Visual responses with and without fixation: neurons in premotor cortex encode spatial locations independently of eye position

 The ventral premotor cortex (PMv) of the macaque monkey contains neurons that respond both to visual and to tactile stimuli. For almost all of these “bimodal” cells, the visual receptive field is anchored to the tactile receptive field on the head or the arms, and remains stationary when the eyes fixate different locations. This study compared the responses of bimodal PMv neurons to a visual stimulus when the monkey was required to fixate a spot of light and when no fixation was required. Even when the monkey was not fixating and the eyes were moving, the visual receptive fields remained in the same location, near the associated tactile receptive field. For many of the neurons, the response to the visual stimulus was significantly larger when the monkey was not performing the fixation task. In control tests, the presence or absence of the fixation spot itself had little or no effect on the response to the visual stimulus. These results show that even when the monkey’s eye position is continuously changing, the neurons in PMv have visual receptive fields that are stable and fixed to the relevant body part. The reduction in response during fixation may reflect a shift of attention from the visual stimulus to the demands of the fixation task. Received: 8 April 1997 / Accepted: 16 July 1997     

Retrograde transneuronal transport of wheat-germ agglutinin to the retina from visual cortex in the cat

Summary The stability of visual perception despite eye movements suggests the existence, in the visual system, of neural elements able to recognize whether a movement of an image occurring in a particular part of the retina is the consequence of an actual movement that occurred in the visual field, or self-induced by an ocular movement while the object was still in the field of view. Recordings from single neurons in area V3A of awake macaque monkeys were made to check the existence of such a type of neurons (called real-motion cells; see Galletti et al. 1984, 1988) in this prestriate area of the visual cortex. A total of 119 neurons were recorded from area V3A. They were highly sensitive to the orientation of the visual stimuli, being on average more sensitive than V1 and V2 neurons. Almost all of them were sensitive to a large range of velocities of stimulus movement and about one half to the direction of it. In order to assess whether they gave different responses to the movement of a stimulus and to that of its retinal image alone (self-induced by an eye movement while the stimulus was still), a comparison was made between neuronal responses obtained when a moving stimulus swept a stationary receptive field (during steady fixation) and when a moving receptive field swept a stationary stimulus (during tracking eye movement). The receptive field stimulation at retinal level was physically the same in both cases, but only in the first was there actual movement of the visual stimulus. Control trials, where the monkeys performed tracking eye movements without any intentional receptive field stimulation, were also carried out. For a number of neurons, the test was repeated in darkness and against a textured visual background. Eighty-seven neurons were fully studied to assess whether they were real-motion cells. About 48% of them (42/87) showed significant differences between responses to stimulus versus eye movement. The great majority of these cells (36/42) were real-motion cells, in that they showed a weaker response to visual stimulation during tracking than to the actual stimulus movement during steady fixation. On average, the reduction in visual response during eye movement was 64.0 ± 15.7% (SD). Data obtained with a uniform visual background, together with those obtained in darkness and with textured background, indicate that real-motion cells receive an eye-motion input, either retinal or extraretinal in nature, probably acting presynaptically on the cell's visual input. In some cases, both retinal and extraretinal eye-motion inputs converge on the same real-motion cell. No correlation was observed between the real-motion behaviour and the sensitivity to either orientation or direction of movement of the visual stimulus used to activate the receptive field, nor with the retinotopic location of the receptive field. We suggest that the visual system uses real-motion cells in order to distinguish real from self-induced movements of retinal images, hence to recognize the actual movement in the visual field. Based on psychophysical data, the hypothesis has been advanced of an internal representation of the field of view, stable despite eye movement (cf. MacKay 1973). The real-motion cells may be neural elements of this network and we suggest that the visual system uses the output of this network to properly interpret the large number of sensory changes resulting from exploratory eye movements in a stable visual world.     

Central control of developmental plasticity in the mammalian visual cortex

Visual experience influences the development of visual cortex functions. By manipulating retinal activity the efficacy of excitatory connections between the eyes and cortical neurones can be modified dramatically. A criterion for the enhancement or impairment of transmission is the temporal contiguity of pre- and postsynaptic activation. For a change to occur it is necessary that the cortical cells respond to retinal activity but this condition is not sufficient. Further permissive gating signals of nonretinal origin are required. It is proposed that these "now print" signals act by controlling the Ca2+-conductance of cortical dendrites. The possible role of these activity dependent modifications is discussed in the context of the development of cooperatively coupled cell assemblies.     

Hemispheric Prevalence Changes in Partial Epileptic Patients on Perceptual and Attentional Tasks

In relation to the general issue of the long-term effects of epileptic activity on the higher nervous functions, monohemispheric epileptic patients--divided into "lesional" [i.e., with computed tomography (CT) scan-visible lesions] and "nonlesional" (i.e., with CT scan-nonvisible lesions)--were submitted to dichotic verbal and tonal tasks, dichoptic verbal and spatial tasks, and a visual tachistoscopic attentional task. The aim was to investigate whether the typical patterns of hemispheric prevalence, which were observed in normal subjects by using these tests, undergo significant changes in epileptic patients. The findings versus normal subjects seem to demonstrate that (a) in lesional epileptic patients, the prevalence of the hemisphere without macroscopic lesions is a constant rule, whether or not this hemisphere is prevalent in normal subjects; (b) in nonlesional epileptic patients, the patterns are the following: when the epileptic hemisphere is the one that is prevalent in normal subjects, its prevalence is enhanced, whichever the hemisphere; when the epileptic hemisphere is not the hemisphere prevalent in normal subjects, the left one attracts and maintains prevalence, whereas the right one reduces and variously interferes with contralateral prevalence. It is concluded that, with respect to the functions tested, the nature of the epileptic foci seems to influence markedly the interhemispheric prevalence pattern.     

Colored neon flanks and line gap enhancement

When a colored line connects two black (or differently colored) lines across a gap, colored neon flanks are seen on either side of it. These flanks extend over gap sizes of 50 min arc foveally and are not explained by Bezold-type assimilation. They may be elicited by black lines as short as 6 min arc adjoining the colored line at each end. To maximize these flanks, the black and colored lines must appear linearly continuous. Nonaligned junctions weaken the effect and an angular tilt of more than 40 dog destroys it. In this and other respects, (local) neon flanks are similar to van Tuijl's (global) neon color spreading (1975). Both phenomena have analogs in brightness perception. We propose that neon spreading is a lateral extension of neon flanks across the empty space between them, and discuss similarities of these effects with other brightness illusions (Schumann, Prandtl, Ehrenstein). For this group of illusions the term "line gap enhancement" is introduced to imply perceptual enhancement of changes in brightness and/or color along lines. Correspondences between the psychophysical properties and structural prerequisites for line gap enhancement on one hand and neuronal response properties of end-zone inhibited (hypercomplex) cortical cells on the other are discussed.     

中文版感知社会支持量表在老年癌症患者中的信效度分析

目的 检验中文版感知社会支持量表（the multidimensional scale of perceived social support, MSPSS）在老年癌症患者中应用的信效度。方法 采用整群抽样的方法,使用中文版感知社会支持量表对老年癌症患者进行调查,并对结果进行信效度检验。结果 共收到有效问卷520份,中文版感知社会支持量表的Cronbach α系数为0.877;探索性因子中共提取出公因子3个,累积方差贡献率为69.5%;通过验证性因子分析得出GFI、CFI、IFI指标范围在0.855～0.921之间。结论 中文版社会支持量表在老年癌症患者中应用具有良好的信效度,可用于评估该人群感知社会支持水平。     

天然水处理剂单宁的改性及性能研究

对单宁进行了胺甲基化、季铵盐化和磺化3种改性,通过红外光谱分析了改性产物的结构,并采用失重法,极化曲线、静态阻垢和杀菌实验等手术对其进行了性能评价与研究。实验结果表明,不同的改性方法可以在很大程度上改善单宁的缓蚀、阻垢和杀菌等性能,具有良好的开发前景。     

氯化钛白氧化反应器壁结疤机理

利用预燃烧直管反应器,研究氯化钛白氧化反应器内的结疤机理。氧化反应器内结疤支要起因子氧化过程生成的超细TiO2颗粒在反应器壁的沉积和烧结,反应器壁面温度越高结疤速率越快。当反应器壁面温度较低时,靠近壁面为ＴiO2颗粒堆结层,而告气体相主体的疤层发生了部分烧结。反应温度升高、反应物浓度增大时,结疤速度增大;壁面状态对结疤速率影响不大。     

Effect of clinical factors on trajectory of functional performance in patients undergoing hemodialysis

PurposeThis study aimed to investigate the association between clinical factors and temporary changes in functional performance in patients undergoing hemodialysis.MethodsThis was a retrospective, longitudinal observational study conducted from 2015 to 2017. Eight-two patients undergoing hemodialysis in the outpatient clinic were enrolled. Functional performance was measured using the Karnofsky Performance Status (KPS) scale. Collected data for analysis included demographics, laboratory parameters, and KPS scale scores. All participants were grouped into a high KPS cluster and a low KPS cluster based on dynamic changes in KPS scales from 2015 to 2017.ResultsParticipants in the high KPS cluster demonstrated an approximate trend, and those in the low KPS cluster demonstrated a low pattern. By stepwise selection model analysis, age (OR 1.12, 95% CI 1.03–1.23, p = 0.011), serum BUN (OR 1.08, 95% CI 1.02–1.16, p = 0.015), calcium levels (OR 3.24, 95% CI 1.2–8.73, p = 0.02), and beta-2-microglobulin (OR > 1.0, CI >1.00-<1.01, p = 0.031) showed risk for the low KPS cluster. Male sex (OR 0.20, 95% CI 0.04–0.96, p = 0.045) and albumin level (OR 0.02, 95% CI 0–0.4, p = 0.009) showed a low risk for the low KPS cluster.ConclusionsA different trajectory pattern was observed between the high and low KPS clusters in a 3-year period. Risk factors for the low KPS cluster were age, serum BUN, calcium, and beta-2-microglobulin levels. Male sex and serum albumin levels reduced the risk for the low KPS cluster.     

Therapeutic effects of the combined androgen blockade therapy versus luteinizing hormone-releasing hormone analog monotherapy in patients with hormone naïve metastatic prostate cancer: a multi-institutional comparative analysis

BackgroundThe clinical benefit of the combined androgen blockade (CAB) therapy over luteinizing hormone-releasing hormone analog (LH-RHa) monotherapy for hormone naïve metastatic prostate cancer (mHNPC) is unclear. Therefore, we retrospectively compare the effectiveness of CAB with the LH-RHa monotherapy on the prognosis of Japanese patients with mHNPC.MethodsWe retrospectively evaluated the prognosis of 517 patients diagnosed with mHNPC between August 2001 and May 2017. The patients’ data were obtained from the Michinoku Urological Cancer Research Group database and Hirosaki University-related hospitals. Patients were divided into the CAB and LH-RHa monotherapy groups based on primary androgen deprivation therapy (ADT). Overall survival (OS), cancer-specific survival (CSS), and castrate-resistant prostate cancer-free survival (CRPC-FS) were compared between the two groups using the Kaplan-Meier curve analysis. Inverse probability of treatment weighting (IPTW)-adjusted Cox hazard proportional analyses was performed to investigate the effect of primary ADT on oncological outcomes.ResultsThe median age was 73 years old. The numbers of patients in the CAB and LH-RHa monotherapy groups were 447 and 70, respectively. The Kaplan-Meier curve analysis showed no significant differences in either 5-year OS (56.7% vs. 52.5%, P=0.277), CSS (61.1% vs. 56.4%, P=0.400), and CRPC-FS (33.1% vs. 31.1%, P=0.529) between the groups. IPTW-adjusted multivariate Cox hazard proportional analyses showed no significant differences in OS, CSS, and CRPC-FS between the two groups.ConclusionsNo significant differences in oncological outcomes were observed between the CAB and LH-RHa monotherapy groups in patients with mHNPC.