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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.

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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.

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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.

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Research suggests that mindfulness-practices may aid smoking cessation. Yet, the neural mechanisms underlying the effects of mindfulness-practices on smoking are unclear. Response inhibition is a main deficit in addiction, is associated with relapse, and could therefore be a candidate target for mindfulness-based practices. The current study hence investigated the effects of a brief mindfulness-practice on response inhibition in smokers using behavioral and electroencephalography (EEG) measures. Fifty participants (33 females, mean age 20 years old) underwent a protocol of cigarette exposure to induce craving (cue-exposure) and were then randomly assigned to a group receiving mindfulness-instructions or control-instructions (for 15 minutes approximately). Immediately after this, they performed a smoking Go/NoGo task, while their brain activity was recorded. At the behavioral level, no group differences were observed. However, EEG analyses revealed a decrease in P3 amplitude during NoGo vs. Go trials in the mindfulness versus control group. The lower P3 amplitude might indicate less-effortful response inhibition after the mindfulness-practice, and suggest that enhanced response inhibition underlies observed positive effects of mindfulness on smoking behavior.

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Our daily interaction with the world is plagued of situations in which we develop expertise through self-motivated repetition of the same task. In many of these interactions, and especially when dealing with computer and machine interfaces, we must deal with sequences of decisions and actions. For instance, when drawing cash from an ATM machine, choices are presented in a step-by-step fashion and a specific sequence of choices must be performed in order to produce the expected outcome. But, as we become experts in the use of such interfaces, is it possible to identify specific search and learning strategies? And if so, can we use this information to predict future actions? In addition to better understanding the cognitive processes underlying sequential decision making, this could allow building adaptive interfaces that can facilitate interaction at different moments of the learning curve. Here we tackle the question of modeling sequential decision-making behavior in a simple human-computer interface that instantiates a 4-level binary decision tree (BDT) task. We record behavioral data from voluntary participants while they attempt to solve the task. Using a Hidden Markov Model-based approach that capitalizes on the hierarchical structure of behavior, we then model their performance during the interaction. Our results show that partitioning the problem space into a small set of hierarchically related stereotyped strategies can potentially capture a host of individual decision making policies. This allows us to follow how participants learn and develop expertise in the use of the interface. Moreover, using a Mixture of Experts based on these stereotyped strategies, the model is able to predict the behavior of participants that master the task.

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Attentional mechanisms have been studied mostly in specific sensory domains, such as auditory, visuospatial, or tactile modalities. In contrast, attention to internal interoceptive visceral targets has only recently begun to be studied, despite its potential importance in emotion, empathy, and self-awareness. Here, we studied the effects of shifting attention to the heart using a cue-target detection paradigm during continuous EEG recordings. Subjects were instructed to count either a series of visual stimuli (visual condition) or their own heartbeats (heart condition). Visual checkerboard stimuli were used as attentional probes throughout the task. Consistent with previous findings, attention modulated the amplitude of the heartbeat-evoked potentials. Directing attention to the heart significantly reduced the visual P1/N1 amplitude evoked by the attentional probe. ERPs locked to the attention-directing cue revealed a novel frontal positivity around 300 ms postcue. Finally, spectral power in the alpha band over parieto-occipital regions was higher while attending to the heart-when compared to the visual task-and correlated with subject's performance in the interoceptive task. These results are consistent with a shared, resource-based attentional mechanism whereby allocating attention to bodily signals can affect early responses to visual stimuli.

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Focusing one's attention by external guiding stimuli towards a specific area of the visual field produces systematical neural signatures. One of the most robust is the change in topological distribution of oscillatory alpha band activity across parieto-occipital cortices. In particular, decreases in alpha activity over contralateral and/or increases over ipsilateral scalp sites, respect to the side of the visual field where attention was focused. This evidence comes mainly from experiments where an explicit cue informs subjects where to focus their attention, thus facilitating detection of an upcoming target stimulus. However, recent theoretical models of attention have highlighted a stochastic or non-deterministic component related to visuospatial attentional allocation. In an attempt to evidence this component, here we analyzed alpha activity in a signal detection paradigm in the lack of informative cues; in the absence of preceding information about the location (and time) of appearance of target stimuli. We believe that the unpredictability of this situation could be beneficial for unveiling this component. Interestingly, although total alpha power did not differ between Seen and Unseen conditions, we found a significant lateralization of alpha activity over parieto-occipital electrodes, which predicted behavioral performance. This effect had a smaller magnitude compared to paradigms in which attention is externally guided (cued). However we believe that further characterization of this spontaneous component of attention is of great importance in the study of visuospatial attentional dynamics. These results support the presence of a spontaneous component of visuospatial attentional allocation and they advance pre-stimulus alpha-band lateralization as one of its neural signatures.

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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.

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BACKGROUND: 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. CONCLUSIONS/SIGNIFICANCE: We conclude that there are reorganizations in several neural processes that contribute differently to perceptual learning in a visual search task. We propose an integrative model of neural activity reorganization, whereby perceptual learning takes place as a two-stage phenomenon including perceptual, attentional and contextual processes.

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We studied brain activity during the displacement of attention in a modified visuo-spatial orienting paradigm. Using a behaviorally relevant no-shift condition as a control, we asked whether ipsi- or contralateral parietal alpha band activity is specifically related to covert shifts of attention. Cue-related event-related potentials revealed an attention directing anterior negativity (ADAN) contralateral to the shift of attention and P3 and contingent negative variation waveforms that were enhanced in both shift conditions as compared to the no-shift task. When attention was shifted away from fixation, alpha band activity over parietal regions ipsilateral to the attended hemifield was enhanced relative to the control condition, albeit with different dynamics in the upper and lower alpha subbands. Contralateral-to-attended parietal alpha band activity was indistinguishable from the no-shift task.

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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 delinsight, 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.

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 generalfor 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 moreencompassing 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 appliedlevels.

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The aim of this special issue of IPBS has been to explore concrete and explicit alternatives to cognitivism. Indeed, in our editorial introduction we set out to give a brief survey of the numerous criticisms that have been made of understanding the mind this way (Ibáñez and Cosmelli, Integrative Psychological and Behavioral Sciences, 2008). Thus in what sense do the contributions here presented succeed in providing novel alternatives, moving into original and potentially generative domains of inquiry? While much remains to be done, we believe that they make significant headway in more than one sense. We do believe, however, that there is one locus that furnishes a convergence ground that is worth considering seriously: the problem of meaning. Meaning as making sense of contextualized action seems to cross the domains of intentionality, intersubjectivity and ecology of mind. The development of multilevel approaches, as the authors here exemplify, argues for a novel research agenda.

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Binocular rivalry provides a useful situation for studying the relation between the temporal flow of conscious experience and the temporal dynamics of neural activity. After proposing a phenomenological framework for understanding temporal aspects of consciousness, we review experimental research on multistable perception and binocular rivalry, singling out various methodological, theoretical, and empirical aspects of this research relevant to studying the flow of experience. We then review an experimental study from our group explicitly concerned with relating the temporal dynamics of rivalrous experience to the temporal dynamics of cortical activity. Drawing attention to the importance of dealing with ongoing activity and its inherent changing nature at both phenomenological and neurodynamical levels, we argue that the notions of recurrence and variability are pertinent to understanding rivalry in particular and the flow of experience in general.

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Convergence of clinical, empirical, methodological and theoretical approaches aimed at understanding the relation between brain function and cognition, is by now standard in most if not all academic programs in the area of Cognitive Science. This confederation of disciplines is one of the liveliest domains of inquiry and discussion into some of the most fundamental--and historically resilient--questions human beings have posed themselves. The contributions gathered in this special issue of Biological Research, directly inspired by the ongoing work at the Instituto de Sistemas Complejos de Valparaiso and the December 2006 CONICYT-INSERM-SFI workshop "Networks in Cognitive Systems/Trends and Challenge in Biomedicine: From Cerebral Process to Mathematical Tools Design", Chile, represent an explicit invitation to the reader to dive deeper into this fascinating terrain.

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This paper describes a notable convergence between biological organization and programming language abstractions. Our aim is to explore possibilities of cross-fertilization, at both conceptual and empirical levels, towards the understanding of what cognition and cognitive systems might be.

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Convergence of clinical, empirical, methodological and theoretical approaches aimed at understanding the relation between brain function and cognition, is by now standard in most if not all academic programs in the area of Cognitive Science. This confederation of disciplines is one of the liveliest domains of inquiry and discussion into some of the most fundamental -and historically resilient- questions human beings have posed themselves. The contributions gathered in this special issue of Biological Research, directly inspired by the ongoing work at the Instituto de Sistemas Complejos de Valparaiso and the December 2006 CONICYT-INSERM-SFI workshop "Networks in Cognitive Systems / Trends and Challenge in Biomedicine: From Cerebral Process to Mathematical Tools Design", Chile, represent an explicit invitation to the reader to dive deeper into this fascinating terrain.

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This paper describes a notable convergence between biological organization and programming language abstractions. Our aim is to explore possibilities of cross-fertilization, at both conceptual and empirical levels, towards the understanding of what cognition and cognitive systems might be.

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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 (tau = 318 +/- 34 micros 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 ( approximately 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.

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This paper reviews in detail Francisco Varela's work on subjectivity and consciousness in the biological sciences. His original approach to this "hard problem" presents a subjectivity that is radically intertwined with its biological and physical roots. It must be understood within the framework of his theory of a concrete, embodied dynamics, grounded in his general theory of autonomous systems. Through concepts and paradigms such as biological autonomy, embodiment and neurophenomenology, the article explores the multiple levels of circular causality assumed by Varela to play a fundamental role in the emergence of human experience. The concept of biological autonomy provides the necessary and sufficient conditions for characterizing biological life and identity as an emergent and circular self-producing process. Embodiment provides a systemic and dynamical framework for understanding how a cognitive self--a mind--can arise in an organism in the midst of its operational cycles of internal regulation and ongoing sensorimotor coupling. Global subjective properties can emerge at different levels from the interactions of components and can reciprocally constrain local processes through an ongoing, recursive morphodynamics. Neurophenomenology is a supplementary step in the study of consciousness. Through a rigorous method, it advocates the careful examination of experience with first-person methodologies. It attempts to create heuristic mutual constraints between biophysical data and data produced by accounts of subjective experience. The aim is to explicitly ground the active and disciplined insight the subject has about his/her experience in a biophysical emergent process. Finally, we discuss Varela's essential contribution to our understanding of the generation of consciousness in the framework of what we call his "biophysics of being."

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Potassium channels in plants play a variety of important physiological roles including K(+) uptake into roots, stomatal and leaf movements, and release of K(+) into the xylem. This review summarizes current knowledge about a class of plant genes whose products are K(+) channel-forming proteins. Potassium channels of this class belong to a superfamily characterized by six membrane-spanning domains (S1-6), a positively charged S4 domain and a region between the S5 and S6 segments that forms the channel selectivity filter. These channels are voltage dependent, which means the membrane potential modifies the probability of opening (P(o)). However, despite these channels sharing the same topology as the outward-rectifying K(+) channels, which are activated by membrane depolarization, some plant K(+) channels such as KAT1/2 and KST1 open with hyperpolarizing voltages. In outward-rectifying K(+) channels, the change in P(o) is achieved through a voltage sensor formed by the S4 segment that detects the voltage transferring its energy to the gate that controls pore opening. This coupling is achieved by an outward displacement of the charges contained in S4. In KAT1, most of the results indicate that S4 is the voltage sensor. However, how the movement of S4 leads to opening remains unanswered. On the basis of recent data, we propose here that in plant-inward rectifiers an inward movement of S4 leads to channel opening and that the difference between it and outward-rectifying channels resides in the mechanism that couples gating charge displacement with pore opening.

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