Modeling of Smooth Pursuit-Related Neuronal Responses in the DLPN and NRTP of the Rhesus Macaque

Abstract

. Modeling of smooth pursuit-related neuronal responses in the DLPN and NRTP of the rhesus macaque. J Neurophysiol 93: 108 -116, 2005. First published August 18, 2004; doi:10.1152/ jn.00588.2004. The dorsolateral pontine nucleus (DLPN) and nucleus reticularis tegmenti pontis (NRTP) comprise obligatory links in the cortico-ponto-cerebellar system supporting smooth pursuit eye movements. We examined the response properties of DLPN and rNRTP neurons during step-ramp smooth pursuit of a small target moving across a dark background. Our neurophysiological studies were conducted in awake, behaving juvenile macaques (Macaca mulatta). We used multiple linear-regression modeling to estimate the relative sensitivities of neurons to eye parameters (position, velocity, and acceleration) and retinal-error parameters (position, velocity, and acceleration). We found that a large proportion of pursuit-related DLPN neurons primarily code eye-velocity information, whereas a large proportion of rNRTP neurons primarily code eye-acceleration information. We calculated the relative decrease in variance found when using a six-component model that included both eye-and retinal-error parameters compared with three-component models that include either eye or retinal error. These comparisons show that a majority of DLPN (14/20) and rNRTP (17/19) neurons have larger contributions from eye compared with retinal-error parameters (P Ͻ 0.001, paired t-test). Even though eye-motion parameters provide the strongest contributions in a given model, a significant contribution from retinal error was often present (i.e., Ͼ20% reduction in variance in 6-component model compared with 3-component models). Thus our results indicate that the DLPN plays a larger role in maintaining steady-state smooth pursuit eye velocity, whereas rNRTP contributes to both the initiation and maintenance of smooth pursuit.

Discharge of Monkey Nucleus Reticularis Tegmenti Pontis Neurons Changes During Saccade Adaptation

“…Tested neurons were all located in midline regions (Ϯ2 mm) from at least 1 mm rostral to rip up to 4 mm anterior. This is the region where saccade-related neurons are most dense and is caudal to the pursuit-related neurons of the NRTP (Ono et al 2005). Recording locations for neurons tested during adaptation were confirmed histologically in monkeys M and R (Fig.…”

Extraretinal Signals in MSTd Neurons Related to Volitional Smooth Pursuit

“…Step-ramp target motion conditions (Morris and Lisberger 1987;Ono et al 2005;Rashbass 1961) were typically used for testing smooth pursuit-related neurons during blink testing (Akao et al 2005;Mustari et al 1988). In this paradigm, the LED laser spot was extinguished for a period 100 -200 ms during step-ramp tracking.…”

Neural dynamics of saccadic and smooth pursuit eye movement coordination during visual tracking of unpredictably moving targets

“…The output from these cells is integrated by the model NRTP's velocity neurons What anatomical substrates realize these mechanisms? In particular, NRTP contains gaze acceleration and gaze velocity cells (Ono et al, 2005;Ono et al, 2004;Suzuki et al, 1999;Suzuki, Yamada, & Yee, 2003;T. Yamada et al, 1996) that act as velocity-comparison and velocity integrator cells (Figure 4).…”

“…(Suzuki et al, 1999;Suzuki et al, 2003;T. Yamada et al, 1996) DLPN to CBM (Mustari et al, 1988;Ono et al, 2005;Ono et al, 2004) DLPN to Vermis (Thielert & Thier, 1993;J. Yamada & Noda, 1987) DLPN to VPF Target and background speed and direction input is transferred.…”