Measuring Plasticity in SFC/dACC Following Theta-Burst-Stimulation Using TMS
Condition: Cognitive Control
Study type: Interventional

Summary: 
      This is a study to determine whether particular forms of brain-stimulation, applied to
      superior frontal cortex/preSMA can affect cognition and associated frontal theta
      oscillations. To perform this study, the investigators first measure brain activity and
      cognitive performance using "BrainE", a cognitive task platform that assesses cognition on
      sustained attention, response inhibition, working memory, interference processing and emotion
      processing assessments. Next, the investigators apply brain-stimulation over a mid-frontal
      region associated with these tasks (mid-line frontal activity overlying superior frontal
      cortex/pre-SMA area). Finally, human subjects perform the "BrainE" task assessments again
      immediately after the brain-stimulation. The investigators compare the effects of brain
      stimulation on average frontal activity evoked across the cognitive tasks, and on the
      cognitive performance averaged across tasks. The investigators primarily compare the effects
      of two types of brain-stimulation against each other: intermittent Theta-Burst Stimulation (a
      protocol designed to excite brain activity) and continuous Theta-Burst-Stimulation (a
      stimulation protocol designed to inhibit brain activity).
    

Detailed description: 
      1. Brain/Behavior Recordings: to measure brain activity as described above, the
           investigators first ask subjects to engage in a cognitive assessment set while measuring
           EEG activity. For this study, the assessment set consists of the following tasks: (1)
           sustained attention; (2) response inhibition; (2) visuo-spatial working-memory; (3)
           Flanker interference processing, and (4) emotional interference processing. This battery
           takes about 30 minutes to complete. 24 channel EEG recordings are performed simultaneous
           to the cognitive tasks. Subjects perform the "BrainE" cognitive assessment, then receive
           brain-stimulation, and will then immediately be tested on the BrainE assessment again.

        2. Brain-Stimulation: Each subject will be asked to come in twice for this study, separated
           by 1 week. On week one they will receive one stimulation protocol, and on the subsequent
           week they will receive the other (order determined randomly for each subject). The
           intermittent Theta-Burst-Stimulation protocol (iTBS) consists of a similar burst pattern
           (3 stimulation pulses 20ms apart; each burst applied every 200ms). However, after 10
           bursts (2 seconds of stimulation) there is a pause for 8 seconds. 200 bursts are still
           applied, however due to the inter-burst intervals, this paradigm takes 200 seconds. The
           continuous Theta-Burst-Stimulation protocol (cTBS) consists of a burst of three
           stimulation pulses, applied 20ms apart; with each burst occurring every 200ms. Thus,
           every second participants receive 5 bursts. This continues for 40 seconds, such that
           participants in total receive 200 bursts or 600 pulses.
    

Intervention name(s): iTBS then cTBS; cTBS then iTBS
Intervention type(s): Device; Device
Intervention description(s): repetitive transcranial magnetic stimulation applied with intermittent theta-burst stimulation protocol applied in week 1 and continuous theta-burst stimulation protocol applied in week 2.; repetitive transcranial magnetic stimulation applied with continuous theta-burst stimulation protocol applied in week 1 and intermittent theta-burst stimulation protocol applied in week 2.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: The investigators will test the effects of two different interventions (iTBS, cTBS) on cognitive control. Each participant will receive both interventions, labeled A & B, separated a week apart.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Basic Science