Separate and overlapping mechanisms of statistical regularities and salience processing in the occipital cortex and dorsal attention network

Attention selects behaviorally relevant inputs for in-depth processing. Beside the role of traditional signals related to goal-directed and stimulus-driven control, a debate exists regarding the mechanisms governing the effect of statistical regularities on attentional selection, and how these are integrated with other control signals. Using a visuo-spatial search task under fMRI, we tested the joint effects of statistical regularities and stimulus-driven salience. We found that both types of signals modulated occipital activity in a spatially specific manner. Salience acted primarily by reducing the attention bias towards the target location when associated with irrelevant distractors, while statistical regularities reduced this attention bias when the target was presented at a low probability location, particularly at the lower levels of the visual hierarchy. In addition, we found that both statistical regularities and salience activated the dorsal frontoparietal network. Additional exploratory analyses of functional connectivity revealed that only statistical regularities modulated the inter-regional coupling between the posterior parietal cortex and the occipital cortex. These results show that statistical regularities and salience signals are both spatially represented at the occipital level, but that their integration into attentional processing priorities relies on dissociable brain mechanisms

LARVICIDAL EFFECT OF THE SEED OILS OF TWO INDIGENOUS PLANTS FROM THE ALGERIAN SAHARA ON THE DESERT LOCUST

The lethal and sublethal effects of the seed oils of two indigenous plants of the Algerian Sahara, Peganum harmala L. (Zygophyllaceae) and Datura stramonium L. (Solanaceae), were investigated. Administration of 60 μl of oil by forced oral injection using a micropipette to the L5 larvae of Schistocerca gregaria Forsk. (Orthoptera: Acrididae) revealed the deterrent effect of these oils on treated larvae. The treatment resulted in various toxicological symptoms, such as intense defecation, diarrhea, weight loss, reduction in motor activity, delay and difficulty in molting and, in the most extreme cases, the death of treated individuals. During the treatment of L5 larvae of S. gregaria with P. harmala seed oil, various toxicological symptoms appeared: 81.81% of individuals presented with diarrhea; 68.18% of individuals lost weight; 72.72% exhibited reduced motor activity, and 100% of surviving individuals experienced a delay in their molt. On the other hand, in L5 larvae treated with D. stramonium seed oil, 77.27% of individuals had diarrhea, 100% showed weight loss and 100% of individuals reduced their motor activity. D. stramonium seed oil has been shown to be more toxic than P. harmala seed oil. The oral administration of 60 μl of D. stramonium seed oil caused the blocking of the phenomenon of exuviation in 100% of the treated L5 larvae, resulting in death after 16 days. While P. harmala seed oils caused 50% mortality after 12 days, the 50% surviving individuals were able to complete their imaginal molt with difficulties, which resulted in malformations. The estimated lethal time 50 (LT50) in larvae (L5) treated with D. stramonium seed oil was 3.67 days. It was more toxic than the LT50 obtained in larvae (L5) treated with the oil of P. harmala seeds, which was 12 days. The food intake in L5 larvae of S. gregaria treated with D. stramonium seed oil was 0.28 ± 0.18 g/day, it was lower than the average daily consumption recorded in the L5 larvae treated with P. harmala seed oil, which was 0.67 ± 0.36 g/day, D. stramonium seed oil appears to be more toxic, and profoundly affects food intake. The values of the apparent digestive utilization coefficient (DUC a) reported for L5 larvae treated with seed oil of P. harmala and D. stramonium were 39.32 ± 13.07% and 34.23 ± 29,07%, respectively. These values were significantly lower compared to the control group value, which was 70.63 ± 19.56%. Likewise, the digestive conversion coefficients (CCD) recorded in the L5 of S. gregaria treated with the seed oils of P. harmala and D. stramonium were -75.07 ± 54.45% and -3.08 ± 1.18, respectively. However, in the control group of L5 larvae, the noted CCD was 1.004 ± 0.073. Values of the consumption index (CI) reported for L5 larvae treated with the seed oils of P. harmala and D. stramonium were low, 6.74 ± 4.45 and 3.82 ± 2.45, respectively, while for the L5 larvae of the control group, it was 15.74 ± 3.51

Temporal context and conditional associative learning

<p>Abstract</p> <p>Background</p> <p>We investigated how temporal context affects the learning of arbitrary visuo-motor associations. Human observers viewed highly distinguishable, fractal objects and learned to choose for each object the one motor response (of four) that was rewarded. Some objects were consistently preceded by specific other objects, while other objects lacked this task-irrelevant but predictive context.</p> <p>Results</p> <p>The results of five experiments showed that predictive context consistently and significantly accelerated associative learning. A simple model of reinforcement learning, in which three successive objects informed response selection, reproduced our behavioral results.</p> <p>Conclusions</p> <p>Our results imply that not just the representation of a current event, but also the representations of past events, are reinforced during conditional associative learning. In addition, these findings are broadly consistent with the prediction of attractor network models of associative learning and their prophecy of a persistent representation of past objects.</p

The demanding world of emotion: A Gestalt approach to emotion experience

Psychology is biased towards thinking of emotions as feelings rather than as an experiences of the world. But they are both. World-focused emotion experiences (WFEE) are how the world appears or is consciously perceived in one's emotion experience. For example, when happy the world may seem welcoming, or when sad the world may seem barren of possibilities. What explains these experiences? This article discusses explanations of WFEE from phenomenology and Gestalt psychology. Influenced by Lewin, I propose an “emotional demand model” of WFEE. The emotional demand character of objects (e.g. bear-to-be-run-from) is distinguished from their expressive character (e.g. angry bear). It is a mistake to think of emotion faces only as expressions—they are also demands. This distinction explains some anomalous findings in infancy and autism research. The model highlights another tool for recognizing our own emotions: noticing when we feel “demanded of” by the world, with implications for emotion regulation

Independence of face identity and expression processing: exploring the role of motion

According to the classic Bruce and Young (1986) model of face recognition, identity and emotional expression information from the face are processed in parallel and independently. Since this functional model was published, a growing body of research has challenged this viewpoint and instead support an interdependence view. In addition, neural models of face processing (Haxby, Hoffman & Gobbini, 2000) emphasise differences in terms of the processing of changeable and invariant aspects of faces. This article provides a critical appraisal of this literature and discusses the role of motion in both expression and identity recognition and the intertwined nature of identity, expression and motion processing. We conclude, by discussing recent advancements in this area and research questions that still need to be addressed

An Open Resource for Non-human Primate Imaging.

Non-human primate neuroimaging is a rapidly growing area of research that promises to transform and scale translational and cross-species comparative neuroscience. Unfortunately, the technological and methodological advances of the past two decades have outpaced the accrual of data, which is particularly challenging given the relatively few centers that have the necessary facilities and capabilities. The PRIMatE Data Exchange (PRIME-DE) addresses this challenge by aggregating independently acquired non-human primate magnetic resonance imaging (MRI) datasets and openly sharing them via the International Neuroimaging Data-sharing Initiative (INDI). Here, we present the rationale, design, and procedures for the PRIME-DE consortium, as well as the initial release, consisting of 25 independent data collections aggregated across 22 sites (total = 217 non-human primates). We also outline the unique pitfalls and challenges that should be considered in the analysis of non-human primate MRI datasets, including providing automated quality assessment of the contributed datasets

Rôle des ganglions de la base dans l'apprentissage associatif conditionnel : une approche multidisciplinaire

Pr. Marc Jeannerod, Président Pr. Bioulac, rapporteur Dr. Apicella, rapporteur Pr. Dubois, examinateur Dr. Burnod, examinateur Dr. Driss BoussaoudThe arbitrary mapping of sensory information onto action forms an important element of the intelligent behavior of primates (also called conditional associative learning). The cortico-basal ganglia-thalamo-cortical loops are thought to play a key role in such behavior. The present research was undertaken to investigate the role of the basal ganglia (BG) in conditional visuo-motor associative learning using three complementary approaches: 1) single-unit recordings in awake monkeys, 2) behavioral testing in patients suffering from Parkinson's disease (a neurodegenerative disease affecting the BG), and 3) functional neuroimaging in healthy subjects. The results of all three studies converge to indicate that the BG are involved in both the acquisition and the retention phases of visuo-motor associations.Avec l'expérience, nous acquérons une panoplie de règles, associations arbitraires entre des stimuli externes et des actes moteurs, qui nous permettent d'adapter notre comportement à l'environnement (apprentissage associatif conditionnel). Ce type d'apprentissage met en jeu les boucles reliant les ganglions de la base (GGB) et le cortex frontal. Ce travail visait à préciser le rôle des GGB dans l'apprentissage de règles visuo-motrices conditionnelles en utilisant plusieurs approches : 1) l'enregistrement de l'activité des neurones du striatum chez le singe éveillé, 2) l'étude chez des patients atteints de la maladie de Parkinson (une pathologie neurodégénérative touchant les GGB) et 3) la neuroimagerie fonctionnelle chez l'homme sain. Les résultats des trois expériences convergent pour indiquer que les GGB sont impliqués à la fois dans l'acquisition et la rétention des associations visuo-motrices