Summary: Getting dressed in the morning seems like a simple sequence, but for those with obsessive-compulsive disorder (OCD), the brain may be working overtime just to keep from \u201cgetting stuck.\u201d A new study reveals that while people with OCD can perform sequential tasks as well as anyone else, their brains recruit significantly more regions to do so.<\/p>\n
Researchers discovered high activity in areas previously unlinked to OCD\u2014such as the middle temporal gyrus and the temporo-occipital junction\u2014suggesting a \u201ccompensation\u201d effect. These findings offer exciting new targets for brain stimulation therapies like TMS, which could make treatment more effective for millions.<\/p>\n
Key Facts<\/p>\n
The Performance Paradox: People with OCD performed sequential cognitive tasks (like naming colors\/shapes in a specific order) just as accurately as the control group, but their brain scans showed a much higher \u201cneural cost.\u201dNew Brain Targets: Regions involved in working memory, language processing, and visual object recognition\u2014previously unlinked to OCD\u2014were found to be hyperactive during sequencing.Abstract Sequencing: The study focused on how we organize complex, multi-step behaviors, which is a core area where OCD symptoms, like repetitive actions, often manifest.TMS Potential: Repositioning magnetic stimulation (TMS) coils to target these newly identified regions could improve the current 30-40% success rate of the therapy.Task as Assessment: Researchers hope to use the specific sequencing task as a tool to measure if treatments are working, by seeing if the patient\u2019s brain activity starts to look more like the \u201ccontrol\u201d group.<\/p>\n
Source: Brown University<\/p>\n
A new study revealed that certain brain regions are more active in people with obsessive-compulsive disorder (OCD) during cognitively demanding tasks. The findings could help inform new ways in which the condition is treated and assessed.<\/p>\n
The study,\u00a0published\u00a0in\u00a0Imaging Neuroscience, was conducted\u00a0by researchers in the laboratory of Theresa Desrochers, an associate professor of brain science and of psychiatry and human behavior at Brown University\u2019s\u00a0Carney Institute for Brain Science.<\/p>\n
Desrochers studies abstract sequential behavior, which is behavior \u2014 such as getting dressed in the morning \u2014 that follows a general sequence even though individual steps may vary.<\/p>\n
For the study, the team examined potential links between abstract sequencing and OCD,\u00a0a prevalent psychiatric disorder characterized by repetitive thoughts and associated compulsive actions that cause distress for the diagnosed person.<\/p>\n
\u201cWe started looking into OCD because symptoms of the condition suggest that patients lose track or get stuck where they are while performing sequences,\u201d said\u00a0lead study author\u00a0Hannah Doyle\u00a0a postdoctoral research associate in Desrochers\u2019 lab.<\/p>\n
For the study, researchers asked participants to perform a sequential cognitive task while in a magnetic resonance imaging (MRI) scanner, naming the color or shape of an object in a specific order.<\/p>\n
Doyle found that while individuals with OCD were able to perform the sequence as well as the control group (people who were not diagnosed with OCD), the MRI scans revealed differences in brain regions connected to motor and cognitive task control, working memory and object recognition.<\/p>\n
\u201cTheir behavior looked similar, but the brains of the participants with OCD recruited more brain regions than the people in the control group,\u201d Doyle said.<\/p>\n
She noted that some of the regions hadn\u2019t previously been linked to OCD. Those regions include the middle temporal gyrus \u2014 involved in working memory, semantic memory retrieval and language processing \u2014 and an area spanning part of the occipital gyrus and the temporo-occipital junction, which is involved in lower-level visual stimulus processing and object recognition.<\/p>\n
Study co-author Nicole McLaughlin, an associate professor of psychiatry and human behavior at Brown and a neuropsychologist at Butler Hospital, said the findings may lead to new treatment targets for OCD, especially when involving transcranial magnetic stimulation (TMS).<\/p>\n
TMS is a therapy that uses magnetic pulses to stimulate brain regions implicated in a psychiatric disorder. The procedure was approved as a treatment for OCD by the U.S. Food and Drug Administration in 2018; research has shown TMS leads to improvement in about 30-40% of OCD patients.<\/p>\n
According to McLaughlin, the treatment might be even more effective if the newly implicated regions are targeted: \u201cIf we reposition coils during TMS treatments to be near these brain regions, we might end up seeing a greater improvement in symptoms,\u201d she said.<\/p>\n
The real-life relevance of the cognitive task used in the study was key to the team\u2019s insights.<\/p>\n
\u201cA lot of tasks that are used in a clinical setting are static,\u201d said Desrochers. \u201cBut as humans, we interact with the world through sequences, where we organize information and make decisions. So we\u2019re asking people to do a task where these different control systems have to interact.\u201d<\/p>\n
The sequencing task calls for participants to name the colors or shapes of a series of images in a particular order, such as color, color, shape, shape, requiring the ability to keep track of a sequence while making a categorization decision.<\/p>\n
\u201cThis task gets us closer to understanding what actually looks different in the brain for folks with OCD when all of these different cognitive control systems are trying to work together,\u201d Desrochers said.<\/p>\n
The researchers are testing the possibility of using the sequence task itself as an assessment tool.<\/p>\n
\u201cWe are planning to use the task between treatments,\u201d McLaughlin said. \u201cIf we start to see OCD patients\u2019 brains looking more like control participants when they perform the task, that could help indicate that TMS treatment may be effective for symptom reduction.\u201d<\/p>\n
Funding: The research was funded by the National Institute of Mental Health (R01MH131615) and the National Institute of General Medical Sciences (P20GM130452).\u00a0<\/p>\n
Key Questions Answered:Q: If people with OCD perform the task just as well, why does the extra brain activity matter?<\/p>\n
A: It shows that the brain is essentially \u201credlining\u201d to stay on track. This extra effort may be what leads to the mental fatigue and distress associated with OCD. It\u2019s like a car needing twice the fuel to travel the same distance as another.<\/p>\n
Q: How does this change OCD treatment?<\/p>\n
A: Currently, FDA-approved brain stimulation (TMS) only targets specific, well-known areas. This study gives doctors a new map. By targeting the middle temporal gyrus or visual processing centers, they may be able to help the 60% of patients who don\u2019t see results with current methods.<\/p>\n
Q: What is \u201cabstract sequential behavior\u201d?<\/p>\n
A: It\u2019s the \u201crecipe\u201d for daily life\u2014like the sequence of making coffee or getting ready for work. For someone with OCD, the brain might lose its place in that sequence, leading to the urge to repeat a step over and over.<\/p>\n
Editorial Notes:This article was edited by a Neuroscience News editor.Journal paper reviewed in full.Additional context added by our staff.About this OCD and neuroscience research news<\/p>\n
Author: Corrie Pikul<\/a>
Source: Brown University<\/a>
Contact: Corrie Pikul \u2013 Brown University
Image: The image is credited to Neuroscience News<\/p>\n