Recognition memory for emotional faces in amnestic mild cognitive impairment: An event-related potential study

ABSTRACT

This study examined the temporal course of emotional face recognition in amnestic mild cognitive impairment (aMCI). Patients and healthy controls (HC) performed a face recognition task, giving old/new responses to previously studied and novel faces displaying a negative or neutral expression. In aMCI patients, recognition accuracy was preserved for negative faces. Event-related potentials (ERPs) revealed disease-related changes in early perceptual components but not in ERP indices of explicit recognition. Specifically, aMCI patients showed impaired recognition effects for negative faces on the amplitudes of N170 and P2, suggesting deficient memory-related processing of negative faces at the stage of structural encoding and during an early recognition stage at which faces are individuated, respectively. Moreover, while a right-lateralized emotion effect specifically observed for correctly recognized faces on the amplitude of N170 was absent in aMCI, a similar emotion effect for successfully recognized faces on P2 was preserved in the patients, albeit with a different distribution. This suggests that in aMCI facilitated processing of successfully recognized emotional faces starts later in the processing sequence. Nonetheless, an early frontal old/new effect confined to negative faces and a parietal old/new effect unaffected by facial emotion were observed in both groups. This indicates that familiarity and conceptual priming processes may specifically contribute to recognition of negative faces in older adults and that aMCI patients can recruit the same retrieval mechanisms as controls, despite disease-related changes on early perceptual ERP components.     

Predictive coding accelerates word recognition and learning in the early stages of language development

The ability to predict future events in the environment and learn from them is a fundamental component of adaptive behavior across species. Here we propose that inferring predictions facilitates speech processing and word learning in the early stages of language development. Twelve‐ and 24‐month olds’ electrophysiological brain responses to heard syllables are faster and more robust when the preceding word context predicts the ending of a familiar word. For unfamiliar, novel word forms, however, word‐expectancy violation generates a prediction error response, the strength of which significantly correlates with children's vocabulary scores at 12 months. These results suggest that predictive coding may accelerate word recognition and support early learning of novel words, including not only the learning of heard word forms but also their mapping to meanings. Prediction error may mediate learning via attention, since infants’ attention allocation to the entire learning situation in natural environments could account for the link between prediction error and the understanding of word meanings. On the whole, the present results on predictive coding support the view that principles of brain function reported across domains in humans and non‐human animals apply to language and its development in the infant brain. A video abstract of this article can be viewed at: http://hy.fi/unitube/video/e1cbb495-41d8-462e-8660-0864a1abd02c . [Correction added on 27 January 2017, after first online publication: The video abstract link was added.]     

An interactional “live eye tracking” study in autism spectrum disorder: combining qualitative and quantitative approaches in the study of gaze

Recent studies on gaze behaviours in individuals with autism spectrum disorder (ASD) have utilised “live eye tracking.” Such research has focused on generating quantitative eye tracking measurements, which provide limited (if any) qualitative contextual details of the actual interactions in which gaze occurs. This article presents a novel methodological approach that combines live eye tracking with qualitative interaction analysis, multimodally informed conversation analysis. Drawing on eye tracking and wide-angle video recordings, this combination renders visible some of the functions, or what gaze “does,” in interactional situations. The participants include three children with ASD and their adult co-participants during body-movement gaming sessions. The article demonstrates how quantitative eye tracking research can be extended qualitatively using a microanalytic interaction analysis to recontextualise the gaze shifts identified. The findings in this article show that the co-participants treat a child’s gaze shifts differently depending on when these occur in a stream of other action. The study suggests that introducing this qualitative dimension to eye tracking research could increase its ecological validity and offer new insight into gaze behaviours in ASD.     

Adverse childhood experiences and autonomic regulation in response to acute stress: the role of the sympathetic and parasympathetic nervous systems

Background and objectives: After a previous report demonstrated blunted heart rate (HR) reactivity in association with adverse childhood experiences (ACEs) [Voellmin, A., Winzeler, K., Hug, E., Wilhelm, F. H., Schaefer, V., Gaab, J.,?…?Bader, K. (2015). Blunted endocrine and cardiovascular reactivity in young healthy women reporting a history of childhood adversity. Psychoneuroendocrinology, 51, 58–67. doi:10.1016/j.psyneuen.2014.09.008], the present analysis aimed at clarifying the role of the sympathetic and parasympathetic branches of the autonomic nervous system in this relationship.

Design and Methods: One hundred eighteen healthy young women provided data on ACEs and underwent psychosocial stress testing. Systolic blood pressure (SBP) and respiratory sinus arrhythmia (RSA, quantified by high-frequency HR variability) were assessed as measures of sympathetic and parasympathetic cardiovascular activity, respectively. A mediation model was calculated to test the indirect effects of ACEs on HR via SBP and RSA.

Results: The effect of ACEs on HR reactivity was mediated by SBP reactivity but not by RSA reactivity. ACEs were associated with reduced SBP at rest.

Conclusions: ACEs were associated with down-regulation in a measure of sympathetic but no alteration in a measure of parasympathetic cardiovascular stress reactivity in adulthood. Future research will need to clarify whether this indicates risk or resilience.     

Observational Context of Mother-Child Interaction: Impact of a stress Context on Emotional Availability

Previous studies have found that a stressful observational context challenges the mother-child relationship, thus highlighting negative interactive behavior. However, the impact of observational context has only been investigated in infants and preschoolers without specifically using the Emotional Availability Scales. Nor have they explored whether the association of mother-child interaction with children’s emotional or behavioral problems depends on the observational context. We observed 140 mothers and their five to 12-year-old children in non-stressful free play and in a stressful task context. In general, dyads showed higher emotional availability in the task context compared to the free play. Specifically, mothers showed higher levels of Sensitivity, Structuring and Nonhostility, but lower levels of Nonintrusiveness during the task compared to the free play context; children showed higher levels of Responsiveness during the task than during free play. After controlling for dyadic stress, contextual effects decreased for all dimensions of emotional availability. The association of mother-child interaction with child problem behavior depended on the observational context. Specifically, we found maternal emotional availability during free play to be more strongly associated with child problem behavior than during the stressful task; however, emotional availability of the child was more strongly associated with problem behavior when obtained during the task. We conclude that context impacts on mother-child interactive behavior and also on the association of mother-child-interaction and child behavior. Stress is a relevant contextual factor influencing mother-child interactive behavior.     

Spatial specificity of tactile enhancement during reaching

Tactile signals on a hand that serves as movement goal are enhanced during movement planning and execution. Here, we examined how spatially specific tactile enhancement is when humans reach to their own static hand. Participants discriminated two brief and simultaneously presented tactile stimuli: a comparison stimulus on the left thumb or little finger from a reference stimulus on the sternum. Tactile stimuli were presented either during right-hand reaching towards the left thumb or little finger or while holding both hands still (baseline). Consistent with our previous findings, stimuli on the left hand were perceived stronger during movement than baseline. However, tactile enhancement was not stronger when the stimuli were presented on the digit that served as reach target, thus the perception across the whole hand was uniformly enhanced. In experiment 2, we also presented stimuli on the upper arm in half of the trials to reduce the expectation of the stimulus location. Tactile stimuli on the target hand, but not on the upper arm, were generally enhanced, supporting the idea of a spatial gradient of tactile enhancement. Overall, our findings argue for low spatial specificity of tactile enhancement at movement-relevant body parts, here the target hand.     

Mirror gazing in body dysmorphic disorder and healthy controls: effects of duration of gazing

Cognitive-behavioural models of body dysmorphic disorder (BDD) suggest that mirrors can act as a trigger for individuals with BDD, resulting in a specific mode of cognitive processing, characterised by an increase in self-focussed attention and associated distress. The aim of the current study was to investigate these factors experimentally by exposing participants with BDD (n = 25) and without BDD (n = 25) to a mirror in a controlled setting. An additional aim was to ascertain the role of duration of mirror gazing in the maintenance of distress and self-consciousness by manipulating the length of gazing (short check vs. long gazing). Findings demonstrated that contrary to what was predicted, not only participants with BDD, but also those without BDD experienced an increase in distress and self-focused attention upon exposure to the mirror. In addition, people without BDD, unlike those with BDD, experienced more distress when looking in the mirror for a long period of time as opposed to a short period of time. This lends some support to the idea that, for people with BDD, gazing in a mirror, regardless of duration, might act as an immediate trigger for an abnormal mode of processing and associated distress, and that this association has developed from past excessive mirror gazing. Further theoretical implications of these findings, as well as subsidiary research questions relating to additional cognitive factors are discussed.     

Neural correlates of metonymy resolution

Metonymies are exemplary models for complex semantic association processes at the sentence level. We investigated processing of metonymies using event-related functional magnetic resonance imaging (fMRI).During an 1.5 Tesla fMRI scan, 14 healthy subjects (12 female) read 124 short German sentences with either literal (like “Africa is arid”), metonymic (“Africa is hungry”), or nonsense (“Africa is woollen”) content. Sentences were constructed so that they obey certain grammatical, semantic, and plausibility conditions and were matched for word frequency, semantic association, length and syntactic structure. We concentrated on metonymies that were not yet fossilised; we also examined a wide variety of metonymic readings.Reading metonymies relative to literal sentences revealed signal changes in a predominantly left-lateralised fronto-temporal network with maxima in the left and right inferior frontal as well as left middle temporal gyri. Left inferior frontal activation may reflect both inference processes and access to world knowledge during metonymy resolution.     

Consciousness lost and found: subjective experiences in an unresponsive state

Anesthetic-induced changes in the neural activity of the brain have been recently utilized as a research model to investigate the neural mechanisms of phenomenal consciousness. However, the anesthesiologic definition of consciousness as “responsiveness to the environment” seems to sidestep the possibility that an unresponsive individual may have subjective experiences. The aim of the present study was to analyze subjective reports in sessions where sedation and the loss of responsiveness were induced by dexmedetomidine, propofol, sevoflurane or xenon in a nonsurgical experimental setting. After regaining responsiveness, participants recalled subjective experiences in almost 60% of sessions. During dexmedetomidine sessions, subjective experiences were associated with shallower “depth of sedation” as measured by an electroencephalography-derived anesthesia depth monitor. Results confirm that subjective experiences may occur during clinically defined unresponsiveness, and that studies aiming to investigate phenomenal consciousness under sedative and anesthetic effects should control the subjective state of unresponsive participants with post-recovery interviews.