Reactions to children's faces: Males are more affected by resemblance than females are, and so are their brains

The detection of genetic relatedness (i.e., kinship) affects the social, parental, and sexual behavior of many species. In humans, self-referent phenotype matching based on facial resemblance may indicate kinship, and it has been demonstrated that facial resemblance increases perceptions of trustworthiness and attractiveness [Proc. R. Soc. Lond., B Biol. Sci. 269 (2002) 1307–1312; Proc. R. Soc. Lond., B Biol. Sci. (in press)]. However, investigations of sex differences in reaction to facial resemblance have produced mixed results [Evol. Hum. Behav. 25 (2004) 142–154; Evol. Hum. Behav. 23 (2002) 159–166; Evol. Hum. Behav. 24 (2003) 81–87]. Here, we replicate the effects of Platek et al. [Evol. Hum. Behav. 23 (2002) 159–166] using high-resolution color morphing. We also extend these findings using functional magnetic resonance imaging (fMRI) to demonstrate a possible neural mechanism that may account for the observed sex difference. These data support the hypothesis that human males may use and favor facial resemblance as a paternity cue.     

形状识别的功能定位和时间过程:功能磁共振与脑电结合的研究

通过结合具有高空间分辨率的功能磁共振成像（fMRI）和具有高时间分辨率的128导脑电事件相关电位（ERP）两项技术,测量了视皮层腹侧区域对图形形状识别任务反应的空间定位和时间过程。fMRI的实验结果表明,图形的形状和觉引起了腹测GTi／GF皮层区域的兴奋。进一步,基于fMRI兴奋区域的种子偶极子模型拟合的的ERP动态定位分析的结果和自由运动的偶极子模型拟合的ERP定位分析结果表明：GTi／GF区域活动的时间发生在刺激呈现之后132－176ms时间段,峰值150ms左右,相应于ERP的N1成分。这些结果在人类大脑皮层上同时确定了视觉通路中涉及图形形状识别的兴奋区域和兴奋的时间过程。     

睡眠剥夺中感觉运动皮层和视觉皮层神经活动及警觉水平的改变

在睡眠剥夺(sleep deprivation, SD)过程中,人类大脑的神经活动和警觉水平如何受到影响,尤其是感觉运动和视觉系统,目前仍是研究的热点。静息状态功能磁共振成像(resting state functional magnetic resonance imaging,rfMRI)作为一种反映人脑自发活动的非侵入式成像技术,在睡眠剥夺的研究中得到了广泛应用。本研究采用9次重复rfMRI和心理运动警觉任务(psychomotor vigilance task,PVT),以探索23名志愿者在整个36小时的睡眠剥夺过程中神经活动和警觉水平的变化。我们采用基于PVT的平均反应时间(mean reaction time, MRT)和失效率(lapses ratio, LR)评估警觉水平的变化。我们采用基于rfMRI的区域同质性(region homogeneity,ReHo)和低频波动幅度(amplitude of low frequency fluctuation,ALFF)评估大脑神经活动变化。结果表明,感觉运动网络(sensorimotor network, SMN)和视觉区域(visual network, VN)是受到睡眠剥夺影响最严重的区域。我们采用组独立成分分析(Group Independent component analysis, GICA)将视觉相关区域划分为视觉I区、视觉II区、视觉关联区,并从解剖自动标记(Anatomical automatic labeling,AAL)模板中提取运动感觉相关区域,包括中央前/中央后回、中央旁小叶和辅助运动区。我们发现,睡眠剥夺后16 - 30小时脑神经活动及警惕性下降。我们采用2×3重复测量方差分析,探讨睡眠压力、昼夜节律及其交互作用对感觉运动相关和视觉相关脑区神经活动的影响。我们观察到睡眠压力与交互作用对感觉运动相关区域和视觉相关区域有显著影响。我们采用皮尔逊相关系数评估警觉水平变化与感觉运动相关和视觉相关脑区神经活动变化的关系。睡眠剥夺期间所有感觉运动相关区域的神经活动变化与警觉变化均存在显著的相关关系。我们的研究结果证实,睡眠剥夺从第一天24：00开始改变SMN和VN的警戒水平和神经活动,睡眠压力和昼夜节律在睡眠剥夺期间调节SMN和VN的神经活动。此外,昼夜节律的效应受到睡眠压力的显著调节。感觉运动相关区域和视觉相关区域的增强导致他们远程连接的减弱,这可能是睡眠剥夺期间响应时间变慢的原因。     

Estradiol: A key biological substrate mediating the response to cocaine in female rats

A consistent finding in drug abuse research is that males and females show differences in their response to drugs of abuse. In women, increased plasma estradiol is associated with increased vulnerability to the psychostimulant and reinforcing effects of drugs of abuse. Our laboratory has focused on the role of estradiol in modulating the response to cocaine. We have seen that ovariectomy increases the locomotor response to a single cocaine injection, whereas estradiol exacerbates the locomotor response to repeated cocaine administration. Cocaine-induced sensitization of brain activity, as measured by fMRI, is also dependent on plasma estradiol. Moreover, we observed that although all ovariectomized rats show conditioned place preference to cocaine, it is more robust in ovariectomized rats with estradiol.Opioid receptors are enriched in brain regions associated with pleasure and reward. We find that in females, the effectiveness of kappa opioid agonists in decreasing the locomotor response to repeated cocaine varies with plasma estradiol. We also find that estradiol regulates the density of mu opioid receptors in brains areas associated with reward. These data hint that in females, estradiol modulates the behavioral effects of cocaine by regulating mu and kappa opioid signaling in mesocorticolimbic brain structures. Identifying the mechanisms that mediate differences in vulnerability to drugs of abuse may lead to effective therapeutic strategies for the treatment and prevention of addiction and relapse. We encourage health practitioners treating persons addicted to drugs to consider gender differences in response to particular pharmacotherapies, as well the sex steroid milieu of the patient.     

Clock genes beyond the clock: CLOCK genotype biases neural correlates of moral valence decision in depressed patients

Gene polymorphisms in the mammalian biological clock system influence individual rhythms. A single nucleotide polymorphism (SNP) in the 3' flanking region of CLOCK (3111 T/C; rs1801260) influenced diurnal preference in healthy humans and caused sleep phase delay and insomnia in patients affected by bipolar disorder. Genes of the biological clock are expressed in many brain structures other than in the 'master clock' suprachiasmatic nuclei. These areas, such as cingulate cortex, are involved in the control of many human behaviors. Clock genes could then bias 'nonclock' functions such as information processing and decision making. Thirty inpatients affected by a major depressive episode underwent blood oxygen–level dependent (BOLD) functional magnetic resonance imaging (fMRI). The cognitive activation paradigm was based on a go/no-go task. Morally connoted words were presented. Genotyping of CLOCK was performed for each patients. We measured activity levels through actimetry during the day before the fMRI study. CLOCK 3111 T/C SNP was associated with activity levels in the second part of the day, neuropsychological performance and BOLD fMRI correlates (interaction of genotype and moral valence of the stimuli). Our results support the hypothesis that individual clock genotype may influence several variables linked with human behaviors in normal and psychopathological conditions.     

Visual and auditory brain areas share a representational structure that supports emotion perception

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Exploring the neural basis of cognitive reserve in aging

The concept of reserve arose from the mismatch between the extent of brain changes or pathology and the clinical manifestations of these brain changes. The cognitive reserve hypothesis posits that individual differences in the flexibility and adaptability of brain networks underlying cognitive function may allow some people to cope better with brain changes than others. Although there is ample epidemiologic evidence for cognitive reserve, the neural substrate of reserve is still a topic of ongoing research. Here we review some representative studies from our group that exemplify possibilities for the neural substrate of reserve including neural reserve, neural compensation, and generalized cognitive reserve networks. We also present a schematic overview of our ongoing research in this area. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.     

Functional neuroimaging using ultrasonic blood-brain barrier disruption and manganese-enhanced MRI

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains technically challenging. One approach, Activation-Induced Manganese-enhanced MRI (AIM MRI), has been used successfully to map neuronal activity in rodents. In AIM MRI, Mn(2+) acts a calcium analog and accumulates in depolarized neurons. Because Mn(2+) shortens the T1 tissue property, regions of elevated neuronal activity will enhance in MRI. Furthermore, Mn(2+) clears slowly from the activated regions; therefore, stimulation can be performed outside the magnet prior to imaging, enabling greater experimental flexibility. However, because Mn(2+) does not readily cross the blood-brain barrier (BBB), the need to open the BBB has limited the use of AIM MRI, especially in mice. One tool for opening the BBB is ultrasound. Though potentially damaging, if ultrasound is administered in combination with gas-filled microbubbles (i.e., ultrasound contrast agents), the acoustic pressure required for BBB opening is considerably lower. This combination of ultrasound and microbubbles can be used to reliably open the BBB without causing tissue damage. Here, a method is presented for performing AIM MRI by using microbubbles and ultrasound to open the BBB. After an intravenous injection of perflutren microbubbles, an unfocused pulsed ultrasound beam is applied to the shaved mouse head for 3 minutes. For simplicity, we refer to this technique of BBB Opening with Microbubbles and UltraSound as BOMUS. Using BOMUS to open the BBB throughout both cerebral hemispheres, manganese is administered to the whole mouse brain. After experimental stimulation of the lightly sedated mice, AIM MRI is used to map the neuronal response. To demonstrate this approach, herein BOMUS and AIM MRI are used to map unilateral mechanical stimulation of the vibrissae in lightly sedated mice. Because BOMUS can open the BBB throughout both hemispheres, the unstimulated side of the brain is used to control for nonspecific background stimulation. The resultant 3D activation map agrees well with published representations of the vibrissae regions of the barrel field cortex. The ultrasonic opening of the BBB is fast, noninvasive, and reversible; and thus this approach is suitable for high-throughput and/or longitudinal studies in awake mice.     

Neural signatures of betrayal aversion: an fMRI study of trust

Decisions are said to be ‘risky’ when they are made in environments with uncertainty caused by nature. By contrast, a decision is said to be ‘trusting’ when its outcome depends on the uncertain decisions of another person. A rapidly expanding literature reveals economically important differences between risky and trusting decisions, and further suggests these differences are due to ‘betrayal aversion’. While its neural foundations have not been previously illuminated, the prevailing hypothesis is that betrayal aversion stems from a desire to avoid negative emotions that arise from learning one''s trust was betrayed. Here, we provide evidence from an fMRI study that supports this hypothesis. In particular, our data indicate that the anterior insula modulates trusting decisions that involve the possibility of betrayal.     

发展性阅读障碍的产生机制——从行为到遗传研究

发展性阅读障碍(developmental dyslexia,DD)是一种特殊的学习障碍,探索DD的产生机制有助于寻求DD儿童的鉴别和治疗方法.目前拼音文宁国家对DD的产生机制研究很多,结果也很丰富,但是很多观点还不一致.汉语DD研究起步较晚,各方面还不够深入和完善.简述了DD在认知、脑神经和基因方面的研究进展,对拼音文字DD与汉语DD的研究结果进行了对比,以揭示不同语言文字系统下DD者的认知神经差异.研究认为,应该大力加强对汉语DD的探究,这样不但为中国DD儿童的诊治提供理论基础,也可以为DD的语种特异性问题提供科学依据.