1. Information-theoretic analysis of de-efferented single muscle spindles
- Author
-
Johan Thunberg, Uwe Windhorst, Gideon F. Inbar, Håkan Johansson, Y. Tock, and Milos Ljubisavljevic
- Subjects
Motor Neurons, Gamma ,General Computer Science ,Models, Neurological ,Normal Distribution ,Root (chord) ,Action Potentials ,Topology ,Mechanotransduction, Cellular ,Upper and lower bounds ,Normal distribution ,symbols.namesake ,Transfer (computing) ,medicine ,Animals ,Neurons, Afferent ,Muscle, Skeletal ,Muscle Spindles ,Simulation ,Physics ,Afferent Pathways ,Code rate ,Spinal cord ,Electric Stimulation ,medicine.anatomical_structure ,Gaussian noise ,Cats ,symbols ,Spike (software development) ,Spinal Nerve Roots ,Muscle Contraction ,Biotechnology - Abstract
The information transmission properties of single, de-efferented primary muscle-spindle afferents from the hind limb of the cat were investigated. The gastrocnemius medialis muscle was stretched randomly while recording spike trains from several muscle-spindle afferents in the dorsal root. Two classes of input stimuli were used: (i) Gaussian noise with band-limited flat spectrum, and (ii) Gaussian noise with a more "naturalistic" 1/f(n) spectrum. The "reconstruction" method was used to calculate a lower bound to the information rate (in bits per second) between the muscle spindles and the spinal cord. Results show that in response to the flat-spectrum input, primary muscle-spindle afferents transfer information mainly about high frequencies, carrying 2.12 bits/spike. In response to naturalistic-spectrum inputs, primary muscle-spindle afferents transfer information about both low and high frequencies, with "spiking efficiency" increasing to 2.67 bits/spike. A simple muscle-spindle simulation model was analyzed with the same method, emphasizing the important part played by the intrafusal fiber mechanical properties in information transmission.
- Published
- 2002