Fearful faces selectively increase corticospinal motor tract excitability: a transcranial magnetic stimulation study

Fearful facial expressions are danger signals that rapidly trigger a cascade of neurobiological processes defensibly associated with action preparation. However, direct evidence for the activating effects of fearful facial expressions on the motor system is absent. The current transcranial magnetic stimulation (TMS) study investigated whether fearful facial expressions selectively increase corticospinal motor tract (CST) excitability. Focal TMS was applied over the left primary motor cortex during the exposure of fearful, happy, and neutral facial expressions in 12 healthy right-handed volunteers. Changes in CST excitability using the motor evoked potential (MEP) were recorded. Results showed significant selective increases in MEP to fearful facial expressions. These findings provide the first direct evidence for selective increases in CST excitability to threat and contribute to evolutionary views on emotion and action preparedness.     

Depression symptomatology and the neural correlates of infant face and cry perception during pregnancy

Depression symptoms during pregnancy may affect emerging maternal sensitivity and have lasting consequences for the dyadic relationship. Here, we examined whether depression was associated with the neural correlates of infant face and cry perception during pregnancy. In 36 women between 34 and 38 weeks gestation, we examined the P300 elicited by infant emotional (happy, distressed, and neutral) faces and cries (high- and low-distress cries and a neutral tone). The Edinburgh Postnatal Depression Scale and the Beck Depression Inventory-II were employed to measure current depression symptomatology. Higher depression symptoms were associated with an attenuated P300 to distressed infant faces, but not with happy or neutral infant faces. There was no association between depression symptoms and the P300 elicited by infant cries. These results suggest that depression symptoms during pregnancy may affect neural processing of infant faces, especially when the infant face is expressing distress.     

Chernoff脸谱图的改进

目的 Chemoff脸谱图在进行脸部容貌对应变量的分配时，不同作图者会有不同的选择，从而产生不同的分组结果。本文尝试对此做出改进。方法 通过实例介绍该方法的具体步骤。并将该方法的分类结果与聚类分析作比较。结果该方法的分类结果与聚类分析的分类结果非常相似。结论 改进了的脸谱图法使脸谱图的变量分配问题变得较为简单并且可以得到较好的分类结果。     

Face Perception in Children with Autism and Asperger's Syndrome

Abstract— Children with diagnoses of either autism or Asperger's syndrome were matched on measures of verbal mental age with nonautistic control children. They were tested on their abilities to process both facial and nonfacial stimuli. There were no significant differences between the low ability autistic and control groups, but the high ability autistic and Asperger's children performed significantly worse than controls across all tests. Group averages masked substantial individual variation. The results are seen as indicating a general perceptual deficit that is not specific to faces or emotions. This appears to be a common correlate of autism and Asperger's syndrome, rather than a core symptom.     

Face identification in the near-absence of focal attention

In contrast to artificial geometric shapes, natural scenes and face-gender can be processed even when spatial attention is not fully available. In this study, we investigate whether a finer discrimination, at the level of the individual, is possible in the near-absence of focal attention. Using the paradigm, subjects performed face identification on faces of celebrities and relatively unfamiliar individuals, along with a task that is known to engage spatial attention. We find that face-identification performance is only modestly impaired under dual-task conditions. These results suggest that the visual system is well able to make complex judgments of natural stimuli, even when attention is not fully available.     

The ependyma and subependymal layer of the young rat: A new contribution with freeze-fracture

The subependymal layer underlying the external wall of the lateral ventricle has been studied with freeze-fracture in 3-week-old rats. Membrane specializations corresponding to gap junction and attachment plates were found on ependymal cells, as well as the characteristic features of cilia and microvilli. Hexagonal arrays of particles previously found in the membrane of astrocytes were also present in ependyma. The membranes of subependymal cells were characterized by a paucity of intramembranous particles, when compared to ependymal and other mature glial cells. Specialized regions corresponding to areas of close membrane apposition seen on the sections were tentatively identified as clustering of particles on the protoplasmic face, corresponding with a cobbly texture on the exoplasmic face. Their possible significance, if they are not artifactual, is discussed.The analysis of replicas obtained from freeze-fractured material provides an additional tool for the study of cell differentiation and maturation, in our case gliogenesis. The comparison of membrane characteristics of neuroepithelial cells—precursors of glia—with those of mature glial cells and intermediate forms may contribute to a better understanding of the mechanism of their maturation.     

Sustained happiness? Lack of repetition suppression in right-ventral visual cortex for happy faces

Emotional stimuli have been shown to preferentially engage initial attention but their sustained effects on neural processing remain largely unknown. The present study evaluated whether emotional faces engage sustained neural processing by examining the attenuation of neural repetition suppression to repeated emotional faces. Repetition suppression of neural function refers to the general reduction of neural activity when processing a repeated stimulus. Preferential processing of emotional face stimuli, however, should elicit sustained neural processing such that repetition suppression to repeated emotional faces is attenuated relative to faces with no emotional content. We measured the reduction of functional magnetic resonance imaging signals associated with immediate repetition of neutral, angry and happy faces. Whereas neutral faces elicited the greatest suppression in ventral visual cortex, followed by angry faces, repetition suppression was the most attenuated for happy faces. Indeed, happy faces showed almost no repetition suppression in part of the right-inferior occipital and fusiform gyri, which play an important role in face-identity processing. Our findings suggest that happy faces are associated with sustained visual encoding of face identity and thereby assist in the formation of more elaborate representations of the faces, congruent with findings in the behavioral literature.     

抑郁症患者恐惧与中性面孔刺激的脑磁图研究

目的:利用脑磁图探讨抑郁症患者给予重复恐惧、中性面孔刺激后早期神经磁场激活特征。方法:8例抑郁症患者及12名健康右利手对照者,在给予恐惧、中性面孔图片刺激同时记录脑磁图信号,使用SPM8b软件进行数据分析;设两样t检验P<0.005(未校正)和K值≥40个体素范围为差异有统计学意义。结果:在0～50Hz频率范围内,与对照组相比,抑郁组在恐惧面孔图片刺激下显示出左侧眶额皮质、腹外侧前额皮质激活增强;在中性面孔刺激下,抑郁组显示出左侧腹外侧前额皮质和眶额皮质、左前扣带回激活增强,双侧顶叶如楔前叶等激活减弱。结论:抑郁症患者情绪感受脑区左侧前额皮质低频脑磁图功率增强。     

A walk on the dark side: TMS over the right inferior frontal gyrus (rIFG) disrupts behavioral responses to infant stimuli

ABSTRACT

Infant signals, including infant sounds and facial expressions, play a critical role in eliciting parental proximity and care. Processing of infant signals in the adulthood brain is likely to recruit emotional empathy neural circuits, including the inferior frontal gyrus (IFG). Here, we used transcranial magnetic stimulation (TMS) to test the role of right IFG (rIFG) in behavioral responses to infant signals. Specifically, a group of nulliparous women were asked to perform a handgrip dynamometer task and an Approach-Avoidance Task (AAT) after receiving TMS over the right IFG or over a control site (vertex). Suppressing activity in the rIFG affected the modulation of handgrip force in response to infant crying. Moreover, the AAT showed that participants tend to avoid the sad infant face after Vertex stimulation, and this bias was counteracted by rIFG stimulation. Our results suggest a causal role of rIFG in sensitive responding towards sad infants and point to the rIFG as a critical node in the neural network underlying the innate releasing mechanism for feelings of love, affection and caring of sad infants.     

Impact of ibuprofen and peroxisome proliferator-activated receptor gamma on emotion-related neural activation: A randomized,placebo-controlled trial

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen have shown initial promise in producing antidepressant effects. This is perhaps due to these drugs being peroxisome proliferator-activated receptor gamma (PPARγ) agonists, in addition to their inhibition of cyclooxygenase enzymes. Some, albeit mixed, evidence suggests that PPARγ agonists have antidepressant effects in humans and animals. This double-blind, placebo-controlled, pharmacologic functional magnetic resonance imaging (ph-fMRI) study aimed to elucidate the impact of ibuprofen on emotion-related neural activity and determine whether observed effects were due to changes in PPARγ gene expression. Twenty healthy volunteers completed an emotional face matching task during three fMRI sessions, conducted one week apart. Placebo, 200 mg, or 600 mg ibuprofen was administered 1 h prior to each scan in a pseudo-randomized order. Peripheral blood mononuclear cells were collected at each session to isolate RNA for PPARγ gene expression. At the doses used, ibuprofen did not significantly change PPARγ gene expression. Ibuprofen dose was associated with decreased blood oxygen level-dependent (BOLD) activation in the dorsolateral prefrontal cortex and fusiform gyrus during emotional face processing (faces-shapes). Additionally, PPARγ gene expression was associated with increased BOLD activation in the insula and transverse and superior temporal gyri (faces-shapes). No interaction effects between ibuprofen dose and PPARγ gene expression on BOLD activation were observed. Thus, results suggest that ibuprofen and PPARγ may have independent effects on emotional neurocircuitry. Future studies are needed to further delineate the roles of ibuprofen and PPARγ in exerting antidepressant effects in healthy as well as clinical populations.