Although motion parallax is closely associated with observer head movement, the underlying neural mechanism appears to rely on a pursuit-like eye movement signal to disambiguate perceived depth sign from the ambiguous retinal motion information [Naji, J. J., & Freeman, T. C. A. (2004). Perceiving depth order during pursuit eye movement. Vision Research, 44, 3025-3034; Nawrot, M. (2003). Eye mov...

Stimulation in the hypothalamus elicits locomotor stepping. Before stepping is initiated, head scanning movements occur. We determined the relationships between the latency of locomotor initiation and the number, extent and direction of the head scanning movements. Chronic stimulation electrodes were stereotaxically implanted in and around the hypothalamus of 29 rats. Under awake conditions, 38...

During free exploration, humans adjust their gaze by combining body, head, and eye movements. Laboratory experiments on the stimulus features driving gaze, however, typically focus on eye-in-head movements, use potentially biased stimuli, and restrict the field of view. Our novel wearable eye-tracking system (EyeSeeCam) overcomes these limitations. We recorded gaze- and head-centered videos of ...

As we navigate through the world, eye and head movements add rotational velocity patterns to the retinal image. When such rotations accompany observer translation, the rotational velocity patterns must be discounted to accurately perceive heading. The conventional view holds that this computation requires efference copies of self-generated eye/head movements. Here we demonstrate that the brain ...

We use an exocentric pointing task to study exocentric visual directions to targets that are opposite to a pointer relative to the observer. (The apparent distance between the target and the pointer always exceeded 90 degrees of visual angle.) All pointing takes place in the horizontal plane at eye height. Observers could not see both target and pointer at a single glance. They had to look back...

Visual stimuli are initially represented in a retinotopic reference frame. To maintain spatial accuracy of gaze (i.e., eye in space) despite intervening eye and head movements, the visual input could be combined with dynamic feedback about ongoing gaze shifts. Alternatively, target coordinates could be updated in advance by using the preprogrammed gaze-motor command ("predictive remapping"). So...

1. Saccadic eye movements during walking were studied in chickens using cinematography. 2. Saccades were made during about 80% of the thrust phases of head bobbing, and not made in the hold phases. 3. The coordination of saccades with head movements maintains clear vision for the largest possible proportion of the time. 4. The absence of saccades in hold phases and in some thrusts is probably n...

The mammalian orienting response to sounds consists of a gaze shift that can be a combination of head and eye movements. In animals with mobile pinnae, the ears also move. During head movements, vision is stabilized by compensatory rotations of the eyeball within the head because of the vestibulo-ocular reflex (VOR). While studying the gaze shifts made by cats to sounds, a previously uncharacte...

A case of spasmus nutans was studied using objective recordings of head and eye displacement in order to generate a precise description of the ocular oscillations and head nodding and to investigate their interrelationships. The ocularoscillations consisted of 11-Hz sinusoidal convergence movements. The head nodding consisted of a 3-Hz, 3 degrees peak to peak, sinusoidal oscillation in the hori...