胫骨性别分级判别及其与传统方法比较

目的：为验证性别分级判别法在实际应用中的效果及提高胫骨的性别判别率,材料和方法：先抽取126侧胫骨（M68,F58）进行研究,并将其结果作为预计值,另抽取168侧胫骨（M90,F78）进行对比实验,将其结果作为实验值。结果：分级判别法的判别率多因素判别及单因素判别的最高正确判别率预计值分别为89．6％,80．2％和78．6％;实验值分别为84．5％,75．6％和73．2％,讨论：新方法无论在理论预计值上还是在实际应用中较传统方法均有较大提高;实验值较预计值的降低是由于抽样误差造成的。因此,此方法将是人类学及其相关学科研究的更有效的手段。     

The ON-OFF dichotomy in visual processing: from receptors to perception

Vision scientists long ago pointed to black and white as separate sensations and saw confirmation in the fact that in the absence of light, one perceives the visual field as gray against which the negative after-image of a bright light appeared blacker. The first recordings from optic nerve fibers in vertebrates revealed ON and OFF signals, later associated with separate streams, arising already at the synapse between receptors and bipolar cells. These can be identified anatomically and physiologically and remain distinct all the way to the lateral geniculate nucleus, whose fibers form the input to the primary visual cortex. The dichotomy has been probed by electroretinography and analyzed by means of pharmacological agents and dysfunction due to genetic causes. The bi- rather than a unidirectional nature of the retinal output has advantages in allowing small signals to remain prominent over a greater dynamic range.

The two streams innervate cortical neurons in a push–pull manner, generating receptive fields with spatial sensitivity profiles featuring ON and OFF subregions. Manifestations of the dichotomy appear in a variety of simple visual discriminations where there are often profound threshold differences in patterns with same polarity as compared with mixed contrast-polarity components. But even at levels in which the spatial, contrast and color attributes have already been securely established and black and white elements participate equally, a categorical difference between blackness and whiteness of a percept persists. It is an opponency, akin to the ones in the color domain, derived from the original ON and OFF signals and subsequently bound with the other attributes to yield a feature's unitary percept.     

A comparison of postcochlear implantation speech scores in an adult population

OBJECTIVES: The vast majority of cochlear implant recipients realize significant improvement in speech perception. However, there continue to be a small group that does not realize such a benefit. In an effort to identify possible predictors for this, we have compared pre- and postimplant audiologic data using Hearing In Noise Test (HINT), City University of New York (CUNY), or Central Institute for the Deaf (CID) scores for 445 consecutive English-speaking adult patients followed for a minimum of 1 year postimplantation in two distinct groups, poor versus excellent performers. STUDY DESIGN: Retrospective. METHODS: Poor performers were those who realized a worsening, no improvement, or an improvement of less than 10%. This group numbered 58 (13%). High performers consisted of a cadre of 194 (44%) patients who scored between 91 and 100% postimplantation. Demographic data relating to onset of deafness, education exposure, etiology, etc., were evaluated. RESULTS: Of the poor performers, 33 (57%) were pre-/perilingually deafened. Of these, 79% had not received any auditory/oral training in childhood. On the other hand, a total of 109 implant recipients were individuals who were pre-/perilingually deafened. Of these, 24 were in the excellent performer category. All were identified early and were recipients of a strong auditory/oral education. Of the high performers, 170 (88%) were deafened late. Other findings such as preoperative electronystagmography with caloric testing, hearing aid use, device type, and high-resolution computed tomography scan of the temporal bone will be discussed for both groups. CONCLUSIONS: A high preimplant speech score, auditory verbal therapy, and postlingual deafness statistically correlate with higher postimplant speech scores 1 year after cochlear implantation. Device type, caloric response and hearing aid use preimplantation, age at surgery, and sex do not statistically correlate with either poor or excellent speech discrimination scores postcochlear implantation.     

Assessing auditory capabilities in young children

OBJECTIVE: Early detection of hearing loss in infants and toddlers has created a need for age-appropriate tests that assess auditory perceptual capabilities. This article describes a progressive test battery we have developed to evaluate phonetic contrast perception, phoneme recognition, and word recognition in children 6 months to 5 years. This battery is part of a clinical research protocol designed to track auditory development in this population. METHODS: The progressive test battery originated from a model of auditory perceptual development to assess phonetic discrimination and word recognition. Phonetic discrimination is evaluated using the Battery of Auditory Speech Perception Tests for Infants and Toddlers (BATIT). The BATIT is composed of four measures (VRASPAC, PLAYSPAC, OLIMSPAC, and VIDSPAC) intended to assess the child's ability to distinguish between phonologically significant contrasts using developmentally appropriate tasks. Designed for children aged 6 months and up, performance is represented either by percent correct or by the level of confidence that the child's responses are not random. Phoneme and word recognition are assessed in children 4 years and older using lists of consonant-vowel-consonant (CVC) phonemes in words and lexically controlled words both in and out of sentence context (LEXSEN). RESULTS: Cross-sectional data show that children with normal hearing may be assessed by the age of 7 months on VRASPAC; by 3 years on PLAYSPAC and OLIMSPAC; and by 4-5 years on VIDSPAC, CVC phonemes in words, and LEXSEN words in isolation and in sentences. Data from infants with hearing loss show that VRASPAC is sensitive to degree of hearing loss, but performance with normally hearing children declines after 12 months of age. CONCLUSION: Assessment of phonetic discrimination and word recognition is, for the most part, attainable in young children using a progressive test battery, but none of the tests used here is effective between 1 and 3 years of age. Continued development will be required to fill this gap and to separate auditory from non-auditory influences on performance.     

Attribute-invariant orientation discrimination at an early stage of processing in the human visual system

This study investigated event-related brain potentials (ERPs) during selective attention to the orientation of a bar comprised of two squares, which were defined by only color or motion (intra-attribute conditions) or both (interattribute condition). An early positive potential in association with orientation selection was elicited for all conditions in similar latency ranges but with different scalp distributions. These results suggest that attribute-invariant orientations can be discriminated at an early stage of processing in the human brain, which fills a gap between monkey electrophysiology and human psychophysics, while attribute-specific orientations are also available in a given context.     

Conceptual model of human blur perception

An empirically based, conceptual model of human blur perception is presented. It incorporates the concepts of blur detection and blur discrimination in depth, and across the central and peripheral retina, in two- and three-dimensional visual space. Key aspects of the model are its dynamic nature, predictability regarding the blur-based depth-ordering of objects, patterns of retinal defocus with far and near viewing, and interactions related to retinal defocus between the central and peripheral retina. Furthermore, a two-dimensional schematic representation of the blur-free region during near viewing is depicted in dioptric space. This model has implications with respect to accommodative control, depth perception, and refractive error development and progression.     

The deleterious effect of contrast reversal on recognition is unique to faces, not objects

Faces reversed in contrast cannot be readily recognized, an effect absent in object recognition. Why? Four factors: expertise, reflectance (pigmentation), high similarity, and the need to discriminate metrically varying smooth surfaces have been offered as explanations. Observers achieved expertise on discriminating smoothly shaped, pigmented, non-face blobs with positive contrast, where distractor similarity matched that of a set of faces in shape and reflectance. On a match-to-sample task, reversal of contrast between sample and matching images had no effect when matching such blobs, but markedly degraded performance when matching faces suggesting that this effect is unique to faces.     

咪唑克生增强吲哚满酯在小鼠视觉暗示空间鉴别中的作用

目的　探讨胆碱能系统与去甲肾上腺素能系统是否共同参与学习记忆过程。方法　小鼠视觉暗示空间鉴别法。结果　合用无效剂量的α2 受体拮抗剂咪唑克生和无效剂量的胆碱酯酶抑制剂吲哚满酯 ,明显促进小鼠视觉暗示空间鉴别的获得和再现。另外 ,咪唑克生与吲哚满酯一样 ,能完全翻转东莨菪碱对小鼠视觉暗示空间鉴别的损害作用。结论　咪唑克生能增强吲哚满酯的向智作用 ,表明胆碱能系统与去甲肾上腺素能系统交互作用 ,共同参与学习记忆功能     

Cardiorespiratory fitness,hippocampal subfield volumes,and mnemonic discrimination task performance in aging

Aging and exercise have opposing effects on mnemonic discrimination task performance, which putatively taxes pattern separation mechanisms reliant on the dentate gyrus (DG) subfield of the hippocampus. In young adults, increasing cardiorespiratory fitness (CRF) has been shown to improve mnemonic discrimination task performance and increase left anterior DG/CA3 volume. It is unknown how these variables interact in cognitive aging, yet this knowledge is critical, given the established effects of aging on hippocampal plasticity. To investigate these relationships, 65 older adults (aged 55–85 years) completed a submaximal treadmill test to estimate CRF, a mnemonic discrimination task, and a high‐resolution MRI scan to determine hippocampal subfield volumes. Our older adult sample demonstrated the lowest task accuracy in the condition with the greatest stimuli similarity and left DG/CA3 body volume significantly predicted accuracy in this condition. Our results did not provide support for relationships between CRF and task accuracy or CRF and DG/CA3 volume as evidenced in studies of young adults. Instead, CRF predicted bilateral subiculum volume in older adult women, not men. Altogether, these findings provide further support for a role of the DG in behavioral pattern separation in humans and suggest that CRF may have differential effects on hippocampal subfield integrity in older adult men and women. ClinicalTrials.gov identifiers: (a) Neuroimaging Study of Exercise and Memory Function, {"type":"clinical-trial","attrs":{"text":"NCT02057354","term_id":"NCT02057354"}}NCT02057354; (b) The Entorhinal Cortex and Aerobic Exercise in Aging, {"type":"clinical-trial","attrs":{"text":"NCT02775760","term_id":"NCT02775760"}}NCT02775760; (c) Physical Activity and Cognition Study, {"type":"clinical-trial","attrs":{"text":"NCT02773121","term_id":"NCT02773121"}}NCT02773121.