抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Function in the human connectome: Task-fMRI and individual differences in behavior

The aim of the present review article is to guide the reader through portions of the human time perception, or temporal processing, literature. After distinguishing the main contemporary issues related to time perception, the article focuses on the main findings and explanations that are available in the literature on explicit judgments about temporal intervals. The review emphasizes studies that are concerned with the processing of intervals lasting a few milliseconds to several seconds and covers studies issuing from either a behavioral or a neuroscience approach. It also discusses the question of whether there is an internal clock (pacemaker counter or oscillator device) that is dedicated to temporal processing and reports the main hypotheses regarding the involvement of biological structures in time perception.

/pdf/timing-and-time-perception-a-review-of-recent-behavioral-and-wksvo5j0qp.pdf

Timing and time perception: A review of recent behavioral and neuroscience findings and theoretical directions

Suppose someone had to prepare a review article on visual perception, instead of time perception. This individual would probably ask for a series of reviews, with at least one—and probably several—dedicated to color, distance, shape, and motion perception, and maybe to other aspects of visual perception. It would be very difficult to complete the same exercise for time perception since the categories of temporal experiences are not as clearly defined. However, for a reader to understand the scope of a text on time perception, it is essential to develop a representation of what the main research avenues or categories are. The present text should help the reader to grasp the scope of recent literature related to psychological time and time perception. After a brief overview of the various perspectives on what could be meant by psychological time, the review will propose to identify of series of key concepts and empirical findings that should delineate the field of time perception and timing, and will discuss some models of time perception. The article also provides a review of the main recent findings in the field in which a neuroscientific approach to timing is adopted. In this section, the roles of the cerebellum, of the cerebral cortices, and of the basal ganglia in the timing processes are emphasized. Time Perception Beyond the Focus of the Present Review

TUTORIAL REVIEW Timing and time perception: A review of recent behavioral and neuroscience findings and theoretical directions

Magnetic resonance imaging (MRI) has transformed our understanding of the human brain through well-replicated mapping of abilities to specific structures (for example, lesion studies) and functions1-3 (for example, task functional MRI (fMRI)). Mental health research and care have yet to realize similar advances from MRI. A primary challenge has been replicating associations between inter-individual differences in brain structure or function and complex cognitive or mental health phenotypes (brain-wide association studies (BWAS)). Such BWAS have typically relied on sample sizes appropriate for classical brain mapping4 (the median neuroimaging study sample size is about 25), but potentially too small for capturing reproducible brain-behavioural phenotype associations5,6. Here we used three of the largest neuroimaging datasets currently available-with a total sample size of around 50,000 individuals-to quantify BWAS effect sizes and reproducibility as a function of sample size. BWAS associations were smaller than previously thought, resulting in statistically underpowered studies, inflated effect sizes and replication failures at typical sample sizes. As sample sizes grew into the thousands, replication rates began to improve and effect size inflation decreased. More robust BWAS effects were detected for functional MRI (versus structural), cognitive tests (versus mental health questionnaires) and multivariate methods (versus univariate). Smaller than expected brain-phenotype associations and variability across population subsamples can explain widespread BWAS replication failures. In contrast to non-BWAS approaches with larger effects (for example, lesions, interventions and within-person), BWAS reproducibility requires samples with thousands of individuals. 

/pdf/reproducible-brain-wide-association-studies-require-3qa0wl93.pdf

Reproducible brain-wide association studies require thousands of individuals

Department of Psychiatry, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030 Written and spoken words activate left hemisphere areas involved in language processing. However, we here show that overlearned sequences (e.g. letters, numbers, weekdays, months) involve an unexpected right hemispheric activation in both the middle temporal gyrus and temporoparietal junction. Our findings offer a framework for understanding neuropsychological patterns seen in conditions such as synesthesia, in which anomalous perceptual experiences are triggered by overlearned sequences, and also in semantic dementia, in which left hemisphere damage disrupts word knowledge even while sequences can be spared.

Why overlearned sequences are special: distinct neural networks in the right hemisphere for ordinal sequences

Several observations suggest that overlearned ordinal categories (e.g., letters, numbers, weekdays, months) are processed differently than non-ordinal categories in the brain. In synesthesia, for example, anomalous perceptual experiences are most often triggered by members of ordinal categories (Rich et al., 2005; Eagleman, 2009). In semantic dementia (SD), the processing of ordinal stimuli appears to be preserved relative to non-ordinal ones (Cappelletti et al., 2001). Moreover, ordinal stimuli often map onto unconscious spatial representations, as observed in the SNARC effect (Dehaene et al., 1993; Fias, 1996). At present, little is known about the neural representation of ordinal categories. Using functional neuroimaging, we show that words in ordinal categories are processed in a fronto-temporo-parietal network biased toward the right hemisphere. This differs from words in non-ordinal categories (such as names of furniture, animals, cars, and fruit), which show an expected bias toward the left hemisphere. Further, we find that increased predictability of stimulus order correlates with smaller regions of BOLD activation, a phenomenon we term prediction suppression. Our results provide new insights into the processing of ordinal stimuli, and suggest a new anatomical framework for understanding the patterns seen in synesthesia, unconscious spatial representation, and SD.

/pdf/why-overlearned-sequences-are-special-distinct-neural-cclm48rbvo.pdf

Why overlearned sequences are special: distinct neural networks for ordinal sequences

Neural responses to a repeated stimulus typically diminish, an effect known as repetition suppression. When a single visual stimulus (e.g., letter of the alphabet, word, object, face) is serially flashed in different locations of a display, several stimuli appear to be present simultaneously due to an effect known as persistence of vision. Normal human observers' estimates of how many stimuli they perceived at any instant of time are significantly lower when the same stimulus is flashed repeatedly than when a different stimulus is used for each flash. This is a result of the brain's diminishing response (repetition suppression) to the repeated stimuli. The present invention generally relates to methods for assessing the normality of neural performance, particularly as relates to the integrity of cortical inhibition, visual persistence, proliferation effect, and repetition suppression. Deficits in repetition suppression serve as early and confirmatory measures of cognitive disorders such as schizophrenia.

Device and method for rapid measurement of repetition suppression in the brain

Brain, Reward, and Drug Addiction

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Vani Pariyadath

Papers

Why overlearned sequences are special: distinct neural networks in the right hemisphere for ordinal sequences

Why overlearned sequences are special: distinct neural networks for ordinal sequences

Device and method for rapid measurement of repetition suppression in the brain

Brain, Reward, and Drug Addiction

Acknowledging Lack of Inclusion in Genetic Analyses.