct link between prefrontal connectivity and glutamate neurotransmission was demonstrated, while showing an acute ketamine-induced surge in prefrontal connectivity, which is attenuated by a glutamate inhibitor.

    “In healthy subjects, a direct link between prefrontal connectivity and glutamate neurotransmission was demonstrated, while showing an acute ketamine-induced surge in prefrontal connectivity, which is attenuated by a glutamate inhibitor [37].”

    From The effects of ketamine on prefrontal glutamate neurotransmission in healthy and depressed subjects (2018) · cites this paper as [37]

    The Results (GBCr & Glutamate Modulators; page unavailable) report that ketamine increased prefrontal connectivity in healthy subjects and that lamotrigine pretreatment significantly reduced those increases. But the Abstract Conclusions call the link to glutamate neurotransmission indirect, and the Discussion notes that the study did not directly show lamotrigine blocking ketamine-induced glutamate transmission in humans. Thus, the claim overstates the evidence by saying a direct link was demonstrated. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • This dysconnectivity is normalized 24 h post-ketamine treatment.

    “a dysconnectivity that is normalized 24 h post-ketamine treatment [37,57].”
  • Reduced PFC global connectivity is implicated in MDD.

    “Using resting state fMRI, researchers have shown reduced PFC global connectivity to be implicated in MDD.209,210”

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Authors
Abdallah, C. G., Averill, C. L., Salas, R., Averill, L. A., Baldwin, P. R., Krystal, J. H., Mathew, S. J., & Mathalon, D. H.
Affiliations
  • United States Department of Veterans Affairs (US)
  • Michael E. DeBakey VA Medical Center (US)
  • San Francisco VA Medical Center (US)
Corresponding author
Abdallah, Chadi G.
Venue
Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
Publisher
Elsevier BV
Published
2017-10
Volume
2
Issue
7
Pages
566-574
ISSN
2451-9022 (ISSN-L)
OpenAlex
W2607285009
Cited by
111
References
67
Citations by year
2026: 4 · 2025: 11 · 2024: 7 · 2023: 10 · 2022: 20 · 2021: 13 · 2020: 15 · 2019: 18 · 2018: 10 · 2017: 3
FWCI
8.79
Type
journal article
Language
en
Open access
Locations
  • Biological Psychiatry Cognitive Neuroscience and Neuroimaging (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
  • eScholarship (California Digital Library) (submittedVersion)
Funders
  • U.S. Department of Veterans Affairs (I01 CX000994)
  • GlaxoSmithKline
  • National Institutes of Health (5k23mh101498-05, UL1TR001863)
  • Genentech
  • National Institute of Mental Health (K23MH-101498(, R01MH081870)
  • National Center for Advancing Translational Sciences
Topics
  • Health Sciences › Medicine › Pharmacology › Treatment of Major Depression
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Functional Brain Connectivity Studies
  • Life Sciences › Neuroscience › Neurology › Transcranial Magnetic Stimulation Studies
Keywords
treatment-resistant depression, global brain connectivity, prefrontal connectivity, ketamine, glutamatergic neurotransmission, lamotrigine, midazolam, dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, ventral prefrontal cortex, depression biomarkers, pharmacological challenge

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