Check or Go? Impact of Doubt on the Hierarchical Organization of the Mediofrontal Area.

Background: Based on numerous imaging and electrophysiological studies, the presupplementary motor area (pre-SMA) and the rostral cingulate motor area are cortical regions considered to be essential to voluntary movement initiation and behavioral control. However, their respective roles and functional interactions remain a long-standing and still debated question.

Methods: Here, we trained 2 rhesus monkeys (Macaca mulatta) in a complex cognitive task to compare the neuronal activity of these 2 regions on the medial wall during both perceptual and internally guided decisions.

Competition, Conflict and Change of Mind: A Role of GABAergic Inhibition in the Primary Motor Cortex.

Deciding between different voluntary movements implies a continuous control of the competition between potential actions. Many theories postulate a leading role of prefrontal cortices in this executive function, but strong evidence exists that a motor region like the primary motor cortex (M1) is also involved, possibly inhibitory mechanisms. This was already shown during the pre-movement decision period, but not after movement onset.

Conscious awareness of motor fluidity improves performance and decreases cognitive effort in sequence learning.

Motor skill learning is improved when participants are instructed to judge after each trial whether their performed movements have reached maximal fluidity. Consequently, the conscious awareness of this maximal fluidity can be classified as a genuine learning factor for motor sequences. However, it is unknown whether this effect of conscious awareness on motor learning could be mediated by the increased cognitive effort that may accompany such judgment making.

A safety mechanism for observational learning.

This empirical article presents the first evidence of a "safety mechanism" based on an observational-learning paradigm. It is accepted that during observational learning, a person can use different strategies to learn a motor skill, but it is unknown whether the learner is able to circumvent the encoding of an uncompleted observed skill. In this study, participants were tested in a dyadic protocol in which an observer watched a participant practicing two different motor sequences during a learning phase.

Checking behavior in rhesus monkeys is related to anxiety and frontal activity.

When facing doubt, humans can go back over a performed action in order to optimize subsequent performance. The present study aimed to establish and characterize physiological doubt and checking behavior in non-human primates (NHP). We trained two rhesus monkeys (Macaca mulatta) in a newly designed "Check-or-Go" task that allows the animal to repeatedly check and change the availability of a reward before making the final decision towards obtaining that reward.

Creating semantics in tool use.

This article presents the first evidence for a functional link between tool use and the processing of abstract symbols like Arabic numbers. Participants were required to perform a tool-use task after the processing of an Arabic number. These numbers represented either a small (2 or 3) or a large magnitude (8 or 9).

Neuronal Circuits for Fear Expression and Recovery: Recent Advances and Potential Therapeutic Strategies.

Recent technological developments, such as single unit recordings coupled to optogenetic approaches, have provided unprecedented knowledge about the precise neuronal circuits contributing to the expression and recovery of conditioned fear behavior. These data have provided an understanding of the contributions of distinct brain regions such as the amygdala, prefrontal cortex, hippocampus, and periaqueductal gray matter to the control of conditioned fear behavior. Notably, the precise manipulation and identification of specific cell types by optogenetic techniques have provided novel avenues to establish causal links between changes in neuronal activity that develop in dedicated neuronal structures and the short and long-lasting expression of conditioned fear memories.

Dorsal premotor cortex: neural correlates of reach target decisions based on a color-location matching rule and conflicting sensory evidence.

We recorded single-neuron activity in dorsal premotor (PMd) and primary motor cortex (M1) of two monkeys in a reach-target selection task. The monkeys chose between two color-coded potential targets by determining which target's color matched the predominant color of a multicolored checkerboard-like Decision Cue (DC). Different DCs contained differing numbers of colored squares matching each target.

Electrophysiological Correlates of a Versatile Executive Control System in the Monkey Anterior Cingulate Cortex.

When a subject faces conflicting situations, decision-making becomes uncertain. The human dorsal anterior cingulate cortex (dACC) has been repeatedly implicated in the monitoring of such situations, and its neural activity is thought to be involved in behavioral adjustment. However, this hypothesis is mainly based on neuroimaging results and is challenged by animal studies that failed to report any neuronal correlates of conflict monitoring.

Neuronal activity correlated with checking behaviour in the subthalamic nucleus of patients with obsessive-compulsive disorder.

Doubt, and its behavioural correlate, checking, is a normal phenomenon of human cognition that is dramatically exacerbated in obsessive-compulsive disorder. We recently showed that deep brain stimulation in the associative-limbic area of the subthalamic nucleus, a central core of the basal ganglia, improved obsessive-compulsive disorder. To understand the physiological bases of symptoms in such patients, we recorded the activity of individual neurons in the therapeutic target during surgery while subjects performed a cognitive task that gave them the possibility of unrestricted repetitive checking after they had made a choice.

Response competition in the primary motor cortex: corticospinal excitability reflects response replacement during simple decisions.

It has been suggested that, during decisions about actions, multiple options are initially specified in parallel and then gradually eliminated in a competition for overt execution. To further test this hypothesis, we studied the modulation of human corticospinal excitability during the reaction time of the Eriksen flanker task. In the task, subjects responded with finger flexion or extension to a central arrow while ignoring congruent or incongruent flanker arrows.

Single medial prefrontal neurons cope with error.

Learning from mistakes is a key feature of human behavior. However, the mechanisms underlying short-term adaptation to erroneous action are still poorly understood. One possibility relies on the modulation of attentional systems after an error.

Primate models of dystonia.

Several models of dystonia have emerged from clinical studies providing a comprehensive explanation for the pathophysiology of this movement disorder. However, several points remain unclear notably concerning the specific role of brainstem, basal ganglia nuclei and premotor cortex. We review data collected in sub-human primate to see whether they might provide new insights into the pathophysiology of dystonia.

Impact of commitment on performance evaluation in the rostral cingulate motor area.

Performance evaluation is a prerequisite for behavioral adaptation. Although the anterior cingulate cortex (ACC) is thought to play a central role in error detection, little is known about the electrophysiological activity of this structure during the performance-monitoring process. We directly addressed this issue by training monkeys to perform a Stroop-like task and then recorded neuronal activity in the rostral cingulate motor area (CMAr), a relatively unexplored region of the ACC known to be involved in motor processing.

[The anterior cingulate cortex in error detection and conflict monitoring. Unitary neuronal activity in monkeys].

Using a Stroop-like visuo-motor task in monkeys, we studied the unitary neuronal activity of the anterior cingulate cortex (ACC, CMAr : 24c) during error detection and conflict monitoring. A high percentage of cingular neurons modified their firing frequency during both attentional and evaluation periods. During the latter period, however, changes in discharge rates were always much more pronounced for erroneous responses than for successful movements that induced reward delivery.

Disruption of the proprioceptive mapping in the medial wall of parkinsonian monkeys.

Parkinsonian patients present an impairment of proprioceptor-guided movement that could imply abnormal processing in the frontal mesial cortex. To test this hypothesis, we compared neuronal response to joint displacement in the supplementary and presupplementary motor areas of two monkeys, before and after the progressive establishment of an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian syndrome. After MPTP administration, neurons were activated by the passive movement of numerous joints in various directions and no longer simply by one or two joints in one direction.