Transcranial Magnetic Stimulation (TMS)
Transcranial magnetic stimulation (TMS) is a non-invasive technique that uses electromagnetic induction to stimulate neurons within the brain. A pulse of TMS delivered to the motor cortex is capable of activating the corticospinal tract, which leads to a muscle response known as the motor-evoked potential (MEP). This muscle response is a measure of corticospinal excitability. Currently we are using TMS to probe intracortical, interhemispheric and sensorimotor neuron circuits in the brain. Further, we are using TMS to create maps of the primary motor cortex and investigate the emergence of discrete peaks and shifts in the centre of gravity within these motor maps. The information will provide fundamental new insights into the organization of the primary motor cortex.
Functional Near-Infrared Spectroscopy (fNIRS)
Functional near-infrared spectroscopy (fNIRS) is a non-invasive technique that uses near-infrared light (700-900 nm) to measure changes in cortical activity. This light passes through multiple channels into the brain tissues and is absorbed by the hemoglobin molecules present in the veins and arteries of the brain. Oxygenated-hemoglobin travels to brain areas of interest as there is more neural activity, the level of which is inferred from the amount of light detected. Common applications include monitoring task-related changes in cerebral blood flow and investigating abnormalities associated with brain disorders.
Electroencephalography Brain Machine Interface (EEG-BMI)
Movement related cortical potential’s (MRCP) are slow brain potentials that are generated approximately two seconds prior to movement and corresponds to movement intention. These potentials can be detected in real time non-invasively with an electroencephalography brain machine interface (EEG-BMI). Through the detection of MRCP’s the BMI can trigger peripheral nerve stimulation that temporally coincides with the maximum response in the motor cortex. These pairings have been shown to induce associativity plasticity in the cortical representation of the stimulated muscle causing improved motor function.
High-Density Electromyography (HD-EMG)
HD-EMG is a powerful, non-invasive technique used to measure muscle activity. A an array of individual EMG electrodes is placed on the skin overlaying a muscle, in very close proximity. Using HD-EMG, it is possible to decompose the EMG signal to identify action potentials from individual motor units and characterize spatiotemporal features at the motor unit level. Further, this signal provides us with information regarding the spatial distribution of activity within a muscle. This technique has potential applications in the study of muscle fatigue, myopathies, neurological injury and diseases of the central nervous system.
Magnetic Resonance Spectroscopy (MRS)
Magnetic Resonance Spectroscopy (MRS) is a technique that identifies the chemical composition of a specific volume or region of interest (a voxel). Using a conventional Magnetic Resonance Imaging (MRI) machine, MRS non-invasively utilizes radio frequency waves and non-iodizing radiation to identify the chemical spectrum of a voxel of interest. The MRS technique allows us to further gather information and determine relative global concentration of a variety of target metabolites and is a very useful tool for in-vivo type research. MRS techniques are often used to research metabolites and/or neurotransmitters in the brain and spinal cord, however, can also be useful in imaging muscle, liver, and other organs.