Abstract: Several studies have provided evidence of a women's better accuracy in interpreting emotional states. Despite this difference is generally ascribed to the primary role of female gender in the affective relation with the offspring, to date, little information is available regarding gender differences in the ability to interpret infant facial expressions. In the present study, we examined the roles of gender and expertise in interpreting infant expression in 34 men and women who differed in their experience with infants. Women showed a significantly higher level of decoding accuracy compared to men. Expertise positively affected facial expressions decoding among women only. Our results suggest that in judging emotional facial expressions of infants, there is an interaction of biological (i.e., gender) and cultural factors that is independent of a woman's socioeconomic status.

Abstract: While there is a general agreement about the sensory properties of the early-latency C1 (P/N80) and P1 components of visual evoked potentials (VEPs), the literature is not consistent about the timing of modulatory attention effects at an early sensory stage for either space- or object-based stimulus features. The aim of this study was to investigate whether inter-individual differences in VEP morphology might affect the nature and polarity of amplitude changes via selective visual attention. EEG was recorded in 20 right-handed individuals while they viewed drawings of familiar objects presented slightly lateralized and performed a categorization task. It consisted in paying attention and responding to a conjunction of space and object features. On the basis of VEP morphology, and independently of task factors, subjects were subdivided in two groups: one group exhibited a prominent N80 and the other a prominent P80 in the same latency range from the same electrode sites. RTs to targets were identical in the two groups, suggesting that morphology was independent of task-related factors. VEP morphology affected the direction and amplitude of spatial and non-spatial attention effects. While attention effects always resulted in increased positivity for the P80 group (at both the C1 and P1 levels), shape relevance was associated with enhanced N80 and P1 responses in the N80 group. These data provide evidence for an inversion of attention effects, in addition to inversion of C1 polarity, in people exhibiting negative C1 at mesial occipital sites.

Abstract: BACKGROUND: Neuroimaging and neuropsychological literature show functional dissociations in brain activity during processing of stimuli belonging to different semantic categories (e.g., animals, tools, faces, places), but little information is available about the time course of object perceptual categorization. The aim of the study was to provide information about the timing of processing stimuli from different semantic domains, without using verbal or naming paradigms, in order to observe the emergence of non-linguistic conceptual knowledge in the ventral stream visual pathway. Event related potentials (ERPs) were recorded in 18 healthy right-handed individuals as they performed a perceptual categorization task on 672 pairs of images of animals and man-made objects (i.e., artifacts). RESULTS: Behavioral responses to animal stimuli were ~50 ms faster and more accurate than those to artifacts. At early processing stages (120-180 ms) the right occipital-temporal cortex was more activated in response to animals than to artifacts as indexed by posterior N1 response, while frontal/central N1 (130-160) showed the opposite pattern. In the next processing stage (200-260) the response was stronger to artifacts and usable items at anterior temporal sites. The P300 component was smaller, and the central/parietal N400 component was larger to artifacts than to animals. CONCLUSION: The effect of animal and artifact categorization emerged at ~150 ms over the right occipital-temporal area as a stronger response of the ventral stream to animate, homomorphic, entities with faces and legs. The larger frontal/central N1 and the subsequent temporal activation for inanimate objects might reflect the prevalence of a functional rather than perceptual representation of manipulable tools compared to animals. Late ERP effects might reflect semantic integration and cognitive updating processes. Overall, the data are compatible with a modality-specific semantic memory account, in which sensory and action-related semantic features are represented in modality-specific brain areas.

Abstract: ABSTRACT: BACKGROUND: It is known that the orthographic properties of linguistic stimuli are processed within the left occipitotemporal cortex at about 150-200 ms. We recorded event-related potentials (ERPs) to words in standard or mirror orientation to investigate the role of visual word form in reading. Word inversion was performed to determine whether rotated words lose their linguistic properties. METHODS: About 1300 Italian words and legal pseudo-words were presented to 18 right-handed Italian students engaged in a letter detection task. EEG was recorded from 128 scalp sites. RESULTS: ERPs showed an early effect of word orientation at ~150 ms, with larger N1 amplitudes to rotated than to standard words. Low-resolution brain electromagnetic tomography (LORETA) revealed an increase in N1 to rotated words primarily in the right occipital lobe (BA 18), which may indicate an effect of stimulus familiarity. N1 was greater to target than to non-target letters at left lateral occipital sites, thus reflecting the first stage of orthographic processing. LORETA revealed a strong focus of activation for this effect in the left fusiform gyrus (BA 37), which is consistent with the so-called visual word form area (VWFA). Standard words (compared to pseudowords) elicited an enhancement of left occipito/temporal negativity at about 250-350 ms, followed by a larger anterior P3, a reduced frontal N400 and a huge late positivity. Lexical effects for rotated strings were delayed by about 100 ms at occipito/temporal sites, and were totally absent at later processing stages. This suggests the presence of implicit reading processes, which were pre-attentive and of perceptual nature for mirror strings. CONCLUSION: The contrast between inverted and standard words did not lead to the identification of a purely linguistic brain region. This finding suggests some caveats in the interpretation of the inversion effect in subtractive paradigms.

Abstract: BACKGROUND: Current cognitive neuroscience models predict a right-hemispheric dominance for face processing in humans. However, neuroimaging and electromagnetic data in the literature provide conflicting evidence of a right-sided brain asymmetry for decoding the structural properties of faces. The purpose of this study was to investigate whether this inconsistency might be due to gender differences in hemispheric asymmetry. RESULTS: In this study, event-related brain potentials (ERPs) were recorded in 40 healthy, strictly right-handed individuals (20 women and 20 men) while they observed infants' faces expressing a variety of emotions. Early face-sensitive P1 and N1 responses to neutral vs. affective expressions were measured over the occipital/temporal cortices, and the responses were analyzed according to viewer gender. Along with a strong right hemispheric dominance for men, the results showed a lack of asymmetry for face processing in the amplitude of the occipito-temporal N1 response in women to both neutral and affective faces. CONCLUSION: Men showed an asymmetric functioning of visual cortex while decoding faces and expressions, whereas women showed a more bilateral functioning. These results indicate the importance of gender effects in the lateralization of the occipito-temporal response during the processing of face identity, structure, familiarity, or affective content.

Abstract: This study sought to determine the influence of gender and parental status on the brain potentials elicited by viewing infant facial expressions. We used ERP recording during a judgement task of infant happy/distressed expression to investigate if viewer gender or parental status affects the visual cortical response at various stages of perceptual processing. ERPs were recorded in 38 adults (male/female, parents/non-parents) during processing of infant facial expressions that varied in valence and intensity. All infants were unfamiliar to viewers. The lateral occipital P110 response was much larger in women than in men, regardless of facial expression, thus indicating a gender difference in early visual processing. The occipitotemporal N160 response provided the first evidence of discrimination of expressions of discomfort and distress and demonstrated a significant gender difference within the parent group, thus suggesting a strong interactive influence of genetic predisposition and parental status on the responsivity of visual brain areas. The N245 component exhibited complete coding of the intensity of facial expression, including positive expressions. At this processing stage the cerebral responses of female and male non-parents were significantly smaller than those of parents and insensitive to differences in the intensity of infant suffering. Smaller P300 amplitudes were elicited in mothers versus fathers, especially with infant expressions of suffering. No major group differences were observed in cerebral responses to happy or comfortable expressions. These findings suggest that mere familiarity with infant faces does not explain group differences.

Abstract: The development of reading skills is a complex and very long-lasting process. In an influential study Booth et al. demonstrated age-related changes in the activation of a network of left hemisphere regions, including the inferior frontal area, the superior temporal gyrus, and the angular gyrus. Interestingly, they found that the angular gyrus, which is involved in the mapping between phonological and orthographic representation, is automatically activated in adults during visual orthographic tasks not requiring this operation.

Abstract: Neuroimaging has provided evidence that the first stages of visual word recognition activate a visual word-form center localized in the left extrastriate cortex (fusiform gyrus). Accordingly, neurological cases of patients suffering from pure alexia reported the left posterior occipital lobe as the possible locus of orthographic analysis. There is less agreement in the literature about which brain structures are involved in the subsequent stages of word processing and, in particular, their time course of activation. Functional magnetic resonance imaging and magnetic source imaging studies recently reported data that could indicate a dual route model of reading. These findings are particularly relevant to studies on the functional deficits associated with phonological and surface dyslexia. There is evidence for the existence of two different brain mechanisms supporting phonological processing in visual word recognition: one mechanism subserving "assembled phonology" for reading letter strings and another one subserving "addressed phonology" for reading meaningful words. However, available knowledge on the time course and neural locus of grapheme-to-phoneme conversion mechanisms in reading is still inadequate. In this study, we compared processing of meaningful and meaningless Italian words in a task requiring a phonemic/phonetic decision task. Stimuli were 1152 different orthographic stimuli presented in the central visual field. Half the stimuli were Italian words (with a high or low frequency of occurrence), the other half were meaningless strings of letters (legal pseudowords and letter strings). Event-related potentials were recorded from 28 scalp sites in 10 Italian university students. The task consisted of deciding about the presence/absence of a given "phone" in the hypothetical enunciation of word read: for example, "Is there a /k/ in cheese?". Results showed that lexical frequency and orthographical regularity affected linguistic processing within 150 msec poststimulus. Indeed, the amplitude of a centroparietal P150 varied as a function of stimulus type, being larger in response to high-frequency words than to low-frequency ones and to words and pseudowords than to letter strings. This component might index visual categorization processes and recognition of familiar objects, being highly sensitive to orthographic regularity and "ill-formedness" of words. The amplitude of the P150 was the same in response to well-formed meaningless and to meaningful words, when these latter had a low lexical frequency. This might indicate that highly familiar words are recognized as meaningful unitary visual objects at very early stages of processing, through a visual route to an orthographic input lexicon. Moreover, the amplitude of the negativity recorded between 250 and 350 msec showed an anteroposterior topographic dissociation for access to the phonemic representation of well- or ill-formed strings of characters. Brain responses were larger over the left occipito-temporal regions during reading of words and pseudowords and over the left frontal regions during reading of letter strings.

Abstract: The goal of the study was to investigate how the color and shape of visual stimuli are processed when they are conjointly presented and represent real, and familiar, entities for which normal individuals presumably have a specific 'object color knowledge' (e.g., piglets are pink, artichokes are green). There is evidence, from event related potential (ERP) literature on selective attention to color in conjunction with other, arbitrarily related, stimulus dimensions (e.g., geometrical shape), that color is processed faster than shape, and that the processing of shape depends on color relevance. In this study we recorded ERPs from 28 scalp sites in right-handed volunteers performing selective attention tasks to either color or shape of pictures representing familiar objects and animals. The results revealed that the selection of color was faster, and probably less demanding, than that of shape. However, it was also evidenced that the selection of color depended on object shape, but not vice versa. Indeed, in the attend-color condition, the N2 responses were significantly greater when stimulus shape was prototypically associated, rather than unassociated, with the color perceived. Topographical mapping of difference voltages identified the posterior occipito/temporal region of the left hemisphere as the possible locus of conjoined color and shape processing. Overall, the data support object-based attention models.

Abstract: Recent event-related potential (ERP) and neuroimaging studies suggest that bilingual individuals are able to inhibit the processing of a non-target language while speaking or reading in another language. The neural mechanisms subserving code switching still remain matter of debate. The aim of the present study was to shed some light on the neurofunctional bases of such mechanisms. ERPs were recorded in native Italian simultaneous interpreters and monolingual controls during a semantic processing task in which the subjects had to evaluate the sensibleness of final words of incomplete sentences. All participants were strictly right-handed. Interpreters knew at least four languages (from four to eight) at a professional level, from among 11 European and Asian languages, and had an excellent command of English (L2). Four hundred short sentences were presented visually; half of them had an unexpected final word, producing a semantic incongruence. Sentences could be entirely in Italian or in English (unmixed); alternatively, the body of the sentence could be in English and the final word in Italian or vice versa (mixed). ERPs were time locked to the onset of the final word. Both reaction times (RTs) and electrophysiological data indicated a lesser degree of hemispheric lateralization for linguistic function during L2 rather than L1 processing in interpreters. The first effect of lexical switching and code switching was recorded in the time window between 140 and 200 ms at left anterior sites. At N400 level, ERPs were significantly larger to L2 than to L1 words only in the mixed and not in the unmixed condition. No effect of language was observed in the unmixed condition, thus suggesting that the difference in L1/L2 processing was not related to a difference in proficiency, but rather to a different functional organization of semantic integration systems due to the later age of acquisition of L2 compared to L1. Interpreters were faster at reading and comprehending sentences in English ending with an Italian word than vice versa (L2 --> L1 switch).

Abstract: The present study sought to investigate the time course of brain activation during grapheme-to-phoneme conversion and phonologic processing of legal Italian syllables. To this goal, we monitored a group of right-handed native Italian volunteers performing a phonologic decision task (same/different judgments). ERPs were recorded from 28 scalp sites during silent reading. Analysis of ERP latency showed faster responses to same syllables than to different ones as early as 105 ms at left temporal electrode site and 160 ms at frontal sites. The first effect of phonologic/graphemic incongruity on the amplitude of ERPs was observed at lateral occipital/posterior temporal sites (N185), where physiologic responses were enhanced to incongruous syllables.

Abstract: The present study investigated brain mechanisms underlying the perception of illusory contours, using recordings of event-related potentials of the brain (ERPs) in right-handed individuals. Forty different stimuli were presented randomly 1600 times in foveal vision; twenty of them produced the perception of illusory contours of a Kanizsa square, the remaining were obtained rotating outwards the inducers and they did not produce any illusory percept. Half of them had white inducers on a black background and vice versa; half of them were symmetrical and the other half asymmetrical. In lateral occipital areas illusory percepts produced larger evoked responses starting as early as 145 ms post-stimulus with the N1 peak. ERP data did not provide evidence of right-sided lateralisation of the processes underlying illusory contours formation at sensory level, as suggested by some neuroimaging and neuropsychological studies. The two cerebral hemispheres were differently activated while the subjective patterns formation progressed through neural processing stages. Indeed, brain response to illusory contours was more pronounced in the left occipital area at N2 component level (about 250 ms post-stimulus) and at right parietal sites at the latency of P300 component. Both background luminance and stimulus symmetry interacted with illusory boundaries formation. Present results confirm the hypothesis that the integration of contours arises at early stages of visual processing and highlight the primary role of edges continuity and boundary alignment in illusory contours perception.

Abstract: The aim of the present study was to investigate how multiple languages are represented in the human brain. Event-related brain potentials (ERPs) were recorded from right-handed polyglots and monolinguals during a task involving silent reading. The participants in the experiment were nine Italian monolinguals and nine Italian/Slovenian bilinguals of a Slovenian minority in Trieste; the bilinguals, highly fluent in both languages, had spoken both languages since birth. The stimuli were terminal words that would correctly complete a short, meaningful, previously shown sentence, or else were semantically or syntactically incorrect. The task consisted in deciding whether the sentences were well formed or not, giving the response by pressing a button. Both groups read the same set of 200 Italian sentences to compare the linguistic processing, while the bilinguals also received a set of 200 Slovenian sentences, comparable in complexity and length, to compare the processing of the two languages within the group. For the bilinguals, the ERP results revealed a strong, left-sided activation, reflected by the N1 component, of the occipitotemporal regions dedicated to orthographic processing, with a latency of about 150 msec for Slovenian words, but bilateral activation of the same areas for Italian words, which was also displayed by topographical mapping. In monolinguals, semantic error produced a long-lasting negative response (N2 and N4) that was greater over the right hemisphere, whereas syntactic error activated mostly the left hemisphere. Conversely, in the bilinguals, semantic incongruence resulted in greater response over the left hemisphere than over the right. In this group, the P615 syntactical error responses were of equal amplitude on both hemispheres for Italian words and greater on the right side for Slovenian words. The present findings support the view that there are interand intrahemispheric brain activation asymmetries when monolingual and bilingual speakers comprehend written language. The fact that the bilingual speakers in the present study were highly fluent and had acquired both languages in early infancy suggests that the brain activation patterns do not depend on the age of acquisition or the fluency level, as in the case of late, not-so-proficient L2 language learners, but on the functional organization of the bilinguals' brain due to polyglotism and based on brain plasticity.

Abstract: The aim of the present study was to investigate the neural mechanisms of stimulus orientation selection in humans by recording event-related potentials (ERPs) of the brain with a 32-channel montage. Stimuli were isoluminant black-and-white gratings (3 cpd) having an orientation of 50, 70, 90, 110 and 130, randomly presented in the foveal portion (2 of visual angle) of the central visual field. The task consisted in selectively attending and responding to one of the five grating orientations, while ignoring the others. ERP results showed that orientation selection affected neural processing starting already at an early post-stimulus latency. The P1 component (80-140 ms) measured at temporal area, which might well be reflecting the activity of the ventral stream (i.e. 'WHAT' system) of the visual pathways, showed an enhanced amplitude for target orientations. These effects increased with progressive neural processing over time as reflected by selection negativity (SN) and P300 components. In addition, both reaction times (RTs) and ERPs showed a strong 'oblique' effect, very probably reflecting the perceptual predominance of orthogonal versus oblique stimulus orientation in the human visual system: RTs were much faster, and SN and P300 components much larger, to gratings presented vertically than in other orientations.

Abstract: Functional neuroimaging and neuropsychological findings suggest that memory retrieval of common and proper names is subserved by different neuro-functional systems but little is known about the topographic localization of neural generators. In the present study brain electrical activity was recorded with a high density electrode montage in healthy young volunteers during lexical retrieval upon written definition. ERPs spatio-temporal mapping showed on one side a strong activation of left anterior temporal and left central-frontal areas for proper names, and on the other side a greater involvement of occipital areas for common names retrieval. The specific pattern of bio-electrical activity recorded during proper names retrieval might index the activation of neural circuits for recalling names of high contextual complexity, poor of sensory-motor associations and dependent on precise spatio-temporal coordinates.

Abstract: Aim of the present study was to investigate the mechanisms of attentional selection of hierarchically organized visual patterns (compound letter stimuli), while subjects were engaged in target selection at either the global or local level. Event-related brain potentials (ERPs) were recorded using a high density electrode montage. Reaction times (RTs) to target stimuli were also recorded. RT data indicated the interference effect of global incongruent information with the local one. ERP data were consistent with behavioral data. In fact, the early sensory N115 component recorded at the primary visual areas exhibited smaller responses to locally attended elements when the global configuration was incongruent rather than congruent, suggesting an interference effect of the global with the local level. Conversely, no interference effect was found for globally attended configurations. These results strongly support the view of a perceptual advantage of globally conveyed information, very likely mediated by low spatial frequency channels. At later processing levels, N1 and P3 components were faster and larger when attention was paid to the global configuration. The difference between target and nontarget responses, indexing the attentional target selection, yielded a broad occipital-temporal negativity focused onto the left hemisphere in the attend-local, and over the right hemisphere in the attend-global condition. The present findings indicate a hemispheric asymmetry in cerebral activation during local/global processing. In addition, they provide robust evidence of a sensory precedence of global information.

Abstract: Hemispheric specialization for spatial frequency processing was investigated by measuring reaction times to sinusoidal gratings in 12 healthy subjects. Stimuli of 1.5, 3, and 6 c/deg were randomly presented at two peripheral locations in the left (LVF) and right (RVF) upper visual hemifields during a selective attention task. Subjects were instructed to pay covert attention and to respond to a frequency in a given hemifield ignoring all other stimuli. Results showed that RTs were significantly faster at LVF than RVF for low frequency gratings, and at RVF than LVF for high frequency gratings. Furthermore, RTs were faster to 6 than 1.5 c/deg at the RVF, while there was not a significant difference at the LVF. In our view, these findings in a task requiring fast and accurate spatial frequency discriminations may be interpreted in terms of a hemispheric asymmetry for spatial frequency processing.

Abstract: In ERP literature on visual selective attention evidence has been provided that selectively directing attention to a spatial frequency affects the visual processing of the attended frequency, and of unattended frequencies within the same channel bandwidth, starting at a relatively late level of post-stimulus processing, i.e., after about 150 msec. Nevertheless, little knowledge is available about the topographic distribution of these attention effects. This study investigated attentional selection of stimulus relative size at occipital and latero-occipital sites, as well as at fronto-lateral sites. ERPs from posterior scalp electrode sites showed that attention to check sizes enhanced the early sensory components, thus indicating that feature-based attention may result in a modulation of sensory processing. Comparisons of the ERPs to relevant and irrelevant patterns showed an enhanced latero-occipital P90 positivity as well as an occipital N115 negativity to relevant patterns, thus also suggesting possible differential mechanisms of early attentional selectivity at these locations. Later effects of attention consisted of a selection negativity to relevant patterns at posterior electrodes, and a selection positivity at latero-frontal sites. A larger late positivity to irrelevant patterns at anterior sites also suggested an active suppression of attentional response to irrelevant information. Moreover, right-and left-sided asymmetries were found to be respectively consistent for the P90 and N115 with left hemispheric specialization for high, and right hemispheric specialization for low spatial frequencies. A stronger left-sided attentional selectivity has also been found.

Abstract: Event-related potentials and reaction times were recorded to stimuli flashed to the left and right visual hemifields under different conditions of covert spatial attention. In different blocks, subjects were instructed to allocate attention primarily to either the left or to the right stimulus locations, or to divide attention equivalently between left and right locations (i.e., neutral condition). Regardless of attention condition, however, speeded motor responses were required to stimuli in both visual fields. In comparison to the neutral attention condition, reaction times were slower for targets at unattended locations (costs) and faster for the targets at attended locations (benefits), however, only costs were statistically significant. Significant attention-related enhancements were observed for both early and late ERP components. Cost/benefit analysis of the ERPs revealed ERP benefits in the amplitudes of the early sensory-evoked cortical component P1 (100-160 ms). In contrast, ERP costs appeared only at a relatively late stage of perceptual processing (200-280 ms latency post-stimulus). The relationship between RT and ERP costs and benefits is discussed with respect to models of spatial attention.

Abstract: Neuropsychological data have shown that the two cerebral hemispheres differ in the control of spatial attention. The present study investigated hemispheric asymmetries and visuomotor integration in a split-brain patient and three control subjects. Simple reaction times (RTs) and event-related potentials (ERPs) were recorded to lateralized stimuli presented at different eccentricities in the left and right visual hemifields. Both electrophysiological and behavioural data showed that, unlike controls, the split-brain patient showed a strong rightward attentional bias resulting in shorter RTs and larger P300 potentials to stimuli falling in the rightmost space. Furthermore, ERPs also showed that while the RH has a bilateral control of visual space, the LH spatial orienting capability is most restricted to the contralateral hemifield.