Linear spatio-temporal convergence in vestibular neurons of the primate nucleus fastigii

VESTIBULAR responses in the primate fastigial nucleus (FN) do often not fol low the simple cosine tuning observed in primary vestibular afferents. The present report demonstrates that these more complex patterns can mostly be attributed to simple linear summation of spatially and temporally diverse c osine-tuned input signals (linear spatio-temporal convergence, STC). Analys es following from this elementary finding, however, reveal frequency-depend ent properties in many FN neurons, which are difficult to reconcile with ex isting concepts of possible functions of STC in central vestibular areas. T he demonstration that STC linearity holds for FN responses is thus of both theoretical and practical relevance, allowing shortening of future experime ntal protocols and facilitating comparison of the observed spatio-temporal response dynamics with those at other stages of vestibular signal processin g. (C) 1999 Lippincott Williams & Wilkins.