Direct evidence for the contribution of the superior colliculus in the control of visually guided reaching movements in the cat

Section: Innate Nature Of the Interceptive Strategymentioning

confidence: 95%

Reflexive Limb Selection and Control of Reach Direction to Moving Targets in Cats, Monkeys, and Humans

Perfiliev

Isa

Johnels

et al. 2010

“…Moreover, direct stimulation of NRG can evoke movement of the upper torso as well as head movements . Although further experiments will be required to determine if stimulation of the superior colliculus might evoke body turning movements in a loosely constrained monkey, the finding that stimulation of the deeper layers of the SC can perturb arm movements (Courjon et al 2004) provides evidence that activation of the SC can influence the control of body segments below the eyes and head.…”

Section: Substrates For Coordinating Eye-head-body Gaze Shiftsmentioning

confidence: 99%

Eye, Head, and Body Coordination During Large Gaze Shifts in Rhesus Monkeys: Movement Kinematics and the Influence of Posture

McCluskey

Cullen

2007

McCluskey MK, Cullen KE. Eye, head, and body coordination during large gaze shifts in rhesus monkeys: movement kinematics and the influence of posture. J Neurophysiol 97: 2976 -2991, 2007. First published January 17, 2007 doi:10.1152/jn.00822.2006. Coordinated movements of the eye, head, and body are used to redirect the axis of gaze between objects of interest. However, previous studies of eyehead gaze shifts in head-unrestrained primates generally assumed the contribution of body movement to be negligible. Here we characterized eye-head-body coordination during horizontal gaze shifts made by trained rhesus monkeys to visual targets while they sat upright in a standard primate chair and assumed a more natural sitting posture in a custom-designed chair. In both postures, gaze shifts were characterized by the sequential onset of eye, head, and body movements, which could be described by predictable relationships. Body motion made a small but significant contribution to gaze shifts that were Ն40°i n amplitude. Furthermore, as gaze shift amplitude increased (40 -120°), body contribution and velocity increased systematically. In contrast, peak eye and head velocities plateaued at velocities of ϳ250 -300°/s, and the rotation of the eye-in-orbit and head-on-body remained well within the physical limits of ocular and neck motility during large gaze shifts, saturating at ϳ35 and 60°, respectively. Gaze shifts initiated with the eye more contralateral in the orbit were accompanied by smaller body as well as head movement amplitudes and velocities were greater when monkeys were seated in the more natural body posture. Taken together, our findings show that body movement makes a predictable contribution to gaze shifts that is systematically influenced by factors such as orbital position and posture. We conclude that body movements are part of a coordinated series of motor events that are used to voluntarily reorient gaze and that these movements can be significant even in a typical laboratory setting. Our results emphasize the need for caution in the interpretation of data from neurophysiological studies of the control of saccadic eye movements and/or eye-head gaze shifts because single neurons can code motor commands to move the body as well as the head and eyes.

“…Various other movements have been evoked by collicular stimulation, including eye and tail movements in goldfish (Herrero et al 1998) and circling behavior in rodents (Tehovnik and Yeomans 1986). In primates, several studies have attributed a collicular role for arm movements (Courjon et al 2004;Nagy et al 2006;Stuphorn et al 2000;Werner et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Effect of Reversible Inactivation of Superior Colliculus on Head Movements

Walton¹,

Bechara²,

Gandhi³

2008

Because of limitations in the oculomotor range, many gaze shifts must be accomplished using coordinated movements of the eyes and head. Stimulation and recording data have implicated the primate superior colliculus (SC) in the control of these gaze shifts. The precise role of this structure in head movement control, however, is not known. The present study uses reversible inactivation to gain insight into the role of this structure in the control of head movements, including those that accompany gaze shifts and those that occur in the absence of a change in gaze. Forty-five lidocaine injections were made in two monkeys that had been trained on a series of behavioral tasks that dissociate movements of the eyes and head. Reversible inactivation resulted in clear impairments in the animals' ability to perform gaze shifts, manifested by increased reaction times, lower peak velocities, and increased durations. In contrast, comparable effects were not found for head movements (with or without gaze shifts) with the exception of a very small increase in reaction times of head movements associated with gaze shifts. Eye-head coordination was clearly affected by the injections with gaze onset occurring relatively later with respect to head onset. Following the injections, the head contributed slightly more to the gaze shift. These results suggest that head movements (with and without gaze shifts) can be controlled by pathways that do not involve SC.