Face versus non-face object perception and the 'other-race' effect: a spatio-temporal event-related potential study

OBJECTIVE

To investigate a modulation of the N170 face-sensitive component related to the perception of other-race (OR) and same-race (SR) faces, as well as differences in face and non-face object processing, by combining different methods of event-related potential (ERP) signal analysis.

METHODS

Sixty-two channel ERPs were recorded in 12 Caucasian subjects presented with Caucasian and Asian faces along with non-face objects. Surface data were submitted to classical waveforms and ERP map topography analysis. Underlying brain sources were estimated with two inverse solutions (BESA and LORETA).

RESULTS

The N170 face component was identical for both race faces. This component and its topography revealed a face specific pattern regardless of race. However, in this time period OR faces evoked significantly stronger medial occipital activity than SR faces. Moreover, in terms of maps, at around 170 ms face-specific activity significantly preceded non-face object activity by 25 ms. These ERP maps were followed by similar activation patterns across conditions around 190-300 ms, most likely reflecting the activation of visually derived semantic information.

CONCLUSIONS

The N170 was not sensitive to the race of the faces. However, a possible pre-attentive process associated to the relatively stronger unfamiliarity for OR faces was found in medial occipital area. Moreover, our data provide further information on the time-course of face and non-face object processing.

Human brain mapping in dystonia reveals both endophenotypic traits and adaptive reorganization

Dystonia has a wide clinical spectrum from early-onset generalized to late-onset sporadic, task-specific forms. The genetic origin of the former has been clearly established. A critical role of repetitive skilled motor tasks has been put forward for the latter, while underlying vulnerability traits are still being searched for. Using magnetoencephalography, we looked for structural abnormalities reflecting a preexisting dysfunction. We studied finger representations of both hands in the primary sensory cortex, as compared in 23 patients with unilateral task-specific dystonia and 20 control subjects. A dramatic disorganization of the nondystonic hand representation was found in all patients, and its amount paralleled the severity of the dystonic limb motor impairment. Abnormalities were also observed in the cortex coding the dystonic limb representation, but they were important only in the most severely affected patients. The abnormal cortical finger representations from the nondystonic limb appear to be endophenotypic traits of dystonia. That finger representations from the dystonic limb were almost normal for the less severely affected patients may be due to intrinsic beneficial remapping in reaction against the primary disorder.

An ERP study of famous face incongruity detection in middle age

Age-related changes in famous face incongruity detection were examined in middle-aged (mean = 50.6) and young (mean = 24.8) subjects. Behavioral and ERP responses were recorded while subjects, after a presentation of a "prime face" (a famous person with the eyes masked), had to decide whether the following "test face" was completed with its authentic eyes (congruent) or with other eyes (incongruent). The principal effects of advancing age were (1) behavioral difficulties in discriminating between incongruent and congruent faces; (2) a reduced N400 effect due to N400 enhancement for both congruent and incongruent faces; (3) a latency increase of both N400 and P600 components. ERPs to primes (face encoding) were not affected by aging. These results are interpreted in terms of early signs of aging.

The effects of apomorphine on attentional processing in Parkinson's disease

To ascertain whether variations in central dopaminergic transmission can differentially affect motor and cognitive processing, we studied the effects of apomorphine (APO) in 9 patients with Parkinson's disease (PD). The UPDRS motor scores and auditory event-related potentials (ERPs) obtained in the 'odd-ball' (OB) and in the 'covert orientation of attention' (COA) tasks were studied in the 'off' and in the 'on' state after an injection of APO. Although APO injection improved patients' motor status, it induced a significant increase in the latencies of the P2 and P3 ERP components in the OB. In the COA task, right-hand reaction times (RTs) were markedly shortened in the 'on' state while left hand RTs remained unchanged. The contrasting effects of dopaminergic stimulation on the motor performance and on some aspects of cognitive processing suggest the existence of complex interactions within pre- and postsynaptic brain dopamine receptors, and an intervention of segregated basal ganglia-prefrontal cortex loops in motor and cognitive behaviour.

A high-resolution map of human chromosome 12

Our sequence-tagged site-content map of chromosome 12 is now integrated with the whole-genome fingerprinting effort. It provides accurate and nearly complete bacterial clone coverage of chromosome 12. We propose that this integrated mapping protocol serves as a model for constructing physical maps for entire genomes.

Anticipation of epileptic seizures from standard EEG recordings

BACKGROUND

New methods derived from non-linear analysis of intracranial recordings permit the anticipation of an epileptic seizure several minutes before the seizure. Nevertheless, anticipation of seizures based on standard scalp electroencephalographical (EEG) signals has not been reported yet. The accessibility to preictal changes from standard EEGs is essential for expanding the clinical applicability of these methods.

METHODS

We analysed 26 scalp-EEG/video recordings, from 60 min before a seizure, in 23 patients with temporal-lobe epilepsy. For five patients, simultaneous scalp and intracranial EEG recordings were assessed. Long-term changes before seizure onset were identified by a measure of non-linear similarity, which is very robust in spite of large artifacts and runs in real-time.

FINDINGS

In 25 of 26 recordings, measurement of non-linear changes in EEG signals allowed the anticipation of a seizure several minutes before it occurred (mean 7 min). These preictal changes in the scalp EEG correspond well with concurrent changes in depth recordings.

INTERPRETATION

Scalp-EEG recordings retain sufficient dynamical information which can be used for the analysis of preictal changes leading to seizures. Seizure anticipation strategies in real-time can now be envisaged for diverse clinical applications, such as devices for patient warning, for efficacy of ictal-single photon emission computed tomography procedures, and eventual treatment interventions for preventing seizures.

Genetic analysis of the APAF1 gene in male germ cell tumors

Cytogenetic and molecular analyses have shown that the chromosome band 12q22 is recurrently deleted in male germ cell tumors (GCTs), indicating the presence of a candidate tumor suppressor gene (TSG) in this region. To identify the TSG, we mapped the APAF1 gene, a proapoptotic mammalian homologue of ced-4, to chromosomal band 12q22, that suggested that this might be the candidate deleted gene in GCTs. We further localized the gene between the polymorphic markers D12S1671 and D12S1082 at 12q22 to determine the role of APAF1 in the pathogenesis of GCT, and we characterized its normal genomic structure and analyzed its alterations in GCTs. The APAF1 gene comprises 27 exons, with the coding region spanning 26. The region containing APAF1 was found to be deleted in GCT by fluorescence in situ hybridization analysis, but without evidence of coding sequence alterations. RT-PCR and Western blot analysis showed APAF1 gene expression at detectable levels in all GCT cell lines analyzed. An aberrant-sized APAF1 protein was seen in one cell line. This and 2 other cell lines carrying APAF1 deletions also exhibited defects in dATP-mediated caspase-3 activation. Caspase-3 activity was effectively restored by addition of recombinant caspase-9 and APAF1 proteins, and to a lesser extent by caspase-9 alone, but not by APAF1 alone. These data do not support a TSG role for APAF1, but defects in other components of the apoptotic pathway that may be related to 12q22 deletion cannot be ruled out. Genes Chromosomes Cancer 28:258-268, 2000.

ERPs and PET analysis of time perception: spatial and temporal brain mapping during visual discrimination tasks

ERPs were recorded from 12 subjects performing duration and intensity visual discrimination tasks which have been previously used in a PET study. PET data showed that the same network was activated in both tasks [P. Maquet et al., NeuroImage 3:119-126, 1996]. Different ERP waveforms were observed for the late latency components depending on the dimension of the stimulus to be processed: frontal negativity (CNV) for the duration task and parieto-occipital positivity (P300) for the intensity task. Using BESA software, the sources were first modelled with a "PET dipolar model" (right prefrontal, right parietal, anterior cingulate, left and right fusiforms). To obtain a better fit for ERPs recorded in each task, two sources (cuneus, left prefrontal area) had to be added. Consistently with PET findings, dipole modelling indicates that duration and intensity dimensions of a visual stimulus are processed in the same areas. However, ERPs also reveal prominent differences between the time course of the dipole activations for each task, particularly for sources contributing to the late latency ERP components. In the intensity task, dipoles located in the cuneus, the anterior cingulate, and the left prefrontal area yield largest activity within the P300 interval, then activity diminishes rapidly as the stimulus ends, whereas in the duration task, the cuneus and anterior cingulate are still active several hundred milliseconds following stimulus offset. Moreover, in the duration task, the activity of the right frontal dipole parallels the CNV waveform, whereas in the intensity task, this dipole is largely inactive. We assume that the right frontal area plays a specific role in the formation of temporal judgments.

Effects of serotonin-selective and classical antidepressants on the auditory P300 cognitive potential

The cognitive potential, P300, is a phenomenon frequently studied in relation to template matching of the brain. To understand the neurochemical mechanisms of its generation, we compared the effects of three antidepressants, fluoxetine, tianeptine and clomipramine after single and repeated application as well as after 1 week of withdrawal on the P300 and N200 waves in an auditory 'odd-ball' paradigm in three parallel groups of 10 healthy volunteers. Following single administration, both fluoxetine and clomipramine reduced (-39 +/- 14%, p < 0.01) the peak amplitude of P300 at the Pz electrode. For fluoxetine and tianeptine, reduced amplitudes of 19 +/- 7% and 24 +/- 11%, respectively, were found following 8 days of treatment, 2 h after administration. However, for clomipramine no additional diminution was found on day 8 with respect to day 1. Topographic distributions tended to be significantly modified at the frontal scalp area 1 h after the tianeptine administration on day 8, whereas the postdosing changes induced by fluoxetine were localised in the midline and right centrotemporal scalp regions. Only minor reductions in peak latencies have been observed. It can be concluded that serotonin selective drugs have a slower onset of P300 amplitude decrease than clomipramine, which has additional effects on monoaminergic and on cholinergic systems. These results suggest that serotonin has a regulatory function in the neurotransmission of cerebral structures which are involved in the evaluation of stimulus relevance.

Automatic attentional shifts induced by a noradrenergic drug in Alzheimer's disease: evidence from evoked potentials

Prior research showed that attentional deficits are observed in Alzheimer's disease (AD). These deficits can further impair other cognitive processes. The present experiment was designed to study the shifts in attention induced by a noradrenergic drug (S 12024-2) through their electrophysiological correlates in 12 outpatients with mild AD, using an auditory oddball paradigm. The P3a component, known to be related to automatic attentional processing, was increased by the drug, whereas no changes occurred either in PN or in P3b, which are considered to reflect conscious processing. These results point to an involvement of the noradrenergic system in the modulation of automatic attentional processing, and provide evidence for weakening of the orienting reflex in AD, due to a possible noradrenergic deficit in patients with mild AD.

A 3-Mb high-resolution BAC/PAC contig of 12q22 encompassing the 830-kb consensus minimal deletion in male germ cell tumors

Cytogenetic and molecular genetic analyses have shown that the 12q22 region is recurrently deleted in male germ cell tumors (GCTs), suggesting that this site may harbor a tumor suppressor gene (TSG). Previous loss of heterozygosity (LOH) analyses identified a consensus minimal deleted region between the markers D12S377 and D12S296, and a YAC clone contig covering the region was generated. Here, we describe a high-resolution sequence-ready physical map of this contig covering a 3-Mb region. The map comprised of 52 cosmids, 49 PACs, and 168 BACs that were anchored to the previous YAC contig; 99 polymorphic, nonpolymorphic, EST, and gene-based markers are now placed on this map in a unique order. Of these, 61 markers were isolated in the present study, including one that was polymorphic. In addition, we have narrowed the minimal deletion to approximately 830 kb between D12S1716 (proximal) and P382A8-AG (distal) by LOH analysis of 108 normal-tumor DNAs from GCT patients using 21 polymorphic STSs. These physical and deletion maps should prove useful for identification of the candidate TSG in GCTs, provide framework to generate complete DNA sequence, and ultimately generate a gene map of this segment of the chromosome 12. [The sequence data described in this paper have been submitted to the Genome Survey Sequence under accession nos. AQ254896-AQ254955 and AQ269251-AQ269266. Online supplementary material is available at http://www.genome.org]

[Interactions between the epileptic network and brain function: an approach by nonlinear analysis of intracranial EEG]

Recent advances in the non-linear dynamics analysis have made it possible to identify hidden recurrences in EEG signals that could be missed by more traditional linear techniques such as power spectrum or coherence analysis. This is particularly true for epileptic EEG recordings either in animals or in humans as epileptic phenomena are usually concomitant with the emergence a strong non-linear EEG behavior. Non-linear dynamical analysis techniques quantify the relations between EEG signals. The literature concerning the spatio-temporal characteristics of the epileptic processes during seizures and interictal periods is reviewed. Our attention has been mainly focused on the interdependences between brain structures or on the dynamical changes of one particular brain region during intracranial recordings. These data could explain in part the dysfunctioning of the cerebral cortex induced by epileptic activities and provide an insight into the spatio-temporal organization of the epileptic network. Futhermore, by tracking the time variation of non-linear indices, one can anticipate the occurrence of seizures in temporal lobe epilepsies. All this information could contribute to improve definitions of the epileptogenic zone in partial epilepsy and also open the way to preventive interventions.

A 3-Mb high-resolution BAC/PAC contig of 12q22 encompassing the 830-kb consensus minimal deletion in male germ cell tumors

Cytogenetic and molecular genetic analyses have shown that the 12q22 region is recurrently deleted in male germ cell tumors (GCTs), suggesting that this site may harbor a tumor suppressor gene (TSG). Previous loss of heterozygosity (LOH) analyses identified a consensus minimal deleted region between the markers D12S377 and D12S296, and a YAC clone contig covering the region was generated. Here, we describe a high-resolution sequence-ready physical map of this contig covering a 3-Mb region. The map comprised of 52 cosmids, 49 PACs, and 168 BACs that were anchored to the previous YAC contig; 99 polymorphic, nonpolymorphic, EST, and gene-based markers are now placed on this map in a unique order. Of these, 61 markers were isolated in the present study, including one that was polymorphic. In addition, we have narrowed the minimal deletion to approximately 830 kb between D12S1716 (proximal) and P382A8-AG (distal) by LOH analysis of 108 normal-tumor DNAs from GCT patients using 21 polymorphic STSs. These physical and deletion maps should prove useful for identification of the candidate TSG in GCTs, provide framework to generate complete DNA sequence, and ultimately generate a gene map of this segment of the chromosome 12. [The sequence data described in this paper have been submitted to the Genome Survey Sequence under accession nos. AQ254896-AQ254955 and AQ269251-AQ269266. Online supplementary material is available at http://www.genome.org]

Event-related potentials to structural familiar face incongruity processing

Thirty scalp sites were used to investigate the specific topography of the event-related potentials (ERPs) related to face associative priming when masked eyes of familiar faces were completed with either the proper features or incongruent ones. The enhanced negativity of N210 and N350, due to structural incongruity of faces, have a "category specific" inferotemporal localization on the scalp. Additional analyses support the existence of multiple ERP features within the temporal interval typically associated with N400 (N350 and N380), involving occipitotemporal and centroparietal areas. Seven reliable dipole locations have been evidenced using the brain electrical source analysis algorithm. Some of these localizations (fusiform, parahippocampal) are already known to be involved in face recognition, the other ones being related to general cognitive processes related to the task's demand. Because of their specific topography, the observed effects suggest that the face structural congruency process might involve early specialized neocortical areas in parallel with cortical memory circuits in the integration of perceptual and cognitive face processing.

Differential processing of part-to-whole and part-to-part face priming: an ERP study

We provide electrophysiological evidence supporting the hypothesis that part and whole face processing involve distinct functional mechanisms. We used a congruency judgment task and studied part-to-whole and part-to-part priming effects. Neither part-to-whole nor part-to-part conditions elicited early congruency effects on face-specific ERP components, suggesting that activation of the internal representations should occur later on. However, these components showed differential responsiveness to whole faces and isolated eyes. In addition, although late ERP components were affected when the eye targets were not associated with the prime in both conditions, their temporal and topographical features depended on the latter. These differential effects suggest the existence of distributed neural networks in the inferior temporal cortex where part and whole facial representations may be stored.

Perception's shadow: long-distance synchronization of human brain activity

Transient periods of synchronization of oscillating neuronal discharges in the frequency range 30-80 Hz (gamma oscillations) have been proposed to act as an integrative mechanism that may bring a widely distributed set of neurons together into a coherent ensemble that underlies a cognitive act. Results of several experiments in animals provide support for this idea. In humans, gamma oscillations have been described both on the scalp (measured by electroencephalography and magnetoencephalography) and in intracortical recordings, but no direct participation of synchrony in a cognitive task has been demonstrated so far. Here we record electrical brain activity from subjects who are viewing ambiguous visual stimuli (perceived either as faces or as meaningless shapes). We show for the first time, to our knowledge, that only face perception induces a long-distance pattern of synchronization, corresponding to the moment of perception itself and to the ensuing motor response. A period of strong desynchronization marks the transition between the moment of perception and the motor response. We suggest that this desynchronization reflects a process of active uncoupling of the underlying neural ensembles that is necessary to proceed from one cognitive state to another.

[Pelvic trauma and pregnancy. Literature review and case report]

The authors are dealing with a case of a pelvic fracture (right superior pubic ramus) after a road traffic accident to a patient who arise a pregnancy with twins at twenty five weeks pregnant. Seven per cent of a road traffic accident affect pregnancy with a maternal death rate from eight to sixteen per cent and a fetal death rate up to fifty seven per cent. Pelvic trauma are more deleterious during the pregnancy because of the gravide uterus, of the abdominal injuries binding more often, and of pregnancy secondary maternal physiology which lead to delay diagnosis and therapeutics. Blunt fetomaternal consequences are ruled by pelvic haematomas, uterine rupture, prematurity, acute fetal distress, fetal injuries and in utero death. At mid and long range arise the problem of child birth way and the risk of mechanical dystocy. Cesarean is store in case of vesical and urethral injuries, or perineal injury, several pelvic fractures or in case of the pelvic belt fracture moved and not reduced, bringing to a surgical unsymmetrical pelvis. In the other cases, the obstetrical prognoses will be done after a dialogue with all medical staff and a full synthesis of the file based on the fetopelvic comparisons (obstetrics previous, clinic, fetal biometry, pelvimetry X ray).

ERPs and chronometry of face recognition: following-up Seeck et al. and George et al

Seeck et al. found that event-related potentials (ERPs) evoked by repeated and non-repeated face photographs differ as early as 50-70ms post-onset. They thus suggested that faces are recognized at these latencies, in contrast with current opinions in ERP literature. However, the similar latencies obtained by George et al. for stimuli not perceived as faces suggest that Seeck et al.'s differences could index repetition rather than face recognition per se. To address this issue, we used matched faces of known and unknown persons. We found the earliest differences between the ERPs to these faces between 76 and 130 ms. These results, which are consistent with other data, suggest that the differentiation of faces takes approximately 100 ms of processing time in humans.

Epileptic seizures can be anticipated by non-linear analysis

Epileptic seizures are a principal brain dysfunction with important public health implications, as they affect 0.8% of humans. Many of these patients (20%) are resistant to treatment with drugs. The ability to anticipate the onset of seizures in such cases would permit clinical interventions. The view of chronic focal epilepsy now is that abnormally discharging neurons act as pacemakers to recruit and entrain other normal neurons by loss of inhibition and synchronization into a critical mass. Thus, preictal changes should be detectable during the stages of recruitment. Traditional signal analyses, such as the count of focal spike density, the frequency coherence or spectral analyses are not reliable predictors. Non-linear indicators may undergo consistent changes around seizure onset. Our objective was to follow the transition into seizure by reconstructing intracranial recordings in implanted patients as trajectories in a phase space and then introduce non-linear indicators to characterize them. These indicators take into account the extended spatio-temporal nature of the epileptic recruitment processes and the corresponding physiological events governed by short-term causalities in the time series. We demonstrate that in most cases (17 of 19), seizure onset could be anticipated well in advance (between 2-6 minutes beforehand), and that all subjects seemed to share a similar 'route' towards seizure.

Entropy maps characterize drug effects on brain dynamics in Alzheimer's disease

Non-linear quantifiers of brain electrical dynamics (entropy maps computed from the degradation of temporal forecasting of EEG signals) were studied in relation to drug treatment of Alzheimer's disease. A placebo condition was compared to three drug doses (50, 100 and 200 mg). A significant general effect of the drug was found when compared to placebo and specific contrasts between placebo and each of the three drug doses only reveal a significant entropy increase for the highest dose. These effects were localized bilaterally in fronto-temporal areas and support changes in the dynamics of the cerebral structures involved in memory processes.

Type I transforming growth factor beta receptor maps to 9q22 and exhibits a polymorphism and a rare variant within a polyalanine tract

In a search for mutations of the type I transforming growth factor beta receptor (TbetaR-I), we mapped the gene to 9q22 and found a common polymorphism [TbetaR-I(6A)] and a rare variant [TbetaR-I(10A)] of TbetaR-I, causing an in-frame deletion of three alanines and an in-frame insertion of one alanine, respectively, in the receptor's extracellular domain. The biological relevance of the polymorphism TbetaR-I(6A) was investigated. When TbetaR-I(6A) was transiently transfected into TbetaR-I-deficient cells, the growth-inhibitory effects of transforming growth factor beta were restored. TbetaR-I(6A) and TbetaR-I(10A) frequency were assessed in 108 tumor samples and 80 nontumor samples from patients with a diagnosis of cancer, as well as in 118 normal blood donors of comparable ethnic composition. The frequency of TbetaR-I(6A) heterozygotes was fairly similar in normal blood donors (8%), in nontumor DNA of patients with a diagnosis of cancer (10%), and in tumor samples (14%). However, the frequency of TbetaR-I(6A) homozygotes among nontumor (4%) and tumor (8%) samples obtained from patients with a diagnosis of cancer was higher than that predicted by the Hardy-Weinberg law. The clinical and biological significance of TbetaR-I(6A) homozygosity needs to be further investigated.

Attentional deficits in Parkinson's disease: partial reversibility with naphtoxazine (SDZ NVI-085), a selective noradrenergic alpha 1 agonist

Several authors have suggested that catecholamine depletion may affect attentional processes in human subjects and could be implicated in the frontal lobe syndrome that has been described in Parkinson's disease (PD). The present study reports the effects of a placebo and naphtoxazine (SDZ-NVI-085), a selective noradrenergic alpha 1 agonist. These substances were administered to nine parkinsonian patients who were assessed on measures of attention, including neuropsychological tests and evoked potentials. The results indicate that naphtoxazine may improve performance on some tests of "frontal functions," including the Stroop and the Odd-Man-Out tests, which have been previously found to be affected in PD. However, the results of some other neuropsychological tests of frontal function were not affected by naphtoxazine. Specific evoked potentials such as the Nd1 and Nd2 curves--which are thought to reflect attentional processes and which have been found to be affected in PD--were improved by naphtoxazine. Finally, naphtoxazine reduced the percentage of errors and restored the lateralization of N100 during the Shifting Reaction Time Task, suggesting that this substance may act on the processes underlying the shifting deficit in these patients. The results are discussed in terms of the specific cognitive processes that may be affected by naphtoxazine and in terms of the role of the noradrenaline in attentional deficits found in PD.

A sequence-ready physical map of a region of 12q24.1

We developed a sequence-ready map of a part of human chromosome 12q24.1. We utilized a number of sequence-tagged site (STS) markers from 12q24.1 to screen large insert bacterial chromosome libraries and a chromosome 12-specific cosmid library. The clones were assembled into contiguous sets (contigs) by STS-content analysis. Contigs were extended by obtaining end sequences of bacterial clones, generation of additional STSs, rescreening the libraries, and screening the additional clones for the presence of STSs. The resulting contig covers nearly 2 Mb of DNA and provides an average marker resolution of 16 kb. Based on the STS content, we developed fingerprints of a subset of clones. The STS content and fingerprint data allowed us to define a minimal tiling path of clones. These clones are being used to sequence this part of chromosome 12. This contig contains the Ataxin 2 gene, and it covers the interval harboring the gene responsible for Darier disease.

Temporal patterns in human epileptic activity are modulated by perceptual discriminations

We studied subdural recordings from a patient with an unusually focal and stable occipito-temporal epileptic discharge under four experimental conditions. The series of time intervals between successive spike discharges displayed a few (3-5) clusters of periodic values representing statistically significant short-term periodicities when tested against surrogate data. This short-term predictability was modulated during the different experimental conditions by periodicity shifts of the order of 15-30 ms. Correspondingly, there was an increased gamma-band (30-70 Hz) coherence between the epileptic focus and surrounding recording sites. We conclude that the focal epileptic activity is part of an extended network of neural activities which exert a fast modulation reflected in changes of transiently periodic activities.

Face and shape repetition effects in humans: a spatio-temporal ERP study

The neural bases of repetition effects for faces and non-significant shapes was studied using Mooneys' faces presented upright (face) or upside down (shape) with a repetition interval of 8 min 30 s-1. Scalp potentials and current density maps on 30 electrodes were compatible with an involvement of the infero-temporal and fusiform gyri (from 50 to at least 250 ms), mainly on the right, for both faces and shapes; the hippocampus and adjacent areas (around 300 ms), specifically for faces; the medial temporal lobes (450-650 ms) again independent of stimulus meaning. These results suggest that the facilitation of perception due to repetition involves both neocortical specialized areas and the medial temporal lobe, with different timings of activation. They further suggest that memory updating takes place more rapidly for faces than for meaningless shapes and that face recognition may be, at least partly, functionally encapsulated.

Gene amplification and proliferative kinetics in relation to prognosis of patients with gastric carcinoma

BACKGROUND

The differences in survival of gastric carcinoma patients who have identical clinical or pathologic stages prompted the authors to investigate the prognostic significance of biologic features that are known to affect the clinical aggressiveness of other tumor types.

METHODS

One hundred twenty-four tumor samples from patients who had received radical or palliative surgery were analyzed for c-myc, c-K-ras, hst, and c-erb B-2 gene amplification by means of the Southern blot technique. Of these tumors, 70 were also examined for cell kinetics by means of the thymidine labeling index (TLI).

RESULTS

The analysis of associations between gene amplification and the anatomicopathologic variables (TNM classification, site of tumor, and histology) showed that amplification represents a late event in the natural history of gastric carcinoma. Gene amplification showed a slight, statistically insignificant, negative impact on overall survival (OS) (P = 0.09). Amplification of c-erb B-2 correlated in a statistically significant way with reduced OS (P = 0.03). Cox multiple regression analysis revealed that neither c-erb B-2 amplification nor TLI had prognostic significance in relation to OS.

CONCLUSIONS

These data indicate that amplification of the examined oncogenes did not reveal a new independent prognostic factor for patients with gastric carcinoma. However, the authors' results did show a strong correlation between gene amplification and tumor progression, which warrants further study involving larger series of patients. At the same time, the TLI results underlined the need to identify the most suitable biologic material for use in the estimation of proliferative indexes in gastric carcinoma.

Gene amplification and proliferative kinetics in relation to prognosis of patients with gastric carcinoma

BACKGROUND

The differences in survival of gastric carcinoma patients who have identical clinical or pathologic stages prompted the authors to investigate the prognostic significance of biologic features that are known to affect the clinical aggressiveness of other tumor types.

METHODS

One hundred twenty-four tumor samples from patients who had received radical or palliative surgery were analyzed for c-myc, c-K-ras, hst, and c-erb B-2 gene amplification by means of the Southern blot technique. Of these tumors, 70 were also examined for cell kinetics by means of the thymidine labeling index (TLI).

RESULTS

The analysis of associations between gene amplification and the anatomicopathologic variables (TNM classification, site of tumor, and histology) showed that amplification represents a late event in the natural history of gastric carcinoma. Gene amplification showed a slight, statistically insignificant, negative impact on overall survival (OS) (P = 0.09). Amplification of c-erb B-2 correlated in a statistically significant way with reduced OS (P = 0.03). Cox multiple regression analysis revealed that neither c-erb B-2 amplification nor TLI had prognostic significance in relation to OS.

CONCLUSIONS

These data indicate that amplification of the examined oncogenes did not reveal a new independent prognostic factor for patients with gastric carcinoma. However, the authors' results did show a strong correlation between gene amplification and tumor progression, which warrants further study involving larger series of patients. At the same time, the TLI results underlined the need to identify the most suitable biologic material for use in the estimation of proliferative indexes in gastric carcinoma.

Mutations in human TBX5 [corrected] cause limb and cardiac malformation in Holt-Oram syndrome

Holt-Oram syndrome is characterized by upper limb malformations and cardiac septation defects. Here, we demonstrate that mutations in the human TBX5 gene underlie this disorder. TBX5 was cloned from the disease locus on human chromosome 12q24.1 and identified as a member of the T-box transcription factor family. A nonsense mutation in TBX5 causes Holt-Oram syndrome in affected members of one family; a TBX5 missense mutation was identified in affected members of another. We conclude that TBX5 is critical for limb and heart development and suggest that haploinsufficiency of TBX5 causes Holt-Oram syndrome.

Functional anatomy of human auditory attention studied with PET

Positron emission tomography was used to investigate the functional anatomy of selective auditory attention in 17 right-handed male volunteers who submitted to different tasks: silent rest (REST) listening to frequent low- or rare high-pitched tones (LIS) delivered randomly to the right or the left ear, selective auditory attention where subjects had to attend to deviants in one ear, right (ATTR) or left (ATTL). Six subjects had the series REST, LIS, ATTR twice, eight subjects the series REST, LIS, ATTL, and the last three subjects the sereis REST, ATTR, ATTL. Event-related potentials were simultaneously recorded with PET and showed significant task and electrode site effects on the N100 amplitude. When compared to REST, LIS elicited bilateral temporal activations of the Heschl's gyri and the planum temporale, with a significant rightward asymmetry, and of the posterior part of the superior temporal gyrus. Significant right precentral and anterior cingulate gyri normalized regional cerebral blood flow increases were observed in the frontal lobe. Both the ATTR and the ATTL conditions, compared to LIS, activated the supplementary motor area, bilateral precentral, and left postcentral cortices without any temporal cortex activation. In addition, the ATTL condition resulted in a right prefrontal cortex activation. Pooling the 14 subjects revealed an asymmetry in the superior temporal gyrus favoring the cortex contralateral to the attended ear. Two major networks seem thus to be involved during selective auditory attention: (1) a local temporal network, on which selective attention produces a modulation of the functional lateralization, and (2) a frontal network that could mediate the temporal cortex modulation by attention.

Physical mapping of the human neurotensin gene (NTS) between markers D12S1444 and D12S81 on chromosome 12q21

Neurotensin (NTS) is an endogenous tridecapeptide of the central nervous system and the gastrointestinal tract of different mammalian species including human. The human gene encoding neurotensin has previously been assigned to chromosome 12 but no regional localization was available. We now confirm this assignment and place the NTS gene on the physical and cytogenetic maps. The NTS gene is located on a yeast artificial chromosome contig that contains several polymorphic markers and is close to a polymorphic marker located at 95.8 cM on the Généthon linkage map. NTS is immediately proximal to four polymorphic markers, including D12S81 (AFM102xg9) and D12S88 (AFM158yb4). Using fluorescence in situ hybridization, we map the gene cytogenetically to band 12q21.

Microsatellite instability and mutations of p53 and TGF-beta RII genes in gastric cancer

To investigate the molecular mechanism of gastric carcinogenesis, we analyzed genetic instability and p53 gene mutations in 40 primary gastric carcinomas. Tumor samples were from untreated patients with no family history suggestive of genetic predisposition to cancer. We screened six microsatellite loci by the polymerase chain reaction (PCR) method, and exons 5-8 of the p53 gene by the PCR-based denaturing gradient gel electrophoresis and sequencing techniques. Microsatellite instability was detected in 32.5% (13/40), and gene mutations in 40% (16/40), of the tumors analyzed. No statistically significant associations were found between genetic alterations and clinico-pathological variables (with the exception of diffusion of lymph node metastases, which was inversely associated with the presence of microsatellite alterations; P < 0.01). Interestingly, a negative association was found between genetic instability and p53 gene mutations: 11 out of 13 tumors showing instability proved to carry a nonmutated p53 gene versus 2/13 carrying a mutated gene (P = 0.03). These observations suggest that genetic instability and p53 gene mutations play a crucial role in the gastric carcinogenic process, but likely act through distinct pathways during cancer development. However, genetic instability is not in and of itself neoplastic. Therefore, we investigated whether insertion/deletion mutations of the polyadenine tract within the transforming growth factor-beta type II receptor gene (TGF-beta RII) were frequently present in gastric tumors with an RER+ (replication error) phenotype. We found RII mutations in 8/40 (20%) samples: mutations were present in 7/13 (54%) RER+ tumors versus 1/27 (4%) RER- cases (P < 0.001).

Linkage of asthma and total serum IgE concentration to markers on chromosome 12q: evidence from Afro-Caribbean and Caucasian populations

To identify genes potentially relevant in atopic asthma, we analyzed markers in chromosome 12q15-q24.1 for linkage to asthma and total serum IgE concentration. Sib-pair analyses of 10 markers in 345 full- and 219 half-sib pairs from 29 multiplex Afro-Caribbean families provided evidence for linkage to this region for both asthma and total serum IgE. Certain alleles at these loci showed significant evidence of transmission disequilibrium with both asthma and high IgE. Using 6 of these markers and 11 additional markers, evidence for linkage of total IgE to 12q was also found in 12 Caucasian Amish kindreds (24 nuclear families) by both sib-pair and transmission disequilibrium analyses. These findings suggest that the 12q15-q24.1 region may contain a gene(s) controlling asthma and the associated "high total IgE" trait.

Brain events related to normal and moderately scrambled faces

The neural basis of normal and scrambled face processing was investigated by recording evoked potentials from 21 electrodes at standard EEG sites, with respect to a nose reference. Temporal negativities were found that result from two overlapping phenomena: they arise from the polarity reversal on temporal electrodes of the vertex P2, a positive wave peaking about 170-200 ms after the onset of a face stimulus, and also from an overlapping 'processing negativity' of long duration associated with the processing difficulty of the scrambled face stimulus. The comparisons of scalp potential and current density mappings support the proposal that some neuronal networks are active both for faces and scrambled faces and are compatible with the involvement of the superior temporal sulcus, the inferotemporal cortex and the parahippocampal and fusiform gyri, whereas the processing negativity would only involve the deepest generators of this network. Furthermore, the encoding of both faces and scrambled faces seems to take place predominantly in the right hemisphere.

N400-like potentials elicited by faces and knowledge inhibition

Within the theoretical framework of reference, the brain errs in processing complex stimuli, such as faces. Thus, these stimuli not only activate accurate representations but also inaccurate representations corresponding to known persons who resemble the face stimulus, and hence knowledge about these known persons. Since more errors are made in processing unfamiliar than familiar stimuli, these inaccurate activations are assumed to be more frequent, and/or more intense, with unknown than with known faces. Moreover, top-down mechanisms favor representations of stimuli that are congruent with the context, and representations of known persons, even if inaccurate, receive an additional amount of activation in contexts wherein known faces are expected. Inaccurate representations have to be inhibited to achieve accurate recognition. Thus, more inhibition would be required for unknown than for known faces, and in contexts wherein known faces are expected. The aim of the present work is to study the hypothesis that the N400 component of the event-related potentials (ERPs) reflects the inhibition of knowledge, and to see whether this hypothesis accounts for the N400-like potential elicited by faces. To achieve that goal, ERPs to known and unknown faces were recorded while the richness in known faces of each experimental block, and thus the expectancy for known faces, was manipulated. Consistent with the hypothesis, the amplitudes of the N400-like components were greater in conditions where more inhibition was required, i.e. for unknown rather than for known faces, and in the context of the block rich in known faces. This context effect was larger for unknown than for faces, and in the context of the block rich in known faces. This context effect was larger for unknown than for known faces.

Physical mapping of a commonly deleted region, the site of a candidate tumor suppressor gene, at 12q22 in human male germ cell tumors

A candidate tumor suppressor gene (TSG) site at 12q22 characterized by a high frequency of loss of heterozygosity (LOH) and a homozygous deletion has previously been reported in human male germ cell tumors (GCTs). In a detailed deletion mapping analysis of 67 normal-tumor DNAs utilizing 20 polymorphic markers mapped to 12q22-q24, we identified the limits of the minimal region of deletion at 12q22 between D12S377 (proximal) and D12S296 (distal). We have constructed a YAC contig map of a 3-cM region of this band between the proximal marker D12S101 and the distal marker D12S346, which contained the minimal region of deletion in GCTs. The map is composed of 53 overlapping YACs and 3 cosmids onto which 25 polymorphic and nonpolymorphic sequence-tagged sites (STSs) were placed in a unique order. The size of the minimal region of deletion was approximately 2 Mb from overlapping, nonchimeric YACs that spanned the region. We also developed a radiation hybrid (RH) map of the region between D12S101 and D12S346 containing 17 loci. The consensus order developed by RH mapping is in good agreement with the YAC STS-content map order. The RH map estimated the distance between D12S101 and D12S346 to be 246 cR8000 and the minimal region of deletion to be 141 cR8000. In addition, four genes that were previously mapped to 12q22 have been excluded as candidate genes. The leads gained from the deletion mapping and physical maps should expedite the isolation and characterization of the TSG at 12q22.

Heterogeneity of information-processing alterations according to dimensions of depression: an event-related potentials study

To identify alterations in elementary cognitive operations according to dimensions of depression, two stages of information processing, namely the response choice and the motor preparation stages, were explored using an event-related potential paradigm in two subgroups of depressed patients (retarded and blunted affect versus anxious-agitated and impulsive) compared to controls. Two results are common to all depressed patients: a slow encoding of stimuli (P1 wave) and a prolonged processing of stimulus-response compatibility (after P3b). This is compensated by a global velocity increase in stimulus evaluation or decision making (P3b) in anxious-agitated patients or, on the contrary, cumulated with its velocity decrease in retarded-blunted-affect patients. Such results could provide an explanation for the massive retardation observed in blunted-affect patients, contrary to anxious-agitated patients, whose normal reaction times may come from a very high energetical involvement at the P3b level. Results as a whole suggest that impairments in blunted-affect patients concern effort mechanisms, whereas those in anxious-agitated patients concern perceptual processes.

Depression as a dynamical disease

Mathematical models are helpful in the understanding of diseases through the use of dynamical indicators. A previous study has shown that brain activity can be characterized by a decrease of dynamical complexity in depressive subjects. The present paper confirms and extends these conclusions through the use of recent methodological advances: first episode and recurrent patients strongly differ in their dynamical response to therapeutic interventions. These results emphasize the need for clinical follow-ups to avoid recurrence and the necessity of specific therapeutic intervention in the case of recurrent patients.