gms | German Medical Science

Even though the knee contains a lot of receptors, it is still uncertain if sensory information of the knee reaches the neocortex, SI in particular. Nevertheless it would be important to know which brain areas are involved in sensory-motor control for clinical interests as well. To address this question and to show cortical projections of knee afferent inputs, we performed electrical stimulation of the tibial and pernoneal nerves at knee level with simultaneous recording of corresponding brain activity.

This study was perfomed on 6 healthy male volunteers. Left and right tibial and peroneal nerves were stimulated transcutaneously with simultaneous recording of a 64 channel EEG. Each subject got a MRI scan for individual brain source analysis.

Results of the 6 healthy male volunteers showed four different brain power maxima. This brain activity was detected 40 ms, 50 ms, 60 ms and 80 ms after nerve stimulation. Source localisation revealed generators of those brain activities in the primary motor cortex (area 4) and the supplementary motor area (area 6).

In this study it was possible to show where exactly sensory information from the knee level is processed in the brain. Area 4, also known as primary motor cortex, is known to control kinematic and dynamic parameters of movement. Motor-related areas other than area 4 use external (e.g. sensory) or internal cues to trigger and guide movements. The results demonstrate that sensory input from the knee is also well integrated in processes of the neocortex.