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From psychology to economics, there has been substantial interest in how costs (e.g., delay, risk) are represented asymmetrically during decision-making when attempting to gain reward or avoid punishment. For example, in decision-making under risk, individuals show a tendency to prefer to avoid punishment rather than to acquire the equivalent reward (loss aversion). Although the cost of physical effort has recently received significant attention, it remains unclear whether loss aversion exists during effort-based decision-making. On the one hand, loss aversion may be hardwired due to asymmetric evolutionary pressure on losses and gains and therefore exists across decision-making contexts. On the other hand, distinct brain regions are involved with different decision costs, making it questionable whether similar asymmetries exist. Here, we demonstrate that young healthy human participants (females, 16; males, 6) exhibit loss aversion during effort-based decision-making by exerting more physical effort to avoid punishment than to gain a same-size reward. Next, we show that medicated Parkinson's disease (PD) patients (females, 9; males, 9) show a reduction in loss aversion compared with age-matched control subjects (females, 11; males, 9). Behavioral and computational analysis revealed that people with PD exerted similar physical effort in return for a reward but were less willing to produce effort to avoid punishment. Therefore, loss aversion is present during effort-based decision-making and can be modulated by altered dopaminergic state. This finding could have important implications for our understanding of clinical disorders that show a reduced willingness to exert effort in the pursuit of reward. [ABSTRACT FROM AUTHOR]

How does a single brain region participate in multiple behaviors? Here we argue that two separate interneuron circuits in the primary motor cortex (M1) contribute differently to two varieties of physiological and behavioral plasticity. To test this in human brain noninvasively, we used transcranial magnetic stimulation (TMS) of M1 hand area to activate two independent sets of synaptic inputs to corticospinal neurons by changing the direction of current induced in the brain: posterior-to-anterior current (PA inputs) and anteriorto-posterior current (AP inputs). We demonstrate that excitability changes produced by repetitive activation of AP inputs depend on cerebellar activity and selectively alter model-based motor learning. In contrast, the changes observed with repetitive stimulation of PA inputs are independent of cerebellar activity and specifically modulate model-free motor learning. Thefindings are highly suggestivethat separate circuits in M1 subserve different forms of motor learning. [ABSTRACT FROM AUTHOR]

Action selection describes the high-level process that selects between competing movements. In animals, behavioral variability is critical for the motor exploration required to select the action that optimizes reward and minimizes cost/punishment and is guided by dopamine (DA). The aim of this study was to test in humans whether low-level movement parameters are affected by punishment and reward in ways similar to high-level action selection. Moreover, we addressed the proposed dependence of behavioral and neurophysiological variability on DA and whether this may underpin the exploration of kinematic parameters. Participants performed an out-and-back index finger movement and were instructed that monetary reward and punishment were based on its maximal acceleration (MA). In fact, the feedback was not contingent on the participant's behavior but predetermined. Blocks highly biased toward punishment were associated with increased MA variability relative to blocks either with reward or without feedback. This increase in behavioral variability was positively correlated with neurophysiological variability, as measured by changes in corticospinal excitability with transcranial magnetic stimula-tion over the primary motor cortex. Following the administration of a DA antagonist, the variability associated with punishment dimin-ished and the correlation between behavioral and neurophysiological variability no longer existed. Similar changes in variability were not observed when participants executed a predetermined MA, nor did DA influence resting neurophysiological variability. Thus, under conditions of punishment, DA-dependent processes influence the selection of low-level movement parameters. We propose that the enhanced behavioral variability reflects the exploration of kinematic parameters for less punishing, or conversely more rewarding, outcomes. [ABSTRACT FROM AUTHOR]

The article reports that sufferers of Parkinson's disease (PD) have a dopamine-sensitive deficit in action reprogramming which is proportional to the prediction error size. It concludes that in reference to a generally predictable sequence, PD patients not taking medication were stated to be impaired in reacting to unexpected events that evoke large prediction errors and require action reprogramming.

The cerebellum is a crucial structure involved in movement control and cognitive processing. Noninvasive stimulation of the cerebellum results in neurophysiological and behavioral changes, an effect that has been attributed to modulation of cerebello-brain connectivity. At rest, the cerebellum exerts an overall inhibitory tone over the primary motor cortex (M1), cerebello- brain inhibition (CBI), likely through dentate-thalamo- cortical connections. The level of excitability of this pathway before and after stimulation of the cerebellum, however, has not been directly investigated. In this study, we used transcranial magnetic stimulation to determine changes in M1, brainstem, and CBI before and after 25 min of anodal, cathodal, or sham transcranial direct current stimulation (tDCS) applied over the right cerebellar cortex. We hypothesized that anodal tDCS would result in an enhancement of CBI and cathodal would decrease it, relative to sham stimulation.Wefound that cathodal tDCS resulted in a clear decrease of CBI, whereas anodal tDCS increased it, in the absence of changes after sham stimulation. These effects were specific to the cerebello- cortical connections with no changes in other M1 or brainstem excitability measures. The cathodal effect on CBI was found to be dependent on stimulation intensity and lasted up to 30 min after the cessation of tDCS. These results suggest that tDCS can modulate in a focal and polarity-specific manner cerebellar excitability, likely through changes in Purkinje cell activity. Therefore, direct current stimulation of the cerebellum may have significant potential implications for patients with cerebellar dysfunction as well as to motor control studies. [ABSTRACT FROM AUTHOR]

A review of the article "Target Selection Signals for Arm Reaching in the Posterior Signals for Arm Reaching in the Posterior Parietal Cortex," published in the 2007 issue of "The Journal of Neuroscience" is presented. It states that the authors propose that the posterior parietal cortex (PPC) plays an active role in the selection of targets for reaching movements. It cites that rhesus monkeys were trained by the authors to make reaching movements to a target.

From psychology to economics, there has been substantial interest in how costs (e.g., delay, risk) are represented asymmetrically during decision-making when attempting to gain reward or avoid punishment. For example, in decision-making under risk, individuals show a tendency to prefer to avoid punishment rather than to acquire the equivalent reward (loss aversion). Although the cost of physical effort has recently received significant attention, it remains unclear whether loss aversion exists during effort-based decision-making. On the one hand, loss aversion may be hardwired due to asymmetric evolutionary pressure on losses and gains and therefore exists across decision-making contexts. On the other hand, distinct brain regions are involved with different decision costs, making it questionable whether similar asymmetries exist. Here, we demonstrate that young healthy human participants (females, 16; males, 6) exhibit loss aversion during effort-based decision-making by exerting more physical effort to avoid punishment than to gain a same-size reward. Next, we show that medicated Parkinson's disease (PD) patients (females, 9; males, 9) show a reduction in loss aversion compared with age-matched control subjects (females, 11; males, 9). Behavioral and computational analysis revealed that people with PD exerted similar physical effort in return for a reward but were less willing to produce effort to avoid punishment. Therefore, loss aversion is present during effort-based decision-making and can be modulated by altered dopaminergic state. This finding could have important implications for our understanding of clinical disorders that show a reduced willingness to exert effort in the pursuit of reward. SIGNIFICANCE STATEMENT Loss aversion-preferring to avoid punishment rather than to acquire equivalent reward-is an important concept in decision-making under risk. However, little is known about whether loss aversion also exists during decisions where the cost is physical effort. This is surprising given that motor cost shapes human behavior, and a reduced willingness to exert effort is a characteristic of many clinical disorders. Here, we show that healthy human individuals exert more effort to minimize punishment than to maximize reward (loss aversion). We also demonstrate that medicated Parkinson's disease patients exert similar effort to gain reward but less effort to avoid punishment when compared with healthy age-matched control subjects. This indicates that dopamine-dependent loss aversion is crucial for explaining effort-based decision-making., (Copyright © 2020 the authors.)

The theoretical basis for the association between high working memory capacity (WMC) and enhanced visuomotor adaptation is unknown. Visuomotor adaptation involves interplay between explicit and implicit systems. We examined whether the positive association between adaptation and WMC is specific to the explicit component of adaptation. Experiment 1 replicated the positive correlation between WMC and adaptation, but revealed this was specific to the explicit component of adaptation, and apparently driven by a sub-group of participants who did not show any explicit adaptation in the correct direction. A negative correlation was observed between WMC and implicit learning. Experiments 2 and 3 showed that when the task restricted the development of an explicit strategy, high WMC was no longer associated with enhanced adaptation. This work reveals that the benefit of high WMC is specifically linked to an individual's capacity to use an explicit strategy. It also reveals an important contribution of individual differences in determining how adaptation is performed.