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

https://www2.econ.iastate.edu/tesfatsi/DeepLearningInNeuralNetworksOverview.JSchmidhuber2015.pdf

Deep learning in neural networks

We have developed a near-real-time computer system that can locate and track a subject's head, and then recognize the person by comparing characteristics of the face to those of known individuals. The computational approach taken in this system is motivated by both physiology and information theory, as well as by the practical requirements of near-real-time performance and accuracy. Our approach treats the face recognition problem as an intrinsically two-dimensional (2-D) recognition problem rather than requiring recovery of three-dimensional geometry, taking advantage of the fact that faces are normally upright and thus may be described by a small set of 2-D characteristic views. The system functions by projecting face images onto a feature space that spans the significant variations among known face images. The significant features are known as "eigenfaces," because they are the eigenvectors (principal components) of the set of faces; they do not necessarily correspond to features such as eyes, ears, and noses. The projection operation characterizes an individual face by a weighted sum of the eigenface features, and so to recognize a particular face it is necessary only to compare these weights to those of known individuals. Some particular advantages of our approach are that it provides for the ability to learn and later recognize new faces in an unsupervised manner, and that it is easy to implement using a neural network architecture.

/pdf/eigenfaces-for-recognition-1vpm5kz4jh.pdf

Eigenfaces for recognition

▪ Abstract The prefrontal cortex has long been suspected to play an important role in cognitive control, in the ability to orchestrate thought and action in accordance with internal goals. Its neural basis, however, has remained a mystery. Here, we propose that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task. We review neurophysiological, neurobiological, neuroimaging, and computational studies that support this theory and discuss its implications as well as further issues to be addressed

/pdf/an-integrative-theory-of-prefrontal-cortex-function-2j9unprn5f.pdf

An integrative theory of prefrontal cortex function

A baseline or control state is fundamental to the understanding of most complex systems. Defining a baseline state in the human brain, arguably our most complex system, poses a particular challenge. Many suspect that left unconstrained, its activity will vary unpredictably. Despite this prediction we identify a baseline state of the normal adult human brain in terms of the brain oxygen extraction fraction or OEF. The OEF is defined as the ratio of oxygen used by the brain to oxygen delivered by flowing blood and is remarkably uniform in the awake but resting state (e.g., lying quietly with eyes closed). Local deviations in the OEF represent the physiological basis of signals of changes in neuronal activity obtained with functional MRI during a wide variety of human behaviors. We used quantitative metabolic and circulatory measurements from positron-emission tomography to obtain the OEF regionally throughout the brain. Areas of activation were conspicuous by their absence. All significant deviations from the mean hemisphere OEF were increases, signifying deactivations, and resided almost exclusively in the visual system. Defining the baseline state of an area in this manner attaches meaning to a group of areas that consistently exhibit decreases from this baseline, during a wide variety of goal-directed behaviors monitored with positron-emission tomography and functional MRI. These decreases suggest the existence of an organized, baseline default mode of brain function that is suspended during specific goal-directed behaviors.

/pdf/a-default-mode-of-brain-function-zwenkbmjw7.pdf

A default mode of brain function.

https://www.oxcns.org/papers/26%20Burton%20MJ%20et%20al(effect%20of%20Hunger%20on%20the%20responses%20of%20neur.pdf

Effects of hunger on the responses of neurons in the lateral hypothalamus to the sight and taste of food

Neurophysiology and functions of the primate amygdala.

Density of cones and ganglion cells was studied in horizontal sections of retina in the rhesus monkey (Macaca, mulatta) and the squirrel monkey (Saimiri sciureus). The lower angular density of cones in the fovea of Saimiri correlates with its visual acuity, which is poorer than that of Macaca (0.74 and 0.65 min of arc respectively). Cone density falls more steeply with angular eccentricity from the fovea in Saimiri, in accordance with its relatively poorer peripheral acuity. Comparable results were obtained with retinal ganglion cells, but the comparisons at the fovea itself are more difficult because of the lateral displacement of these elements in the foveal region. The cortical magnification of the visual field (that is, the number of mm of cortex per degree of visual field) is lower for both the foveal and parafoveal representations at the striate cortex in Saimiri. This was correlated with its poorer foveal and parafoveal acuity. It was shown that with increasing eccentricity from the fovea, the fall in the magnification of the visual field at the striate cortex is approximately proportional to the decrease in ganglion cell density at the retina. The results of this study, in which acuity and topography of the visual system are compared in two species of monkey, are consistent with the view that both retinal topography, and the cortical magnification of the visual field, are closely related to visual acuity.

https://www.oxcns.org/papers/2%20Rolls%20Cowey%201970%20Topography%20of%20the%20Retina%20and%20Striate%20Cortex,%20and%20visual%20acuity.pdf

Topography of the retina and striate cortex and its relationship to visual acuity in rhesus monkeys and squirrel monkeys.

We describe here hippocampal cells that respond during whole-body motion when a monkey is moved on a remote-controlled robot-mounted platform in a cue-controlled test chamber (2 x 2 x 2 m). Some of these cells responded to linear motion, and others to axial rotation. Some of these cells responded when the same motion occurred without a view of the visual field. Such cells appeared to be driven by vestibular inputs. Other cells required a view of the visual field for their response, and these cells appeared to be driven by the visual motion relative to the monkey of the test chamber. Further evidence that this was the case was that some of the cells responded to rotation and linear motion of the test chamber while the monkey remained stationary. Other cells responded to combinations of whole-body motion and a view of the environment. These findings show that information about whole-body motion, as well as about where the animal is looking in an environment, is represented in the primate hippocampus. We suggest that this information is important in spatial memory and thus in spatial navigation.

https://www.oxcns.org/papers/184%20OMara%20Rolls%20Berthoz%20Kesner%201994%20Whole%20body%20motion%20and%20hippocampal%20neurons.pdf

Edmund T. Rolls

Papers

Effects of hunger on the responses of neurons in the lateral hypothalamus to the sight and taste of food

Neurophysiology and functions of the primate amygdala.

Topography of the retina and striate cortex and its relationship to visual acuity in rhesus monkeys and squirrel monkeys.

Neurons responding to whole-body motion in the primate hippocampus

The neuronal encoding of information in the brain.