Orientation selectivity and noise correlation in awake monkey area V1 are modulated by the γ cycle

Gamma-band synchronization adjusts the timing of excitatory and inhibitory inputs to a neuron. Neurons in the visual cortex are selective for stimulus orientation because of dynamic interactions between excitatory and inhibitory inputs. We hypothesized that these interactions and hence also orientation selectivity vary during the gamma cycle. We determined for each spike its phase relative to the gamma cycle. As a function of gamma phase, we then determined spike rates and their orientation selectivity. Orientation selectivity was modulated by gamma phase. The firing rate of spiking activity that occurred close to a neuron's mean gamma phase of firing was most orientation selective. This stimulus-selective signal could best be conveyed to postsynaptic neurons if it were not corrupted by noise correlations. Noise correlations between firing rates were modulated by gamma phase such that they were not statistically detectable for the spiking activity occurring close to a neuron's mean gamma phase of firing. Thus, gamma-band synchronization produces spiking activity that carries maximal stimulus selectivity and minimal noise correlation in its firing rate, and at the same time synchronizes this spiking activity for maximal impact on postsynaptic targets.     

Sex and hemispheric differences in facial invariants extraction

This present study investigates sex differences in hemispheric cooperation during a facial identity matching task. The method used was a divided visual field paradigm in which the probe face was neutral or expressive and the target face was always neutral. Probe and target faces were presented both unilaterally and sequentially. A total of 28 right-handed women and 32 right-handed men participated in this study. The results confirm the women's advantage in face recognition and reveal symmetrical interhemispheric cooperation in women only. In men, processing time was faster when the probe face appeared in the left visual field—and encoded by the right hemisphere—and the target in the right visual field—projected to the left hemisphere—compared to the reverse direction. Interestingly, the data also show that women were not influenced by the expression of the probe face when matching identity, whereas men were always faster when the probe face was neutral, like the target, than when it was expressive. These results are discussed in light of Bruce and Young's (1986) model, and in terms of view-dependent and view-independent processes.     

Designing trauma registry system using a logical framework approach

While trauma registries provide the mechanisms to collect comprehensive, timely and accurate data related to the injuries and evaluate trauma care systems, they have not been established in most developing countries. On the other hand, in complex projects that have large aims, a logical framework approach （LFA） can help summarize and describe the multiple branches of the project systematically, and elucidate the main goals, extensive objectives, activities and expected outcomes. Therefore a LFA can be used to design and guide trauma registry project management, to integrate the cultural, clinical and capacity variations among countries; and to ensure early alignment of the project＇s design and evaluation.     

Multisensory integration across exteroceptive and interoceptive domains modulates self-experience in the rubber-hand illusion

Identifying with a body is central to being a conscious self. The now classic “rubber hand illusion” demonstrates that the experience of body-ownership can be modulated by manipulating the timing of exteroceptive (visual and tactile) body-related feedback. Moreover, the strength of this modulation is related to individual differences in sensitivity to internal bodily signals (interoception). However the interaction of exteroceptive and interoceptive signals in determining the experience of body-ownership within an individual remains poorly understood. Here, we demonstrate that this depends on the online integration of exteroceptive and interoceptive signals by implementing an innovative “cardiac rubber hand illusion” that combined computer-generated augmented-reality with feedback of interoceptive (cardiac) information. We show that both subjective and objective measures of virtual-hand ownership are enhanced by cardio-visual feedback in-time with the actual heartbeat, as compared to asynchronous feedback. We further show that these measures correlate with individual differences in interoceptive sensitivity, and are also modulated by the integration of proprioceptive signals instantiated using real-time visual remapping of finger movements to the virtual hand. Our results demonstrate that interoceptive signals directly influence the experience of body ownership via multisensory integration, and they lend support to models of conscious selfhood based on interoceptive predictive coding.     

64排螺旋CT与选择性冠状动脉造影评价急性冠状动脉综合征患者易损斑块形态、成分及大小的价值对比研究

目的 探讨64排螺旋CT评价急性冠状动脉综合征(ACS)患者易损斑块形态、成分及大小的价值.方法 65例冠心病患者(其中ACS组32例,稳定性心绞痛组33例)行64排螺旋CT冠状动脉成像及选择性冠状动脉造影.对ACS组及稳定性心绞痛组的管腔狭窄程度、斑块最低密度值、钙化形态(点状钙化或大钙化)及斑块大小进行评价.计算64排MDCT对ACS易损斑块诊断的敏感性、特异性、阳性预测值、阴性预测值.采用SPSS 13.0统计软件进行ACS组与SAP两组之间特征的差异描述和分析,定性变量用卡方检验,定量变量采用两独立样本t检验,P ＜0.05为差异有显著性.结果 两组之间管腔的狭窄程度无差别.ACS组斑块的最低密度CT值[(39±78)HU]低于稳定性心绞痛组斑块的最低密度CT值[(103±114)HU],两组比较差异有统计学意义(P＜0.05,t=0.315).斑块的总体积两组比较无差异,软斑块体积比例＞40％的例数,ACS组较稳定性心绞痛组大,差异不具有统计学意义(P＞0.05).点状钙化在ACS组更频繁而稳定性心绞痛组大钙化更为常见,两组比较差异均有统计学意义(P＜0.01,t=0.221).斑块最小密度CT值＜35 HU的比例在ACS组较SAP组更频繁(P＜0.01,t=0.161).同时存在点状钙化及斑块最小CT值＜35 HU这两个特征对ACS诊断显示很高的阳性预测值,而缺少这两个特征阴性预测值很高.结论 ACS易损斑块CT特征包括:斑块低密度、点状钙化、软斑块体积所占比例较大的特点.冠状动脉粥样斑块同时具有CT值＜35 HU、点状钙化特征高度提示斑块的易损性.     

Use-dependent control of presynaptic calcium signalling at central synapses

Voltage-gated Ca(2+) channels activated by action potentials evoke Ca(2+) entry into presynaptic terminals thus briefly distorting the resting Ca(2+) concentration. When this happens, a number of processes are initiated to re-establish the Ca(2+) equilibrium. During the post-spike period, the increased Ca(2+) concentration could enhance the presynaptic Ca(2+) signalling. Some of the mechanisms contributing to presynaptic Ca(2+) dynamics involve endogenous Ca(2+) buffers, Ca(2+) stores, mitochondria, the sodium-calcium exchanger, extraterminal Ca(2+) depletion and presynaptic receptors. Additionally, subthreshold presynaptic depolarization has been proposed to have an effect on release of neurotransmitters through a mechanism involving changes in resting Ca(2+). Direct evidence for the role of any of these participants in shaping the presynaptic Ca(2+) dynamics comes from direct recordings of giant presynaptic terminals and from fluorescent Ca(2+) imaging of axonal boutons. Here, some of this evidence is presented and discussed.     

Developmental changes in odor-evoked activity in rat piriform cortex

In adult rats, odor-evoked Fos protein expression is found in rostrocaudally-oriented bands of cells in anterior piriform cortex (APC), likely indicating functionally distinct subregions, while activated cells in posterior piriform cortex (PPC) lack apparent spatial organization. To determine whether these patterns are present during early postnatal life, and whether they change during development, Fos expression was assessed following acute exposure to single aliphatic acid odors in developing rats beginning at postnatal day 3 (P3). In the olfactory bulb, Fos-immunoreactive cells were present in the granule cell, mitral cell and glomerular layers at the earliest ages examined. Cells immunopositive for Fos were clustered in areas previously reported as active in response to these odors. In piriform cortex, activation in layers II/III shared some features with that seen in the adult; in APC, rostro-caudally oriented bands of Fos-positive cells alternated with bands relatively free of label, while labeled cells were found dispersed throughout PPC. However, in P3-P7 animals, Fos-positive cells in APC were found in a central rostro-caudally oriented band that was flanked by two bands relatively free of Fos-positive cells. This contrasted with the adult pattern, a central cell-poor band flanked by cell-rich bands, which was observed beginning at P10. These results suggest that subregions of APC visualized by odor-evoked Fos expression are active and functionally distinct shortly after birth. Changes in activity within these subregions during early postnatal development coincide with a shift toward adult-like olfactory learning behavior in the second postnatal week, and may play a role in this behavioral shift.     

New Evaluation and Management Code Level Selection Trends in Hip and Knee Osteoarthritis Patients

BackgroundOn January 1, 2021, the American Medical Association implemented changes regarding the outpatient Evaluation and Management (E/M) criteria dictating Current Procedural Terminology code level selection to help diminish administrative burden and emphasize medical decision-making as the primary determinant in E/M level of service (EML). The goal of this study was to describe EML coding trends in outpatient visits for hip and knee osteoarthritis after the 2021 Centers for Medicare and Medicaid Services changes to the E/M system.MethodsAll outpatient visits for primary hip and knee osteoarthritis within the divisions of Joint Replacement, Operative Sports Medicine, and Nonoperative Sports Medicine at a single orthopaedic practice were retrospectively analyzed during 2 separate 10-month timeframes in 2019 and 2021. The primary endpoint was the visit EML (1 through 5) based on Current Procedural Terminology E/M codes.ResultsIn 2019, 7.8% of all visits were billed as level 2, 85.8% of all visits were billed as level 3, and 6.3% of all visits were billed as level 4. In 2021, 2.8% of visits were billed as level 2, 54% of visits were billed as level 3, and 41.3% of visits were billed as level 4. Level 1 and Level 5 visits did not exceed 2% in either year. Across all 3 divisions, level 2 and 3 visits decreased significantly (P < .05), while level 4 visits increased significantly (P < .05).ConclusionSince the E/M coding criteria overhaul in 2021, there has been a significant trend towards higher level of service code selection across multiple divisions in our orthopaedic practice.