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

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

Social interaction is a cornerstone of human life, yet the neural mechanisms underlying social cognition are poorly understood. Recently, research that integrates approaches from neuroscience and social psychology has begun to shed light on these processes, and converging evidence from neuroimaging studies suggests a unique role for the medial frontal cortex. We review the emerging literature that relates social cognition to the medial frontal cortex and, on the basis of anatomical and functional characteristics of this brain region, propose a theoretical model of medial frontal cortical function relevant to different aspects of social cognitive processing.

http://people.uncw.edu/tothj/PSY595/Amodio-Social%20Cognition-NRN-2006.pdf

Meeting of minds: the medial frontal cortex and social cognition.

http://psych.colorado.edu/~kimlab/Botvinick.etal.TICS.2004.pdf

Conflict monitoring and anterior cingulate cortex: an update

In recent years, three attentional networks have been defined in anatomical and functional terms. These functions involve alerting, orienting, and executive attention. Reaction time measures can be used to quantify the processing efficiency within each of these three networks. The Attention Network Test (ANT) is designed to evaluate alerting, orienting, and executive attention within a single 30-min testing session that can be easily performed by children, patients, and monkeys. A study with 40 normal adult subjects indicates that the ANT produces reliable single subject estimates of alerting, orienting, and executive function, and further suggests that the efficiencies of these three networks are uncorrelated. There are, however, some interactions in which alerting and orienting can modulate the degree of interference from flankers. This procedure may prove to be convenient and useful in evaluating attentional abnormalities associated with cases of brain injury, stroke, schizophrenia, and attention-deficit disorder. The ANT may also serve as an activation task for neuroimaging studies and as a phenotype for the study of the influence of genes on attentional networks.

http://people.qc.cuny.edu/Faculty/Jin.Fan/Documents/Fan2002_14.pdf

Testing the Efficiency and Independence of Attentional Networks

Two different attentional networks have been associated with visuospatial attention and conflict resolution. In most situations either one of the two networks is active or both are increased in activity together. By using functional magnetic resonance imaging and a flanker task, we show conditions in which one network (anterior attention system) is increased in activity whereas the other (visuospatial attention system) is reduced, showing that attentional conflict and selection are separate aspects of attention. Further, we distinguish between neural systems involved in different forms of conflict. Specifically, we dissociate patterns of activity in the basal ganglia and insula cortex during simple violations in expectancies (i.e., sudden changes in the frequency of an event) from patterns of activity in the anterior attention system specifically correlated with response conflict as evidenced by longer response latencies and more errors. These data provide a systems-level approach in understanding integrated attentional networks.

https://www.pnas.org/content/pnas/97/15/8728.full.pdf

Dissociation of response conflict, attentional selection, and expectancy with functional magnetic resonance imaging

https://tauruspet.med.yale.edu/staff/edm42/papers/modeling/alpert-LSRRM-2003.pdf

A novel method for noninvasive detection of neuromodulatory changes in specific neurotransmitter systems.

Previous neuroimaging studies of perceptual priming have reported priming-related decreases in the extrastriate cortex. However, because these experiments have used visual stimuli, it is unclear whether the observed decreases are associated specifically with some aspect of visual perceptual processing or with more general aspects of priming. We studied within-and cross-modality priming using an auditory word stem completion paradigm. Positron emission tomography (PET) images were obtained during stem completion and a fixation task. Within-modality auditory priming was associated with blood flow decreases in the extrastriate cortex (bilateral), medial/right anterior prefrontal cortex, right angular gyrus, and precuneus. In cross-modality priming, the study list was presented visually, and subjects completed auditory word stems. Cross-modality priming was associated with trends for blood flow decreases in the left angular gyrus and increases in the medial/right anterior prefrontal cortex. Results thus indicate that reduced activity in the extrastriate cortex accompanies within-modality priming in both visual and auditory modalities.

/pdf/auditory-priming-within-and-across-modalities-evidence-from-2rha2th1nb.pdf

Auditory Priming within and across Modalities: Evidence from Positron Emission Tomography

Striatal dopamine release in sequential learning

Priming refers to a change in the ability to identify or produce an item as a consequence of a specific prior encounter. Priming has been studied extensively in cognitive studies of healthy volunteers, neuropsychological investigations of brain-damaged patients, and, more recently, studies using modern functional neuroimaging techniques such as positron emission tomography a nd functional magnetic resonance imaging. We review recent neuroimaging studies that have converged upon the conclusion that priming is reliably accompanied by decreased activity in a variety of brain regions. The establishment of this cortical signature of priming is beginning to generate new hypotheses concerning the relation between priming and explicit retrieval, which we illustrate by considering recent experiments on withinand cross-modality priming.

Rajendra D. Badgaiyan

Papers

Dissociation of response conflict, attentional selection, and expectancy with functional magnetic resonance imaging

A novel method for noninvasive detection of neuromodulatory changes in specific neurotransmitter systems.

Auditory Priming within and across Modalities: Evidence from Positron Emission Tomography

Striatal dopamine release in sequential learning

Neuroimaging of Priming: New Perspectives on Implicit and Explicit Memory