Abstract
Background and Objectives: Previous research has demonstrated that
anatomical complexities of cortical regions determine transcranial magnetic stimulation (TMS) induced electric fields in the brain, which impact
the response to TMS-based therapies. The current objective was to investigate the effect of individual neuroanatomy on first dorsal interosseous
(FDI) and biceps brachii resting motor thresholds (RMT) in response to
TMS.
Methods: We performed a cross-sectional study using a convenience
sample of ten healthy individuals (7 females, 23.5 ± 5 years). Each
participant completed two TMS sessions (one each targeting the FDI and
biceps cortical hotspots) and an MRI of the head on separate days. RMTs
were determined using a Magstim Super BiStim stimulator via a 70 mm
figure-of-eight coil to the left primary motor cortex and electromyography
signals were measured from right FDI and biceps. Head models were
generated based on T1 & T2 weighted MRI, while diffusion tensor imaging
was used to determine fiber tract geometry for FDI and biceps corticospinal tracts. Via the models, we established neuroanatomical parameters
including: fiber tract surface area (FTSA), tract fiber count (TFC), and brain
scalp distance (BSD). Cortical electric field strength (EFS) was calculated
using simulated stimulation of head models and finite element analysis.
Results: For the FDI, RMT was dependent on the interaction between
individually modeled parameters: 1) EFS and FTSA (p =0.036), and 2) EFS
and TFC (p =0.004). For the biceps, RMT was dependent on the interaction
between 1) EFS and FTSA (p =0.022) and 2) EFS and BSD (p =0.010).
Conclusions: Our study results show that MRI-based measures of neuroanatomy, specifically cortical architecture and tract anatomy, differentially impact how the motor system responds to TMS. MRI-based modeling of individual neuroanatomy may be a useful approach to select appropriate motor targets when designing TMS based therapies.
anatomical complexities of cortical regions determine transcranial magnetic stimulation (TMS) induced electric fields in the brain, which impact
the response to TMS-based therapies. The current objective was to investigate the effect of individual neuroanatomy on first dorsal interosseous
(FDI) and biceps brachii resting motor thresholds (RMT) in response to
TMS.
Methods: We performed a cross-sectional study using a convenience
sample of ten healthy individuals (7 females, 23.5 ± 5 years). Each
participant completed two TMS sessions (one each targeting the FDI and
biceps cortical hotspots) and an MRI of the head on separate days. RMTs
were determined using a Magstim Super BiStim stimulator via a 70 mm
figure-of-eight coil to the left primary motor cortex and electromyography
signals were measured from right FDI and biceps. Head models were
generated based on T1 & T2 weighted MRI, while diffusion tensor imaging
was used to determine fiber tract geometry for FDI and biceps corticospinal tracts. Via the models, we established neuroanatomical parameters
including: fiber tract surface area (FTSA), tract fiber count (TFC), and brain
scalp distance (BSD). Cortical electric field strength (EFS) was calculated
using simulated stimulation of head models and finite element analysis.
Results: For the FDI, RMT was dependent on the interaction between
individually modeled parameters: 1) EFS and FTSA (p =0.036), and 2) EFS
and TFC (p =0.004). For the biceps, RMT was dependent on the interaction
between 1) EFS and FTSA (p =0.022) and 2) EFS and BSD (p =0.010).
Conclusions: Our study results show that MRI-based measures of neuroanatomy, specifically cortical architecture and tract anatomy, differentially impact how the motor system responds to TMS. MRI-based modeling of individual neuroanatomy may be a useful approach to select appropriate motor targets when designing TMS based therapies.
| Original language | English |
|---|---|
| Pages | 1694 (P3.082) |
| Number of pages | 1 |
| DOIs | |
| Publication status | Published - 9 Dec 2021 |
| Event | 4th International Brain Stimulation Conference - Charleston, United States Duration: 7 Dec 2021 → 10 Dec 2021 Conference number: 4th https://neuromodec.org/events/4th-international-brain-stimulation-conference-2/ |
Conference
| Conference | 4th International Brain Stimulation Conference |
|---|---|
| Country/Territory | United States |
| City | Charleston |
| Period | 7/12/21 → 10/12/21 |
| Internet address |
Keywords
- Corticospinal Tract
- Simulation
- Fiber Tracts
