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

: The concept of attention as central to human performance extends back to the start of experimental psychology, yet even a few years ago, it would not have been possible to outline in even a preliminary form a functional anatomy of the human attentional system. New developments in neuroscience have opened the study of higher cognition to physiological analysis, and have revealed a system of anatomical areas that appear to be basic to the selection of information for focal (conscious) processing. The importance of attention is its unique role in connecting the mental level of description of processes used in cognitive science with the anatomical level common in neuroscience. Sperry describes the central role that mental concepts play in understanding brain function. As is the case for sensory and motor systems of the brain, our knowledge of the anatomy of attention is incomplete. Nevertheless, we can now begin to identify some principles of organization that allow attention to function as a unified system for the control of mental processing. Although many of our points are still speculative and controversial, we believe they constitute a basis for more detailed studies of attention from a cognitive-neuroscience viewpoint. Perhaps even more important for furthering future studies, multiple methods of mental chronometry, brain lesions, electrophysiology, and several types of neuro-imaging have converged on common findings.

/pdf/the-attention-system-of-the-human-brain-w797wllpat.pdf

The Attention System of the Human Brain

Learners rely on a combination of experience-independent and experience-dependent mechanisms to extract information from the environment. Language acquisition involves both types of mechanisms, but most theorists emphasize the relative importance of experience-independent mechanisms. The present study shows that a fundamental task of language acquisition, segmentation of words from fluent speech, can be accomplished by 8-month-old infants based solely on the statistical relationships between neighboring speech sounds. Moreover, this word segmentation was based on statistical learning from only 2 minutes of exposure, suggesting that infants have access to a powerful mechanism for the computation of statistical properties of the language input.

https://science.sciencemag.org/content/sci/274/5294/1926.full.pdf

Statistical Learning by 8-Month-Old Infants

Despite decades of research, the functional neuroanatomy of speech processing has been difficult to characterize. A major impediment to progress may have been the failure to consider task effects when mapping speech-related processing systems. We outline a dual-stream model of speech processing that remedies this situation. In this model, a ventral stream processes speech signals for comprehension, and a dorsal stream maps acoustic speech signals to frontal lobe articulatory networks. The model assumes that the ventral stream is largely bilaterally organized--although there are important computational differences between the left- and right-hemisphere systems--and that the dorsal stream is strongly left-hemisphere dominant.

The cortical organization of speech processing

Preparing words in speech production is normally a fast and accurate process. We generate them two or three per second in fluent conversation; and overtly naming a clear picture of an object can easily be initiated within 600 msec after picture onset. The underlying process, however, is exceedingly complex. The theory reviewed in this target article analyzes this process as staged and feed-forward. After a first stage of conceptual preparation, word generation proceeds through lexical selection, morphological and phonological encoding, phonetic encoding, and articulation itself. In addition, the speaker exerts some degree of output control, by monitoring of self-produced internal and overt speech. The core of the theory, ranging from lexical selection to the initiation of phonetic encoding, is captured in a computational model, called WEAVER++. Both the theory and the computational model have been developed in interaction with reaction time experiments, particularly in picture naming or related word production paradigms, with the aim of accounting for the real-time processing in normal word production. A comprehensive review of theory, model, and experiments is presented. The model can handle some of the main observations in the domain of speech errors (the major empirical domain for most other theories of lexical access), and the theory opens new ways of approaching the cerebral organization of speech production by way of high-temporal-resolution imaging.

/pdf/a-theory-of-lexical-access-in-speech-production-4daokag4lw.pdf

A theory of lexical access in speech production.

Recent Findings about Language Acquisition

On early development of oriented mouthing in neonate: Perspective on mental representation

Some Remarks On Psycholinguistic Studies

Response from paulesu and mehler.

Music, like language, is a universal and specific trait Isabelle Peretz,1,2,8 Julie Ayotte,1,2 Robert J. Zatorre,3 Jacques Mehler,4,5 Pierre Ahad,6 Virginia B. Penhune,7 and Benoit Jutras2 to humans. Similarly, music appreciation, like language 1 Department of Psychology comprehension, appears to be the product of a dediUniversity of Montreal cated brain organization (Peretz and Morais, 1993). AcC.P. 6128 succursale Centre-ville cordingly, as with language, normal acquisition of musiMontreal, Quebec H3C 3J7 cal competence is expected to recruit and fine tune 2 Research Centre distinct neural networks in the human brain. In the adInstitut Universitaire de Geriatrie de Montreal vent of a slight but congenital neural deviation, selective 4565 Queen Mary deficits of learning may occur. Indeed, some individuals Montreal, Quebec H3W 1W5 suffer from language-specific disorders, and a large re3 Montreal Neurological Institute search effort has been undertaken to understand the McGill University origin and varieties of these disorders. Some research3801 University ers claim that language impairments arise from failures Montreal, Quebec H3A 2B4 specific to language or cognitive processing (StuddertCanada Kennedy and Mody, 1995). Others hold that language 4 International School for Advanced Studies deficiencies result from a more elemental problem that Cognitive Neuroscience makes individuals unable to hear fine acoustic temporal via Beirut 4 changes (Tallal and Piercy, 1973). Nothing comparable 34014 Trieste has been initiated in the musical domain. Italy The possibility that certain persons are born with a 5 L.S.C.P. 54 specific musical deficit has been envisaged for more Boulevard Raspail than a century (Grant-Allen, 1878; Geshwind, 1984). 75006 Paris However, the evidence rests on anecdotal case descripFrance tions. In this paper, we present the study of a female 6 Psychology Department volunteer, Monica, who manifests a music-specific disMcGill University order, sometimes called tone deafness but for which 1205 Dr. Penfield we prefer the term “congenital amusia”. The term better Montreal, Quebec H3A 1B1 reflects the likelihood that there are multiple forms of 7 Psychology Department music developmental disorders, as there are various Concordia University patterns of acquired amusia resulting from brain acci7141 Sherbrooke W. dent (Marin and Perry, 1999). Montreal, Quebec H4B1R6

Jacques Mehler

Papers

Recent Findings about Language Acquisition

On early development of oriented mouthing in neonate: Perspective on mental representation

Some Remarks On Psycholinguistic Studies

Response from paulesu and mehler.

Congenital Amusia: A Disorder of Case Study Fine-Grained Pitch Discrimination