Motor control in humans.
The focus of Dr. Perez's research is on understanding how the brain and spinal cord control voluntary movements in healthy humans and in individuals with spinal cord injury. This theme is mainly investigated from a neurophysiological point of view, using a combination of transcranial magnetic stimulation (TMS) and peripheral nerve stimulation techniques.
Single and paired-pulse TMS and spinal cord reflex protocols are used to examine changes in excitatory and inhibitory pathways in humans. Particularly we use TMS-based methods to investigate the physiology of intrinsic cortical connections in the brain as well as the interactions between them. These protocols open the possibility to estimate excitability in GABA-ergic circuit in the human cortex. We employ spinal cord reflex protocols to examine changes in presynaptic inhibition and reciprocal inhibition between antagonistic lower and upper limb muscles during movement.
This work is complemented by studies that focus on understanding the neuronal mechanisms involved in motor skill acquisition involving the hand and leg representation of the primary motor cortex. Current research projects focus on topics such as interhemispheric interactions between primary motor cortices during unimanual and bimanual movements and intermanual transfer of motor learning in healthy humans and in individuals with spinal cord injury.
Perez, M.A., Butler, J.E. and Taylor, J.L. Modulation of transcallosal inhibition by bilateral activation of agonist and antagonist proximal arm muscles. J Neurophysiology, in press, 2013.
Tazoe, T. and Perez, M.A. Speed-Dependent Contribution of Callosal Pathways to Ipsilateral Movements. J Neuroscience, 33: 16178-16188, 2013.
Bunday, K.L., Oudega, M. and Perez, M.A. Aberrant Crossed Corticospinal Facilitation in Muscles Distant from a Spinal Cord Injury. PLoS One, 8: e76747, 2013.
Barry, M.D., Bunday, K.L., Chen, R. and Perez, M.A. Selective Effects of Baclofen on Use-Dependent Modulation of GABAB Inhibition after Tetraplegia. J Neuroscience, 33: 12898-12907, 2013.
Bunday, K.L. and Perez, M.A. Motor Recovery after Spinal Cord Injury Enhanced by Strengthening Corticomotoneuronal Synapses. Current Biology, 22, 2355-2361, 2012.
Oudega, M. and Perez, M.A. Corticospinal reorganization after spinal cord injury. J Physiology, 590: 364736-63, 2012.
Bunday, K.L. and Perez, M.A. Impaired Crossed Facilitation of the Corticospinal Pathway after Cervical Spinal Cord Injury. J Neurophysiology, 107; 2901-2911, 2012.
Perez, M.A., Soteropoulos, D.S. and Baker, S.N. Corticomuscular coherence during bilateral isometric arm voluntary contractions in healthy humans. J Neurophysiology, 107: 2154-2162, 2012.
Soteropoulos, D.S. and Perez, M.A. Physiological changes underlying bilateral isometric arm voluntary contractions in healthy humans. J Neurophysiology, 105: 1594-1602, 2011.
Yedimenko, J.A. and Perez, M.A. The effect of bilateral isometric forces in different directions on motor cortical function in humans. J Neurophysiology 104; 2922-2931, 2010.
Perez, M.A. and Cohen, L.G. Interhemispheric inhibition between primary motor cortices: what have we learned? J Physiology. 587: 725-726, 2009.
Perez, M.A. and Cohen LG. Scaling of motor cortical excitability during unimanual force generation. Cortex. 45: 1065-1071, 2009.