Stroke-linked psychiatric syndromes point to new targets for brain stimulation

By AI, Created 9:58 AM UTC, May 20, 2026, /AGP/ – New research from Gonçalo Cotovio and Albino J. Oliveira-Maia argues that rare strokes and other focal brain injuries can reveal the distributed circuits that produce psychiatric symptoms. The work could help make transcranial magnetic stimulation more precise for conditions such as mania, obsessive-compulsive disorder, psychosis and PTSD.

Why it matters: - Focal strokes that trigger psychiatric symptoms can help identify brain circuits that cause suffering, not just correlate with it. - The framework could make transcranial magnetic stimulation more precise by matching treatment targets to a patient’s connectivity profile. - The approach may help turn a useful but inconsistent therapy into a more predictable, circuit-informed treatment.

What happened: - Gonçalo Cotovio of the Champalimaud Foundation in Lisbon published two papers this week with Albino J. Oliveira-Maia. - A Brain Health Viewpoint, “From lesions to brain health: Causal circuits in psychiatry,” argues that lesions can reveal causal brain networks in psychiatric disease. - A companion interview in Brain Medicine lays out Cotovio’s case for using lesion-derived circuits to personalize neuromodulation. - Both pieces became freely available on 5 May 2026. - The Viewpoint is available at the open-access article. - The interview is available at the companion interview.

The details: - A small stroke can trigger mania, obsessive-compulsive symptoms or other psychiatric syndromes even in people with no prior mental illness. - Lesion studies help establish temporal order because the brain injury happens before the psychiatric symptoms appear. - Cases that cause the same syndrome rarely share one anatomical spot. - The lesions instead converge on the same distributed network. - Cotovio calls the method causal network mapping. - Lesions causing Capgras delusion converge on circuits tied to familiarity and belief evaluation. - Lesions causing secondary psychosis converge on hippocampal connectivity, and that convergence has already suggested a stimulation target now being trialled. - Lesions associated with smoking cessation share a connectivity fingerprint involving the cingulate, insula and prefrontal cortex. - In veterans with penetrating head injuries, damage intersecting a circuit involving the medial prefrontal cortex, amygdala and temporal lobe appears linked to lower posttraumatic stress disorder risk. - The same circuit predicts who will respond to TMS for PTSD in people without lesions. - Cotovio and colleagues have extended the framework to lesional obsessive-compulsive disorder. - Depression-related stimulation sites and lesion sites also appear on the same functional map.

Between the lines: - The work challenges the old search for a single brain region for depression, schizophrenia or addiction. - The authors argue that psychiatric symptoms emerge from distributed networks that support emotion, cognition and behavior. - That view reframes brain health as the capacity of those networks to sustain adaptive regulation. - The analysis is still a hypothesis about treatment, not proof of a new standard of care. - Cotovio said the key question is whether circuit-informed neuromodulation can be validated by trials and replication.

What’s next: - The lesion-network approach will need trial data and replication before it can be treated as routine clinical guidance. - If validated, the framework could guide where clinicians place a TMS coil for a specific patient on a specific day. - The same logic may continue to expand into deep brain stimulation, gene expression atlases and functional imaging studies.

The bottom line: - A stroke can do more than injure tissue; it can expose the brain circuits that generate psychiatric illness, and that may be the map psychiatry has been missing.