Selective reward affects the rate of saccade adaptation

Abstract

In this study we tested whether a selective reward could affect the adaptation of saccadic eye movements in monkeys. We induced the adaptation of saccades by displacing the target of a horizontal saccade vertically as the eye moved toward it, thereby creating an apparent vertical dysmetria. The repeated upward target displacement caused the originally horizontal saccade to gradually deviate upward over the course of several hundred trials. We induced this directional adaptation in both right- and leftward saccades in every experiment (n=20). However, in half of the experiments (n=10), we rewarded monkeys only when they made leftward saccades and in the other half only for rightward saccades. The reaction time of saccades in the rewarded direction was shorter and we, like others, interpreted this change as a sign of the reward’s preferential effect in that direction. Saccades in the rewarded direction showed more rapid adaptation of their directions than did saccades in the non-rewarded direction, indicating that the selective reward increased the speed of saccade adaptation. The differences in adaptation speed were reflected in changes in saccade metrics, which were usually more noticeable in the deceleration phases of saccades than in their acceleration phases. Because previous studies have shown that the oculomotor cerebellum is involved with saccade deceleration and also participates in saccade adaptation, it is possible that selective reward could influence cerebellar plasticity.

Reward-based improvements in motor control are driven by multiple error-reducing mechanisms

“…– a phenomenon dubbed “loss aversion”. Next, radial accuracy has been shown to improve with reward, both in monkeys (Kojima & Soetedjo, 2017; Takikawa et al, 2002) and humans (Manohar et al, 2019, 2015), but these studies all focused on saccadic eye movements. In contrast, one reported case in a reaching task showed improvements in angular accuracy (Summerside et al, 2018).…”

Task errors contribute to implicit aftereffects in sensorimotor adaptation

“…However, how reward prediction errors and rewards affect sensorimotor adaptation is not fully understood. Mounting evidence shows that extrinsic rewards such as gaining or losing pleasing feedback, points, money, or food can modulate sensorimotor adaptation (e.g., Gajda, Sülzenbrück, & Heuer, ; Galea, Mallia, Rothwell, & Diedrichsen, ; Kojima & Soetedjo, ; van der Kooij & Overvliet, ; Madelain, Paeye, & Wallman, ; Nikooyan & Ahmed, ; Quattrocchi, Greenwood, Rothwell, Galea, & Bestmann, ; Song & Smiley‐Oyen, ), but less is known about how adaptation is affected by intrinsic rewards associated with accomplishing task goals (Kim, Parvin, Hernandez, & Ivry, ; Widmer, Ziegler, Held, Luft, & Lutz, ).…”

Reward-driven enhancements in motor control are robust to TMS manipulation

“…In saccadic eye movements, reward has a well-known ability to invigorate motor control, 30 enhance accuracy, and promote accurate action selection in the face of potential distractors 31 (Kojima and Soetedjo, 2017;Manohar et al, 2015;Sohn and Lee, 2006;Takikawa et al, 2002). 32…”