Carla Barros

Salience in a social landscape: electrophysiological effects of task-irrelevant and infrequent vocal change

In a dynamically changing social environment, humans have to face the challenge of prioritizing stimuli that compete for attention. In the context of social communication, the voice is the most important sound category. However, the existing studies do not directly address whether and how the salience of an unexpected vocal change in an auditory sequence influences the orientation of attention. In this study, frequent tones were interspersed with task-relevant infrequent tones and task-irrelevant infrequent vocal sounds (neutral, happy and angry vocalizations). Eighteen healthy college students were asked to count infrequent tones. A combined event-related potential (ERP) and EEG time-frequency approach was used, with the focus on the P3 component and on the early auditory evoked gamma band response, respectively. A spatial-temporal principal component analysis was used to disentangle potentially overlapping ERP components. Although no condition differences were observed in the 210-310 ms window, larger positive responses were observed for emotional than neutral vocalizations in the 310-410 ms window. Furthermore, the phase synchronization of the early auditory evoked gamma oscillation was enhanced for happy vocalizations. These findings support the idea that the brain prioritizes the processing of emotional stimuli, by devoting more attentional resources to salient social signals even when they are not task-relevant.

Is laughter a better vocal change detector than a growl

The capacity to predict what should happen next and to minimize any discrepancy between an expected and an actual sensory input (prediction error) is a central aspect of perception. Particularly in vocal communication, the effective prediction of an auditory input that informs the listener about the emotionality of a speaker is critical. What is currently unknown is how the perceived valence of an emotional vocalization affects the capacity to predict and detect a change in the auditory input. This question was probed in a combined event-related potential (ERP) and time-frequency analysis approach. Specifically, we examined the brain response to standards (Repetition Positivity) and to deviants (Mismatch Negativity - MMN), as well as the anticipatory response to the vocal sounds (pre-stimulus beta oscillatory power). Short neutral, happy (laughter), and angry (growls) vocalizations were presented both as standard and deviant stimuli in a passive oddball listening task while participants watched a silent movie and were instructed to ignore the vocalizations. MMN amplitude was increased for happy compared to neutral and angry vocalizations. The Repetition Positivity was enhanced for happy standard vocalizations. Induced pre-stimulus upper beta power was increased for happy vocalizations, and predicted the modulation of the standard Repetition Positivity. These findings indicate enhanced sensory prediction for positive vocalizations such as laughter. Together, the results suggest that positive vocalizations are more effective predictors in social communication than angry and neutral ones, possibly due to their high social significance.

Does emotion change auditory prediction and deviance detection

In the last decades, a growing number of studies provided compelling evidence supporting the interplay of cognitive and affective processes. However, it remains to be clarified whether and how an emotional context affects the prediction and detection of change in unattended sensory events. In an event-related potential (ERP) study, we probed the modulatory role of pleasant, unpleasant and neutral visual contexts on the brain response to automatic detection of change in spectral (intensity) vs. temporal (duration) sound features. Twenty participants performed a passive auditory oddball task. Additionally, we tested the relationship between ERPs and self-reported mood. Participants reported more negative mood after the negative block. The P2 amplitude elicited by standards was increased in a positive context. Mismatch Negativity (MMN) amplitude was decreased in the negative relative to the neutral and positive contexts, and was associated with self-reported mood. These findings suggest that the detection of regularities in the auditory stream was facilitated in a positive context, whereas a negative visual context interfered with prediction error elicitation, through associated mood changes. Both ERP and behavioral effects highlight the intricate links between emotion, perception and cognitive processes.

Laughter catches attention

In social interactions, emotionally salient and sudden changes in vocal expressions attract attention. However, only a few studies examined how emotion and attention interact in voice processing. We investigated neutral, happy (laughs) and angry (growls) vocalizations in a modified oddball task. Participants silently counted the targets in each block and rated the valence and arousal of the vocalizations. A combined event-related potential and time-frequency analysis focused on the P3 and pre-stimulus alpha power to capture attention effects in response to unexpected events. Whereas an early differentiation between emotionally salient and neutral vocalizations was reflected in the P3a response, the P3b was selectively enhanced for happy voices. The P3b modulation was predicted by pre-stimulus frontal alpha desynchronization, and by the perceived pleasantness of the targets. These findings indicate that vocal emotions may be differently processed based on task relevance and valence. Increased anticipation and attention to positive vocal cues (laughter) may reflect their high social relevance.

QR codes and Java applied to physiological data acquisition in biomedical engineering education

A remote laboratory should meet the students’ pedagogical needs, and should be accessible anytime and anywhere. This work briefly describes a remote laboratory directed to biomedical engineering education, developed using LabVIEW software. The most apparent limitationin the use of LabVIEW is the inability to access from some technological platforms. Therefore, the present paper provides an overview of the workin progress and new developments, in a new remote laboratory, using an independent platform programming language – Java. Moreover, it is also presented new additional functionalities. For instance, the development of remote experiments supporting applications making use of augmented reality tools.

A virtual workbench applied to automation: student's response analysis

This paper presents a Virtual Workbench for Automation teaching/ learning at undergraduate education level. The methodology defined as well as the formalism and the software tools adopted in the implementation are presented. A case study is detailed following the defined steps. The platform was tested by students attending the Process Control and Automation curricular unit from the 3rd year of the Master in Engineering and Industrial Management of University of Minho. A questionnaire was design to gauge the undergraduate student’s acceptance and the platform’ effectiveness. The research found that the Virtual Workbench allows new strategies and teaching methodologies related with laboratorial practice providing illustrative real-world examples.

Ambient assisted living platform for remote monitoring of bedridden people

The aim of this paper is to present a platform for remote monitoring of bedridden people developed in the context of Ambient Assisted Living (AAL). This platform, Medical Care Terminal (MCT), includes the measurement of biomedical data (body temperature, galvanic skin resistance, electrocardiogram and electromyogram, level of oxygen, body position and breathing) as well environmental data (level of alcohol in the air, carbon monoxide level in the air, brightness and temperature). It presents three main issues, namely: it has a user-friendly interface; it is simple to use by a single elderly person; it can be adapted to the needs of a specific patient (custom-made solution), as the system can be configured in function of the measurements required for that specific patient (modular configuration). Finally, it is a low cost solution, affordable for low budget markets.

Assessing Remote Physiological Signals Acquisition Experiments

The authors are grateful to the FEDER funds through the Operational Programme for Competitiveness Factors - COMPETE and National Funds through FCT- Foundation for Science and Technology within the project FCOMP-01-0124- FEDER-022601 (ref. FCT PTDC/CPE-PEC/122329/2010) and to all the students for their voluntary cooperation and help in the evaluation of the remote lab experiments.

Students' perspectives on remote physiological signals acquisition experiments

Data acquisition of physiological signals is a very important issue since further health treatment depends on them. With recent developments in technology, new medical devices and new ways of monitoring and acquisition of physiological information emerge. So, not only medicals but also biomedical engineers must be prepared and aware of the characteristics and requirements needed. Following this tendency, this paper describes the developments of a remote lab for the study of biomedical and physiological systems in undergraduate and graduate level. The remote acquisition of ECG and body acceleration data was the experiments performed and evaluated by a group of biomedical engineering students. The experiments were conducted according to a protocol designed for the physiological data acquisition task. A pre and post questionnaires were applied to a group of students to obtain qualitative and quantitative evaluation to validate the remote experiment. The first results show a very positive attitude of the graduate students, motivating for further developments in this area.