We combine many different experimental approaches to address these questions and achieve our goals. The basic approach is electrophysiological, which includes simultaneous single unit recordings from a large number of neurons using multiple electrodes, multiunit neurophysiological mapping and intracortical microstimulation. Neuroanatomical techniques are used to determine anatomical basis of the functional organization of the brain, and to determine the changes in the brain wiring which result in plasticity. Behavioural assessments are done to determine the extent of recoveries from injuries.
Brain is a dynamic organ. It is continuously adapting and changing in response to changes in the external and internal environments. This property of the brain, which is also called brain plasticity, allows learning. It also facilitates recoveries from injuries to the brain, spinal cord or peripheral nerves. Goal of the research in our laboratory is to understand how organization of different areas of the brain is altered by spinal cord injuries, and how we can use the ability of the brain to change for better recoveries from the injuries. The second goal of our research is to understand how the somatosensory and the motor areas of the brain process sensory information to enable tactile perception.
Research
Following spinal cord injuries, the neurons that no longer receive sensory inputs get reactivated by the remaining uninjured inputs, resulting in reorganization of the information processing streams in the brain. Such reorganization can also affect perceptual abilities. In our lab we are determining the nature and extent of such reorganizations, and the mechanisms that underlie such changes. We address these questions using in vivo models of partial spinal cord injuries. In order to help recoveries from spinal cord injuries we are using transplant of stem cells and neural precursor cells to establish parameters for optimum recoveries from spinal cord injuries. We are also developing brain-machine interface devices to help patients with injuries.
Do rats have multiple motor areas similar to other mammals such as primates? The rat motor cortex has two forelimb areas, the caudal forelimb area and the rostral forelimb area. But it was believed to contain a single whisker representation, as shown in green above. Our experiments show that there are two separate whisker representations. The caudal whisker area, which also has neck representation, and the rostral whisker area, which has only the whisker representation. Neck movements in the caudal whisker region can be seen by stimulating at higher than threshold currents. The image on the right shows the whisker motor cortex where neck movements are seen at suprathreshold currents. For details see Tandon et al., 2008.