Slow–fast control of eye movements: an instance of Zeeman’s model for an action

Abstract

The rapid eye movements (saccades) used to transfer gaze between targets are examples of an action. The behaviour of saccades matches that of the slow–fast model of actions originally proposed by Zeeman. Here, we extend Zeeman’s model by incorporating an accumulator that represents the increase in certainty of the presence of a target, together with an integrator that converts a velocity command to a position command. The saccadic behaviour of several foveate species, including human, rhesus monkey and mouse, is replicated by the augmented model. Predictions of the linear stability of the saccadic system close to equilibrium are made, and it is shown that these could be tested by applying state-space reconstruction techniques to neurophysiological recordings. Moreover, each model equation describes behaviour that can be matched to specific classes of neurons found throughout the oculomotor system, and the implication of the model is that build-up, burst and omnipause neurons are found throughout the oculomotor pathway because they constitute the simplest circuit that can produce the motor commands required to specify the trajectories of motor actions.

Visual attentional guidance during smooth pursuit eye movements: Distractor interference is independent of distractor‐target similarity

“…However, this finding is in line with the assumption that OPN activity scales with decision times prior to an eye movement, too (cf. Clement & Akman, 2020). Thus, the current study's distractor‐elicited OPN activity modulation that impacted initial pursuit gain probably also reflected the longer decision times that were created by the duration of the distractor‐target motion (or position) conflict (which both are proportional to distractor duration).…”

Catastrophe theory in work from heartbeats to eye movements

“…The action potential initiates at this point. With another equation for a neural integrator (Equation (4) in Clement and Akman 2020 ), they compared the behavior of their system of equation (4) with experimental eye movement data and found the model could explain the saccadic eye movement.…”