Cerebellum and processing of negative facial emotions: Cerebellar transcranial DC stimulation specifically enhances the emotional recognition of facial anger and sadness

Some evidence suggests that the cerebellum participates in the complex network processing emotional facial expression. To evaluate the role of the cerebellum in recognising facial expressions we delivered transcranial direct current stimulation (tDCS) over the cerebellum and prefrontal cortex. A facial emotion recognition task was administered to 21 healthy subjects before and after cerebellar tDCS; we also tested subjects with a visual attention task and a visual analogue scale (VAS) for mood. Anodal and cathodal cerebellar tDCS both significantly enhanced sensory processing in response to negative facial expressions (anodal tDCS, p=.0021; cathodal tDCS, p=.018), but left positive emotion and neutral facial expressions unchanged (p>.05). tDCS over the right prefrontal cortex left facial expressions of both negative and positive emotion unchanged. These findings suggest that the cerebellum is specifically involved in processing facial expressions of negative emotion.     

Cognitive control of response inhibition and switching: Hemispheric lateralization and hand preference

Changing environmental constraints often make already prepared responses unnecessary or inappropriate. Under such circumstances, cognitive control enables to suppress the response or switch to alternative behavior. Here, we examine the neural dynamics of both functions in left- and right-handers who performed two variants of a paradigm that required either inhibition of the response or switching the response between hands. The EEG coherence data showed strengthening of interregional coupling in the alpha band (8–12 Hz) following the target cues with an essential contribution of fronto-medial circuitry and a specific involvement of parietal areas in response switching. Brain-behavioral correlations revealed the functional significance of left-sided regions for successful response inhibition and switching, underlining the significant role of the left hemisphere for the organization of goal-directed activities. This lateralization pattern was observed for both left- and right-handers and suggests dominance of higher-order aspects of action planning in the left hemisphere.     

Conscious and unconscious face recognition is improved by high-frequency rTMS on pre-motor cortex

Simulation process and mirroring mechanism appear to be necessary to the recognition of emotional facial expressions. Prefrontal areas were found to support this simulation mechanism. The present research analyzed the role of premotor area in processing emotional faces with different valence (positive vs. negative faces), considering both conscious and unconscious pathways. High-frequency rTMS (10 Hz) stimulation was applied to prefrontal area to induce an activation response when overt (conscious) and covert (unconscious) processing was implicated. Twenty-two subjects were asked to detect emotion/no emotion (anger, fear, happiness, neutral). Error rates (ERs) and response times (RTs) were considered in response to the experimental conditions. ERs and RTs decreased in case of premotor brain activation, specifically in response to fear, for both conscious and unconscious condition. The present results highlight the role of the premotor system for facial expression processing, supporting the existence of two analogous mechanisms for conscious and unconscious condition.     

Neurophysiological bases underlying the organization of intentional actions and the understanding of others’ intention

Philosophical and neuroscientific investigation on intentional actions focused on several different aspects, making difficult to define what should be meant with the concept of intention. Most of our everyday actions are constituted by complex and finely organized motor sequences, planned and executed in order to attain a desired final goal. In this paper, we will identify the final goal of the action as the motor intention of the acting individual. First, we will review the relative contribution of the vast neuroscientific literature on the role of different cortical areas in the organization of goal-directed movement. In particular, we will describe recent data on the cortical organization of natural action sequences, showing that this organization could be at the basis not only of our capacity of acting intentionally, but also of our ability to understand the motor intentions underlying others’ behaviour which is crucial during social interactions.     

Development and initial validation of the Brief Adolescent Life Event Scale (BALES)

We report initial validity analyses of the Brief Adolescent Life Event Scale (BALES). This instrument addresses negative and positive events pertinent to the well being of adolescent boys and girls, and is designed for use in studies utilizing an extended research protocol. Selection of items was guided by emerging perspectives on positive psychology , action theory , and personality vulnerability , as well as by new developments in statistical modeling theory. The 36 items of the scale tap negative and positive events, each of which addresses interpersonal and achievement life domains. Using a large sample of early-adolescents ( N = 895), we confirmed the hypothesized structure that includes four domain-level latent factors (i.e., negative interpersonal events, negative achievement events, positive interpersonal events, positive achievement events), and two overarching factors (negative events and positive events). Indices of positive and negative events predicted adolescent depressive symptoms in expected ways, and positive events buffered the effect of negative events on depressive symptoms. These findings encourage an informed use of the BALES and highlight considerations involved in the development of brief measures of stress and coping processes.     

Attentional bias for words and faces in social anxiety

Conflicting findings concerning the nature and presence of attentional bias in social anxiety and social phobia have been reported in the literature. This paper reports the findings of two studies comparing people with high and low social anxiety on dot probe tasks using words, faces photographed in front view, and faces photographed in profile as stimuli. In Study 1 those with high social anxiety displayed an attentional bias towards negative faces. The low social anxiety group showed an attentional bias towards positive faces. No significant effects were observed on the dot probe using words as stimuli. Study 2 used pairs of faces presented in profile as though looking at each other. One of the faces displayed either a positive, negative or neutral expression. The second face always had a neutral expression, and in half of the trials it was the subject's own face. The findings of this more ecologically valid procedure replicated those of Study 1. Facilitated attention to dots following emotional faces was specific to threatening facial stimuli. From these studies it appears that the facial dot probe task is a more sensitive index of attentional bias than the word task in a non-clinical sample with social anxiety.     

Young children's ability to solve spatial problems involving a choice

When do young children become able to make an adequate choice between two alternatives based on spatial information? Children of 20, 30, and 40 months of age were either presented with two objects with different cross-sections and one aperture, or one object and two different apertures. In each trial there was one object – aperture match and the task was to find that match and insert the object. All the children understood the task and tried to solve the problems but the 20-month-olds performed randomly and not even the 40-month-olds chose all the correct correspondences consistently. The results also showed that it is easier to choose between apertures than objects. This contrasts with the ability to solve the insertion problem once the choice was made. When choosing the correct object or aperture, the 40-month-olds inserted the triangle successfully in 85% of the cases. The boys and girls were equally good at solving the task, but the boys did it faster. The results show that making a choice adds significantly to the difficulty of solving spatial problems. It requires systematic examination of the objects and apertures involved, a working memory that can handle at least three items at a time, and an ability to inhibit an incorrect choice. Such executive functions are typically found in older preschool children but the present task shows that with an appropriate setup their development can be traced from a much earlier age.     

Approach and avoidance as action effects

Numerous studies use arm movements (arm flexion and extension) to investigate the interaction between emotional stimuli and approach/avoidance behaviour. In many experiments, however, these arm movements are ambiguous. Arm flexion can be interpreted either as pulling (approach) or as withdrawing (avoidance). On the contrary, arm extension can be interpreted as reaching (approach) or as pushing (avoidance). This ambiguity can be resolved by regarding approach and avoidance as flexible action plans that are represented in terms of their effects. Approach actions reduce the distance between a stimulus and the self, whereas avoidance actions increase that distance. In this view, action effects are an integral part of the representation of an action. As a result, a neutral action can become an approach or avoidance reaction if it repeatedly results in decreasing or increasing the distance to a valenced stimulus. This hypothesis was tested in the current study. Participants responded to positive and negative words using key-presses. These “neutral” responses (not involving arm flexion or extension) were consistently followed by a stimulus movement toward or away from the participant. Responses to emotional words were faster when the response's effect was congruent with stimulus valence, suggesting that approach/avoidance actions are indeed defined in terms of their outcomes.     

Priming of reach trajectory when observing actions: Hand-centred effects

When another person's actions are observed it appears that these actions are simulated, such that similar motor processes are triggered in the observer. Much evidence suggests that such simulation concerns the achievement of behavioural goals, such as grasping a particular object, and is less concerned with the specific nature of the action, such as the path the hand takes to reach the goal object. We demonstrate that when observing another person reach around an obstacle, an observer's subsequent reach has an increased curved trajectory, reflecting motor priming of reach path. This priming of reach trajectory via action observation can take place under a variety of circumstances: with or without a shared goal, and when the action is seen from a variety of perspectives. However, of most importance, the reach path priming effect is only evoked if the obstacle avoided by another person is within the action (peripersonal) space of the observer.     

Tone‐affect compatibility with affective stimuli and affective responses

Three experiments examine multimodal integration of tone pitch (high/low), facial expression stimuli (happy/angry), and responses (happy/angry) in a compatibility paradigm. When the participants' task is to imitate facial expressions (Experiment 1), smiles are facilitated by high tones whereas frowns are facilitated by low tones. Experiments 2 and 3 further analyse this effect and show that there is both integration between the tone stimulus and the facial stimulus and between the tone stimulus and the facial response. Results suggest that pitch height is associated with emotion. An interpretation in terms of an embodied cognition approach that emphasizes an interweavement of perception and action is discussed.