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

We review evidence for partially segregated networks of brain areas that carry out different attentional functions. One system, which includes parts of the intraparietal cortex and superior frontal cortex, is involved in preparing and applying goal-directed (top-down) selection for stimuli and responses. This system is also modulated by the detection of stimuli. The other system, which includes the temporoparietal cortex and inferior frontal cortex, and is largely lateralized to the right hemisphere, is not involved in top-down selection. Instead, this system is specialized for the detection of behaviourally relevant stimuli, particularly when they are salient or unexpected. This ventral frontoparietal network works as a 'circuit breaker' for the dorsal system, directing attention to salient events. Both attentional systems interact during normal vision, and both are disrupted in unilateral spatial neglect.

Control of goal-directed and stimulus-driven attention in the brain

https://surfer.nmr.mgh.harvard.edu/ftp/articles/desikan06-parcellation.pdf

An automated labeling system for subdividing the human cerebral cortex on MRI scans into gyral based regions of interest.

https://surfer.nmr.mgh.harvard.edu/ftp/articles/dale99-recon1.pdf

Cortical surface-based analysis. I. Segmentation and surface reconstruction

Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Background: Generalization from previous experiences allows us to evaluate the affective value of novel events. A breakdown of this fundamental ability may lead to incorrect attributions of affective value that could give rise to psychotic symptoms. To examine this hypothesis, we tested whether the generalization of conditioned fear responses is abnormal in schizophrenia, using functional magnetic resonance imaging (fMRI). Methods: 37 schizophrenia and 32 healthy subjects, matched for age, and sex, underwent an fMRI scan while participating in a Pavlovian fear conditioning and generalization paradigm. During the conditioning phase, one face was used as a conditioned stimulus and paired with an electrical shock (the CS+), whereas a different face was used as a neutral stimulus that was never paired with a shock (the CS−). In the generalization phase, five stimuli that were different morphs between the CS+ to the CS- were selected based on each individual’s ability to discriminate the two faces. Afterwards, subjects were asked to rate the likelihood each stimulus was followed by a shock (explicit ratings). In the fMRI analyses, we identified the regions of the brain that showed significant CS+ vs. CS− responses during the conditioning phase in both groups. Those regions were then tested for generalization responses using an anatomical regions-of-interest approach and a mixed design ANOVA. Results: There were no between-group differences in CS+ vs. CS− responses of the brain during the conditioning phase. In both groups, CS+ > CS− activation was observed in the anterior insula and dorsal anterior cingulate cortex, whereas the reversed pattern (CS− > CS+) was observed in the ventromedial prefrontal cortex and angular gyri. During the generalization phase, patients with schizophrenia exhibited impaired generalization, both behaviorally (explicit ratings) and in the brain, most prominently in the right anterior insula, due to a lack of differentiation between the morphs and the CS−. This abnormality correlated with positive symptom severity. Conclusion: Schizophrenia patients are able to successfully acquire conditioned fear responses, but show impaired generalization of those fear memories. This impairment in fear generalization is associated with abnormal functioning of the anterior insula. These findings suggest that psychosis may arise in part from a deficit in the immediate retrieval of associative memory traces—a basic process that can be quantified as impaired fear generalization.

/pdf/52-abnormal-anterior-insula-activity-during-fear-1rk8293bph.pdf

Roger B. H. Tootell

Papers

52. Abnormal Anterior Insula Activity During Fear Generalization in Schizophrenia

Color selectivity in macaque inferior temporal cortex

Neural differences between developmental prosopagnosics and super-recognizers

FMRI of Retinotopy and Color Sensitivity in Human Visual Cortex

fMRI Analysis of 2nd-Order Visual Motion Perception & Attentive-Tracking