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Biomedical subjects

S Campanella

Publications and source records attributed to S Campanella.

18 recordsLinked to original sources
PubMed2007

Is the P300 deficit in alcoholism associated with early visual impairments (P100, N170)? An oddball paradigm.

OBJECTIVE: Studies exploring chronic alcoholism with event-related potentials (ERPs) have shown delayed latency and reduced amplitude of the P300, a long-lasting positive potential reflecting decisional processing. This P300 deficit in alcoholism is generally interpreted as a disturbance in central nervous system inhibition or in memory/attention. The present study aimed at identifying if this electrophysiological deficit is already present on earlier components, and advances a new hypothesis concerning the interpretation of the P300 alteration. METHODS: Patients suffering from alcoholism and matched healthy controls had to detect, in an oddball paradigm, emotional faces among a succession of neutral faces. Behavioral performance and ERP data (recorded from 32 electrodes) were analyzed. RESULTS: In line with previous studies, data showed that alcoholism led to a P300 deficit. Moreover, we observed for the first time that this deficit begins at earlier visual (P100) and face-processing (N170) stages, and we found high positive correlations between P100, N170 and P300 for amplitude and latency values, suggesting cumulative deficits on the cognitive continuum. CONCLUSIONS: We suggest that the P300 deficit observed in chronic alcoholism could be linked to earlier visuo-spatial deficits rather than being an impairment of the specific processes linked to the P300. SIGNIFICANCE: These results call for reconsidering the interpretation of P300 impairments at a fundamental and clinical level, and shows that earlier ERP components must be taken into account in future studies.

Alcoholism↗
PubMed2006

Early visual components (P100, N170) are disrupted in chronic schizophrenic patients: an event-related potentials study.

INTRODUCTION: On the basis of the Positive and Negative Syndrome Scale (PANSS), fourteen schizophrenic patients and 7 normal controls were confronted with pictures from the Ekman & Friesen series in an event-related potentials study. PROCEDURE: Participants were confronted with a visual face-detection task, in which they had to detect, as quickly as possible, deviant faces amongst a train of standard stimuli (neutral faces). Deviant faces changed either on identity (different identity, neutral expression), or on emotion (same identity, happy, fearful or sad expression). RESULTS: Schizophrenics exhibited a decrease in amplitude of the face N170, recorded around 170 ms at occipito-temporal sites; this was observed as well for emotional as for identity faces, which suggests a global involvement of face processing. Moreover, this decrease of the face-N170 was positively correlated to positive, but not negative, symptoms of schizophrenia. Finally, the amplitude of P100 was also decreased, which suggests that the N170 decrement would result from a more global deficit in visual processing deficit. DISCUSSION: It is suggested that, in schizophrenics, an involvement of early visual processing might underlie the decreased amplitudes and the higher onset latencies of later P300 and N400 components.

Adult↗
PubMed2005

Emotional deficit in subjects with psychopathic tendencies as assessed by the Minnesota Multiphasic Personality Inventory-2: an event-related potentials study.

On the basis of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2), 20 male students were separated in low (LP) versus high (HP) subjects with psychopathic tendencies. Pictures from the Ekman and Friesen series were used in an event-related potentials study to investigate the neurophysiological correlates of the emotional deficit described in psychopathy. Subjects were confronted with a visual oddball design, in which they had to detect, as quickly as possible, deviant happy, sad or fearful faces amongst a train of standard stimuli (neutral faces). Behavioral results suggest that LP subjects are more efficient in the detection of emotional deviant faces. This emotional deficit was neurophysiologically indexed, in HP subjects, by a decreased N300 component, which is supposed to be particularly sensitive to affective features of stimuli rather than to physical characteristics. Moreover, independently of the nature of the deviant faces, the P3a component shows an earlier latency in the HP group as compared to the LP group, whereas the reversed pattern was shown for the P3b component. Implications of these results were discussed.

Antisocial Personality Disorder↗
PubMed2005

The perception of fearful and happy facial expression is modulated by anxiety: an event-related potential study.

Anxiety is supposed to interfere with cognitive and emotional processing and high level of trait-anxiety has been associated with an attentional bias for fearful faces, even in sub-clinical anxiety. On the basis of the Spielberger State and Trait Anxiety Inventory (STAI), twenty students were grouped as low vs. high anxious. Pictures from the Ekman and Friesen series were used in an event-related potentials study to investigate the neurophysiological correlates of the emotional processing of fear and happiness in sub-clinical anxiety. Subjects were confronted with a visual oddball design, in which they had to detect, as quickly as possible, deviant happy or fearful faces amongst a train of standard stimuli (neutral faces). Anxiety does not modify early perceptual (N100, P100, N170, VPP) or attentional (N2b) component, but later components are affected. Indeed, high anxious subjects are faster to detect deviant faces as suggested by earlier reaction times and P3b component. However, they show a reduced ability to process the emotional content of faces, this deficit being indexed by a decreased N300 component. Indeed, N300 is supposed to be particularly sensitive to affective features of stimuli rather than to physical characteristics. We propose that the earlier P3b observed in high anxious subjects could be interpreted as a way to overcome the deficient emotional appraisal by a more salient conscious processing.

Adult↗
PubMed2005

Event-related potentials (ERPs) in ecstasy (MDMA) users during a visual oddball task.

Ecstasy is the common name for a drug mainly containing a substance identified as 3,4-methylenedioxymethamphetamine (MDMA). It has become popular with participants in "raves", because it enhances energy, endurance and sexual arousal, together with the widespread belief that MDMA is a safe drug [Byard, R.W., Gilbert, J., James, R., Lokan, R.J., 1998. Amphetamine derivative fatalities in South Australia. Is "ecstasy" the culprit? Am. J. Forensic Med. Pathol. 19, 261-265]. However, it is suggested that this drug causes a neurotoxicity to the serotonergic system that could lead to permanent physical and cognitive problems. In order to investigate this issue, and during an ERP recording with 32 channels, we used a visual oddball design, in which subjects (14 MDMA abusers and 14 paired normal controls) saw frequent stimuli (neutral faces) while they had to detect as quickly as possible rare stimuli with happy or fearful expression. At a behavioral level, MDMA users imply longer latencies than normal controls to detect rare stimuli. At the neurophysiological level, ERP data suggest as main result that the N200 component, which is involved in attention orienting associated to the detection of stimulus novelty (e.g. [Campanella, S., Gaspard, C., Debatisse, D., Bruyer, R., Crommelinck, M., Guerit, J.M., 2002. Discrimination of emotional facial expression in a visual oddball task: an ERP study. Biol. Psychol. 59, 171-186]), shows shorter latencies for fearful rare stimuli (as compared to happy ones), but only for normal controls. This absence of delay was interpreted as an attentional deficit due to MDMA consumption.

Adult↗
PubMed2004

When audition alters vision: an event-related potential study of the cross-modal interactions between faces and voices.

Ten healthy volunteers took part in this event-related potential (ERP) study aimed at examining the electrophysiological correlates of the cross-modal audio-visual interactions in an identification task. Participants were confronted either to the simultaneous presentation of previously learned faces and voices (audio-visual condition; AV), either to the separate presentation of faces (visual, V) or voices (auditive, A). As expected, an interference effect of audition on vision was observed at a behavioral level, as the bimodal condition was performed more slowly than the visual condition. At the electrophysiological level, the subtraction (AV - (A + V)) gave prominence to three distinct cerebral activities: (1) a central positive/posterior negative wave around 110 ms, (2) a central negative/posterior positive wave around 170 ms, AND (3) a central positive wave around 270 ms. These data suggest that cross-modal cerebral interactions could be independent of behavioral facilitation or interference effects. Moreover, the implication of unimodal and multisensory convergence regions in these results, as suggested by a source localization analysis, is discussed.

Acoustic Stimulation↗
PubMed2004

Human gender differences in an emotional visual oddball task: an event-related potentials study.

Pictures from the Ekman and Friesen series were used in an event-related potentials study to define the timing of occurrence of gender differences in the processing of positive (happy) and negative (fear) facial expressions. Ten male and 10 female volunteers were confronted with a visual oddball design, in which they had to detect, as quickly as possible, deviant happy or fearful faces amongst a train of standard stimuli (neutral faces). Behavioral results suggest that men and women detected fearful faces more quickly than happy ones. The main result is that the N2b component, functionally considered as an attentional orienting mechanism, was delayed in men for happy stimuli as compared with fearful ones. Gender differences observed in the processing of emotional stimuli could then originate at the attentional level of the information processing system.

Adult↗
PubMed2004

The electrophysiological correlates sustaining the retrieval of face-name associations: an ERP study.

An ERP study on 9 healthy participants was carried out to temporally constrain the neural network proposed by Campanella et al. (2001) in a PET study investigating the cerebral areas involved in the retrieval of face-name associations. Three learning sessions served to familiarize the participants with 24 face-name associations grouped in 12 male/female couples. During EEG recording, participants were confronted with four experimental conditions, requiring the retrieval of previously learned couples on the basis of the presentation of name-name (NN), face-face (FF), name-face (NF), or face-name (FN) pairs of stimuli. The main analysis of this experiment consisted in the subtraction of the nonmixed conditions (NN and FF) from the mixed conditions (NF and FN). It revealed two main ERP components: a negative wave peaking at left parieto-occipital sites around 285 ms and its positive counterpart recorded at left centro-frontal electrodes around 300 ms. Moreover, a dipole modeling using three dipoles whose localization corresponded to the three cerebral areas observed in the PET study (left inferior frontal gyrus, left medial frontal gyrus, left inferior parietal lobe) explained more than 90% of the variance of the results. The complementarity between anatomical and neurophysiological techniques allowed us to discuss the temporal course of these cerebral activities and to propose an interactive and original anatomo-temporal model of the retrieval of face-name associations.

Adult↗
PubMed2004

Treatment of severe epistaxis by superselective embolization: a review of 22 cases.

OBJECTIVES: Epistaxis represents one of the most common ENT emergencies. In this paper, the authors report their experience in treating some cases of severe epistaxis by super-selective embolization of the afferent vessels of the nasal fossae. PATIENTS AND METHODS: A retrospective study of 22 patients with severe recurrent epistaxis (1 anterior and 21 posterior). All patients had been treated unsuccessfully with repeated anteroposterior nasal packing, and presented significant secondary anaemia. Selective embolization procedures were performed under local anaesthesia. An arterial introducer is inserted into the femoral artery -generally the right one- and diagnosis as well as treatment are performed with the same guide catheter. In all cases, the terminal branches of the facial artery and of the internal maxillary artery on the side on which the haemorrhage occurred were embolized. Moreover the contralateral internal maxillary artery was always embolized as well, in order to prevent immediate recurrence of hypervascularisation of the mucosa through anastomotic paths. RESULTS: In all patients, complete devascularisation was achieved in the areas of the embolized arteries at the nasal mucous membranes, arresting the epistaxis. None of the cases experienced complications attributable to treatment. DISCUSSION AND CONCLUSION: Superselective arteriography with embolization can be considered as the method of choice in treating severe epistaxis because it can be performed under local anaesthesia and can easily be repeated if the first procedure is not successful. Moreover, it is at least as effective as ligation of the internal maxillary artery, if not more so, but it has a significantly lower complication rate which is destined to fall as the quality of the materials being used continues to improve.

Adult↗
PubMed2002

Categorical perception of happiness and fear facial expressions: an ERP study.

Behavioral studies have shown that two different morphed faces perceived as reflecting the same emotional expression are harder to discriminate than two faces considered as two different ones. This advantage of between-categorical differences compared with within-categorical ones is classically referred as the categorical perception effect. The temporal course of this effect on fear and happiness facial expressions has been explored through event-related potentials (ERPs). Three kinds of pairs were presented in a delayed same-different matching task: (1) two different morphed faces perceived as the same emotional expression (within-categorical differences), (2) two other ones reflecting two different emotions (between-categorical differences), and (3) two identical morphed faces (same faces for methodological purpose). Following the second face onset in the pair, the amplitude of the bilateral occipito-temporal negativities (N170) and of the vertex positive potential (P150 or VPP) was reduced for within and same pairs relative to between pairs. This suggests a repetition priming effect. We also observed a modulation of the P3b wave, as the amplitude of the responses for the between pairs was higher than for the within and same pairs. These results indicate that the categorical perception of human facial emotional expressions has a perceptual origin in the bilateral occipito-temporal regions, while typical prior studies found emotion-modulated ERP components considerably later.

Adult↗
PubMed2002

Discrimination of emotional facial expressions in a visual oddball task: an ERP study.

Several ERP studies have shown an orienting complex, the N2/P3a, associated to the detection of stimulus novelty. Its role consists in preparing the organism to process and react to biologically prepotent stimuli. Whether this N2/P3a: (1) could be obtained with complex visual stimuli, such as with emotional facial expressions; and (2) could take part in a complex discrimination process has yet to be determined. To investigate this issue, event-related potentials were recorded in response to repetitions of a particular facial expression (e.g. sadness) and in response to two different deviant (rare) stimuli, one depicting the same emotion as the frequent stimulus, while the other depicted a different facial expression (e.g. fear). As expected, deviant stimuli evoked an N2/P3a complex of larger amplitude than frequent stimuli. But more interestingly, when the deviant stimulus depicted the same emotion as the frequent stimulus the N2/P3a was delayed compared to the response elicited by the different-emotion deviant. The N2/P3a was thus implicated in the detection of physical facial changes, with a higher sensitivity to changes related to a new different emotional content, perhaps leading to faster adaptive reactions.

Adult↗
PubMed2001

Association of the distinct visual representations of faces and names: a PET activation study.

A PET study of seven normal individuals was carried out to investigate the neural populations involved in the retrieval of the visual representation of a face when presented with an associated name, and conversely. Face-name associations were studied by means of four experimental matching conditions, including the retrieval of previously learned (1) name-name (NN), (2) face-face (FF), (3) name-face (NF), and (4) face-name (FN) associations, as well as a resting scan with eyes closed. Before PET images acquisition, subjects were presented with 24 unknown face-name associations to encode in 12 male/female couples. During PET scanning, their task was to decide whether the presented pair was a previously learned association. The right fusiform gyrus was strongly activated in FF condition as compared to NN and Rest conditions. However, no specific activations were found for NN condition relative to FF condition. A network of three areas distributed in the left hemisphere, both active in (NF-FF) and (FN-NN) comparisons, was interpreted as the locus of the integration of visual faces and names representations. These three regions were localized in the inferior frontal gyrus (BA 45), the medial frontal gyrus (BA 6) and the supramarginal gyrus of the inferior parietal lobe (BA 40). An interactive model accounting for these results, with BA 40 seen as an amodal binding region, is proposed.

Adult↗
PubMed2000

Right N170 modulation in a face discrimination task: an account for categorical perception of familiar faces.

Behavioral studies have shown that two different morphed faces belonging to the same identity are harder to discriminate than two faces stemming from two different identities. The temporal course of this categorical perception effect has been explored through event-related potentials. Three kinds of pairs were presented in a matching task: (1) two different morphed faces representing the same identity (within), (2) two other faces representing two different identities (between), and (3) two identical morphed faces (same). Following the second face onset in the pair, the amplitude of the right occipitotemporal negativity (N170) was reduced for within and same pairs as compared with between pairs, suggesting an identity priming effect. We also observed a modulation of the P3b wave, as the amplitude of the responses for within pairs was higher than for between and same pairs, suggesting a higher complexity of the task for within pairs. These results indicate that categorical perception of human faces has a perceptual origin in the right occipitotemporal hemisphere.

Adult↗
PubMed1999

[A comparison between group-average and individual evoked potential analysis].

PURPOSE: Event-related potentials (ERPs) studies in human subjects have shown inter-individual response variations, probably linked to anatomical and functional brain disparities. The present study was conducted to compare the results obtained by a standard grand-average method and a single subject analysis of VEPs to faces. MATERIAL AND METHOD: Fifty-eight channel ERPs (analysis time: 1,024 ms) were recorded in 13 normal volunteers during gender or familiarity judgements on unknown and known faces, as well as on a control task using meaningless patterns. Data were then submitted to individual and group averages. RESULTS AND CONCLUSION: Three activities were identified by both procedures: a P1/N1 complex, a vertex positive potential (P2 or VPP) associated with a temporal negativity, and a N2 negativity. These peaks displayed a marked inter-individual topographical variability. Regarding the outcome of statistical analyses, a certain number of differences were found: on P1, in which individual analyses revealed a strong effect of experimental conditions, while the grand-average method did not; on VPP, in which grand-average analyses suggested an interaction between experimental conditions, face familiarity and cerebral lateralization, while individual analyses did not; and on N2, in which grand-average data showed a clear lateralization effect, while individual analyses did not. A P3 component (Pz, 250 ms) was also defined in grand-average data, but could not be clearly described in individual data. Statistical analyses on this P3 component were thus only performed on group data and revealed a right lateralization and an interaction between face familiarity and experimental conditions. These findings confirmed the existence of a marked topographical variability of ERPs to face and, therefore, question the validity of grand-average studies. Moreover, these results suggest a better efficiency of individual analyses for studying short and middle-latency peaks, while grand-averages appear to be better suited for studying late components.

Adult↗
PubMed1999

Task modulation of brain activity related to familiar and unfamiliar face processing: an ERP study.

In order to investigate stimulus-related and task-related electrophysiological activity relevant for face processing, event-related potentials (ERPs) from 58 electrodes at standard EEG sites were recorded while subjects performed a simple visual discrimination (control) task, in addition to various face processing tasks: recognition of previously learned faces and gender decision on familiar and unfamiliar faces. Three electrophysiological components or dipolar complex were recorded in all subjects: an occipital early component (P1, around 110 ms); a vertex positive potential (VPP; around 158 ms) which appeared to be specific to faces; and a negative central component, N2 (around 230 ms). Parametric analysis and source localization were applied to these components by means of a single-subject analysis methodology. No effect of familiarity was observed on any of these early component. While the VPP appears to be independent of the kind of processing performed, face task modulations of the early P1 and the N2 were observed, with a higher amplitude for the recognition than for the gender discrimination task. An attentional modulation of early visual areas is proposed for the first effect (P1 modulation), while the N2 seems to be related to general visual memory processing. This study strongly suggests that the VPP reflects an early visual stage of face processing in the fusiform gyrus that is strictly stimulus-related and independent of familiarity. It also shows that source localization algorithms may give reliable solutions on single subject averages for early visual components despite high inter-subject variability of the surface characteristics of ERPs.

Adult↗