Summary: Getting dressed or making coffee may seem simple, but for people with obsessive-compulsive disorder (OCD) the brain often works much harder to keep a sequence moving without getting “stuck.” A new Brown University study finds that people with OCD perform step-by-step cognitive tasks as accurately as others, yet their brains recruit many more regions to achieve the same result. These findings point to new neural targets for treatments such as transcranial magnetic stimulation (TMS) and offer a measurable task that could track therapy progress.
Researchers observed elevated activity in brain areas not previously linked to OCD—such as the middle temporal gyrus and the temporo-occipital junction—suggesting these regions may act as compensatory systems during demanding sequential tasks. The discovery expands our understanding of how OCD affects the neural systems that coordinate working memory, visual recognition, language processing and task control.
Key Facts
- The Performance Paradox: People with OCD completed sequencing tasks (for example, naming colors and shapes in a set order) with accuracy comparable to controls, but functional MRI showed a substantially higher neural “cost” in the OCD group.
- New Brain Targets: Hyperactivity was detected in regions tied to working memory, semantic and language processing, and visual object recognition—areas not traditionally associated with OCD treatment.
- Abstract Sequencing: The study examined abstract sequential behavior—the mental rules that organize multi-step activities—an area closely related to the repetitive rituals seen in OCD.
- TMS Potential: Current TMS protocols target a limited set of brain regions and help roughly 30–40% of patients. Adjusting coil placement to stimulate the newly identified regions may increase treatment effectiveness.
- Task as Assessment: The sequencing task used in the study could serve as an objective measure to monitor whether a patient’s brain activity shifts toward a typical control pattern after treatment.
Source: Brown University
A recent study finds elevated activity in specific brain networks of people with obsessive-compulsive disorder during cognitively demanding, sequential tasks. These results may guide improved treatment strategies and assessment tools for OCD.
The research, published in Imaging Neuroscience, was led by the laboratory of Theresa Desrochers, associate professor of brain science and of psychiatry and human behavior at Brown University’s Carney Institute for Brain Science. Desrochers focuses on abstract sequential behavior—the internal rules that organize multi-step activities such as dressing, preparing a meal, or following a routine.
To explore links between abstract sequencing and OCD, the team had participants perform a sequenced cognitive task inside an MRI scanner. Subjects named the color or shape of images in a specified order—for example, color, color, shape, shape—requiring them to track the sequence while classifying stimuli.
Lead author Hannah Doyle, a postdoctoral research associate in Desrochers’ lab, reports that although individuals with OCD matched controls in task performance, their brains engaged a broader network of regions. These included motor and cognitive control areas, working memory centers, and visual object recognition cortex.
“Behavior looked the same, but participants with OCD recruited more brain regions than those without the diagnosis,” Doyle said. Notably, some hyperactive regions had not been previously implicated in OCD. The middle temporal gyrus—important for working memory and semantic retrieval—and areas overlapping the occipital gyrus and temporo-occipital junction—key to visual processing and object recognition—showed elevated activity during sequencing.
Nicole McLaughlin, study co-author and associate professor of psychiatry and human behavior at Brown, emphasized the clinical implications. TMS, a noninvasive therapy approved by the FDA for OCD in 2018, uses magnetic pulses to modulate brain regions associated with the disorder. Because TMS helps only a subset of patients, targeting the newly identified regions may improve outcomes for many who do not currently respond.
Desrochers highlighted the advantage of using a realistic, sequence-based task. “Many clinical tasks are static,” she noted. “But everyday behavior depends on sequences that require different control systems to interact. Our task forces these systems to coordinate, revealing brain differences that static tests might miss.”
The research team is also testing whether the sequencing task can act as an assessment tool between treatments. McLaughlin explained: “If a patient’s brain activity during the task begins to resemble control participants after TMS, that change could indicate treatment effectiveness and symptom reduction.”
Funding: The study was supported by the National Institute of Mental Health (R01MH131615) and the National Institute of General Medical Sciences (P20GM130452).
Key Questions Answered:
A: The elevated activity indicates the brain is working harder—“redlining”—to maintain sequence control. That extra neural effort may contribute to the mental fatigue, distress, and vulnerability to getting stuck that characterize OCD.
A: Current FDA-approved TMS targets a small set of brain areas. By expanding stimulation targets to include regions like the middle temporal gyrus and visual processing centers, clinicians may improve response rates for the many patients who do not benefit from existing protocols.
A: It refers to the mental rules or “recipes” that organize ordered actions—such as making coffee or getting dressed—where the overall sequence matters more than the exact identity of each individual step. Disruptions in this control can lead to repetitive or ritualized behavior in OCD.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was added by editorial staff.
About this OCD and neuroscience research news
Author: Corrie Pikul
Source: Brown University
Contact: Corrie Pikul – Brown University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Cognitive sequences in obsessive-compulsive disorder are supported by frontal cortex ramping activity” by Hannah Doyle, Nicole C.R. McLaughlin, Sarah L. Garnaat, and Theresa M. Desrochers. Imaging Neuroscience
DOI: 10.1162/IMAG.a.1084
Abstract
Cognitive sequences in obsessive-compulsive disorder are supported by frontal cortex ramping activity
Completing sequences is a routine part of daily life. Many sequences are abstract—defined by a rule about order rather than by the identity of each step (for example, getting dressed). In obsessive-compulsive disorder (OCD), excessive ritualized behavior suggests a disruption in the ability to complete these abstract sequences.
Executing abstract sequences requires at least two hierarchical levels of cognitive control: abstract sequential control (tracking steps across a sequence) and task-level switching (shifting between different tasks). Task switching has been studied in OCD, but less is known about sequencing within a hierarchical context.
Previous work shows the rostrolateral prefrontal cortex (RLPFC) supports abstract sequence monitoring in healthy people, with activity that ramps up across each sequence. Ramping beyond RLPFC may reflect additional processes such as progress tracking and growing working memory demands. The authors hypothesized that OCD would show altered ramping dynamics in RLPFC and other cortical regions, and predicted task-switching deficits with altered activity in canonical control regions.
The study found partial support for these predictions. Behaviorally, abstract sequential control did not differ between groups, but individuals with OCD exhibited increased ramping activity in the anterior cingulate cortex (ACC) and superior frontal sulcus (SFS), as well as ramping differences in additional cortical regions that varied with sequence complexity. Task switching showed behavioral differences in OCD without clear neural group differences.
Overall, results indicate that several brain regions support sequential control differently in OCD compared with healthy controls despite similar performance. This pattern appears unlikely to stem from basic deficits in task switching and instead points to altered recruitment of cortical networks during complex sequence-based behavior. These findings illuminate how OCD affects neural processing during everyday, multi-step activities and may inform future treatment approaches.