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Sensory guidance of behavior often involves standard visuo-motor mapping of body movements onto objects and spatial locations. For example, looking at and reaching to grasp a glass of wine requires the mapping of the eyes and hand to the location of the glass in space, as well as the formation of a hand configuration appropriate to the shape of the glass. But our brain is far more than just a standard sensorimotor mapping machine. Through evolution, the brain of advanced mammals, in particular human and non-human primates, has acquired a formidable capacity to construct non-standard, arbitrary mapping using associations between external events and behavioral responses that bear no direct relationship. For example, we have all learned to stop at a red traffic light and to go at a green one, or to wait for a specific tone before dialing a phone number and to hang up when hearing a busy signal. These arbitrary associations are acquired through experience, thereby providing primates with a rich and flexible sensorimotor repertoire. Understanding how they are learned, and how they are recalled and used when the context requires them, has been one of the challenging issues for cognitive neuroscience. Valuable insights have been gained over the last two decades through the convergence of multiple complementary approaches. Human neuropsychology and experimental lesions in monkeys have identified a network of brain structures important for conditional sensorimotor associations, whereas imaging studies in healthy human subjects and electrophysiological recordings in awake monkeys have sought to identify the different functional processes underlying the overall function. The present review focuses on the contribution of a network linking the prefrontal cortex, basal ganglia, and dorsal premotor cortex, with special emphasis on results from recording experiments in monkeys. We will first review data pointing to a specific contribution of each component of the network to the performance of well-learned arbitrary visuo-motor associations, as well as data suggesting how novel associations are formed. Then we will propose a model positing that each component of the fronto-striatal network makes a specific contribution to the formation and/or execution of sensorimotor associations. In this model, the basal ganglia are thought to play a key role in linking the sensory, motor, and reward information necessary for arbitrary mapping. [Copyright &y& Elsevier]

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]

Abstract The role of norepinephrine (NE) in visuo-spatial attention remains poorly understood. Our goal was to identify the attentional processes influenced by atomoxetine (ATX) injections, a NE-reuptake inhibitor that boosts the level of NE in the brain, and to characterize these influences. We tested the effects of ATX injections, on seven monkeys performing a saccadic cued task in which cues and distractors were used to manipulate spatial attention. We found that when the cue accurately predicted the location of the upcoming cue in 80% of the trials, ATX consistently improved attentional orienting, as measured from reaction times (RTs). These effects were best accounted for by a faster accumulation rate in the valid trials, rather than by a change in the decision threshold. By contrast, the effect of ATX on alerting and distractor interference was more inconsistent. Finally, we also found that, under ATX, RTs to non-cued targets were longer when these were presented separately from cued targets. This suggests that the impact of NE on visuo-spatial attention depends on the context, such that the adaptive changes elicited by the highly informative value of the cues in the most frequent trials were accompanied by a cost in the less frequent trials. Highlights • Atomoxetine decreases reaction time of the most prevalent trials. • Atomoxetine modulates the accumulation rate of sensory information. • Atomoxetine adapts the response strategy to the context. [ABSTRACT FROM AUTHOR]

Any animal, human or non-human, lives in a world where there are others like itself. Individuals’ behaviors are thus inevitably influenced by others, and cognition is no exception. Long acknowledged in psychology, social modulations of cognition have been neglected in cognitive neuroscience. Yet, infusing this classic topic in psychology with brain science methodologies could yield valuable educational insights. In recent studies, we used a non-human primate model, the rhesus macaque, to identify social influences representing ancient biases rooted in evolution, and neuroimaging to shed light on underlying mechanisms. The behavioral and neural data garnered in humans and macaques are summarized, with a focus on two findings relevant to human education. First, peers’ mistakes stand out as exceptional professors and seem to have devoted areas and neurons in the primates’ brain. Second, peers’ mere presence suffices to enhance performance in well-learned tasks, possibly by boosting activity in the brain network involved in the task at hand. These findings could be translated into concrete pedagogical interventions in the classroom. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the accuracy of clinical examination and of three imaging modalities (ultrasound [US] scan, mammography, and magnetic resonance imaging [MRI]) to assess the tumor response of breast cancer to a preoperative regimen of concurrent radiochemotherapy for large breast cancers, using pathologic data as the reference. Methods and Materials: Sixty women were accrued. Treatment consisted of 4 cycles of (5-fluorouracil-vinorelbine) chemotherapy with, starting with the second cycle of chemotherapy, locoregional radiotherapy to the breast and the internal mammary and supraclavicular and infraclavicular lymph nodes. Breast surgery and axillary lymph node dissection were subsequently performed. Breast imaging assessments were performed both before chemotherapy and preoperatively. Results: The correlation coefficients between tumor dimension at imaging and pathology were statistically significant for US scan (r = 0.4; p = 0.006) and MRI (r = 0.4; p = 0.004) but not for clinical examination (r = 0.2; p = 0.16) or mammography (r = −0.15; p = 0.31). Furthermore, the area under the receiver operating characteristic curve for MRI was 0.81, compared with 0.67 for US scan. At the optimal threshold score, MRI performed with 81% sensitivity and 75% specificity. Conclusion: Compared with clinical examination, US scan, or mammography, MRI substantially improved the prediction of pathologic tumor response to preoperative concurrent radiochemotherapy for large breast cancers. [Copyright &y& Elsevier]

Abstract: This study evaluated, in terms of pathological complete response (pCR) and acute toxicity, preoperative concurrent (5-fluorouracil (5-FU)-vinorelbine) chemoradiotherapy for large breast cancers. A total of 60women were included in the study. Chemotherapy consisted of 4 cycles of 5-FU, 500mg/m2/d, continuous infusion (d1–d5) and vinorelbine, 25mg/m2 (d1; d6). Starting with the second cycle, radiotherapy delivered 50Gy to the breast and 46Gy to the internal mammary and supra/infra-clavicular lymph nodes. Breast surgery and axillary lymph node dissection were then performed. Four patients did not complete their chemotherapy. Breast conservation was possible in 69% of patients. The rate of pCR was 27%. Three factors were associated with pCR: histological grade 3, absence of hormonal receptors and high mitotic index. Grade 4 haematological toxicity occurred in 22% of patients. In conclusion, chemoradiotherapy demonstrated good efficacy, both in terms of pCR and in allowing breast conservation with acceptable tolerance. [Copyright &y& Elsevier]

Visuo-spatial attentional orienting is fundamental to selectively process behaviorally relevant information, depending on both low-level visual attributes of stimuli in the environment and higher-level factors, such as goals, expectations and prior knowledge. Growing evidence suggests an impact of the locus-cœruleus-norepinephrine (LC-NE) system in attentional orienting that depends on taskcontext. Nonetheless, most of previous studies used visual displays encompassing a target and various distractors, often preceded by cues to orient the attentional focus. This emphasizes the contribution of goal-driven processes, at the expense of other factors related to the stimulus content. Here, we aimed to determine the impact of NE on attentional orienting in more naturalistic conditions, using complex images and without any explicit task manipulation. We tested the effects of atomoxetine (ATX) injections, a NE reuptake inhibitor, on four monkeys during free viewing of images belonging to three categories: landscapes, monkey faces and scrambled images. Analyses of the gaze exploration patterns revealed, first, that the monkeys spent more time on each fixation under ATX compared to the control condition, regard less of the image content. Second, we found that, depending on the image content, ATX modulated the impact of low-level visual salience on attentional orienting. This effect correlated with the effect of ATX on the number and duration of fixations. Taken together, our results demonstrate that ATX adjusts the contribution of salience on attentional orienting depending on the image content, indicative of its role in balancing the role of stimulus-driven and top-down control during free viewing of complex stimuli. • Atomoxetine increases fixation durations during image exploration. • Atomoxetine modulates the contribution of low-level signaling on spatial orienting. • Atomoxetine adjusts attentional orienting depending on the image content. [ABSTRACT FROM AUTHOR]