SMILE术后散射的变化特征及相关影响因素

目的探讨SMILE术后眼内散射的变化,并对其相关影响因素进行分析。方法前瞻性病例研究。选取拟行SMILE手术的近视及近视散光患者67例（67眼）,应用C-quant散射仪分别测量患者手术前、术后1周、术后1个月、术后3个月及术后6个月眼内散射光计量值,并与年龄、球镜度、等效球镜度、CCT、角膜平均曲率值（Km）、角膜曲率半径等做相关分析,同时采用Pearson相关分析术后散射光计量值变化与角膜帽直径、小切口大小、切削深度、切削比、剩余角膜厚度（RBT）、RBT／CCT、能量等关系。结果SMILE手术前、术后1周、术后1个月、术后3个月、术后6个月的散射光计量值分别为0．93±0．16、0．97±0．14、0．94±0．17、0．94±0．17、0．90±0．17,术后1周散射光计量值较术前稍增加,但差异无统计学意义,各时间点散射光计量值比较差异无统计学意义（F=2．253,P〉0．05）;术后散射光计量值的变化与术中相关参数无明显相关性,仅在术后3个月散射光计量值与切口大小呈较弱正相关（r=0．356,P〈0．01）。结论SMILE术后散射光计量值较术前虽有变化,但变化不明显。术后由散射变化造成视觉质量下降的可能性较小。     

可视化融合成像技术诊治腰关节突关节综合征的疗效分析*

目的探讨可视化融合成像技术诊治腰关节突关节综合征的临床效果。方法临床纳入2017年6月至2020年5月于深圳市龙岗中心医院住院和门诊收治的80例腰关节突关节综合征患者作为研究对象,按随机数字表法分为两组,各40例。其中40例患者采用可视化融合成像技术引导下诊断及介入治疗者作为研究组,仅采用X线透视引导下诊断及介入治疗者作为对照组。观察两组患者治疗前后疼痛情况,分析两组患者诊疗效果及不良反应情况。结果研究组治疗后1周、3个月、6个月、12个月的VAS评分明显低于对照组,两组比较差异有统计学意义(P<0.05);在不同治疗时期疼痛缓解方面,对照组患者总有效率明显低于研究组,差异有统计学意义(P<0.05);在术区血肿形成、术区疼痛、消化道症状及下肢疼痛等不良反应方面,对照组不良事件发生率为25%,研究组为7.5%,两组比较差异有统计学意义(P<0.05)。结论可视化融合成像技术诊治腰关节突关节综合征的临床效果明显、持久及安全性高,值得临床应用推广。     

The influence of Mozart's sonata K.448 on visual attention: an ERPs study

In the present study, the effects of Mozart's sonata K.448 on voluntary and involuntary attention were investigated by recording and analyzing behavioral and event-related potentials (ERPs) data in a three-stimulus visual oddball task. P3a (related to involuntary attention) and P3b (related to voluntary attention) were analyzed. The "Mozart effect" was showed on ERP but not on behavioral data. This study replicated the previous results of Mozart effect on voluntary attention: the P3b latency was influenced by Mozart's sonata K.448. But no change of P3a latency was induced by this music. At the same time, decreased P3a and P3b amplitudes in music condition were found. We interpret this change as positive "Mozart effect" on involuntary attention (P3a) and negative "Mozart effect" on voluntary attention (P3b). We conclude that Mozart's sonata K.448 has shown certain effects on both involuntary attention and voluntary attention in our study, but their effects work on different mechanisms.     

Brain-derived neurotrophic factor-mediated retrograde signaling required for the induction of long-term potentiation at inhibitory synapses of visual cortical pyramidal neurons

High-frequency stimulation (HFS) induces long-term potentiation (LTP) at inhibitory synapses of layer 5 pyramidal neurons in developing rat visual cortex. This LTP requires postsynaptic Ca²⁺ rise for induction, while the maintenance mechanism is present at the presynaptic site, suggesting presynaptic LTP expression and the necessity of retrograde signaling. We investigated whether the supposed signal is mediated by brain-derived neurotrophic factor (BDNF), which is expressed in pyramidal neurons but not inhibitory interneurons. LTP did not occur when HFS was applied in the presence of the Trk receptor tyrosine kinase inhibitor K252a in the perfusion medium. HFS produced LTP when bath application of K252a was started after HFS or when K252a was loaded into postsynaptic cells. LTP did not occur in the presence of TrkB-IgG scavenging BDNF or function-blocking anti-BDNF antibody in the medium. In cells loaded with the Ca²⁺ chelator BAPTA, the addition of BDNF to the medium enabled HFS to induce LTP without affecting baseline synaptic transmission. These results suggest that BDNF released from postsynaptic cells activates presynaptic TrkB, leading to LTP. Because BDNF, expressed activity dependently, regulates the maturation of cortical inhibition, inhibitory LTP may contribute to this developmental process, and hence experience-dependent functional maturation of visual cortex.     

Role of protein kinase C in selective inhibition of mouse retinal neurites during contacts with chondroitin sulfates

Chondroitin sulfate proteoglycans elicit a selective inhibition to neurite growth from ventrotemporal (VT) but not dorsonasal (DN) retina, potentiating the bilateral routing of axons in the mouse optic chiasm. We examined whether this selective response is mediated by a difference in protein kinase C (PKC) expression. Effects of suppressing PKC activity in explant preparations of embryonic day 14 retinae with inhibitor Gö6976 or Ro-32-0432 abolished the chondroitin sulfate inhibition to the VT neurites but had no effect to the DN neurites. Whether these responses rely on a difference in expression of PKC in the growth cones was examined using antibodies against six isozymes of PKC. Among these the α, βI and ? isozymes were expressed prominently in the retinal growth cones; whilst the βII, δ and γ isozymes were barely detected. Moreover, while the α and ? isozymes were abundant in the filopodial and lamellipodial processes, the βI isozyme was restricted largely in the core region of the growth cones. Despite these subtype specific localization, there was no significant difference in expression of any of these PKC isozymes between growth cones from VT and DN retina, indicating that the selective response to chondroitin sulfates is not likely generated by a regulation of PKC expression, but by expression of surface molecules that interact with chondroitin sulfate proteoglycans.     

Differential effects of non-informative vision and visual interference on haptic spatial processing

The primary purpose of this study was to examine the effects of non-informative vision and visual interference upon haptic spatial processing, which supposedly derives from an interaction between an allocentric and egocentric reference frame. To this end, a haptic parallelity task served as baseline to determine the participant-dependent biasing influence of the egocentric reference frame. As expected, large systematic participant-dependent deviations from veridicality were observed. In the second experiment we probed the effect of non-informative vision on the egocentric bias. Moreover, orienting mechanisms (gazing directions) were studied with respect to the presentation of haptic information in a specific hemispace. Non-informative vision proved to have a beneficial effect on haptic spatial processing. No effect of gazing direction or hemispace was observed. In the third experiment we investigated the effect of simultaneously presented interfering visual information on the haptic bias. Interfering visual information parametrically influenced haptic performance. The interplay of reference frames that subserves haptic spatial processing was found to be related to both the effects of non-informative vision and visual interference. These results suggest that spatial representations are influenced by direct cross-modal interactions; inter-participant differences in the haptic modality resulted in differential effects of the visual modality.     

<Superscript>31</Superscript>P magnetic resonance spectroscopy study of the human visual cortex during stimulation in mild hypoxic hypoxia

Effects of mild hypoxic hypoxia on cerebral energy state, as assessed by phosphocreatine (PCr)/γ-ATP and inorganic phosphate (P_i)/(P_i + PCr) ratios and intracellular pH (pH_i) in the human visual cortex, were studied using ³¹P nuclear magnetic resonance spectroscopy (MRS) at 3 T. The working hypothesis that, during compromised O₂ availability obtained by hypoxic hypoxia, both cerebral energy state and pH_i decline due to insufficient O₂ supply for energy metabolism was addressed. Under baseline hypoxic hypoxia, with blood O₂ saturation ranging from 0.95 to 0.83, neither the PCr/γ-ATP and P_i/(P_i + PCr) ratios nor pH_i was affected, thus, showing that cerebral energy metabolism was maintained. Contrary to the formulated hypothesis, visual stimulation during hypoxic hypoxia influenced neither the indicator ratios for energy state nor pH_i in the occipital cortex. Taking these results, together with previous observations showing that cerebral blood flow responses are the same in size both in euoxia and in hypoxia at this depth (Mintun et al. in Proc Natl Acad Sci USA 98:6859–6864, 2001; Tuunanen et al. in J Cereb Blood Flow Metab 26:263–273, 2006a), it is concluded that O₂ delivery to the brain during mild hypoxic hypoxia meets the demand by the energy metabolism both under baseline and stimulated states.     

Adaptation changes the spatial frequency tuning of adult cat visual cortex neurons

The modular layout of striate cortex is arguably a hallmark of all cortical organization. Neurons of a given module or domain respond optimally to very few specific properties, such as orientation or direction. However, it is possible, under appropriate conditions, to compel a neuron to respond preferentially to a different optimal property. In anesthetized cats, prepared for electrophysiological recordings in the visual cortex, we applied a spatial frequency (SF) that differs (by 0.25–3.0 octaves) from the optimal one for 7–13 min without interruption. This application shifted the tuning curve of the cell mainly in the direction of the imposed SF. Indeed, results indicate an attractive push occurring more frequently (50%) than a repulsive (30%) shift in cortical cells. The increase of responsivity is band-limited and is around the imposed SF, while flanked responses remained unmodified in all conditions. We hypothesize that the observed reversible plasticity is obtained by a modulation of the balance between the strengths of the respective synaptic inputs. These changes in preferred original optimal spatial frequencies may allow a dynamic reaction of cortex to a new environment and particularly to ‘‘zoom’’ cellular activity toward persistent stimuli in spite of the tuning inherited from genetic programming of response properties and environmental conditions during critical periods in new born animals.     

Visual information gain and the regulation of constant force levels

Visual information is essential in human motor control, and especially in the continuous modulation of isometric force. The gain of visual feedback, that is, the amount of space used to represent change in force, has been shown to affect both the magnitude and time-dependent properties of variability in the force output. However, little is known regarding the interacting effects of visual gain and target force level on force variability and whether the effects of force level can be mediated by a gain that is adjusted to force level. We examined the effect of different types and levels of visual feedback gain and target force level (1, 2, 4, 8, and 12 N) on the magnitude (standard deviation, SD) and regularity (approximate entropy, ApEn) of isometric force variability. Young adults performed an isometric force task with high and low levels of constant (same gain level for all forces) and scaled (proportional to force level) gain. The magnitude of force variability increased exponentially as a function of force level once the SD was corrected for the limits of the display area. The time-dependent properties of force variability remained constant across force levels when gain was adjusted to force level. These findings suggest that the time-dependent properties of force variability are the result an interaction between visual feedback and task force level demands, while the increases in SD over force levels are primarily due to the invariant properties of human muscle and the motor system.     

Distortions of perceived auditory and visual space following adaptation to motion

Adaptation to visual motion can induce marked distortions of the perceived spatial location of subsequently viewed stationary objects. These positional shifts are direction specific and exhibit tuning for the speed of the adapting stimulus. In this study, we sought to establish whether comparable motion-induced distortions of space can be induced in the auditory domain. Using individually measured head related transfer functions (HRTFs) we created auditory stimuli that moved either leftward or rightward in the horizontal plane. Participants adapted to unidirectional auditory motion presented at a range of speeds and then judged the spatial location of a brief stationary test stimulus. All participants displayed direction-dependent and speed-tuned shifts in perceived auditory position relative to a ‘no adaptation’ baseline measure. To permit direct comparison between effects in different sensory domains, measurements of visual motion-induced distortions of perceived position were also made using stimuli equated in positional sensitivity for each participant. Both the overall magnitude of the observed positional shifts, and the nature of their tuning with respect to adaptor speed were similar in each case. A third experiment was carried out where participants adapted to visual motion prior to making auditory position judgements. Similar to the previous experiments, shifts in the direction opposite to that of the adapting motion were observed. These results add to a growing body of evidence suggesting that the neural mechanisms that encode visual and auditory motion are more similar than previously thought.