Predictive motor control is essential to achieve rapid and precise motor action in all vertebrates. Visuomotor transformations have been a popular model system to study the underlying neural mechanisms, in particular, the role of the cerebellum in both predictive and gain adaptations. In all species, large-field visual motion produces an involuntary conjugate ocular movement facilitating gaze stabilization called the optokinetic response. Gain adaptation can be induced by prolonged optokinetic visual stimulation; and if the visual stimulation is temporally periodic, predictive behavior emerges. Two predictive timing components were identifiable in this behavior. The first was prediction of stimulus initiation (when to move) and the other was stimulus termination (when to stop). We designed visual training that allowed us to evaluate initiation and termination independently that included the recording of cerebellar activity followed by acute and chronic cerebellar removal in goldfish of both sexes. We found that initiation and termination predictions were present in the cerebellum and more robust than conflicting visual sensory signals. Each prediction could be acquired independently, and both the acquisition and maintenance of each component were cerebellar-dependent. Subsequent analysis of the neuronal connectivity strongly supports the hypothesis that the acquired eye velocity behaviors were dependent on feedforward velocity buildup signals from the brainstem, but the adaptive timing mechanism itself originates within the circuitry of the cerebellum.

predictive motor control is ubiquitously employed in animal kingdom to achieve rapid and precise motor action. in most vertebrates large, moving visual scenes induce an optokinetic response (oKR) control of eye movements to stabilize vision. In goldfish, the OKR was found to be predictive after a prolonged exposure to temporally periodic visual motion. A recent study showed the cerebellum necessary to acquire this predictive OKR (pOKR), but it remained unclear as to whether the cerebellum alone was sufficient. Herein we examined different fish species known to share the basic architecture of cerebellar neuronal circuitry for their ability to acquire pOKR. Carps were shown to acquire pOKR like goldfish while zebrafish and medaka did not, demonstrating the cerebellum alone not to be sufficient. Interestingly, those fish that acquired pOKR were found to exhibit long-lasting optokinetic after nystagmus (OKAN) as opposed to those that didn't. To directly manipulate OKAN vestibularneurectomy was performed in goldfish that severely shortened OKAN, but pOKR was acquired comparable to normal animals. these results suggest that the neuronal circuitry producing oKAn, known as the velocity storage mechanism (VSM), is required to acquire pOKR irrespective of OKAN duration. Taken together, we conclude that pOKR is acquired through recurrent cerebellum-brainstem parallel loops in which the cerebellum adjusts VSM signal flow and, in turn, receives appropriately timed eye velocity information to clock visual world motion.

Microsaccades together with drift and tremor are fixational eye movements that are generated when we try to fixate our gaze on a visual target. Besides their function in vision to prevent neural adaptation to unchanging retinal image, microsaccades have been studied in neuroscience as an indicator of attentional states for the last decade. Most of microsaccade researches have been conducted in unnatural laboratory environments, using controlled artificial visual stimuli. Thus, little is known about the characteristics of microsaccades in natural viewing conditions. Here we attempted to evaluate microsaccades during car driving condition in the aim of estimating driver's spatial attention. We demonstrate that microsaccades are generated during car driving, and the rate of microsaccade generation is modulated by road conditions such as appearance of pedestrians or/and other cars.

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SSVEP (steady-state visual evoked potential) is known as EEG response for alternated visual stimulation about 3.5-75 Hz that used for signal source of the brain-computer interface. Whereas there are many studies for SSVEP or visual sensory system, little is known that how is central nerves system generate EEG response at high frequency visual stimulation such as SSVEP. To simplify the experimental neural pathway, we focused on the optic tectum of the Goldfish that receives direct visual inputs from the retina. For the Goldfish has been used as experimental animal for oculomotor reflex, thought to be suitable for experimental model for visual system. In this study, single unit activities of the optic tectum were recorded during flashing stimulation at 1 Hz or 15 Hz to pupil of the Goldfish. Most part of unit group 1 that only showed ON-or OFF-response at 1 Hz showed abolished response at 15 Hz stimulation. In contrast, most part of unit group 2 that showed ON-OFF response at 1 Hz remained ON-or OFF-response at 15 Hz stimulation. In addition, unit group 2 showed shorter latency of OFF response than ON response at 1 Hz stimulation significantly. These results suggests unit group that showed ON-OFF response at low frequency have a following activity with high frequency stimulation.