The corticospinal system underlying voluntary movement
THE CORTICOSPINAL SYSTEM UNDERLYING VOLUNTARY MOVEMENT
The main projects in Physiology of motor control’s laboratory are devoted to understanding the cerebral control of hand and finger movements in humans. Such interest is driven by the need to understand why hand and finger movements are particularly affected by damage to the cortex, and its major descending pathways, for instance as a result of stroke and spinal injury.
Data on non-human primates highlighted the crucial role exerted by the corticospinal tract (CTS) in controlling the spinal machine to produce skilled hand and finger movements. The CST originates from multiple areas of the cortex, presumably each one devoted to control a specific aspect of voluntary movement. In order to disclose the code adopted by the nervous system to allow humans to perform high motor skill, it seems necessary to understand tree main aspects of this powerful descending system: i) the properties of areas originating CST fibers; ii) description of the circuit and the pattern of termination of fibers coming from the different CTS areas onto motoneurons in the spinal cord; iii) description of the cortical working network by studying the functional properties of the neural circuits through which all the areas cooperate during the execution of the motor task.
This experimental investigation in humans cannot be accomplished with the same experimental tools used in animals and needed to get reliable results. However the new techniques developed in neurosurgery, in particular the Brain Mapping technique adopted to guide tumor resection, can give a great opportunity to shed light of neural circuits in humans by-passing the animal model. Data obtained in this setting can be greatly improved by data obtained with the advanced neuroimaging techniques and by the “lesion studies” (as investigation in patients affected by stroke). The study of the mirror neuron system in humans and motor resonance, a phenomenon closely related to the corticospinal system, also provides a unique approach to the investigation of the functional properties of the system.
The main effort of the future years will be devoted, by using different experimental approaches (TMS e H-reflex, Behavioural paradigms, neuroimaging e di intraoperative electrophysiology), to describe, in humans, the functional properties of the neural circuits linking the different cortical areas involved in motor control and to deepen the knowledge of how the CST exerts it action on the spinal machine when performing highly skilled voluntary movements.
INTRAOPERATIVE INVESTIGATION OF CORTICOSPINAL SYSTEM
Investigation on the functional properties of cortico-cortical and corticospinal projections from non primary motor areas in human brain.
Investigation on the functional properties of Broca’s area and it’s function in the motor system.
STUDIES ON LESIONS
Control exerted by the primary motor area on the ipsilateral side and on controlateral side: analysis in healthy subjects and patients affected by stroke.
Control exerted by non-primary motor area on ispialteral and controlateral side
Role exerted by the somatosensory afferents from specific sites of the feet on motor and cardiovascular autonomic control in the up-right position in Parkinson’s patients.
THE MOTOR RESONANCE IN HUMANS
Excitability changes in human spinal neurons and corticospinal projections to muscles moving hand/fingers and foot while viewing actions performed by others.
The Mirror Neuron System and Motor resonance: Functional magnetic resonance investigating the role of the motor constraints (such as the handendness) in the resonant response.
The Mirror Neuron System and Motor resonance: Functional magnetic resonance investigating the role of the Broca’s area (BA44) and face / hand premotor cortex (BA6) in motor resonant response
PHYSIOLOGY OF MOTOR CONTROL’S LAB
Dr. Gabriella Cerri (assistant professor)
Dr. Luca Fornia (post-doctoral fellow)
Dr. Valentina Ferpozzi (PhD student)
Prof Lorenzo BELLO, Dr Enrica Fava (BIOMETRA , Unimi) and collaborators
Prof Andrea Falini (CERMAC, Università San Raffaele) and collaborators
Prof Paola Borroni (Dipartimento di Scienze della Salute, Unimi) and collaborators
Prof Anna Berti (Dipartimento di Psicologia, Unito) and collaborators