In JoVE (1)

Other Publications (42)

Articles by Arcangelo Merla in JoVE

 JoVE Behavior

Using Fiberless, Wearable fNIRS to Monitor Brain Activity in Real-world Cognitive Tasks

1Department of Medical Physics and Biomedical Engineering, Malet Place Engineering Building, University College London, 2Infrared Imaging Lab, Institute for Advanced Biomedical Technology (ITAB), Department of Neuroscience, Imaging and Clinical Sciences, University of Chieti-Pescara, 3Institute of Cognitive Neuroscience, Alexandra House, University College London


JoVE 53336

Other articles by Arcangelo Merla on PubMed

Use of Infrared Functional Imaging to Detect Impaired Thermoregulatory Control in Men with Asymptomatic Varicocele

Fertility and Sterility. Jul, 2002  |  Pubmed ID: 12095517

Infrared Functional Imaging Applied to Raynaud's Phenomenon

IEEE Engineering in Medicine and Biology Magazine : the Quarterly Magazine of the Engineering in Medicine & Biology Society. Nov-Dec, 2002  |  Pubmed ID: 12613214

Quantifying the Relevance and Stage of Disease with the Tau Image Technique

IEEE Engineering in Medicine and Biology Magazine : the Quarterly Magazine of the Engineering in Medicine & Biology Society. Nov-Dec, 2002  |  Pubmed ID: 12613216

Assessment of the Effects of Varicocelectomy on the Thermoregulatory Control of the Scrotum

Fertility and Sterility. Feb, 2004  |  Pubmed ID: 14967396

Infrared functional imaging was successfully used to assess restoration of the normal thermal control of the scrotum after surgical treatment of varicoceles. The technique may be used to study the relationship between impaired scrotal thermoregulation and spermatogenesis.

Dynamics of Male Sexual Arousal: Distinct Components of Brain Activation Revealed by FMRI

NeuroImage. Jul, 2005  |  Pubmed ID: 15961048

The peripheral mechanisms of male sexual arousal are well known. Recently, neuroimaging techniques, such as PET or fMRI, allowed the investigation of the subjacent cerebral mechanisms. In ten healthy subjects, we have simultaneously recorded fMRI images of brain activation elicited by viewing erotic scenes, and the time course of penile tumescence by means of a custom-built MRI-compatible pneumatic cuff. We have compared activation elicited by video clips with a long duration, that led to sexual arousal and penile erection, and activation elicited by briefly presented still images, that did induce sexual arousal without erection. This comparison and the use of the time course of penile tumescence in video clips allowed to perform a time resolved data analysis and to correlate different patterns of brain activation with different phases of sexual response. The activation maps highlighted a complex neural circuit involved in sexual arousal. Of this circuit, only a few areas (anterior cingulate, insula, amygdala, hypothalamus, and secondary somatosensory cortices) were specifically correlated with penile erection. Finally, these areas showed distinct dynamic relationships with the time course of sexual response. These differences might correspond to different roles in the development and appraisal of the sexual response. These findings shed light on the psychophysiology of male sexuality and open new perspectives for the diagnosis, therapy, and possible rehabilitation of sexual dysfunction.

Field-warp Registration for Biomedical High-resolution Thermal Infrared Images

Conference Proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference. 2006  |  Pubmed ID: 17946013

Biomedical protocols based on thermal infrared images often require effective image registration. Algorithms specifically designed for registration of thermal images are hardly available and use of algorithms designed for other imaging techniques may result poorly reliable. In fact, registration algorithms developed for other biomedical images often require rigid-body assumption or limited range for intensity values. Such assumption may not be applicable for human body thermal images. Therefore, we present here an adaptation of a field-warp based method as a possible solution for thermal image registration. The method was applied for registering images taken from an experimental protocol aimed at comparing total body skin temperature distribution in natural or altered posture. The method appears to be effective into providing a reliable tool for objective intra and inter individual skin temperature distribution comparisons.

Erectile Dysfunction in Systemic Sclerosis: Effects of Longterm Inhibition of Phosphodiesterase Type-5 on Erectile Function and Plasma Endothelin-1 Levels

The Journal of Rheumatology. Aug, 2007  |  Pubmed ID: 17611982

To investigate the effects of prolonged inhibition of phosphodiesterase type-5, using once-daily long-acting phosphodiesterase type-5 inhibitor (tadalafil) on erectile function and biomarkers of endothelial function in male patients with systemic sclerosis (SSc) and erectile dysfunction (ED).

Contact-free Measurement of Cardiac Pulse Based on the Analysis of Thermal Imagery

IEEE Transactions on Bio-medical Engineering. Aug, 2007  |  Pubmed ID: 17694862

We have developed a novel method to measure human cardiac pulse at a distance. It is based on the information contained in the thermal signal emitted from major superficial vessels. This signal is acquired through a highly sensitive thermal imaging system. Temperature on the vessel is modulated by pulsative blood flow. To compute the frequency of modulation (pulse), we extract a line-based region along the vessel. Then, we apply fast Fourier transform (FFT) to individual points along this line of interest to capitalize on the pulse's thermal propagation effect. Finally, we use an adaptive estimation function on the average FFT outcome to quantify the pulse. We have carried out experiments on a data set of 34 subjects and compared the pulse computed from our thermal signal analysis method to concomitant ground-truth measurements obtained through a standard contact sensor (piezo-electric transducer). The performance of the new method ranges from 88.52% to 90.33% depending on the clarity of the vessel's thermal imprint. To the best of our knowledge, it is the first time that cardiac pulse has been measured several feet away from a subject with passive means.

Imaging Facial Signs of Neurophysiological Responses

IEEE Transactions on Bio-medical Engineering. Feb, 2009  |  Pubmed ID: 19272941

In the present paper, we introduce an integrated framework for detecting peripheral sympathetic responses through purely imaging means. The measurements are performed on three facial areas of sympathetic importance, that is, periorbital, supraorbital, and maxillary. To the best of our knowledge, this is the first time that the sympathetic importance of the maxillary area is analyzed. Because the imaging measurements are thermal in nature and are composed of multiple components of variable frequency (i.e., blood flow, sweat gland activation, and breathing), we chose wavelets as the image analysis framework. The measurements also carry substantial noise due to imperfections in tissue tracking and segmentation. The image analysis is grounded on galvanic skin response (GSR) signals, which are still considered the golden standard in peripheral neurophysiological and psychophysiological studies. The experimental results show that monitoring of the facial channels yields similar detecting power to GSR's. However, detailed quantification of the responses, although feasible in GSR through appropriate modeling, is quite difficult in the facial channels for the moment. Further improvements in facial tissue tracking and segmentation are bound to overcome this limitation. This paper opens a new research area that leads to unobtrusive screening technologies in neurophysiology and psychophysiology.

Finger Thermoregulatory Model Assessing Functional Impairment in Raynaud's Phenomenon

Annals of Biomedical Engineering. Dec, 2009  |  Pubmed ID: 19760147

Raynaud's Phenomenon (RP) is a paroxysmal vasospastic disorder of small arteries, pre-capillary arteries, and cutaneous arteriovenous shunts of the extremities, typically induced by cold exposure and emotional stress. RP is either primary (PRP) or secondary to systemic sclerosis. In this study we use Control System Theory to model finger thermoregulatory processes in response to a standardized cold challenge (a diagnostic test routinely performed for differential diagnosis of RP). The proposed model is based on a homeostatic negative feedback loop, characterized by five distinct parameters which describe how the control mechanisms are activated and maintained. Thermal infrared imaging data from 14 systemic sclerosis subjects (SSc), 14 PRP, and 16 healthy control subjects (HCS) were processed. HCS presented the fastest active recovery, with the highest gain. PRP presented the slowest and weakest recovery, mostly due to passive heat exchange with the environment. SSc presented an intermediate behavior, with the longest delay of response onset. The estimated model parameters elucidated the level of functional impairment expressed in the various forms of this disease.

Thermal Imaging of Cutaneous Temperature Modifications in Runners During Graded Exercise

Annals of Biomedical Engineering. Jan, 2010  |  Pubmed ID: 19798579

In this paper we used high-resolution thermal imaging to visualize the human whole body anterior cutaneous temperature (T(c)) variations in well-trained runners during graded exercise. Fifteen male volunteers underwent a graded treadmill test until reaching their individual maximal heart rate. Total body T(c) decreased as the subjects started the exercise. Thighs and forearms exhibited the earliest response. A further T(c) diminution occurred with the progress of the exercise. At the exercise interruption, T(c) values were in average 3-5 degrees C lower than at baseline. T(c) increased during recovery from exercise. Forearms and thighs exhibited the earliest increase, followed by total body T(c) increase. Thermal imaging documented the presence of hyperthermal spots (occasionally tree-shaped) due to the presence of muscle perforator vessels during baseline and recovery, but not during exercise. The results we report indicate that thermal infrared imaging permits the quantitative evaluation of specific cutaneous whole body thermal adaptations which occur during and after graded physical activity. Thus providing the basis for evaluating local and systemic cutaneous blood flow adaptation as a function of specific type, intensity and duration of exercise, and helping to determine the ideal conditions (in terms of environment and apparel) in which physical activities should be conducted in order to favor thermal regulatory processes.

Step-by-step: the Effects of Physical Practice on the Neural Correlates of Locomotion Imagery Revealed by FMRI

Human Brain Mapping. May, 2010  |  Pubmed ID: 19862697

Previous studies have shown that mental imagery is a suitable tool to study the progression of the effect of practice on brain activation. Nevertheless, there is still poor knowledge of changes in brain activation patterns during the very early stages of physical practice. In this study, early and late practice stages of different kinds of locomotion (i.e., balanced and unbalanced) have been investigated using functional magnetic resonance imaging during mental imagery of locomotion and stance. During the task, cardiac activity was also recorded. The cerebral network comprising supplementary motor area, basal ganglia, bilateral thalamus, and right cerebellum showed a stronger activation during the imagery of locomotion with respect to imagery of stance. The heart beat showed a significant increase in frequency during the imagery of locomotion with respect to the imagery of stance. Moreover, early stages of practice determined an increased activation in basal ganglia and thalamus with respect to late stages. In this way, it is proposed the modulation of the brain network involved in the imagery of locomotion as a function of physical practice time.

Postural Adjustment in Experimental Leg Length Difference Evaluated by Means of Thermal Infrared Imaging

Physiological Measurement. Jan, 2010  |  Pubmed ID: 19940346

Limb length discrepancy (LLD) is defined as a condition in which limbs are unequal. The asymmetric load of body segments secondary to LLD may cause a tonic contraction of back and lower limb muscles, thus resulting in subtle cutaneous temperature variations. The aim of this study was to test the capability of high-resolution thermal infrared (IR) imaging to measure the cutaneous temperature short-term adaptation, potentially associated with 'forced' LLD conditions. An experimental LLD, obtained by placing a 20 mm foot support under the dominant foot, was used. IR imaging on 18 male healthy volunteers was performed in three experimental conditions of standing position: (T(0)) neutral posture; (T(1)) experimental LLD; (T(2)) neutral posture as in T(0). Temperature variations were evaluated on the cutaneous projection of postural muscles bellies. Significant and specific temperature variations among conditions were ipsilaterally observed on the tibialis anterior, gastrocnemius, quadriceps and latissimus dorsi muscles. Specific patterns characterized the cutaneous temperature as a consequence of the muscle activity associated with the posture variation. IR imaging was able to highlight specific functional activations. The method is non-invasive and it can be repeated without any discomfort for the physiopathological and clinical evaluation of LLD patients.

Infrared Thermographic Evaluation of Temperature Modifications Induced During Implant Site Preparation with Cylindrical Versus Conical Drills

Clinical Implant Dentistry and Related Research. Dec, 2011  |  Pubmed ID: 19681941

A few studies have investigated the influence of drilling on bone healing. Many factors have been reported to influence temperature rise during surgical preparation for implant placement: drill geometry, drilling depth, sharpness of the cutting tool, drilling speed, pressure applied to the drill, use of graduated versus one-step drilling, intermittent versus continuous drilling, and use or not of irrigation.

Scrotal Thermoregulatory Model and Assessment of the Impairment of Scrotal Temperature Control in Varicocele

Annals of Biomedical Engineering. Feb, 2011  |  Pubmed ID: 20976556

Varicocele is defined as the pathological dilatation of the pampiniform plexus and scrotal veins with venous blood reflux. Varicocele may impair scrotal thermoregulation and spermatogenesis, even when present in asymptomatic forms. In this study, we use the control system theory to model scrotal thermoregulation in response to a standardized cold challenge in order to study the functional thermal impairment secondary to varicocele. The proposed model is based on a homeostatic negative feedback loop, characterized by four distinct parameters, which describe how the control mechanisms are activated and maintained. Thermal infrared images series from 49 young patients suffering from left varicocele and 17 healthy controls were processed. With respect to healthy controls, left varicocele patients presented higher basal scrotal temperature and faster recovery of the left hemiscrotum. The model indicated that varicocele alters local heat exchange processes among cutaneous layers and inner structures. The estimated model parameters help in the assessment of the scrotal thermoregulatory impairment secondary to the disease.

Situational and Dispositional Determinants of Intentional Deceiving

PloS One. 2011  |  Pubmed ID: 21559381

Does opportunity make the thief or are people dispositionally prone to deceive? The interaction between personality and the circumstances surrounding deception is crucial to understand what promotes dishonesty in our society. Due to its inherent spontaneity and sociality, deceptive behaviour may be hardly reproducible in experimental settings. We developed a novel paradigm in the form of an interactive game where participants can choose whether to lie to another person in situations of loss vs. gain, and of no-reputation-risk vs. reputation-risk linked to the disclosure of their deceptive behaviour to others. Thus, our ecological paradigm allowed subjects to spontaneously decide when to lie and face the challenge of deceiving others. In the case of loss, participants lied to reverse the outcome in their favour. Deception was lower in the reputation-risk condition where personality traits concerning social interactions also played an important role. The results suggest that deception is definitely promoted by unfavourable events, and that maintaining one's own reputation encourages honesty, particularly in socially inclined individuals.

Mother and Child in Synchrony: Thermal Facial Imprints of Autonomic Contagion

Biological Psychology. Jan, 2012  |  Pubmed ID: 22001267

Mothers' ability to empathically share offspring's emotional feelings is considered integral to primary affective bonds and a healthy socio-emotional development. What neurobiological mechanism is responsible for this ability in humans? It has been proposed that the psychological and neural components of affective experiences are strictly associated with autonomic-visceral changes. Hence, the vicarious response of empathy may also embody a sharing of changes in body physiology. The present study aimed at investigating whether maternal empathy is accompanied by a synchrony in autonomic responses. We simultaneously recorded, in an ecological context with contact free methodology, the facial thermal imprints of mother and child, while the former observed the latter when involved in a distressing situation. The results showed a situation-specific parallelism between mothers' and children's facial temperature variations, providing preliminary evidence for a direct affective sharing involving autonomic responding. These findings support a multidimensional approach for the comprehension of emotional parent-child relationships.

Non-invasive in Vivo Detection of Peripheral Limb Ischemia Improvement in the Rat After Adipose Tissue-derived Stromal Cell Transplantation

Circulation Journal : Official Journal of the Japanese Circulation Society. 2012  |  Pubmed ID: 22473453

Adipose tissue-derived stromal cells (ADSCs) might help repair ischemic cardiovascular tissue. Their in vivo effects on the bioenergetics and microcirculation of ischemic muscle through a variety of non-invasive techniques was examined.

The Role of Left Superior Parietal Lobe in Male Sexual Behavior: Dynamics of Distinct Components Revealed by FMRI

The Journal of Sexual Medicine. Jun, 2012  |  Pubmed ID: 22510246

Despite the interest for the brain correlates of male sexual arousal, few studies investigated neural mechanisms underlying psychogenic erectile dysfunction (ED). Although these studies showed several brain regions active in ED patients during visual erotic stimulation, the dynamics of inhibition of sexual response is still unclear.

Please Don't! The Automatic Extrapolation of Dangerous Intentions

PloS One. 2012  |  Pubmed ID: 23155444

Facial emotions and emotional body postures can easily grab attention in social communication. In the context of faces, gaze has been shown as an important cue for orienting attention, but less is known for other important body parts such as hands. In the present study we investigated whether hands may orient attention due to the emotional features they convey. By implying motion in static photographs of hands, we aimed at furnishing observers with information about the intention to act and at testing if this interacted with the hand automatic coding. In this study, we compared neutral and frontal hands to emotionally threatening hands, rotated along their radial-ulnar axes in a Sidedness task (a Simon-like task based on automatic access to body representation). Results showed a Sidedness effect for both the palm and the back views with either neutral and emotional hands. More important, no difference was found between the two views for neutral hands, but it emerged in the case of the emotional hands: faster reaction times were found for the palm than the back view. The difference was ascribed to palm views' "offensive" pose: a source of threat that might have raised participants' arousal. This hypothesis was also supported by conscious evaluations of the dimensions of valence (pleasant-unpleasant) and arousal. Results are discussed in light of emotional feature coding.

Fast Optical Signal in Visual Cortex: Improving Detection by General Linear Convolution Model

NeuroImage. Feb, 2013  |  Pubmed ID: 23110889

In this study we applied the General Linear Convolution Model to fast optical signals (FOS). We modeled the Impulse Response Function (IRF) as a rectangular function lasting 30ms, with variable time delay with respect to the stimulus onset. Simulated data confirmed the feasibility of this approach and its capability of detecting simulated activations in case of very unfavorable Signal to Noise Ratio (SNR), providing better results than the grand average method. The model was tested in a cohort of 10 healthy volunteers who underwent to hemi-field visual stimulation. Experimental data quantified the IRF time delay at 80-100ms after the stimulus onset, in agreement with classical visual evoked potential literature and previous optical imaging studies based on grand average approach and a larger number of trails. FOS confirmed the expected contralateral activation in the occipital region. Correlational analysis between hemodynamic intensity signal, phase and intensity FOS supports diffusive rather than optical absorption changes associated with neuronal activity in the activated cortical volume. Our study provides a feasible method for detecting fast cortical activations by means of FOS.

Studying Social Cognition Using Near-infrared Spectroscopy: the Case of Social Simon Effect

Journal of Biomedical Optics. Feb, 2013  |  Pubmed ID: 23416925

In order to understand the so-called "social brain," we need to monitor social interactions in face-to-face paradigms. Near-infrared spectroscopy (NIRS) is a promising technique to achieve this goal. We investigate the neuronal underpinnings of sharing a task in a proper social context. We record cortical activity by means of NIRS, while participants perform a joint Simon task. Different from other hemodynamic techniques, NIRS allows us to have both participants sit comfortably close to each other in a realistic and ecological environment. We found higher activation in the sensorimotor cortex while processing compatible trials as compared to incompatible ones referring to one's own action alternative. Strikingly, when the participant was not responding because it was the turn of the other member of the pair, the inferior parietal was activated. This study provides twofold findings: first, they suggest that the joint Simon effect relies more on shared attentional mechanisms than a proper mapping of the other's motor response. Second, they highlight the invaluable contribution NIRS can afford to social neuroscience in order to preserve ecological and naturalistic settings.

Effects of Viewing Affective Pictures on SEMG Activity of Masticatory and Postural Muscles

Neuroscience Letters. Jun, 2013  |  Pubmed ID: 23567744

Recently there has been an upsurge of interest in the question to what extent the human motor control system is influenced by the emotional state of the actor. The aim of this study was to evaluate whether emotional inputs modify the activity of masticatory and postural muscles. Twenty healthy young adults viewed affective pictures, while surface electromyography (sEMG) of masticatory and postural muscles was recorded to investigate the coupling between emotional reactions and body muscular activity. One hundred and twenty pictures, chosen from the International Affective Picture System (IAPS), divided in two blocks of six sets, were presented to the subjects. sEMG data were statistically analyzed (RM ANOVA on Ranks). Root Mean Square (RMS) amplitudes, comparing the subsequent sets (Neutral, Unpleasant, Neutral, Pleasant) with the first and the last Baseline set, changed significantly only randomly. The results show that emotional inputs seems not influence the activity of masticatory and postural muscles, recorded by sEMG.

The Body Beyond the Body: Expectation of a Sensory Event is Enough to Induce Ownership over a Fake Hand

Proceedings. Biological Sciences / The Royal Society. Aug, 2013  |  Pubmed ID: 23804622

More than 100 papers have been published on the rubber hand illusion since its discovery 14 years ago. The illusion has been proposed as a demonstration that the body is distinguished from other objects by its participation in specific forms of intermodal perceptual correlation. Here, we radically challenge this view by claiming that perceptual correlation is not necessary to produce the experience of this body as mine. Each of 15 participants was seated with his/her right arm resting upon a table just below another smaller table. Thus, the real hand was hidden from the participant's view and a life-sized rubber model of a right hand was placed on the small table in front of the participant. The participant observed the experimenter's hand while approaching--without touching--the rubber hand. Phenomenology of the illusion was measured by means of skin conductance response and questionnaire. Both measures indicated that participants experienced the illusion that the experimenter's hand was about to touch their hidden hand rather than the rubber hand, as if the latter replaced their own hand. This did not occur when the rubber hand was rotated by 180° or replaced by a piece of wood. This illusion indicates that our brain does not build a sense of self in a merely reactive way, via perceptual correlations; rather it generates predictions on what may or may not belong to itself.

Mom Feels What Her Child Feels: Thermal Signatures of Vicarious Autonomic Response While Watching Children in a Stressful Situation

Frontiers in Human Neuroscience. 2013  |  Pubmed ID: 23805091

Maternal attunement with an infant's emotional states is thought to represent a distinctive feature of the human primary bond. It implies the mother's ability of empathizing with her child in order to fulfil the child's needs in an immediate and appropriate manner. Thus, it is particularly involved in stressful situations. By assuming that maternal attunement embodies a direct sharing of physiological responses with the child, we compared the autonomic response of mothers observing their own distressed child with those of other women observing an unknown child involved in an ecological distressful condition (mishap paradigm). The hypothesis was that the adult's response was more attuned with the child's response in the former group than in the latter group. The autonomic response was non-invasively evaluated through the recording of the thermal facial imprints by means of thermal infrared (IR) imaging. Nine mother-child dyads and 9 woman-unknown child dyads were studied. We found marked similarities between the facial temperature dynamics of women and children along the experimental procedure, thus providing evidence for a direct emotional sharing within the adult-child dyad. The evidence for common dynamics in the time course of the temperatures was assessed through correlation analysis and, nevertheless, resulted stronger in the mother-child dyads than in the other women-child dyads. In addition, temporal analysis showed a faster response in mothers than in other women, thus confirming our study hypothesis. Besides confirming the extraordinary capability of IR imaging to preserve ecological context in the study of social or non-verbal interactions, these results suggest that maternity appears to potentiate the emotional attunement with the child. Although based on preliminary results, this study opens new perspectives in the study of the factors modulating vicarious socio-emotional processes.

Effects of Affective Picture Viewing on Postural Control in Healthy Male Subjects

Cranio : the Journal of Craniomandibular Practice. Jul, 2013  |  Pubmed ID: 23971161

Emotion theory holds that unpleasant events prime withdrawal actions, whereas pleasant events prime approach actions. Recent studies have suggested that passive viewing of emotion-eliciting images results in postural adjustments. The main objective of this research was to investigate the effects of emotional inputs on the postural control. Ten healthy young adults looked at a series of emotion-eliciting images while standing on a force plate. The images were taken from the International Affective Picture System (IAPS). The posture-stabilometric parameters were statistically analyzed (RM ANOVA on Ranks). The results showed that the emotional inputs might influence body balance.

Infant Cortex Responds to Other Humans from Shortly After Birth

Scientific Reports. 2013  |  Pubmed ID: 24092239

A significant feature of the adult human brain is its ability to selectively process information about conspecifics. Much debate has centred on whether this specialization is primarily a result of phylogenetic adaptation, or whether the brain acquires expertise in processing social stimuli as a result of its being born into an intensely social environment. Here we study the haemodynamic response in cortical areas of newborns (1-5 days old) while they passively viewed dynamic human or mechanical action videos. We observed activation selective to a dynamic face stimulus over bilateral posterior temporal cortex, but no activation in response to a moving human arm. This selective activation to the social stimulus correlated with age in hours over the first few days post partum. Thus, even very limited experience of face-to-face interaction with other humans may be sufficient to elicit social stimulus activation of relevant cortical regions.

Scleroderma Capillary Pattern Identification Using Texture Descriptors and Ensemble Classification

Conference Proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference. 2013  |  Pubmed ID: 24110975

Various connective tissue diseases lead to morphological alternations of blood capillaries. Consequently, observation of the capillaries at the finger nailfold - nailfold capillaroscopy (NC) - is a standard method for diagnosing diseases such as scleroderma or Raynaud's phenomenon. This is typically performed through manual inspection by an expert to lead to a determination of one of the established NC scleroderma patterns (early, active, and late). In this paper, we present an automated method of analysing nailfold capillaroscopy images and categorising them into NC patterns. For this purpose, we extract a carefully chosen set of texture features from the images and employ an ensemble classification approach to arrive at decisions for each captured finger which are then aggregated to form a diagnosis for the patient. Experimental results on a set of 60 NC images from 16 subjects demonstrate the accuracy and usefulness of our presented approach.

The Autonomic Signature of Guilt in Children: a Thermal Infrared Imaging Study

PloS One. 2013  |  Pubmed ID: 24260220

So far inferences on early moral development and higher order self conscious emotions have mostly been based on behavioral data. Emotions though, as far as arguments support, are multidimensional notions. Not only do they involve behavioral actions upon perception of an event, but they also carry autonomic physiological markers. The current study aimed to examine and characterise physiological signs that underlie self-conscious emotions in early childhood, while grounding them on behavioral analyses. For this purpose, the "mishap paradigm" was used as the most reliable method for evoking feelings of "guilt" in children and autonomic facial temperature variation were detected by functional Infrared Imaging (fIRI). Fifteen children (age: 39-42 months) participated in the study. They were asked to play with a toy, falsely informed that it was the experimenter's "favourite", while being unaware that it was pre-planned to break. Mishap of the toy during engagement caused sympathetic arousal as shown by peripheral nasal vasoconstriction leading to a marked temperature drop, compared to baseline. Soothing after the mishap phase induced an increase in nose temperature, associated with parasympathetic activity suggesting that the child's distress was neutralized, or even overcompensated. Behavioral analyses reported signs of distress evoked by the paradigm, backing up the thermal observation. The results suggest that the integration of physiological elements should be crucial in research concerning socio-emotional development. fIRI is a non invasive and non contact method providing a powerful tool for inferring early moral emotional signs based on physiological observations of peripheral vasoconstriction, while preserving an ecological and natural context.

Upcoming Tactile Events and Body Ownership in Schizophrenia

Schizophrenia Research. Jan, 2014  |  Pubmed ID: 23835002

Schizophrenic patients may report unusual perception of their own body. Studies using the rubber hand illusion (RHI) proposed that they exhibit a distorted sense of body ownership. However, since the RHI is mostly achieved with the contribution of visuo-tactile integration, the stronger RHI observed in schizophrenic patients could reflect either a general increase of the response to multisensory stimuli or a larger influence of visual cues on the tactile sensory experience. The purpose of the present study is to investigate patients' perception of their own body by means of a behavioral paradigm that measures their proneness to the RHI without relying on multisensory integration occurring during actual experience of touch. In a previous study we demonstrated in healthy participants that expectation of touch experience arising at the sight of a human hand approaching a rubber hand is enough to induce a sense of ownership over the same hand. Here we take advantage of the same paradigm to investigate body ownership in schizophrenia. Patients observed the experimenter's hand while approaching--without touching--either a rubber hand or a piece of wood placed in front of them. The seen object could be either aligned to participant's hand or rotated by 180°. Phenomenology of the illusion revealed that schizophrenic patients exhibited sense of ownership over the rubber hand, but more weakly than healthy controls. The present study sheds new light on the experience of body ownership in schizophrenic patients, corroborating the notion that alterations of bodily self-awareness play an important role in schizophrenia.

Fast Optical Signals in the Sensorimotor Cortex: General Linear Convolution Model Applied to Multiple Source-detector Distance-based Data

NeuroImage. Jan, 2014  |  Pubmed ID: 23867556

In this study, we applied the General Linear Convolution Model to detect fast optical signals (FOS) in the somatosensory cortex, and to study their dependence on the source-detector separation distance (2.0 to 3.5 cm) and irradiated light wavelength (690 and 830 nm). We modeled the impulse response function as a rectangular function that lasted 30 ms, with variable time delay with respect to the stimulus onset. The model was tested in a cohort of 20 healthy volunteers who underwent supra-motor threshold electrical stimulation of the median nerve. The impulse response function quantified the time delay for the maximal response at 70 ms to 110 ms after stimulus onset, in agreement with classical somatosensory-evoked potentials in the literature, previous optical imaging studies based on a grand-average approach, and grand-average based processing. Phase signals at longer wavelength were used to identify FOS for all the source-detector separation distances, but the shortest one. Intensity signals only detected FOS at the greatest distance; i.e., for the largest channel depth. There was no activation for the shorter wavelength light. Correlational analysis between the phase and intensity of FOS further confirmed diffusive rather than optical absorption changes associated with neuronal activity in the activated cortical volume. Our study demonstrates the reliability of our method based on the General Linear Convolution Model for the detection of fast cortical activation through FOS.

Exploring the Use of Thermal Infrared Imaging in Human Stress Research

PloS One. 2014  |  Pubmed ID: 24675709

High resolution thermal infrared imaging is a pioneering method giving indices of sympathetic activity via the contact-free recording of facial tissues (thermal imprints). Compared to established stress markers, the great advantage of this method is its non-invasiveness. The goal of our study was to pilot the use of thermal infrared imaging in the classical setting of human stress research. Thermal imprints were compared to established stress markers (heart rate, heart rate variability, finger temperature, alpha-amylase and cortisol) in 15 participants undergoing anticipation, stress and recovery phases of two laboratory stress tests, the Cold Pressor Test and the Trier Social Stress Test. The majority of the thermal imprints proved to be change-sensitive in both tests. While correlations between the thermal imprints and established stress markers were mostly non-significant, the thermal imprints (but not the established stress makers) did correlate with stress-induced mood changes. Multivariate pattern analysis revealed that in contrast to the established stress markers the thermal imprints could not disambiguate anticipation, stress and recovery phases of both tests. Overall, these results suggest that thermal infrared imaging is a valuable method for the estimation of sympathetic activity in the stress laboratory setting. The use of this non-invasive method may be particularly beneficial for covert recordings, in the study of special populations showing difficulties in complying with the standard instruments of data collection and in the domain of psychophysiological covariance research. Meanwhile, the established stress markers seem to be superior when it comes to the characterization of complex physiological states during the different phases of the stress cycle.

Thermal Infrared Imaging in Psychophysiology: Potentialities and Limits

Psychophysiology. Oct, 2014  |  Pubmed ID: 24961292

Functional infrared thermal imaging (fITI) is considered an upcoming, promising methodology in the emotional arena. Driven by sympathetic nerves, observations of affective nature derive from muscular activity subcutaneous blood flow as well as perspiration patterns in specific body parts. A review of 23 experimental procedures that employed fITI for investigations of affective nature is provided, along with the adopted experimental protocol and the thermal changes that took place on selected regions of interest in human and nonhuman subjects. Discussion is provided regarding the selection of an appropriate baseline, the autonomic nature of the thermal print, the experimental setup, methodological issues, limitations, and considerations, as well as future directions.

The Motor Cost of Telling Lies: Electrocortical Signatures and Personality Foundations of Spontaneous Deception

Social Neuroscience. 2014  |  Pubmed ID: 24979665

Although universal, lying is generally considered immoral behavior. Most neuroscience studies on lying sanction or instruct deceptive behaviors and thus might fail to acknowledge the significance of lie-related moral conflicts. By combining electroencephalogram (EEG) recordings with a novel paradigm in which participants decided freely whether to deceive another person, we have generated indices of the cognitive (reaction times and stimulus-locked event-related components) and moral (readiness potential and its correlations with deception-related personality traits) cost of spontaneous deception. Our data fail to support the consensus that deception is cognitively more demanding than truth telling, suggesting that spontaneous deception, as opposed to lying out of requirement, might not mandate additional cognitive workload. Interestingly, lying was associated with decreased motor readiness, an event-related potential (ERP) component that is linked to motor preparation of self-determined actions and modulated when we face moral dilemmas. Notably, this reduction was less extensive in manipulative participants and greater in those who cared highly about their impression management. Our study expands on previous findings on deception by associating a cortical marker of reduced preparation to act with individual differences in moral cognition.

Thermal Expression of Intersubjectivity Offers New Possibilities to Human-machine and Technologically Mediated Interactions

Frontiers in Psychology. 2014  |  Pubmed ID: 25101046

The evaluation of the psychophysiological state of the interlocutor is an important element of interpersonal relationships and communication. Thermal infrared (IR) imaging has proved to be a reliable tool for non-invasive and contact-less evaluation of vital signs, psychophysiological responses, and emotional states. This technique is quickly spreading in many fields, from psychometrics to social and developmental psychology; and from the touch-less monitoring of vital signs and stress, up to the human-machine interaction. In particular, thermal IR imaging promises to be of use for gathering information about affective states in social situations. This paper presents the state of the art of thermal IR imaging in psychophysiology and in the assessment of affective states. The goal is to provide insights about its potentialities and limits for its use in human-artificial agent interaction in order to contribute to a major issue in the field: the perception by an artificial agent of human psychophysiological and affective states.

Time-domain Analysis of Scrotal Thermoregulatory Impairment in Varicocele

Frontiers in Physiology. 2014  |  Pubmed ID: 25278903

Varicocele is a common male disease defined as the pathological dilatation of the pampiniform plexus and scrotal veins with venous blood reflux. Varicocele usually impairs the scrotal thermoregulation via a hemodynamic alteration, thus inducing an increase in cutaneous temperature. The investigation of altered scrotal thermoregulation by means of thermal infrared imaging has been proved to be useful in the study of the functional thermal impairment. In this study, we use the Control System Theory to analyze the time-domain dynamics of the scrotal thermoregulation in response to a mild cold challenge. Four standard time-domain dynamic parameters of a prototype second order control system (Delay Time, Rise Time, closed poles locations, steady state error) and the static basal temperatures were directly estimated from thermal recovery curves. Thermal infrared imaging data from 31 healthy controls (HCS) and 95 varicocele patients were processed. True-positive predictions, by comparison with standard echo color Doppler findings, higher than 87% were achieved into the proper classification of the disease stage. The proposed approach could help to understand at which specific level the presence of the disease impacts the scrotal thermoregulation, which is also involved into normal spermatogenesis process.

Functional-thermoregulatory Model for the Differential Diagnosis of Psoriatic Arthritis

Biomedical Engineering Online. 2014  |  Pubmed ID: 25494626

Psoriasis arthritis (PsA) is a chronic inflammatory arthritis of joints of uncertain pathogenesis. PsA may lead to severe disabilities even in the absence of any clinical symptom. Therefore, PsA diagnosis in its early stages is critical.

Assessing Embodied Interpersonal Emotion Regulation in Somatic Symptom Disorders: a Case Study

Frontiers in Psychology. 2015  |  Pubmed ID: 25713544

The aim of the present study was to examine the intra- and interpersonal emotion regulation of patients with somatic symptom disorders (SSDs) during interactions with significant others (i.e., romantic partners). We presented two case couples for analysis. The first couple consisted of a patient with SSD and his healthy partner, whereas the second couple consisted of two healthy partners. The couples underwent an interpersonal experiment that involved baseline, anger and relaxation tasks. During each task, partners' cutaneous facial temperature, heart rate and skin conductance levels were measured simultaneously. Participants' trait-emotion regulation, state-affect reports for self and other, and attachment styles were also examined. The experimental phases were successful in creating variations in physiological processes and affective experience. As expected, emotion regulation difficulties predicted higher increase in the course of temperature at each phase. Besides, the patient showed restricted awareness and reflection to emotions despite his higher autonomic activity compared to healthy controls. Both partners of the first couple revealed limited ability in understanding the other's emotions, whereas the second couple performed relatively better in that domain. The temperature variations between the patient and his partner were significantly correlated while the correlations of temperature changes between the second couple were negligible except anger task. The study supported the merits of an embodied interpersonal approach in clinical studies. The tentative results of the cases were discussed in the light of findings in emotion regulation and attachment research.

The Devil is in the Detail: Brain Dynamics in Preparation for a Global-local Task

Journal of Cognitive Neuroscience. Aug, 2015  |  Pubmed ID: 25761005

When analyzing visual scenes, it is sometimes important to determine the relevant "grain" size. Attention control mechanisms may help direct our processing to the intended grain size. Here we used the event-related optical signal, a method possessing high temporal and spatial resolution, to examine the involvement of brain structures within the dorsal attention network (DAN) and the visual processing network (VPN) in preparation for the appropriate level of analysis. Behavioral data indicate that the small features of a hierarchical stimulus (local condition) are more difficult to process than the large features (global condition). Consistent with this finding, cues predicting a local trial were associated with greater DAN activation. This activity was bilateral but more pronounced in the left hemisphere, where it showed a frontal-to-parietal progression over time. Furthermore, the amount of DAN activation, especially in the left hemisphere and in parietal regions, was predictive of subsequent performance. Although local cues elicited left-lateralized DAN activity, no preponderantly right activity was observed for global cues; however, the data indicated an interaction between level of analysis (local vs. global) and hemisphere in VPN. They further showed that local processing involves structures in the ventral VPN, whereas global processing involves structures in the dorsal VPN. These results indicate that in our study preparation for analyzing different size features is an asymmetric process, in which greater preparation is required to focus on small rather than large features, perhaps because of their lesser salience. This preparation involves the same DAN used for other attention control operations.

Thermal Infrared Imaging-Based Computational Psychophysiology for Psychometrics

Computational and Mathematical Methods in Medicine. 2015  |  Pubmed ID: 26339284

Thermal infrared imaging has been proposed as a potential system for the computational assessment of human autonomic nervous activity and psychophysiological states in a contactless and noninvasive way. Through bioheat modeling of facial thermal imagery, several vital signs can be extracted, including localized blood perfusion, cardiac pulse, breath rate, and sudomotor response, since all these parameters impact the cutaneous temperature. The obtained physiological information could then be used to draw inferences about a variety of psychophysiological or affective states, as proved by the increasing number of psychophysiological studies using thermal infrared imaging. This paper presents therefore a review of the principal achievements of thermal infrared imaging in computational physiology with regard to its capability of monitoring psychophysiological activity.

Behavioral and Facial Thermal Variations in 3-to 4-month-old Infants During the Still-Face Paradigm

Frontiers in Psychology. 2015  |  Pubmed ID: 26528229

Behavioral and facial thermal responses were recorded in twelve 3- to 4-month-old infants during the Still-Face Paradigm (SFP). As in the usual procedure, infants were observed in a three-step, face-to-face interaction: a normal interaction episode (3 min); the "still-face" episode in which the mother became unresponsive and assumed a neutral expression (1 min); a reunion episode in which the mother resumed the interaction (3 min). A fourth step that consisted of a toy play episode (5 min) was added for our own research interest. We coded the behavioral responses through the Infant and Caregiver Engagement Phases system, and recorded facial skin temperature via thermal infrared (IR) imaging. Comparing still-face episode to play episode, the infants' communicative engagement decreased, their engagement with the environment increased, and no differences emerged in self-regulatory and protest behaviors. We also found that facial skin temperature increased. For the behavioral results, infants recognized the interruption of the interactional reciprocity caused by the still-face presentation, without showing upset behaviors. According to autonomic results, the parasympathetic system was more active than the sympathetic, as usually happens in aroused but not distressed situations. With respect to the debate about the causal factor of the still-face effect, thermal data were consistent with behavioral data in showing this effect as related to the infants' expectations of the nature of the social interactions being violated. Moreover, as these are associated to the infants' subsequent interest in the environment, they indicate the thermal IR imaging as a reliable technique for the detection of physiological variations not only in the emotional system, as indicated by research to date, but also in the attention system. Using this technique for the first time during the SFP allowed us to record autonomic data in a more ecological manner than in previous studies.

"The Face of Ostracism": The Impact of the Social Categorization on the Thermal Facial Responses of the Target and the Observer

Acta Psychologica. Nov, 2015  |  Pubmed ID: 26613387

Ostracism has been shown to elicit pain in both the target and the observers. Two experiments investigated the autonomic thermal signature associated with an ostracism experience and assessed whether and how social categorization impacts the autonomic arousal of both the target and the observer. Autonomic response was assessed using thermal infrared imaging, recording facial temperature variation during an online game of ball toss (i.e., Cyberball). Social categorization was manipulated using a minimal group paradigm. The results show a more intense autonomic response during ostracism (vs. inclusion), marked by an increase in facial temperature in the nose and the perioral area. This autonomic response is stronger when individuals are ostracized by ingroup (vs. outgroup) members. Similar pattern of temperature variations emerge when individuals observe an ostracism episode involving ingroup members. Our findings advance the understanding of psycho-physiological mechanisms underlying the ostracism experience and emphasize the impact of social categorization in such mechanisms.

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