Current theories propose that coherence of oscillatory brain activity in the gamma band (30–80 Hz) constitutes an avenue for communication among remote neural populations. However, reports ...documenting stimulus dependency and time variability of gamma frequency suggest that distant neuronal populations may, at any one time, operate at different frequencies precluding synchronization. To test this idea, we recorded from macaque V1 and V2 simultaneously while presenting gratings of varying contrast. Although gamma frequency increased with stimulus contrast in V1 and V2 (by ∼25 Hz), V1-V2 gamma coherence was maintained for all contrasts. Moreover, while gamma frequency fluctuated by ∼15 Hz during constant contrast stimulation, this fluctuation was highly correlated between V1 and V2. The strongest coherence connections showed a layer-specific pattern, matching feedforward anatomical connectivity. Hence, gamma coherence among remote populations can occur despite large stimulus-induced and time-dependent changes in gamma frequency, allowing communication through coherence to operate without a stimulus independent, fixed-frequency gamma channel.
•Gamma frequency increases with stimulus contrast in both areas V1 and V2•Interareal coherence persists despite large frequency shifts•Matched gamma frequencies allow communication through coherence to be maintained•Layer-specific interareal coherence matches known anatomical connectivity
Roberts et al. examine the robustness of interareal gamma coherence under conditions of variable gamma frequency by recording in macaque V1 and V2 while presenting gratings of varying contrast. Gamma coherence among remote neuronal populations occurs despite large stimulus-induced and time-dependent changes in frequency.
This research explores early Event-Related Potentials (ERPs) sensitivity to facial stimuli, investigating various facial features aimed to unveil underlying neural mechanisms. Two experiments, each ...involving 15 undergraduate students, utilized a multidimensional stimulus set incorporating race, gender, age, emotional expression, face masks, and stimulus orientation. Findings highlight significant modulations in N170 and P200 amplitudes and latencies for specific attributes, replicating prior research and revealing novel insights. Notably, age-related facial feature variations, facial inversion, and the presence of face masks significantly impact neural responses. Several speculative explanations are proposed to elucidate these results: First, the findings lend support to the idea that the increased N170 amplitude observed with facial inversion is closely tied to the activation of object-sensitive neurons. This is further bolstered by a similar amplitude increase noted when masks (effective objects) are added to faces. Second, the absence of an additional amplitude increase, when inverting face images with face masks suggests that neural populations may have reached a saturation point, limiting further enhancement. Third, the study reveals that the latency deficit in N170 induced by facial inversion is even more pronounced in the subsequent ERP component, the P200, indicating that face inversion may impact multiple stages of face processing. Lastly, the significant increase in P200 amplitude, typically associated with face typicality, for masked faces in this study aligns with previous research that demonstrated elevated P200 amplitudes for scrambled faces. This suggests that obscured faces may be processed as typical, potentially representing a default state in face processing.
The strength of the affective priming effect is influenced by various factors, including the duration of the prime. Surprisingly, short-duration primes that are around the threshold for conscious ...awareness typically result in stronger effects compared to long-duration primes. The misattribution effect theory suggest that subliminal primes do not provide sufficient cognitive processing time for the affective feeling to be attributed to the prime. Instead, the neutral target being evaluated is credited for the affective experience. In everyday social interactions, we shift our gaze from one face to another, typically contemplating each face for only a few seconds. It is reasonable to assume that no affective priming takes place during such interactions. To investigate whether this is indeed the case, participants were asked to rate the valence of faces displayed one by one. Each face image simultaneously served as both a target (primed by the previous trial) and a prime (for the next trial). Depending on the participant's response time, images were typically displayed for about 1-2 s. As predicted by the misattribution effect theory, neutral targets were not affected by positive affective priming. However, non-neutral targets showed a robust priming effect, with emotional faces being perceived as even more negative or positive when the previously seen face was emotionally congruent. These results suggest that a "correct attribution effect" modulates how we perceive faces, continuously impacting our social interactions. Given the importance of faces in social communication, these findings have wide-ranging implications.
Clinical use of valid biomarkers enables the prediction of alloreactive response (risk of rejection) and personal susceptibility to immunosuppressive treatment could lead to personalized ...immunosuppressive therapy.
In clinical transplantation, it has been reported that cytokine production and secretion could be modified by immunosuppressive drugs, as well as during the rejection process. Some cytokines such as interferon (IFN)-γ, interleukin (IL)-2, IL-10, and transforming growth factor (TGF)-β have been identified as candidate biomarkers that correlate with graft outcome and personal response to immunosuppressive agents.
This review will focus on the current state of knowledge, indicating that monitoring changes in cytokine production could be used to predict the risk of rejection and to guide immunosuppression therapy in transplant recipients. In addition, many questions regarding the characteristics and standardization of the methods used for cytokine monitoring (ELISA; ELISPOT; Flow Cytometry) that need to be addressed before these assays can be clinically applied will be discussed in light of recent studies showing an association between the expression of some cytokines and genetic variants, the impact of immunosuppression, and the incidence of rejection.
The clinical implementation of cytokine monitoring should be tested in prospective multicenter clinical trials with standard operating procedures and objective interpretation of the results obtained.
► Cytokine monitoring will lead to better clinical outcomes and graft survival. ► Cytokines as surrogate markers of the risk of rejection and infection. ► CD4+‐CD8+-IFN-γ+ as predictive biomarker of alloreactivity and risk of rejection. ► CD4+‐CD8+-IL-2+: biomarker of rejection and personal response to tacrolimus. ► Gene polymorphisms associated with the expression and activity of cytokines
Granzymes in cancer and immunity Cullen, S P; Brunet, M; Martin, S J
Cell death and differentiation,
04/2010, Letnik:
17, Številka:
4
Journal Article
Recenzirano
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Cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells are indispensable factors in the body's ongoing defence against viral infection and tumor development. CTL/NK cells recognize and kill ...infected or aberrant target cells by two major pathways: either through introduction of a battery of proteases - called granzymes - to the target cell cytosol, or through TNF superfamily-dependent killing. During granzyme-dependent killing, target cell death is quick and efficient and is mediated by multiple granzymes, acting via redundant cell death pathways. Although granzyme-mediated cell death has been intensively studied, recent work has also hinted at an alternative, proinflammatory role for these enzymes. Thus, in addition to their well-established role as intracellular effectors of target cell death, recent data suggest that granzymes may have an extracellular role in the propagation of immune signals. In this study, we discuss the role of granzymes as central factors in antitumor immunity, as well possible roles for these proteases as instigators of inflammation.
The performance of a new historical reanalysis, the NOAA–CIRES–DOE Twentieth Century Reanalysis version 3 (20CRv3), is evaluated via comparisons with other reanalyses and independent observations. ...This dataset provides global, 3-hourly estimates of the atmosphere from 1806 to 2015 by assimilating only surface pressure observations and prescribing sea surface temperature, sea ice concentration, and radiative forcings. Comparisons with independent observations, other reanalyses, and satellite products suggest that 20CRv3 can reliably produce atmospheric estimates on scales ranging from weather events to long-term climatic trends. Not only does 20CRv3 recreate a ‘‘best estimate’’ of the weather, including extreme events, it also provides an estimate of its confidence through the use of an ensemble. Surface pressure statistics suggest that these confidence estimates are reliable. Comparisons with independent upper-air observations in the Northern Hemisphere demonstrate that 20CRv3 has skill throughout the twentieth century. Upper-air fields from 20CRv3 in the late twentieth century and early twenty-first century correlate well with full-input reanalyses, and the correlation is predicted by the confidence fields from 20CRv3. The skill of analyzed 500-hPa geopotential heights from 20CRv3 for 1979–2015 is comparable to that of modern operational 3–4-day forecasts. Finally, 20CRv3 performs well on climate time scales. Long time series and multidecadal averages of mass, circulation, and precipitation fields agree well with modern reanalyses and station- and satellite-based products. 20CRv3 is also able to capture trends in tropospheric-layer temperatures that correlate well with independent products in the twentieth century, placing recent trends in a longer historical context.
In healthy cells, cytochrome c (Cyt c) is located in the mitochondrial intermembrane/intercristae spaces, where it functions as an electron shuttle in the respiratory chain and interacts with ...cardiolipin (CL). Several proapoptotic stimuli induce the permeabilization of the outer membrane, facilitate the communication between intermembrane and intercristae spaces and promote the mobilization of Cyt c from CL, allowing for Cyt c release. In the cytosol, Cyt c mediates the allosteric activation of apoptosis-protease activating factor 1, which is required for the proteolytic maturation of caspase-9 and caspase-3. Activated caspases ultimately lead to apoptotic cell dismantling. Nevertheless, cytosolic Cyt c has been associated also to vital cell functions (i.e. differentiation), suggesting that its release not always occurs in an all-or-nothing fashion and that mitochondrial outer membrane permeabilization may not invariably lead to cell death. This review deals with the events involved in Cyt c release from mitochondria, with special attention to its regulation and final consequences.
The Twentieth Century Reanalysis Project Compo, G. P.; Whitaker, J. S.; Sardeshmukh, P. D. ...
Quarterly journal of the Royal Meteorological Society,
January 2011 Part A, 2011, 2011-01-00, 20110101, 2011-01-01, Letnik:
137, Številka:
654
Journal Article
Stress or heat shock proteins (HSPs) are the most conserved proteins present in both prokaryotes and eukaryotes. Their expression is induced in response to a wide variety of physiological and ...environmental insults. These proteins play an essential role as molecular chaperones by assisting the correct folding of nascent and sress‐accumulated misfolded proteins, and preventing their aggregation. HSPs have a dual function depending on their intracellular or extracellular location. Intracellular HSPs have a protective function. They allow the cells to survive lethal conditions. Various mechanisms have been proposed to account for the cytoprotective functions of HSPs. Several HSPs have also been demonstrated to directly interact with various components of the tightly regulated programmed cell death machinery, upstream and downstream of the mitochondrial events. On the other hand, extracellular located or membrane‐bound HSPs mediate immunological functions. They can elicit an immune response modulated either by the adaptive or innate immune system. This review will focus on HSP27, HSP70, and HSP90. We will discuss the dual role of these HSPs, protective vs. immunogenic properties, making a special emphasis in their utility as targets in cancer therapy.
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