The next step in personalizing transcranial magnetic stimulation may involve what people do while receiving it. A new study in Brain Stimulation suggests that engaging specific mental processes during stimulation can influence subsequent cognitive performance.
University of Minnesota researchers found that pairing prefrontal stimulation with a demanding cognitive task improved measures of cognitive control. Delivering identical stimulation during a simpler perceptual task produced little comparable change. The findings concern cognitive performance in adults without reported psychiatric diagnoses, rather than depression treatment outcomes.
The Brain Brings Its Own Starting Conditions
TMS protocols specify factors such as stimulation location, intensity, and pulse timing. Yet matching these settings does not necessarily produce matching effects across people.
One possible explanation is brain state: the activity already occurring in targeted networks. A circuit engaged in maintaining goals or suppressing an automatic response may respond differently from the same circuit performing a less demanding task.
Putting Cognitive Engagement During TMS To The Test
Researchers tested whether deliberately engaging cognitive control could shape stimulation effects. Cognitive control supports goal-directed behavior, including using context to guide decisions and overriding habitual responses.
In one condition, participants completed a task requiring these abilities during repetitive TMS. In the comparison condition, they judged visual orientations, preserving visual input and responses while reducing demands on prefrontal control processes.
A Comparison Within The Same Participants
The analysis included 23 participants who completed both conditions in separate sessions approximately one week apart. Session order was counterbalanced, and cognitive control was measured before and after stimulation.
The researchers used identical stimulation parameters across conditions and recorded brain activity with electroencephalography, or EEG. This design helped distinguish differences associated with task engagement from differences between individuals.
Performance Improved After The Demanding Task
After stimulation paired with cognitive control, participants showed improvements in accuracy and contextual processing. Response-time changes also favored this condition over the perceptual comparison.
The pattern suggests that cognitive engagement influenced how stimulation affected later behavior. A separate, unstimulated experiment involving 16 participants indicated that practice and switching between tasks were unlikely to explain the primary behavioral findings.
A Neural Signal With Two Interpretations
EEG revealed reduced task-evoked theta activity after stimulation paired with cognitive control. Because performance improved, the authors proposed that this reduction could reflect more efficient processing, requiring less recruitment of control resources.
That explanation remains an interpretation. Exploratory analyses at the stimulation site also showed stronger TMS-evoked theta responses during the demanding task, although broader electrode-cluster comparisons were not significant.
Why An Active Circuit Might Respond Differently
The proposed mechanism draws on activity-dependent plasticity: ongoing neural activity may influence which circuits respond to stimulation and become more susceptible to modification.
Engaging a relevant task could therefore bias stimulation toward networks supporting that activity. The study supports this framework, but it does not directly establish lasting synaptic changes or identify a single mechanism responsible for the effects.
More Specific Than Simply Staying Busy
This experiment compared two active tasks rather than treating all mental engagement as equivalent. Its central question was whether the kind of activity accompanying stimulation matters.
However, the tasks differed along dimensions beyond cognitive control, and the study lacked sham stimulation. Its modified intermittent burst pattern also differed from standard clinical theta-burst protocols, limiting direct translation to routine treatment.
Connecting Cognitive Effects To Clinical Questions
Cognitive control is relevant to depression, making these findings clinically interesting. A separate B-SMART-fMRI study found that cognitive and circuit improvements after TMS differed according to baseline circuit connectivity. That study did not test tasks performed during stimulation.
Together, the findings motivate research into both patients’ starting circuit characteristics and their cognitive state during treatment.
A Treatment Variable Worth Testing
The study does not establish that reading, watching videos, or completing exercises during clinical TMS improves depression outcomes. It identifies a testable possibility: carefully selected activities may help shape stimulation effects.
Larger, sham-controlled studies in clinical populations will need to determine which tasks, timing, and stimulation protocols produce meaningful, durable benefits.
Citations
- McInnes AN, et al. “Cognitive State Dependent Enhancement Of Cognitive Control With Transcranial Magnetic Stimulation.” Brain Stimulation. 2026;19:103227. Read The Study. PIIS1935861X26002044
- Tozzi L, et al. “A Cognitive Neural Circuit Biotype Of Depression Showing Functional And Behavioral Improvement After Transcranial Magnetic Stimulation In The B-SMART-fMRI Trial.” Nature Mental Health. 2024;2:987–998. Read The Study.
Explore more at https://www.interventionalpsychiatry.org/
