中国人限制性饮食和食物渴求的认知神经机制

物质丰富的时代, 如何抵御美味食物线索带来的食物渴求, 并限制饮食从而保持健康成为人们关注的重要话题之一。近年来, 国内学者为了探讨节食成功的原因, 创建中国食物图片库, 考察限制性饮食的认知神经机制, 以及成功和失败限制性饮食者的脑机制差异; 开展了特质食物渴求及中国特色的辣食渴求的认知神经研究。对推进饮食行为研究的理论发展, 也为肥胖、饮食失调等健康干预工作提供重要支持。     

“羊毛薅尽口味乏”:节俭心态如何影响食物预期享受与体验评估

节俭心态是一种广泛存在的思维模式, 但以往研究对其如何影响个体心理和行为仍知之甚少。基于6项研究和1个补充性元分析, 文章揭示了“羊毛薅尽口味乏”的现象、解释机制及边界条件。具体而言, 研究1通过分析来自美国大型外卖平台GRUBHUB的二手数据, 发现节俭心态与食物口味好评率呈负相关关系; 研究2通过模拟外卖点餐情景验证了节俭心态对预期享受的负面影响; 研究3以试吃活动的名义开展了一项实地实验, 证实了节俭心态削弱了个体对巧克力的预期享受, 并导致在吃完巧克力后整体评价更低; 研究4验证了认知资源耗竭在节俭心态对果蔬沙拉预期享受的影响中发挥中介作用; 研究5则识别了获利成本的边界条件, 即当获利成本较高时, 节俭心态对蛋糕预期享受的消极影响更明显; 研究6进一步为缓解这种负面效应提供了一种干预手段, 即当施以正念干预时, 节俭心态对火锅预期享受的消极影响被削弱。最后, 单文章元分析证实了节俭心态对食物预期享受和体验评估的效应稳健。文章不仅丰富和拓展了节俭心态和认知资源相关的理论研究, 同时为食物营销和饮食福祉提供实践启示。     

Neuronal changes in normal human aging and Alzheimer's disease

This article discusses age-related changes in brain weight, total number of cortical neurons, cortical dendrites, spine, and synapse density. The conclusion is that the present outlook is less grim than it was 30 years ago. Age-related reduction appears to be specific to brain region and cortical layer rather than a general feature. In addition, we describe a different pattern of changes that occur in Alzheimer's disease patients. This review concludes that the association cortices in particular are affected in aging and Alzheimer's disease and that the primary visual and somatosensory cortices are relatively spared.     

Energy,Complexity, and Strategies of Evolution: As Illustrated by Maya Indians of Guatemala

Using free energy rate density (Φ_m) I differentiate two evolutionary strategies common to cosmic, biological, and cultural systems: the horizontal when energy increases proportional to mass, with no increase in complexity; and the vertical when it increases disproportionately to the mass and complexity increases. The vertical process is a continuing increase in complexity such that the system becomes vulnerable to collapse when energy sources fail. This is illustrated by a comparison of four Mayan Indian groups in Guatemala.     

Sweet Necessities: Food, Sex, and Saint Augustine

Central to Augustine's understanding of rightly ordered sexuality is his belief that the pleasure of the act should not be separated from its good (procreation). It is useful to observe that he reasons in a similar way about eating: that the pleasure of eating should not be separated from its good (nourishment). Inadequacies in his understanding of the purpose of food and eating may be instructive when we think about inadequacies in his understanding of sex. If there is more to food than he imagines, the same may be true of sex. Correcting for such inadequacies may also help correct for the (inadvertent) way in which his understanding of the purpose of sex may seem to legitimize technologies of assisted reproduction.     

The stress of food allergy issues in daily life

Objective: Food allergies are a growing health concern, but their implications for daily psychological functioning are unknown. This micro-longitudinal study investigated the daily frequency of food allergy issues and how this related to experiences of stress, mood and physical energy.

Design: One hundred and eight adults with physician-diagnosed food allergies completed an initial Internet survey followed by a 2-week Internet daily diary survey.

Main outcome measures: The initial survey collected socio-demographic and food allergy information. The daily survey collected information about the participants’ experiences of stress, mood, physical energy and food allergy issues during that day.

Results: Commonly experienced allergy issues included negative physical symptoms, higher food prices, anxiety about safety of food, trouble maintaining a healthy diet and anxiety/stress at social occasions. Furthermore, multilevel modelling analyses showed that stress and negative mood were significantly higher on days with more allergy issues. Older adults experienced lower positive mood and physical energy on days with more issues.

Conclusion: This is the first study to incorporate near to real-time tracking to examine the frequency of food allergy issues and the implications for daily psychological functioning. Targeting the issues we identified could reduce stress in patients with food allergies and improve their overall quality of life.     

Statistical manifold as an affine space: A functional equation approach

A statistical manifold M_μ consists of positive functions f such that defines a probability measure. In order to define an atlas on the manifold, it is viewed as an affine space associated with a subspace of the Orlicz space L^Φ. This leads to a functional equation whose solution, after imposing the linearity constrain in line with the vector space assumption, gives rise to a general form of mappings between the affine probability manifold and the vector (Orlicz) space. These results generalize the exponential statistical manifold and clarify some foundational issues in non-parametric information geometry.     

Concurrent access to two concentrations of orally delivered phencyclidine: effects of feeding conditions.

Two experiments addressed the effects of food satiation and deprivation on oral self-administration of two concurrently available phencyclidine concentrations. In the first experiment, 8 rhesus monkeys self-administered either of two concentrations of phencyclidine ("PCP, angel dust") and water under concurrent fixed-ratio 16 schedules. One concentration was always held constant (0.25 mg/mL) while a series of other phencyclidine concentrations, ranging from 0 (water) to 1.0 mg/mL, was presented in a nonsystematic order. Initially the monkeys were tested while food satiated, and the procedure was then repeated during food deprivation. The monkeys usually selected the higher concentration within the first few minutes of the session, indicating that taste and/or other immediate postingestional effects were important factors. Contrary to a number of previous reports, there were no consistent differences across subjects in the mean number of liquid deliveries or mean drug intake (mg/kg) during food satiation and deprivation. However, for all monkeys the within-session time course of responding during food satiation consistently differed from that during deprivation. A second experiment assessed whether the failure to find consistent differences in drug intake during food satiation and deprivation had been due to the history of concurrent access to different phencyclidine concentrations or to the extended experience with phencyclidine under food-satiation conditions. Six additional monkeys (Group 2) were exposed to the phencyclidine self-administration procedure (during food satiation and deprivation) for the same length of time as the monkeys in Experiment 1 (Group 1), except they received only concurrent access to phencyclidine (0.25 mg/mL) and water. Both groups then received concurrent access to phencyclidine and water during five repeated cycles of food deprivation and satiation. There were also marked individual differences in Group 2: During food satiation, 2 of the monkeys' responding increased, 1 showed no change, and 3 decreased. Examination of a number of historical variables indicated that the greater the percentage of total sessions spent during food satiation with phencyclidine available (before these experiments began), the greater the amounts of phencyclidine consumed during food satiation and the smaller the differences in phencyclidine intake when the two feeding conditions were compared.     

Effects of food deprivation and reinforcement magnitude on conditioned suppression

In Experiment I, the responding of rats lever pressing on a variable-interval schedule for sucrose solution was partially suppressed by a variable duration conditioned stimulus followed by shock. When food deprivation was increased, response rates during and before the conditioned stimulus increased monotonically. Varying the concentration of sucrose across blocks of sessions or from session to session in a semi-random sequence had little effect on response rates either before or during the conditioned stimulus. With a fixed sequence of increasing concentrations across a five-session block, increased concentration produced much more rapid increases in response rates before than during the conditioned stimulus. In Experiment II, rats were presented with the same sequence of increasing concentrations across a five-session block. When tested at 80% body weight, response rates increased rapidly as concentration increased, but at 100%, body-weight rates increased only slightly. The effect of a change in body weight in Experiment II thus mimicked the effect of the conditioned stimulus in the latter part of Experiment I. These findings support the view that the effect of a pre-aversive conditioned stimulus is similar to that of a change in food deprivation, but unlike that of a change in reinforcement magnitude.