A new paper in Imaging Neuroscience reports that people with obsessive-compulsive disorder (OCD) show greater recruitment of brain regions when performing a cognitively demanding sequence task. The research was conducted in Theresa Desrochers’ laboratory at Brown University’s Carney Institute for Brain Science.
During functional MRI scanning, participants named either the color or the shape of images in a predefined order—an example sequence was color, color, shape, shape. Lead author Hannah Doyle, a postdoctoral research associate in Desrochers’ lab, notes that people with OCD performed the task as well as control participants, yet their scans revealed broader neural activation.
The extra activity appeared in areas associated with motor and cognitive task control, working memory, and object recognition. Several implicated regions had not been previously linked to OCD; these include the middle temporal gyrus and an area spanning part of the occipital gyrus and the temporo-occipital junction. The middle temporal gyrus supports working memory, semantic memory retrieval and aspects of language processing, while the occipital/temporo‑occipital region supports visual stimulus processing and object recognition.
Nicole McLaughlin, an associate professor of psychiatry and neuropsychologist at Butler Hospital, says the findings could point to new treatment targets. Transcranial magnetic stimulation (TMS), which uses magnetic pulses to stimulate brain regions, was approved by the US Food and Drug Administration for OCD in 2018 and has produced improvement in about 30–40% of patients. McLaughlin suggests that repositioning TMS coils to reach the newly implicated regions might yield greater symptom improvement. The research team also highlights that the sequence task reflects how people organise information and make decisions in daily life, and they are testing whether changes in task-related brain activity between treatments could indicate TMS effectiveness. The study was funded by the National Institute of Mental Health and the National Institute of General Medical Sciences.
Difficult words
- recruitment — engaging additional brain regions during a task
- demanding — requiring a lot of mental effort
- sequence — an ordered set of steps or items
- activation — increase in activity, often in brain regions
- implicate — show or suggest involvement of somethingimplicated
- working memory — short-term memory used to hold information
- transcranial magnetic stimulation — noninvasive brain treatment using magnetic pulses
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Why might people with OCD show broader brain activation even when their task performance matches controls? Give possible explanations based on the article.
- What are the potential benefits and challenges of repositioning TMS coils to target the newly implicated regions?
- How could a sequence task that reflects everyday organisation and decision making help researchers test treatment effectiveness in clinical practice?
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