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.     

Spatiotemporal analysis of event-related potentials to upright, inverted, and contrast-reversed faces: effects on encoding and recognition

In an n-back face recognition task where subjects responded to repeated stimuli, ERPs were recorded to upright, inverted, and contrast-reversed faces. The effects of inversion and contrast reversal on face encoding and recognition were investigated using the multivariate spatiotemporal partial least squares (PLS) analysis. The configural manipulations affected early processing (100-200 ms) at posterior sites: Inversion effects were parietal and lateral, whereas contrast-reversal effects were more occipital and medial, suggesting different underlying generators. A later reactivation of face processing areas was unique to inverted faces, likely due to processing difficulties. PLS also indicated that the "old-new" repetition effect was maximal for upright faces and likely involved frontotemporal areas. Marked processing differences between inverted and contrast-reversed faces were seen, but these effects were similar at encoding and recognition.     

不同类型皮瓣修复面部深Ⅲ度烧伤创面

目的探讨面部深Ⅲ度烧伤创面皮瓣移植类型的选择方法与临床治疗效果。方法1998年1月至2007年12月应用4种类型皮瓣（共38个）移植修复面部深Ⅲ度烧伤患者32例，其中游离皮瓣2个，轴型皮瓣16个（含岛状皮瓣5个），局部皮瓣18个，皮管转移2个。结果38个移植皮瓣，除5个皮瓣远端有小面积坏死，经换药愈合，余33个皮瓣完全成活。术后随访5月～3年，移植皮瓣质地柔韧，延展性好，组织挛缩轻，皮肤色泽变化小，外形满意。结论皮瓣血运丰富，有完整的皮下脂肪组织，移植后除了可用以修复皮肤缺损外，可明显改善受区局部组织血液循环，防止感染，最大程度地恢复面部的形态与功能。术中依据创面大小和创周皮肤条件，首选局部皮瓣或轴形皮瓣，局部无条件时行游离皮瓣或皮管移植。     

ERP and RT Delays in Long‐Term Abstinent Alcoholics in Processing of Emotional Facial Expressions During Gender and Emotion Categorization Tasks

Background: There is considerable evidence that alcoholics differ from nonalcoholics in the processing of stimuli that have emotional content. The current study examines those differences that are present in multi‐year abstinent individuals. Methods: We compared reaction time (RT), accuracy, and Event Related Potentials (ERP) measures in long‐term abstinent alcoholics (LTAA, n = 52) with that in age‐ and gender‐comparable nonalcoholic controls (NAC, n = 47). Subjects were presented with male and female faces exhibiting happy, neutral, or sad facial expressions and were instructed to identify the picture gender in 1 task and the emotion being expressed in a subsequent task. Results: LTAA had slower RTs than NAC when instructed to identify emotion, while RT was comparable when identifying gender. There were no differences between groups on task accuracy. P160 latency was increased in LTAA for both tasks compared to NAC, though P160 amplitude did not differ between groups. The P160 effect was about 5 × as large as the RT effect and was statistically independent of the RT effect, while the RT effect was no longer present after removing variance because of the P160 effect. Conclusions: Our data demonstrate slower early processing of emotional facial stimuli in alcoholics that is unresolved by long‐term abstinence and is most sensitively indexed by delayed P160 latency in LTAA.     

Dysfunctions within limbic–motor networks in amyotrophic lateral sclerosis

Previous studies have shown that affective symptoms are part of the clinical picture in amyotrophic lateral sclerosis (ALS), the most common motor neuron disorder in elderly people. Diffuse neurodegeneration of limbic regions (e.g., prefrontal cortex [PFC], amygdala) was demonstrated in ALS post-mortem, although the mechanisms of emotional dysregulation in ALS in vivo remain unclear. Using functional imaging, we assessed the brain responses to emotional faces in 11 cognitively unimpaired ALS patients and 12 healthy controls (HCs). We tested whether regional activities and connectivity patterns in the limbic system differed between ALS patients and HCs and whether the variability in clinical measures modulated the neuroimaging data. Relative to HCs, ALS patients displayed greater activation in a series of PFC areas and altered left amygdala–PFC connectivity. Anxiety modulated the right amygdala–PFC connectivity in HCs but not in ALS patients. Reduced right premotor cortex activity and altered left amygdala–supplementary motor area connectivity were associated with longer disease duration and greater disease severity, respectively. Our findings demonstrate dysfunctions of the limbic system in ALS patients at early stages of the disease, and extend our knowledge about the interplay between emotional brain areas and the regions traditionally implicated in motor control.     

How experience shapes memory for faces: An event-related potential study on the own-age bias

Young adults more accurately remember own-age than older faces. We tested whether this own-age bias (OAB) is reduced by increased experience. Young experts (geriatric nurses) and controls performed a recognition experiment with young and old faces. Critically, while control participants demonstrated better memory for young faces, no OAB was observed in the experts. Event-related potentials revealed larger N170 and P2 amplitudes for young than old faces in both groups, suggesting no group differences during early perceptual processing. At test, N250 repetition effects were more anteriorily distributed for own- than other-age faces in control participants, whereas experts showed no corresponding effects. A larger late positive component (LPC) for old than young faces was observed in controls, but not in experts. Larger LPCs may reflect prolonged stimulus processing compromising memory retrieval. In sum, experience with other-age faces does not affect early perceptual processing, but modulates later stages related to memory retrieval.     

Attentional Bias Toward Facial Stimuli Under Conditions of Social Threat in Socially Phobic and Nonclinical Participants

The present studies examined attentional bias for photographed faces and household objects among individuals diagnosed with generalised social phobia using a letter-probe computer task. Study 1 was conducted to replicate previous findings showing evidence of avoidance for faces among individuals diagnosed with generalised social phobia using a similar methodology as Mansell, W., Clark, D., Ehlers, A., and Chen, Y. P. (1999, Cognition and Emotion, 13(6), 673–690) on a clinical sample. Thirty-one clinical participants and 32 matched controls received identical threat instructions regarding an upcoming speech-task following the computer task. Contrary to previous findings, clinical participants demonstrated a preference for attending toward faces than household objects, regardless of facial expression and more so than controls. Study 2 was conducted on a different clinical sample in an attempt to replicate the findings of Study 1 with clearer instructions regarding the upcoming speech task. Thirty-one clinical participants and 32 matched controls were administered the same speech threat and task instructions as those used by Mansell, W., Clark, D., Ehlers, A., and Chen, Y. P. (1999, Cognition and Emotion, 13(6), 673–690). Findings revealed the same pattern found in Study 1. Hence, in contrast to previous findings, both studies demonstrated that under conditions of social threat individuals diagnosed with generalised social phobia are more vigilant of pictorial faces generally than non-anxious individuals. The current findings lend support to cognitive models predicting that anxious individuals prefer to attend more to social cues of threat, in this case, faces. Explanations for these contradictory findings on attentional processing in social phobia are discussed with reference to the possible impact of perceived social threat and altered levels of state anxiety. Suggestion is also made for clearer research to reconcile these seemingly opposing results.

Using fNIRS to examine occipital and temporal responses to stimulus repetition in young infants: Evidence of selective frontal cortex involvement

How does the developing brain respond to recent experience? Repetition suppression (RS) is a robust and well-characterized response of to recent experience found, predominantly, in the perceptual cortices of the adult brain. We use functional near-infrared spectroscopy (fNIRS) to investigate how perceptual (temporal and occipital) and frontal cortices in the infant brain respond to auditory and visual stimulus repetitions (spoken words and faces). In Experiment 1, we find strong evidence of repetition suppression in the frontal cortex but only for auditory stimuli. In perceptual cortices, we find only suggestive evidence of auditory RS in the temporal cortex and no evidence of visual RS in any ROI. In Experiments 2 and 3, we replicate and extend these findings. Overall, we provide the first evidence that infant and adult brains respond differently to stimulus repetition. We suggest that the frontal lobe may support the development of RS in perceptual cortices.