My scientific interests are centred on how the brain controls skilled actions – in particular, how we perceive the locations of different objects in the world around us, and how we coordinate actions towards them. This has led me to study activity of neurons in a part of the brain named the posterior parietal cortex, which encodes how we perceive the space around our bodies, during actions such as reaching and grasping. The ability to perform such movements is essential for independent life, but can be compromised in many diseases, and following lesions of the nervous system.
My most significant research results address how the third dimension of space (depth, or distance from one’s body) is represented in the electrophysiological activity of neurons. I am interested in how this information is processed across areas of visual, somatic sensory and association cortices to guide hand movements. This has been a neglected topic in Neuroscience, which however has marked clinical relevance, since studies in human patients with parietal lesions suggest that the amplitude and direction of arm movements are controlled by different neural systems. The following are examples of discoveries I made in the last 5 years, which set the scene for the present project:
- Neural representation of distance: In a region of parietal cortex, the neural responses evoked by visualization of an object depend on distance from the body. Specifically, I found a group of neurons for which the electrophysiological activity is much higher when objects are within reach, compared to when they are located further away.
- Neural representation of 3D space: I found that some parietal neurons process two neural signals in parallel: one related to which direction of space our eyes look at, and the other to distance, as measured by eye convergence. “Reading” these signals allows one to specify a location relative to the head, in 3D space.
- Neural representation of hand movement parameters: I found that, when the hand moves in 3D space, a population of parietal cortex neurons sequentially process information, first about hand movement direction, and then about movement depth.
