How does the motor cortex encode gait? Analysis of intra-cortical recordings in rats during treadmill locomotion

Routhe, Jakob Skriver ; Niemeier, Marko

4. term

Biomedical Engineering and Informatics, Master

2012

2012-06-01

108

Formålet med studiet var at undersøge, om primær motorisk cortex (M1), et hjerneområde for frivillige bevægelser, er vigtig for igangsættelse og afslutning af gang samt for gang på skrå underlag. Ti Sprague-Dawley-rotter indgik. I fem rotter blev der kronisk implanteret en 16-kanals mikrotrådselektrode i M1 og fire fine-wire EMG-elektroder (bipolære) i to muskler i højre bagben: vastus lateralis (forlår) og biceps femoris (baglår/hasemuskel). Over fem dage registrerede vi intracortikale signaler (hjernesignaler), EMG (muskelaktivitet) og højhastighedsvideo, mens rotterne gik på et vandret og et skråt løbebånd. Hos to rotter havde den gennemsnitlige aktivitet fra én M1-kanal en lignende form på tværs af alle gangopgaver, og der sås ingen stigning i fyringsraten mellem de forskellige opgaver. EMG-amplituden steg derimod signifikant i biceps femoris under skrå gang sammenlignet med vandret gang. Resultaterne tyder på, at M1 ikke spiller en større rolle i igangsættelse og afslutning af gang eller under skrå gang. Protokollen muliggør samtidig og tidsmæssig kobling af hjernesignaler, EMG og bevægelsesdata og kan bruges til at undersøge, hvordan neurale og muskulære signaler hænger sammen under gang.

This study examined whether the primary motor cortex (M1), a brain area involved in voluntary movement, is important for starting and stopping walking and for walking on an incline. Ten Sprague–Dawley rats took part. In five rats we chronically implanted a 16-channel microwire array in M1 and four fine-wire EMG electrodes (bipolar) in two right hindlimb muscles: vastus lateralis (front thigh) and biceps femoris (back thigh/hamstring). Over five days we recorded intracortical signals (brain activity), EMG (muscle activity), and high-speed video while the rats walked on a horizontal and an inclined treadmill. In two rats, the average activity from one M1 channel showed a similar pattern across all walking tasks, with no increase in firing rate between tasks. EMG amplitude increased significantly in biceps femoris during inclined walking compared with horizontal walking. These findings suggest that M1 does not play a major role in the initiation and end phase of locomotion or during inclined walking. The protocol allows precise time alignment of brain signals, EMG, and kinematic measures to study how neuronal activity relates to muscle activity during gait.

[This abstract was generated with the help of AI]

Neurophysiology ; Gait analysis ; Intramuscular EMG (iEMG) ; Intracortical signals ; Motor cortex ; Treadmill locomotion

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