Proprioception in extraocular muscles of the rat.

Stretch receptor afferents from extraocular muscles were found in the rat. Their first-order somata, responding specifically to eye muscle displacements, were restricted to the ipsilateral semilunar ganglion. Over a broad range of stimulus frequencies the sensitivity of receptors increased by a factor of 2.2 per decade with a mean sensitivity of 125 imp. s-1 mm-1 at 1 Hz.