Ketamine and sleep modulate neural complexity dynamics in cats.

There is increasing evidence that the level of consciousness can be captured by neural informational complexity: for instance, complexity, as measured by the Lempel Ziv (LZ) compression algorithm, decreases during anaesthesia and non-rapid eye movement (NREM) sleep in humans and rats, when compared with LZ in awake and REM sleep. In contrast, LZ is higher in humans under the effect of psychedelics, including subanaesthetic doses of ketamine. However, it is both unclear how this result would be modulated by varying ketamine doses, and whether it would extend to other species. Here, we studied LZ with and without auditory stimulation during wakefulness and different sleep stages in five cats implanted with intracranial electrodes, as well as under subanaesthetic doses of ketamine (5, 10, and 15 mg/kg i.m.). In line with previous results, LZ was lowest in NREM sleep, but similar in REM and wakefulness. Furthermore, we found an inverted U-shaped curve following different levels of ketamine doses in a subset of electrodes, primarily in prefrontal cortex. However, it is worth noting that the variability in the ketamine dose-response curve across cats and cortices was larger than that in the sleep-stage data, highlighting the differential local dynamics created by two different ways of modulating conscious state. These results replicate previous findings, both in humans and other species, demonstrating that neural complexity is highly sensitive to capture state changes between wake and sleep stages while adding a local cortical description. Finally, this study describes the differential effects of ketamine doses, replicating a rise in complexity for low doses, and further fall as doses approach anaesthetic levels in a differential manner depending on the cortex.

Affective modulation of cognitive control: A systematic review of EEG studies.

In recent years, a growing corpus of research has been conducted utilizing a variety of behavioral and neurophysiological methodologies to investigate the relationship of emotion and cognition, yielding unique insights into fundamental concerns about the human mind and mental disease. Electroencephalography (EEG) has been utilized to investigate how emotional states alter neural markers of cognitive control. The current study is a systematic analysis of EEG research that looks at affective modulation (mood, emotion) of cognitive control and its many sub-processes (e.g., cognitive flexibility, inhibitory control, and working memory). The PRISMA standards were followed in this review, which looked at experimental designs and tasks, as well as methodological elements of EEG recording and analysis across research. A total of 35 articles were chosen for qualitative synthesis as a consequence of the search. The examination of event-related potentials (ERPs), which showed affective modulation of 19 different components, was the most common electrophysiological approach used across research. The majority of the investigations focused on N2 and P3, indicating that affective induction has a strong influence on attentional processes and response inhibition. Future research should look into different methodologies such as source location and connection metrics to better understand the brain's areas and dynamic response during affective induction activities. It is also suggested that the technical components of the report be more explicit in order to promote study comparability and replication.

Heart evoked potential triggers brain responses to natural affective scenes: A preliminary study.

The relationship between ongoing brain interoceptive signals and emotional processes has been addressed only indirectly through external stimulus-locked measures. In this study, an internal body trigger (heart evoked potential, HEP) was used to measure ongoing internally triggered signals during emotional states. We employed high-density electroencephalography (hd-EEG), source reconstruction analysis, and behavioral measures to assess healthy participants watching emotion-inducing video-clips (positive, negative, and neutral emotions). Results showed emotional modulation of the HEP at specific source-space nodes of the fronto-insulo-temporal networks related to affective-cognitive integration. This study is the first to assess the direct convergence among continuous triggers of viscerosensory cortical markers and emotion through dynamic stimuli presentation.

Neurophenomenology revisited: second-person methods for the study of human consciousness.

In the study of consciousness, neurophenomenology was originally established as a novel research program attempting to reconcile two apparently irreconcilable methodologies in psychology: qualitative and quantitative methods. Its potential relies on Francisco Varela's idea of reciprocal constraints, in which first-person accounts and neurophysiological data mutually inform each other. However, since its first conceptualization, neurophenomenology has encountered methodological problems. These problems have emerged mainly because of the difficulty of obtaining and analyzing subjective reports in a systematic manner. However, more recently, several interview techniques for describing subjective accounts have been developed, collectively known as "second-person methods." Second-person methods refer to interview techniques that solicit both verbal and non-verbal information from participants in order to obtain systematic and detailed subjective reports. Here, we examine the potential for employing second-person methodologies in the neurophenomenological study of consciousness and we propose three practical ideas for developing a second-person neurophenomenological method. Thus, we first describe second-person methodologies available in the literature for analyzing subjective reports, identifying specific constraints on the status of the first-, second- and third- person methods. Second, we analyze two experimental studies that explicitly incorporate second-person methods for traversing the "gap" between phenomenology and neuroscience. Third, we analyze the challenges that second-person accounts face in establishing an objective methodology for comparing results across different participants and interviewers: this is the "validation" problem. Finally, we synthesize the common aspects of the interview methods described above. In conclusion, our arguments emphasize that second-person methods represent a powerful approach for closing the gap between the experiential and the neurobiological levels of description in the study of human consciousness.

Disentangling interoception: insights from focal strokes affecting the perception of external and internal milieus.

Interoception is the moment-to-moment sensing of the physiological condition of the body. The multimodal sources of interoception can be classified into two different streams of afferents: an internal pathway of signals arising from core structures (i.e., heart, blood vessels, and bronchi) and an external pathway of body-mapped sensations (i.e., chemosensation and pain) arising from peripersonal space. This study examines differential processing along these streams within the insular cortex (IC) and their subcortical tracts connecting frontotemporal networks. Two rare patients presenting focal lesions of the IC (insular lesion, IL) or its subcortical tracts (subcortical lesion, SL) were tested. Internally generated interoceptive streams were assessed through a heartbeat detection (HBD) task, while those externally triggered were tapped via taste, smell, and pain recognition tasks. A differential pattern was observed. The IC patient showed impaired internal signal processing while the SL patient exhibited external perception deficits. Such selective deficits remained even when comparing each patient with a group of healthy controls and a group of brain-damaged patients. These outcomes suggest the existence of distinguishable interoceptive streams. Results are discussed in relation with neuroanatomical substrates, involving a fronto-insulo-temporal network for interoceptive and cognitive contextual integration.

Auditory Feedback Differentially Modulates Behavioral and Neural Markers of Objective and Subjective Performance When Tapping to Your Heartbeat.

Interoception, the perception of our body internal signals, plays a key role in maintaining homeostasis and guiding our behavior. Sometimes, we become aware of our body signals and use them in planning and strategic thinking. Here, we show behavioral and neural dissociations between learning to follow one's own heartbeat and metacognitive awareness of one's performance, in a heartbeat-tapping task performed before and after auditory feedback. The electroencephalography amplitude of the heartbeat-evoked potential in interoceptive learners, that is, participants whose accuracy of tapping to their heartbeat improved after auditory feedback, was higher compared with non-learners. However, an increase in gamma phase synchrony (30-45 Hz) after the heartbeat auditory feedback was present only in those participants showing agreement between objective interoceptive performance and metacognitive awareness. Source localization in a group of participants and direct cortical recordings in a single patient identified a network hub for interoceptive learning in the insular cortex. In summary, interoceptive learning may be mediated by the right insular response to the heartbeat, whereas metacognitive awareness of learning may be mediated by widespread cortical synchronization patterns.

Hypnoanalgesia and the study of pain experience: from Cajal to modern neuroscience.

Santiago Ramón y Cajal (1852-1934) did not only contribute to neurobiology and neurohistology. At the end of the 19th century, he published one of the first clinical reports on the employment of hypnotic suggestion to induce analgesia (hypnoanalgesia) in order to relieve pain in childbirth. Today, the clinical application of hypnoanalgesia is considered an effective technique for the treatment of pain in medicine, dentistry, and psychology. However, the knowledge we have today on the neural and cognitive underpinnings of hypnotic suggestion has increased dramatically since Cajal's times. Here we review the main contributions of Cajal to hypnoanalgesia and the current knowledge we have about hypnoanalgesia from neural and cognitive perspectives.

[Validity evidence of the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) in Chile]. / Evidencia de validez en Chile del Alcohol, Smoking and Substance Involvement Screening Test (ASSIST).

This study aims to psychometrically validate the Chilean version of the Alcohol, Smoking and Substance Involvement Screening Test ASSIST. Specifically, this study is interested in evaluating the reliability, consistency and concurrent and discriminant validity of this instrument. The sample was composed for a total of 400 people from four different settings: treatment centers (residential and ambulatories), primary health care, police stations and companies. The reliability of the ASSIST was high (α = .86 for Alcohol, α = .84 for marijuana and α = .90 for cocaine). The intra class correlation coefficient (ICC) with test-retest comparison was statistically significant for Alcohol (ICC = .66), marijuana (ICC = .74) and cocaine (ICC = .80). There were statistically significant correlations between the ASSIST and the AUDIT score (Pearson’s r = .85), the ASSIST and the ASI-Lite score (r between .66 and .83 for tobacco, alcohol, marijuana and cocaine), and the ASSIST and the SDS score (r = .65). The original cutoff point for high risk detection was 27 points, however, in order to have a better balance between sensitivity and specificity the cut was changed to 21 points. The ASSIST presents good psychometric properties and therefore is a reliable and valid instrument to be used as a mechanism to detect risk levels of substance use in the Chilean population.

Toward an experimental account of argumentation: the case of the slippery slope and the ad hominem arguments.

Argumentation is a crucial component of our lives. Although in the absence of rational debate our legal, political, and scientific systems would not be possible, there is still no integrated area of research on the psychology of argumentation. Furthermore, classical theories of argumentation are normative (i.e., the acceptability of an argument is determined by a set of norms or logical rules), which sometimes creates a dissociation between the theories and people's behavior. We think the current challenge for psychology is to bring together the cognitive and normative accounts of argumentation. In this article, we exemplify this point by analyzing two cases of argumentative structures experimentally studied in the context of cognitive psychology. Specifically, we focus on the slippery slope argument and the ad hominem argument under the frameworks of Bayesian and pragma-dialectics approaches, respectively. We think employing more descriptive and experimental accounts of argumentation would help Psychology to bring closer the cognitive and normative accounts of argumentation with the final goal of establishing an integrated area of research on the psychology of argumentation.

Attachment patterns trigger differential neural signature of emotional processing in adolescents.

BACKGROUND: Research suggests that individuals with different attachment patterns process social information differently, especially in terms of facial emotion recognition. However, few studies have explored social information processes in adolescents. This study examined the behavioral and ERP correlates of emotional processing in adolescents with different attachment orientations (insecure attachment group and secure attachment group; IAG and SAG, respectively). This study also explored the association of these correlates to individual neuropsychological profiles. METHODOLOGY/PRINCIPAL FINDINGS: We used a modified version of the dual valence task (DVT), in which participants classify stimuli (faces and words) according to emotional valence (positive or negative). Results showed that the IAG performed significantly worse than SAG on tests of executive function (EF attention, processing speed, visuospatial abilities and cognitive flexibility). In the behavioral DVT, the IAG presented lower performance and accuracy. The IAG also exhibited slower RTs for stimuli with negative valence. Compared to the SAG, the IAG showed a negative bias for faces; a larger P1 and attenuated N170 component over the right hemisphere was observed. A negative bias was also observed in the IAG for word stimuli, which was demonstrated by comparing the N170 amplitude of the IAG with the valence of the SAG. Finally, the amplitude of the N170 elicited by the facial stimuli correlated with EF in both groups (and negative valence with EF in the IAG). CONCLUSIONS/SIGNIFICANCE: Our results suggest that individuals with different attachment patterns process key emotional information and corresponding EF differently. This is evidenced by an early modulation of ERP components' amplitudes, which are correlated with behavioral and neuropsychological effects. In brief, attachments patterns appear to impact multiple domains, such as emotional processing and EFs.

[Francisco Varela's neurophenomenology of time: temporality of consciousness explained?]. / Neurofenomenologia del tiempo segun Francisco Varela: ¿la temporalidad de la conciencia explicada?

This article attempts to clarify Francisco Varela's proposal of a neurophenomenology of time consciousness in the light of distinctions based on the philosophical literature of phenomenology and recent advances of neurobiology. The analysis is carried out considering three aspects. In the first of them, we discuss the phenomenological aspect of consciousness, accessible in first-person, which describes time as a structure with three inseparable moments (past-present-future) and three levels of temporality, and not merely as the chronometric time or clock time. In the second one, we analyze the neurobiological aspect of consciousness that tends to "explain" the phenomenological time in terms of three possible levels of neuronal integration. Thus, we propose a correspondence between the levels of phenomenological time and neural integration processes. Finally, we try to analyze this "correspondence" and the issues that follow from this by considering that the notion of time in this correspondence is, in essence, the clock time and not the phenomenological time consciousness.

Evaluación de la enfermedad de Alzheimer en etapa temprana: biomarcadores y pruebas neuropsicológicas / Early evaluation of Alzheimer's disease: biomarkers and neuropsychological tests

Background: Alzheimer disease is a neurodegenerative condition that affects cognitive, behavioral and global functioning of patients. Currently and due to the lack of conclusive biological testing, Alzheimer's disease diagnosis is based primarily on clinical criteria. Since its early diagnosis allows clinical interventions when neurological damage is relatively mild, the development of early detection tools has become a major topic of interest. In this article, we review the main neuro-biological and neuropsychological features of Alzheimer's disease, analyzing the use of biomarkers and neuropsychological testing for early detection.

What event-related potentials (ERPs) bring to social neuroscience?

Social cognitive neuroscience is a recent interdisciplinary field that studies the neural basis of the social mind. Event-related potentials (ERPs) provide precise information about the time dynamics of the brain. In this study, we assess the role of ERPs in cognitive neuroscience, particularly in the emerging area of social neuroscience. First, we briefly introduce the technique of ERPs. Subsequently, we describe several ERP components (P1, N1, N170, vertex positive potential, early posterior negativity, N2, P2, P3, N400, N400-like, late positive complex, late positive potential, P600, error-related negativity, feedback error-related negativity, contingent negative variation, readiness potential, lateralized readiness potential, motor potential, re-afferent potential) that assess perceptual, cognitive, and motor processing. Then, we introduce ERP studies in social neuroscience on contextual effects on speech, emotional processing, empathy, and decision making. We provide an outline of ERPs' relevance and applications in the field of social cognitive neuroscience. We also introduce important methodological issues that extend classical ERP research, such as intracranial recordings (iERP) and source location in dense arrays and simultaneous functional magnetic resonance imaging recordings. Further, this review discusses possible caveats of the ERP question assessment on neuroanatomical areas, biophysical origin, and methodological problems, and their relevance to explanatory pluralism and multilevel, contextual, and situated approaches to social neuroscience.

[Early evaluation of Alzheimer's disease: biomarkers and neuropsychological tests]. / Evaluación de la enfermedad de Alzheimer en etapa temprana: biomarcadores y pruebas neuropsicológicas.

BACKGROUND: Alzheimer disease is a neurodegenerative condition that affects cognitive, behavioral and global functioning of patients. Currently and due to the lack of conclusive biological testing, Alzheimer's disease diagnosis is based primarily on clinical criteria. Since its early diagnosis allows clinical interventions when neurological damage is relatively mild, the development of early detection tools has become a major topic of interest. In this article, we review the main neuro-biological and neuropsychological features of Alzheimer's disease, analyzing the use of biomarkers and neuropsychological testing for early detection.

The cortical processing of facial emotional expression is associated with social cognition skills and executive functioning: a preliminary study.

Several lines of experimental evidence support an association between facial processing and social cognition, but no direct link between cortical markers of facial processing and complex cognitive processes has been reported until now. In the current study, we tested the hypothesis that cortical electrophysiological markers for the processing of facial emotion are associated with individual differences in executive and social cognition skills. We tested for correlations between the amplitude of event-related potentials (N170) in a dual valence task and participants' scores on three neuropsychological assessments (general neuropsychology, executive functioning, and social cognition). N170 was modulated by the stimulus type (face versus word) and the valence of faces (positive versus negative). The neural source of N170 was estimated to be the fusiform gyrus. Robust correlations were found between neuropsychological markers and measures of facial processing. Social cognition skills (as measured by three tests: the Reading the Mind in the Eyes test, the Faux Pas test, and the Iowa Gambling Task) correlated with cortical measures of emotional discrimination. Executive functioning ability also correlated with the cortical discrimination of complex emotional stimuli. Our findings suggest that the cortical processing of facial emotional expression is associated with social cognition skills.

Fluid intelligence and psychosocial outcome: from logical problem solving to social adaptation.

BACKGROUND: While fluid intelligence has proved to be central to executive functioning, logical reasoning and other frontal functions, the role of this ability in psychosocial adaptation has not been well characterized. METHODOLOGY/PRINCIPAL FINDINGS: A random-probabilistic sample of 2370 secondary school students completed measures of fluid intelligence (Raven's Progressive Matrices, RPM) and several measures of psychological adaptation: bullying (Delaware Bullying Questionnaire), domestic abuse of adolescents (Conflict Tactic Scale), drug intake (ONUDD), self-esteem (Rosenberg's Self Esteem Scale) and the Perceived Mental Health Scale (Spanish adaptation). Lower fluid intelligence scores were associated with physical violence, both in the role of victim and victimizer. Drug intake, especially cannabis, cocaine and inhalants and lower self-esteem were also associated with lower fluid intelligence. Finally, scores on the perceived mental health assessment were better when fluid intelligence scores were higher. CONCLUSIONS/SIGNIFICANCE: Our results show evidence of a strong association between psychosocial adaptation and fluid intelligence, suggesting that the latter is not only central to executive functioning but also forms part of a more general capacity for adaptation to social contexts.

The role of consciousness in the urge-for-action.

Abstract A neuroanatomical model of urge-for-action phenomena has been proposed based on the "motivation-for-action" network (e.g., insula and mid-cingulate cortex). Notwithstanding the sound evidence presented regarding the functional and anatomical correlates of this model, the nature of the relationship between urges and conscious awareness remains to be addressed. Moreover, this model does not seem to explain (1) how a conscious access threshold is reached, and (2) the way in which the urges are related to more general contents of consciousness.