Mandi: A mathematical simulation study on non-invasive brain simulation techniques was conducted by an international team of scientists led by the Indian Institute of Technology Mandi.
A mathematical model to understand the physiological effects of non-invasive brain stimulation was established by the multi-institutional study team, which included experts from the National Brain Research Centre and the University of Buffalo in the United States.
Transcranial electrical stimulation (tES) is a non-invasive brain stimulation technique that uses an electrical current to study or change brain activity.
Multiple electrodes are attached to the patient's scalp, and electricity is transferred between the electrodes through the soft tissue and skull during the treatment.
tES is considered useful to map the functions of the brain, that is, to understand the relationship between the brain part and behaviours/actions. Part of the current penetrates the brain and affects the nerves, resulting in an altered activity.
Given the important nature of the brain, the use of electricity on it can be dangerous if outcomes are not known. The response of various blood vessels in the cranium and various neurological pathways to tES must be clearly understood to get maximum benefit of the procedure, with minimum damage.
"We simulated a physiologically detailed mathematical model of the neurovascular unit (NVU) with four compartments: synaptic space, astrocyte space, perivascular space, and arteriole smooth muscle cell space, called NeuroVascular Units or NVU," said Dr. Shubhajit Roy Chowdhury, Associate Professor, School of Computing and Electrical Engineering, IIT Mandi, in the statement.
The mathematical model involved the application of perturbations of varying frequencies (0.1 Hz to 10 Hz) to simulate the electrical field, to the four nested NVU compartmental pathways and analysed the changes in blood vessel diameter in response to the frequencies.
Three types of non-invasive brain stimulation -- transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), and transcranial oscillatory current stimulation (tOCS) -- were modelled to investigate their physiological effects.
The initial tES effects on the blood vessels were also found to occur via the perivascular space -- a fluid-filled space surrounding the blood vessels in the brain.
"Our study can help brain- and neuro-specialists plan patient-specific restorative neurorehabilitation activities for stroke, post-traumatic brain injury, mild cognitive impairment, dementia, and other neuropsychiatric disorders," Chowdhury said.
Such a mathematical model-based quantitative analysis would help in individualised therapeutic protocols for neuropsychiatric disorders. The team has planned experimental studies that involve the blocking of various pathways to validate their modelling results.
The results have been published in the journal Brain Stimulation.
