Hand–eye coordination relies on extra-retinal signals: Evidence from reactive saccade adaptation

Abstract

a b s t r a c tExecution of a saccadic eye movement towards the goal of a hand pointing movement improves the accuracy of this hand movement. Still controversial is the role of extra-retinal signals, i.e. efference copy of the saccadic command and/or ocular proprioception, in the definition of the hand pointing target. We report here that hand pointing movements produced without visual feedback, with accompanying saccades and towards a target extinguished at saccade onset, were modified after gain change of reactive saccades through saccadic adaptation. As we have previously shown that the adaptation of reactive saccades does not influence the target representations that are common to the eye and the hand motor

Controlling an effector with eye movements: The effect of entangled sensory and motor responsibilities

“…The typical temporal sequence of events consisted of the appearance of the task target, followed by the eye fixation, and finally the hand reaching the target location ( Fig 4 ). This is consistent with observations made in other studies [ 38 , 39 ].…”

Adaptation of hand movements to double-step targets and to distorted visual feedback: Evidence for shared mechanisms

“…This is in contrast to previous studies on eye adaptation with the hand held still: there, aftereffects of the eyes were as high as 24-36% (Alahyane et al, 2007;Bock et al, 2008;Xu-Wilson et al, 2009). One possible interpretation for this discrepancy is that adaptive recalibration of saccades -as gauged by aftereffects (Bock, 2005;McNay & Willingham, 1998;Pisella et al, 2004;Redding & Wallace, 1996) -is strong when the eyes move alone, but is marginal when eyes and hand move together, possibly because the latter situation can be mastered more efficiently by yoking oculomotor commands to arm motor commands rather than by recalibrating both motor systems (Cotti, Vercher, & Guillaume, 2011). This interpretation is consistent with the finding that eye and arm movements are naturally coupled (Grankek et al, 2009;Jackson, Newport, Mort, & Husain, 2005;Neggers & Bekkering, 2002), but it is difficult to reconcile with the present observation that during the transfer phase of group ROT, eye and hand directions were dissociated by 5.9°.…”

Computer Vision for Brain Disorders Based Primarily on Ocular Responses

“…Brain disorders such as stroke, Parkinson disease (PD), autism, Alzheimer disease (AD), depression and schizophrenia, which intensively lead to vast personal suffering, enormous financial costs, and an imposing social burden 6 , have been already indicated to be associated with some various ocular changes to some extent during available ophthalmological assessments. We propose here it will be promising to assess ocular changes as a potential early-biomarker for brain disorders 2 ; mainly because not only the visual system is our dominant sensory input in CNS, but also we rely upon a precise timing and accuracy of visual signal about our social and physical stimuli for high-order cortex processing and then to do output actions rapidly 7 . With a manifestation of AI application in brain healthcare, big data of many ocular parameters in response to brain emotional and cognitive state in real time might be very helpful for early detection and evaluation to brain disorders especially with the help of advanced computer vision (CV) and deep learning algorithms.…”