Maarten A. Frens

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The ability to search and scan the environment effectively is a prerequisite for spatial behavior. A longstanding theory proposes that inhibition of previously attended loci (Inhibition of return; IOR) serves to facilitate exploration by increasing the likelihood to inspect new areas instead of returning to locations that have been inspected before. In this(More)
To the Editor: Over the last decades, cellular bistability or multistable states of the membrane potential have been demonstrated both in vitro and in vivo for different types of neurons throughout the brain, and various functions have been proposed for this phenomenon1,2. Recently, Loewenstein et al.3 proposed that bistability in Purkinje cells has a key(More)
A video-based 2D eye-tracking system (EyeLink version 2.04, SR Research Ltd/SMI) was compared with the scleral search coil technique for its performance on recording the properties of fixations and saccadic eye movements. Fixation positions and saccadic properties (amplitude, duration, and peak velocity) were calculated independently from the data of the(More)
It has been argued that precision in throwing is limited by the precision in the timing of the release. When precision is the only goal, as in throwing darts, one could therefore expect people to throw in a way that reduces sensitivity for imprecision in timing. We show that subjects do not do so, but throw in a way that reduces the sensitivity for speed(More)
Patients with Hodgkin's disease can develop paraneoplastic cerebellar ataxia because of the generation of autoantibodies against mGluR1 (mGluR1-Abs). Yet, the pathophysiological mechanisms underlying their motor coordination deficits remain to be elucidated. Here, we show that application of IgG purified from the patients' serum to cerebellar slices of mice(More)
The spatial properties of horizontal cells in the cat retina have been studied by means of intracellular recordings in the optically intact, in situ, eye. The spread of potentials in the horizontal cell layer and the spatial summation properties have been investigated using "white light" stimuli in several different configurations. Area-response curves were(More)
Tasks such as reading or visual search consist of series of saccades. We have investigated to what extent saccades that are made within a series of self-paced movements are influenced by preceding movements. The present paper concerns an analysis of the duration of the fixations preceding saccades. We tested human subjects in a paradigm where they had to(More)
PURPOSE To study three-dimensional optokinetic eye movements of wild-type C57BL/6J mice, the most commonly used mouse in oculomotor physiology. Optokinetic eye movements are reflexive eye movements that use visual feedback to minimize image motion across the retina. These gaze-stabilizing reflexes are a prominent model system for studying motor control and(More)
The cervico-ocular reflex (COR) is an ocular stabilization reflex that is elicited by rotation of the neck. It works in conjunction with the vestibulo-ocular reflex (VOR) and the optokinetic reflex (OKR) in order to prevent visual slip over the retina due to self-motion. The gains of the VOR and OKR are known to decrease with age. We have investigated(More)
Cerebellar long-term depression (LTD) at parallel fibre-Purkinje cell (P-cell) synapses is thought to embody neuronal information storage for motor learning. Transgenic L7-protein kinase C inhibitor (PKCI) mice in which cerebellar LTD is selectively blocked do indeed exhibit impaired adaptation in the vestibulo-ocular reflex (VOR) while their default(More)