Biomedical subjects

Marco Tamietto

Publications and source records attributed to Marco Tamietto.

8 recordsLinked to original sources

PubMed2006

Fast recognition of social emotions takes the whole brain: interhemispheric cooperation in the absence of cerebral asymmetry.

Hemispheric asymmetry in emotional perception has been traditionally studied for basic emotions and very little is known about laterality for more complex social emotions. Here, we used the "redundant target paradigm" to investigate interhemispheric asymmetry and cooperation for two social emotions in healthy subjects. Facial expressions of flirtatiousness or arrogance were briefly presented either unilaterally in the left (LVF) or right visual field (RVF), or simultaneously to both visual fields (BVF) while participants responded to the target expression (flirtatious or arrogant, counterbalanced between blocks). In bilateral conditions the faces could show the same emotion (congruent condition) or two different expressions (incongruent condition). No difference between unilateral presentations was found, suggesting that the perception of social emotions is not hemispherically lateralized. Responses were faster and more accurate in bilateral displays with two emotionally congruent but physically different faces (i.e., a male and a female expressing the same emotion) than in unilateral conditions. This "redundant target effect" was consistent with a neural summation model, thereby showing that interhemispheric cooperation may occur for social emotions despite major perceptual differences between faces posing the same expression.

Adult↗

PubMed2006

Beyond the face: exploring rapid influences of context on face processing.

Humans optimize behavior by deriving context-based expectations. Contextual data that are important for survival are extracted rapidly, using coarse information, adaptive decision strategies, and dedicated neural infrastructure. In the field of object perception, the influence of a surrounding context has been a major research theme, and it has generated a large literature. That visual context, as typically provided by natural scenes, facilitates object recognition as has been convincingly demonstrated (Bar, M. (2004) Nat. Rev. Neurosci., 5: 617-629). Just like objects, faces are generally encountered as part of a natural scene. Thus far, the facial expression literature has neglected such context and treats facial expressions as if they stand on their own. This constitutes a major gap in our knowledge. Facial expressions tend to appear in a context of head and body orientations, body movements, posture changes, and other object-related actions with a similar or at least a closely related meaning. For instance, one would expect a frightened face when confronted to an external danger to be at least accompanied by withdrawal movements of head and shoulders. Furthermore, some cues provided by the environment or the context in which a facial expression appears may have a direct relation with the emotion displayed by the face. The brain may even fill in the natural scene context typically associated with the facial expression. Recognition of the facial expression may also profit from processing the vocal emotion as well as the emotional body language that normally accompany it. Here we review the emerging evidence on how the immediate visual and auditory contexts influence the recognition of facial expressions.

Electroencephalography↗

PubMed2006

Visual experience is not necessary for efficient survey spatial cognition: evidence from blindness.

This study investigated whether the lack of visual experience affects the ability to create spatial inferential representations of the survey type. We compared the performance of persons with congenital blindness and that of blindfolded sighted persons on four survey representation-based tasks (Experiment 1). Results showed that persons with blindness performed better than blindfolded sighted controls. We repeated the same tests introducing a third group of persons with late blindness (Experiment 2). This last group performed better than blindfolded sighted participants, whereas differences between participants with late and congenital blindness were nonsignificant. The present findings are compatible with results of other studies, which found that when visual perception is lacking, skill in gathering environmental spatial information provided by nonvisual modalities may contribute to a proper spatial encoding. It is concluded that, although it cannot be asserted that total lack of visual experience incurs no cost, our findings are further evidence that visual experience is not a necessary condition for the development of spatial inferential complex representations.

Adult↗

PubMed2006

Unawareness in schizophrenia: neuropsychological and neuroanatomical findings.

The lack of insight in schizophrenia has so far been interpreted as a primary symptom of the illness, namely a defensive mechanism rather than a neurologically-based condition. However, recent findings have emphasized its relationship with damage to specific brain areas as well as the domain specificity in which it may occur. This supports a neuropsychological interpretation of the lack of insight in schizophrenia. The present article reviews the foregoing data, and takes into account the most relevant anatomo-clinical results. There is evidence that the lack of insight in schizophrenia may occur as a neurological disease per se following brain damage that seems related to frontal lobe areas. Additionally, it could either be related to all aspects of the disease or be domain-specific, occurring for one kind of symptom but not for others. These data indicate several analogies with the phenomenon called anosognosia for a neurological deficit.

Awareness↗

PubMed2006

To drive or not to drive (after TBI)? A review of the literature and its implications for rehabilitation and future research.

Development of reliable procedures to assess fitness to safe driving after traumatic brain injury (TBI) is a crucial step in rehabilitation. However, prior studies are highly inconsistent in the choice of measures recommended for predicting driving fitness from different pre-driving measures. In the present paper the relevant literature is reviewed with the aim of shedding light on the reasons for these inconsistencies. The discrepant results reflect investigative choices which differ in five aspects: (1) the type of predictors used as pre-driving screening; (2) the type of measures considered as the criterion for the determination of fitness to drive after TBI; (3) the severity of the TBI in the sample of patients studied; (4) the extent of the neural structures damaged by TBI and the overlap of these areas with those involved in driving tasks; (5) the length of the follow-up considered. The strengths and weaknesses of the different methods and measures are discussed with their implications for future research and clinical rehabilitation. Encouraging findings come from recent studies that combined together medical, psychosocial, and personality measures, thereby improving the explanatory power of the predictors used. The use of post-injury driving fitness measures with great ecological and external validity seems equally promising in assessing actual driving in the real world.

Automobile Driving↗

PubMed2005

Functional asymmetry and interhemispheric cooperation in the perception of emotions from facial expressions.

The present study used the redundant target paradigm on healthy subjects to investigate functional hemispheric asymmetries and interhemispheric cooperation in the perception of emotions from faces. In Experiment 1 participants responded to checkerboards presented either unilaterally to the left (LVF) or right visual half field (RVF), or simultaneously to both hemifields (BVF), while performing a pointing task for the control of eye movements. As previously reported (Miniussi et al. in J Cogn Neurosci 10:216-230, 1998), redundant stimulation led to shorter latencies for stimulus detection (bilateral gain or redundant target effect, RTE) that exceeded the limit for a probabilistic interpretation, thereby validating the pointing procedure and supporting interhemispheric cooperation. In Experiment 2 the same pointing procedure was used in a go/no-go task requiring subjects to respond when seeing a target emotional expression (happy or fearful, counterbalanced between blocks). Faster reaction times to unilateral LVF than RVF emotions, regardless of valence, indicate that the perception of positive and negative emotional faces is lateralized toward the right hemisphere. Simultaneous presentation of two congruent emotional faces, either happy or fearful, produced an RTE that cannot be explained by probability summation and suggests interhemispheric cooperation and neural summation. No such effect was present with BVF incongruent facial expressions. In Experiment 3 we studied whether the RTE for emotional faces depends on the physical identity between BVF stimuli, and we set a second BVF congruent condition in which there was only emotional but not physical or gender identity between stimuli (i.e. two different faces expressing the same emotion). The RTE and interhemispheric cooperation were present also in this second BVF congruent condition. This shows that emotional congruency is the sufficient condition for the RTE to take place in the intact brain and that the cerebral hemispheres can interact in spite of physical differences between stimuli.

Adult↗

PubMed2005

Role of premorbid factors in predicting safe return to driving after severe TBI.

PRIMARY OBJECTIVE: The present study explored the possibility of predicting post-injury fitness to safe driving in patients with severe traumatic brain injury (TBI) (n = 66). METHODS AND PROCEDURE: Sixteen different measures, derived from four domains (demo/biographic, medico-functional, neuropsychological, and psychosocial) were used as predictor variables, whereas driving outcomes were assessed in terms of driving status (post-TBI drivers versus non-drivers) and driving safety (number of post-TBI car accidents and violations). MAIN OUTCOMES AND RESULTS: About 50% of the patients resumed driving after TBI. Compared to post-TBI non-drivers, post-injury drivers had shorter coma duration. With regard to driving safety, the final multiple regression model combined four predictors (years post-injury, accidents and violations before TBI, pre-TBI-risky-personality-index, and pre-TBI-risky-driving-style-index) and explained 72.5% of variance in the outcome measure. CONCLUSIONS: Since the best three predictors of post-injury driving safety addressed patients' premorbid factors, the results suggest that in order to evaluate the actual possibility of safe driving after TBI, it would be advisable to consider carefully patients' pre-TBI histories.

Accidents, Traffic↗

PubMed2005

Effects of emotional face cueing on line bisection in neglect: a single case study.

One patient with left neglect (FM) and four right brain-damaged controls were tested on a line bisection task with pictures of neutral and emotional faces as unilateral cues. We thus manipulated the attentional salience of the cues (higher for emotional and lower for neutral faces) while keeping constant their physical dimensions. Our findings showed that left emotional faces were more effective than left neutral faces in reducing bisection errors only in FM. These data indicate that in the neglected hemispace cues bias attention rather than simply altering the perceptual point of balance of the line in the horizontal plane.

Aged↗