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Abstract: Recent neurophysiological studies have begun to uncover the neuronal correlates of eye hand coordination. This study was designed to test whether the frontal eye field (FEF) saccadic activity is modulated by hand position. Single neurons were recorded in two macaque monkeys performing visually guided saccades while holding their hand at given locations on a touchscreen. To determine the relative contributions of hand vision and its proprioception, monkeys executed the task with or without vision of the hand. We found that saccadic activity of more than half of the neuronal sample (54%; n =130) was dependent on hand position relative to the saccade end point. Both visual and proprioceptive signals contributed to this modulation. These data demonstrate that the oculomotor function of the FEF takes into account hand position in space. [Copyright &y& Elsevier]

Our ability to engage and perform daily activities relies on balancing the associated benefits and costs. Rewards, as benefits, act as powerful motivators that help us stay focused for longer durations. The noradrenergic (NA) system is thought to play a significant role in optimizing our performance. Yet, the interplay between reward and the NA system in shaping performance remains unclear, particularly when actions are driven by external incentives (reward). To explore this interaction, we tested four female rhesus monkeys performing a sustained Go/NoGo task under two reward sizes (low/high) and three pharmacological conditions (saline and two doses of atomoxetine, a NA reuptake inhibitor: ATX-0.5 mg/kg and ATX-1 mg/kg). We found that increasing either reward or NA levels equally enhanced the animal's engagement in the task compared to low reward saline; the animals also responded faster and more consistently under these circumstances. Notably, we identified differences between reward size and ATX. When combined with ATX, high reward further reduced the occurrence of false alarms (i.e., incorrect go trials on distractors), implying that it helped further suppress impulsive responses. In addition, ATX (but not reward size) consistently increased movement duration dose-dependently, while high reward did not affect movement duration but decreased its variability. We conclude that noradrenaline and reward modulate performance, but their effects are not identical, suggesting differential underlying mechanisms. Reward might energize/invigorate decisions and action, while ATX might help regulate energy expenditure, depending on the context, through the NA system. • ATX and reward size improve task engagement and perceptual decision. • ATX (but not reward size) increases movement duration. • Reward size energizes both decision and action. • ATX might guide the allocation of energetical resources during goal-directed actions. [ABSTRACT FROM AUTHOR]