High gamma oscillations in medial temporal lobe during overt production of speech and gestures

The study of the production of co-speech gestures (CSGs), i.e., meaningful hand movements that often accompany speech during everyday discourse, provides an important opportunity to investigate the integration of language, action, and memory because of the semantic overlap between gesture movements and speech content. Behavioral studies of CSGs and speech suggest that they have a common base in memory and predict that overt production of both speech and CSGs would be preceded by neural activity related to memory processes. However, to date the neural correlates and timing of CSG production are still largely unknown. In the current study, we addressed these questions with magnetoencephalography and a semantic association paradigm in which participants overtly produced speech or gesture responses that were either meaningfully related to a stimulus or not. Using spectral and beamforming analyses to investigate the neural activity preceding the responses, we found a desynchronization in the beta band (15-25 Hz), which originated 900 ms prior to the onset of speech and was localized to motor and somatosensory regions in the cortex and cerebellum, as well as right inferior frontal gyrus. Beta desynchronization is often seen as an indicator of motor processing and thus reflects motor activity related to the hand movements that gestures add to speech. Furthermore, our results show oscillations in the high gamma band (50-90 Hz), which originated 400 ms prior to speech onset and were localized to the left medial temporal lobe. High gamma oscillations have previously been found to be involved in memory processes and we thus interpret them to be related to contextual association of semantic information in memory. The results of our study show that high gamma oscillations in medial temporal cortex play an important role in the binding of information in human memory during speech and CSG production

Rapamycin causes down-regulation of CCR5 and accumulation of anti-HIV β-chemokines: An approach to suppress R5 strains of HIV-1

Propagation of R5 strains of HIV-1 on CD4 lymphocytes and macrophages requires expression of the CCR5 coreceptor on the cell surface. Individuals lacking CCR5 (CCR5Δ32 homozygous genotype) are phenotypically normal and resistant to infection with HIV-1. CCR5 expression on lymphocytes depends on signaling through the IL-2 receptor. By FACS analysis we demonstrate that rapamycin (RAPA), a drug that disrupts IL-2 receptor signaling, reduces CCR5 surface expression on T cells at concentrations as low as 1 nM. In addition, lower concentrations of RAPA (0.01 nM) were sufficient to reduce CCR5 surface expression on maturing monocytes. PCR analysis on peripheral blood mononuclear cells (PBMCs) showed that RAPA interfered with CCR5 expression at the transcriptional level. Reduced expression of CCR5 on PBMCs cultured in the presence of RAPA was associated with increased extracellular levels of macrophage inflammatory protein (MIP)-1α and MIP-1β. In infectivity assays, RAPA suppressed the replication of R5 strains of HIV-1 both in PBMC and macrophage cultures. In total PBMC cultures, RAPA-mediated inhibition of CCR5-using strains of HIV-1 occurred at 0.01 nM, a concentration of drug that is ∼10(3) times lower than therapeutic through levels of drug in renal transplant recipients. In addition, RAPA enhanced the antiviral activity of the CCR5 antagonist TAK-779. These results suggest that low concentrations of RAPA may have a role in both the treatment and prevention of HIV-1 infection

Water Absorption in the Transmission Spectrum of the Water World Candidate GJ 9827 d

Recent work on the characterization of small exoplanets has allowed us to accumulate growing evidence that sub-Neptunes with radii greater than ∼2.5 R _⊕ often host H _2 /He-dominated atmospheres both from measurements of their low bulk densities and from direct detections of their low mean molecular mass atmospheres. However, the smaller sub-Neptunes in the 1.5–2.2 R _⊕ size regime are much less understood and often have bulk densities that can be explained either by the H _2 /He-rich scenario or by a volatile-dominated composition known as the “water world” scenario. Here we report the detection of water vapor in the transmission spectrum of the 1.96 ± 0.08 R _⊕ sub-Neptune GJ 9827 d obtained with the Hubble Space Telescope (HST). We observe 11 HST Wide Field Camera 3 transits of GJ 9827 d and find an absorption feature at 1.4 μ m in its transit spectrum, which is best explained (at 3.39 σ ) by the presence of water in GJ 9827 d’s atmosphere. We further show that this feature cannot be caused by unocculted starspots during the transits by combining an analysis of the K2 photometry and transit light source effect retrievals. We reveal that the water absorption feature can be similarly well explained by a small amount of water vapor in a cloudy H _2 /He atmosphere or a water vapor envelope on GJ 9827 d. Given that recent studies have inferred an important mass-loss rate (>0.5 M _⊕ Gyr ^−1 ) for GJ 9827 d, making it unlikely to retain a H-dominated envelope, our findings highlight GJ 9827 d as a promising water world candidate that could host a volatile-dominated atmosphere. This water detection also makes GJ 9827 d the smallest exoplanet with an atmospheric molecular detection to date