rsfMRI

TMS can modulate the resting-state activity of the brain and fine-tune DMN plasticity; the direction (increase or decrease in activity) and the extent of this modulation depends on designing a specific rTMS protocol for each individual patient’s brain activity. Our work in clinical and fundamental neuroscience has been essential in improving the technology and its integration with brain-imaging methodologies such as rsfMRI.

We offer existing clinical applications of rsfMRI guided TMS therapy for many psychiatric and neurological diseases and a sample of our work on emerging possibilities such as in traumatic brain injury, dementia and stroke is available on this site.

This gives fMRI an advantage as it detects signals from the whole brain at a very high spatial resolution (mm resolution), including deep thalamic regions that are intimately involved in neuropsychiatric disorders. EEG can detect cortical (surface) regions and guide TMS therapy with its superior temporal resolution of millisecond range, which is close to the temporal activity of neuronal electrical signals, but due to its lower spatial resolution (i.e., inverse problem in EEG), is unable to identify where a particular type of activity originates in the brain (poor spatial resolution), making EEG incapable of fine-tuning specific cortical regions in need of treatment.

The temporal resolution of fMRI, on the other hand, is based on the time-scale of hemodynamic response which is about one second.

This enables fMRI to detect coherent BOLD activity in very low-frequency range, i.e., <0.1 Hz, which although not directly associated with the EEG activity in this frequency range, universal observation of BOLD activity in <0.1 Hz range has turned it into a powerful tool for the depiction of brain networks³.

Furthermore, it has been shown that there is a correspondence between BOLD and EEG, low-frequency BOLD signal fluctuations track spontaneous changes in the main EEG rhythms. At the heart of this relationship lies the role of local field potentials (LFP) in both BOLD and EEG signals that points to the common neurophysiological roots of the two techniques.
We use both BOLD (which is due to low-frequency LFPs and low-frequency modulations of high-frequency LFPs) and EEG which detects high-frequency LFPs directly to guide our TMS treatments.

The DMN is a sensitive brain feature that we use to diagnose and treat neuropsychiatric disorders. This is because DMN has an activity pattern that inversely correlates with arousal and effort.

DMN responsiveness to arousal or external stimulation also contains precious information about other networks because it interacts intimately with them. We use this powerful tool as a sensitive state-of-art therapeutic technique for psychiatry and neurology.