Static and dynamic discharge properties of vestibular-nerve afferents in the mouse are affected by core body temperature.

The goal of this study was to determine the effect of changes in core body temperature on the resting discharge rate and sensitivity of vestibular-nerve afferents. Extracellular recordings were made from vestibular-nerve afferents innervating the semicircular canals in anesthetized C57BL/6 mice maintained at a core body temperature of either 30-32 degrees C (T (31)) or 35-37 degrees C (T (36)). The resting rates of regular (CV* < 0.1) and irregular afferents (CV* > 0.1) were lower at T (31) than at T (36). Sensitivity and phase were compared for rotations ranging from 0.1 to 12 Hz by calculating coefficients of a transfer function, g . t(c)S . (t(z)S +1)/(t(c)S + 1), for each afferent. The sensitivity (g) increased with CV* and with higher core body temperature. The value of the coefficient representing the low-frequency dynamics (t (c)) varied inversely with CV* but did not change with core body temperature. The high-frequency dynamics represented by t (z) increased with CV* and decreased with higher core body temperature. These findings indicate that changes in temperature have effects on the static and dynamic properties of vestibular-nerve afferents.