tactile-dependant corticomotor facilitation is influenced by discrimination performance in seniorstactile-dependant corticomotor便利化是受歧视老年人的性能的影响.pdfVIP

Master and Tremblay Behavioral and Brain Functions 2010, 6:16 /content/6/1/16 RESEARCH Open Access Tactile-dependant corticomotor facilitation is influenced by discrimination performance in seniors 1 2* Sabah Master , François Tremblay Abstract Background: Active contraction leads to facilitation of motor responses evoked by transcranial magnetic stimulation (TMS). In small hand muscles, motor facilitation is known to be also influenced by the nature of the task. Recently, we showed that corticomotor facilitation was selectively enhanced when young participants actively discriminated tactile symbols with the tip of their index or little finger. This tactile-dependant motor facilitation reflected, for the large part, attentional influences associated with performing tactile discrimination, since execution of a concomitant distraction task abolished facilitation. In the present report, we extend these observations to examine the influence of age on the ability to produce extra motor facilitation when the hand is used for sensory exploration. Methods: Corticomotor excitability was tested in 16 healthy seniors (58-83 years) while they actively moved their right index finger over a surface under two task conditions. In the tactile discrimination (TD) condition, participants attended to the spatial location of two tactile symbols on the explored surface, while in the non discrimination (ND) condition, participants simply moved their finger over a blank surface. Changes in amplitude, in latency and in the silent period (SP) duration were measured from recordings of motor evoked potentials (MEP) in the right first dorsal interosseous muscle in response to TMS of the left motor cortex. Results: Healthy seniors exhibited widely varying levels of performance with the TD task, o