The underlying social dynamics of paradigm shifts

We develop here a multi-agent model of the creation of knowledge (scientific progress or technological evolution) within a community of researchers devoted to such endeavors. In the proposed model, agents learn in a physical-technological landscape, and weight is attached to both individual search and social influence. We find that the combination of these two forces together with random experimentation can account for both i) marginal change, that is, periods of normal science or refinements on the performance of a given technology (and in which the community stays in the neighborhood of the current paradigm); and ii) radical change, which takes the form of scientific paradigm shifts (or discontinuities in the structure of performance of a technology) that is observed as a swift migration of the knowledge community towards the new and superior paradigm. The efficiency of the search process is heavily dependent on the weight that agents posit on social influence. The occurrence of a paradigm shift becomes more likely when each member of the community attaches a small but positive weight to the experience of his/her peers. For this parameter region, nevertheless, a conservative force is exerted by the representatives of the current paradigm. However, social influence is not strong enough to seriously hamper individual discovery, and can act so as to empower successful individual pioneers who have conquered the new and superior paradigm.Fil: Rodriguez Sickert, Carlos. Universidad del Desarrollo; ChileFil: Cosmelli, Diego. Pontificia Universidad Católica de Chile; ChileFil: Claro, Francisco. Pontificia Universidad Católica de Chile; ChileFil: Fuentes, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad San Sebastián; Chil

Emotional Influences on Cognitive Flexibility Depend on Individual Differences: A Combined Micro-Phenomenological and Psychophysiological Study

Imagine a scenario where you are cooking and suddenly, the contents of the pot start to come out, and the oven bell rings. You would have to stop what you are doing and start responding to the changing demands, switching between different objects, operations and mental sets. This ability is known as cognitive flexibility. Now, add to this scenario a strong emotional atmosphere that invades you as you spontaneously recall a difficult situation you had that morning. How would you behave? Recent studies suggest that emotional states do modulate cognitive flexibility, but these findings are still controversial. Moreover, there is a lack of evidence regarding the underlying brain processes. The purpose of the present study was, therefore, to examine such interaction while monitoring changes in ongoing cortical activity using EEG. In order to answer this question, we used two musical stimuli to induce emotional states (positive/high arousal/open stance and negative/high arousal/closed stance). Twenty-nine participants performed two blocks of the Madrid Card Sorting Task in a neutral silence condition and then four blocks while listening to the counterbalanced musical stimuli. To explore this interaction, we used a combination of first-person (micro-phenomenological interview) and third-person (behavior and EEG) approaches. Our results show that compared to the positive stimuli and silence condition, negative stimuli decrease reaction times (RTs) for the shift signal. Our data show that the valance of the first emotional block is determinant in the RTs of the subsequent blocks. Additionally, the analysis of the micro-phenomenological interview and the integration of first- and third-person data show that the emotional disposition generated by the music could facilitate task performance for some participants or hamper it for others, independently of its emotional valence. When the emotional disposition hampered task execution, RTs were slower, and the P300 potential showed a reduced amplitude compared to the facilitated condition. These findings show that the interaction between emotion and cognitive flexibility is more complex than previously thought and points to a new way of understanding the underlying mechanisms by incorporating an in-depth analysis of individual subjective experience

Molecular Coupling between Voltage Sensor and Pore Opening in the Arabidopsis Inward Rectifier K+ Channel KAT1

Animal and plant voltage-gated ion channels share a common architecture. They are made up of four subunits and the positive charges on helical S4 segments of the protein in animal K+ channels are the main voltage-sensing elements. The KAT1 channel cloned from Arabidopsis thaliana, despite its structural similarity to animal outward rectifier K+ channels is, however, an inward rectifier. Here we detected KAT1-gating currents due to the existence of an intrinsic voltage sensor in this channel. The measured gating currents evoked in response to hyperpolarizing voltage steps consist of a very fast (τ = 318 ± 34 μs at −180 mV) and a slower component (4.5 ± 0.5 ms at −180 mV) representing charge moved when most channels are closed. The observed gating currents precede in time the ionic currents and they are measurable at voltages (less than or equal to −60) at which the channel open probability is negligible (≈10−4). These two observations, together with the fact that there is a delay in the onset of the ionic currents, indicate that gating charge transits between several closed states before the KAT1 channel opens. To gain insight into the molecular mechanisms that give rise to the gating currents and lead to channel opening, we probed external accessibility of S4 domain residues to methanethiosulfonate-ethyltrimethylammonium (MTSET) in both closed and open cysteine-substituted KAT1 channels. The results demonstrate that the putative voltage–sensing charges of S4 move inward when the KAT1 channels open

The impact of MEG source reconstruction method on source-space connectivity estimation: A comparison between minimum-norm solution and beamforming.

Despite numerous important contributions, the investigation of brain connectivity with magnetoencephalography (MEG) still faces multiple challenges. One critical aspect of source-level connectivity, largely overlooked in the literature, is the putative effect of the choice of the inverse method on the subsequent cortico-cortical coupling analysis. We set out to investigate the impact of three inverse methods on source coherence detection using simulated MEG data. To this end, thousands of randomly located pairs of sources were created. Several parameters were manipulated, including inter- and intra-source correlation strength, source size and spatial configuration. The simulated pairs of sources were then used to generate sensor-level MEG measurements at varying signal-to-noise ratios (SNR). Next, the source level power and coherence maps were calculated using three methods (a) L2-Minimum-Norm Estimate (MNE), (b) Linearly Constrained Minimum Variance (LCMV) beamforming, and (c) Dynamic Imaging of Coherent Sources (DICS) beamforming. The performances of the methods were evaluated using Receiver Operating Characteristic (ROC) curves. The results indicate that beamformers perform better than MNE for coherence reconstructions if the interacting cortical sources consist of point-like sources. On the other hand, MNE provides better connectivity estimation than beamformers, if the interacting sources are simulated as extended cortical patches, where each patch consists of dipoles with identical time series (high intra-patch coherence). However, the performance of the beamformers for interacting patches improves substantially if each patch of active cortex is simulated with only partly coherent time series (partial intra-patch coherence). These results demonstrate that the choice of the inverse method impacts the results of MEG source-space coherence analysis, and that the optimal choice of the inverse solution depends on the spatial and synchronization profile of the interacting cortical sources. The insights revealed here can guide method selection and help improve data interpretation regarding MEG connectivity estimation

Chilean students’ ideas on the evolution of living beings: what do they think at the end of primary education?

Conocer las ideas de los estudiantes es el punto de partida para una enseñanza orientada a la comprensión. En relación a la teoría de la evolución por selección natural, un eje estructurante de la biología, sabemos que estudiantes secundarios y universitarios muestran una comprensión limitada, sosteniendo ideas alternativas incluso después de la instrucción. Pero poco sabemos de las ideas de estudiantes de educación primaria, lo que es esencial para la discusión respecto a la organización curricular de este contenido y las estrategias de enseñanzas apropiadas para promover su comprensión. Con el objetivo de describir las ideas de los estudiantes de enseñanza primaria, se realizó un estudio descriptivo en el que participaron 137 estudiantes de entre 11 y 12 años de educación pública en Santiago de Chile. Los estudiantes contestaron una prueba de comprensión de la evolución de los seres vivos y un cuestionario de aceptación de la teoría de la evolución. Los resultados muestran que los estudiantes en un alto porcentaje aceptan la teoría y, aunque existe una proporción que comprende en algún grado conceptos claves, ningún estudiante es capaz de elaborar una explicación coherente. Más aún, se aprecian ideas alternativas reportadas en estudiantes mayores (cambios por necesidad, intencionalidad de los cambios, herencia de rasgos adquiridos, herencia funcional a la sobrevivencia, entre otros), y aparecen otras ideas relevantes de atender, como el cambio evolutivo provocado por la innovación tecnológica humana. Se discuten las implicancias curriculares y pedagógicas de los hallazgos.Knowing students’ ideas is the starting point of a comprehension oriented teaching. Regarding natural selection, research show that secondary and undergraduate students sustain a limited understanding, holding misconceptions even after instruction. However, we know little about primary students’ ideas on natural selection, which is crucial to discuss, from a curricular and pedagogical point of view, the best ways to prompt its comprehension. We conducted a study aimed at describing primary students’ ideas on natural selection. 137 sixth grade students (11 and 12 years of age) of public education in Santiago, Chile, participated in the study. Students answered a test on evolution and a questionnaire of theory of evolution acceptance. Results show that overall students accept the theory of evolution and, although in some degree they understand some related and key concepts, they are not able to formulate coherent explanations. Moreover, misconceptions already reported in older students emerged (need, intentionality, heredity of acquired traits, heredity of useful traits, among others), along with interesting new ideas, as the change as provoked by technological changes induced by humans. Implications for pedagogical practice and curriculum organization are discussed

Enhanced response inhibition and reduced midfrontal theta activity in experienced Vipassana meditators

Response inhibition - the ability to suppress inappropriate thoughts and actions - is a fundamental aspect of cognitive control. Recent research suggests that mental training by meditation may improve cognitive control. Yet, it is still unclear if and how, at the neural level, long-term meditation practice may affect (emotional) response inhibition. The present study aimed to address this outstanding question, and used an emotional Go/Nogo task and electroencephalography (EEG) to examine possible differences in behavioral and electrophysiological indices of response inhibition between Vipassana meditators and an experience-matched active control group (athletes). Behaviorally, meditators made significantly less errors than controls on the emotional Go/Nogo task, independent of the emotional context, while being equally fast. This improvement in response inhibition at the behavioral level was accompanied by a decrease in midfrontal theta activity in Nogo vs. Go trials in the meditators compared to controls. Yet, no changes in ERP indices of response inhibition, as indexed by the amplitude of the N2 and P3 components, were observed. Finally, the meditators subjectively evaluated the emotional pictures lower in valence and arousal. Collectively, these results suggest that meditation may improve response inhibition and control over emotional reactivity

Neural Mechanisms of Human Perceptual Learning: Electrophysiological Evidence for a Two-Stage Process

Artículo de publicación ISIBackground: Humans and other animals change the way they perceive the world due to experience. This process has been labeled as perceptual learning, and implies that adult nervous systems can adaptively modify the way in which they process sensory stimulation. However, the mechanisms by which the brain modifies this capacity have not been sufficiently analyzed. Methodology/Principal Findings: We studied the neural mechanisms of human perceptual learning by combining electroencephalographic (EEG) recordings of brain activity and the assessment of psychophysical performance during training in a visual search task. All participants improved their perceptual performance as reflected by an increase in sensitivity (d') and a decrease in reaction time. The EEG signal was acquired throughout the entire experiment revealing amplitude increments, specific and unspecific to the trained stimulus, in event-related potential (ERP) components N2pc and P3 respectively. P3 unspecific modification can be related to context or task-based learning, while N2pc may be reflecting a more specific attentional-related boosting of target detection. Moreover, bell and U-shaped profiles of oscillatory brain activity in gamma (30-60 Hz) and alpha (8-14 Hz) frequency bands may suggest the existence of two phases for learning acquisition, which can be understood as distinctive optimization mechanisms in stimulus processing.This research was supported by CONICYT doctoral grant to C.M.H. and by an ECOS-Sud/CONICYT grant C08S02 and FONDECYT 1090612 grant to D.C. and F.A

Neural Correlates of Conscious Motion Perception

The nature of the proper neural signature of conscious perception remains a topic of active debate. Theoretical support from integrative theories of consciousness is consistent with such signature being P3b, one of the main candidates in the literature. Recent work has also put forward a mid-latency and more localized component, the Visual Awareness Negativity (VAN), as a proper Neural Correlate of Consciousness (NCC). Early local components like P1 have also been proposed. However, experiments exploring visual NCCs are conducted almost exclusively using static images as the content to be consciously perceived, favoring ventral stream processing, therefore limiting the scope of the NCCs that have been identified. Here we explored the visual NCCs isolating local motion, a dorsally processed feature, as the primary feature being consciously perceived. Physical equality between Seen and Unseen conditions in addition to a minimal contrast difference between target and no-target displays was employed. In agreement with previous literature, we found a P3b with a wide centro-parietal distribution that strongly correlated with the detection of the stimuli. P3b magnitude was larger for Seen vs. Unseen conditions, a result that was consistently observed at the single subject level. In contrast, we were unable to detect VAN in our data, regardless of whether the subject perceived or not the stimuli. In the 200–300 ms time window we found a N2pc component, consistent with the high attentional demands of our task. Early components like P1 were not observed in our data, in agreement with their proposed role in the processing of visual features, but not as proper NCCs. Our results extend the role of P3b as a content independent NCC to conscious visual motion perception

Des montagnes et des vallées (Perception consciente et structure dynamique de l'intégration cérébrale chez l'être humain dans l'expérience de rivalité binoculaire)

PALAISEAU-Polytechnique (914772301) / SudocSudocFranceF

Aportes de la Psicología y las Neurociencias al concepto del “Insight”: la necesidad de un marco integrativo de estudio y desarrollo.

The experience of insight, understood as the cognitive process whereby one reaches a solution or comprehension of a conflict and that is lived as a surprising yet certain discovery, has captured the attention of psychologists, psychiatrists and scientists in general for more than a century. Because of the notorious role that this phenomenon has in the psychotherapeutic context, as well as its relation to such important cognitive processes as learning, creativity and problem solving, it is important to advance towards a more encompassing understanding that can incorporate such different perspectives. Through a review of how psychoanalysis, Gestalt theory, cognitive psychology and neuroscience have attempted to capture the essence of the experience of insight, we wish to contribute to the ongoing discussion from an integrative perspective. We are especially interested in the possibility of encounter and cross-fertilization between the neuroscientific approach and the psychotherapeutic tradition at the theoretical, empirical and applied levels.La experiencia del Insight, entendida como fenómeno cognitivo en el que se llega a la solución o comprensión de un conflicto en asociación con una vivencia afectiva de sorpresa y certeza ante el descubrimiento, ha captado la atención de psicólogos, psiquiatras y científicos desde hace ya más de un siglo. Debido al rol que juega en el contexto psicoterapéutico en cuanto a su papel en los procesos de cura y a su relación con procesos cognitivos tan relevantes como el aprendizaje, la creatividad y las estrategias de resolución de problemas, el lograr una mayor compresión que incorpore todas las aristas del fenómeno e integre los aportes de las diversas miradas se torna una tarea de fundamental importancia. A través de un recorrido por algunos de los esfuerzos que disciplinas como el psicoanálisis, la teoría de la Gestalt, la psicología cognitiva y las neurociencias han realizado para captar la esencia del insight, queremos poner sobre a mesa algunos elementos con el fin de contribuir a la discusión sobre este concepto. Nos interesa el desarrollo de una perspectiva integradora, que posibilite a su vez el encuentro y la fertilización mutua entre las aproximaciones neurocientíficas y psicoterapéuticas a niveles tanto teóricos como empíricos y aplicados