Foot-and-mouth disease virus localisation on follicular dendritic cells and sustained induction of neutralising antibodies is dependent on binding to complement receptors (CR2/CR1).

Previous studies have shown after the resolution of acute infection and viraemia, foot-and-mouth disease virus (FMDV) capsid proteins and/or genome are localised in the light zone of germinal centres of lymphoid tissue in cattle and African buffalo. The pattern of staining for FMDV proteins was consistent with the virus binding to follicular dendritic cells (FDCs). We have now demonstrated a similar pattern of FMDV protein staining in mouse spleens after acute infection and showed FMDV proteins are colocalised with FDCs. Blocking antigen binding to complement receptor type 2 and 1 (CR2/CR1) prior to infection with FMDV significantly reduced the detection of viral proteins on FDCs and FMDV genomic RNA in spleen samples. Blocking the receptors prior to infection also significantly reduced neutralising antibody titres, through significant reduction in their avidity to the FMDV capsid. Therefore, the binding of FMDV to FDCs and sustained induction of neutralising antibody responses are dependent on FMDV binding to CR2/CR1 in mice.

Are Faculty Changing? How Reform Frameworks, Sampling Intensities, and Instrument Measures Impact Inferences about Student-Centered Teaching Practices.

Although recent studies have used the Classroom Observation Protocol for Undergraduate STEM (COPUS) to make claims about faculty reform, important questions remain: How should COPUS measures be situated within existing reform frameworks? Is there a universal sampling intensity that allows for valid inferences about the frequency of student-centered instruction within a semester or across semesters of a course? These questions were addressed using longitudinal COPUS observations (128 classes, three faculty, 4 years). COPUS behaviors were used to categorize classes into didactic, interactive lecture, or student-centered instructional styles. Sampling intensities (one to 11 classes) were simulated (1000 times) within a course and across semesters. The sampling intensities required for generating valid inferences about 1) the presence of student-centered instruction and 2) the proportion of instructional styles in a course and through time were calculated. Results indicated that the sampling intensity needed to characterize courses and instructors varied and was much higher than previously recommended for instructors with: 1) rare instances of student-centered classes, 2) variability in instructional style, and 3) longitudinal changes in instructional patterns. These conditions are common in early reform contexts. This study highlights the risks of broad, decontextualized sampling protocol recommendations and illustrates how reform frameworks, sampling intensities, and COPUS measures interact to impact inferences about faculty change.

Response-specific effects of pain observation on motor behavior.

How does seeing a painful event happening to someone else influence the observer's own motor system? To address this question, we measured simple reaction times following videos showing noxious or innocuous implements contacting corporeal or noncorporeal objects. Key releases in a go/nogo task were speeded, and key presses slowed, after subjects saw a video of a needle pricking a fingertip. No such effect was seen when the observed hand was replaced by a sponge, nor when the needle was replaced by a cotton bud. These findings demonstrate that pain observation modulates the motor system by speeding withdrawal movements and slowing approach movements of the finger. This illustrates a basic mechanism by which visual information about pain is used to facilitate appropriate behavioral responses.

Characteristics of motor resonance predict the pattern of flash-lag effects for biological motion.

BACKGROUND: When a moving stimulus and a briefly flashed static stimulus are physically aligned in space the static stimulus is perceived as lagging behind the moving stimulus. This vastly replicated phenomenon is known as the Flash-Lag Effect (FLE). For the first time we employed biological motion as the moving stimulus, which is important for two reasons. Firstly, biological motion is processed by visual as well as somatosensory brain areas, which makes it a prime candidate for elucidating the interplay between the two systems with respect to the FLE. Secondly, discussions about the mechanisms of the FLE tend to recur to evolutionary arguments, while most studies employ highly artificial stimuli with constant velocities. METHODOLOGY/PRINCIPAL FINDING: Since biological motion is ecologically valid it follows complex patterns with changing velocity. We therefore compared biological to symbolic motion with the same acceleration profile. Our results with 16 observers revealed a qualitatively different pattern for biological compared to symbolic motion and this pattern was predicted by the characteristics of motor resonance: The amount of anticipatory processing of perceived actions based on the induced perspective and agency modulated the FLE. CONCLUSIONS/SIGNIFICANCE: Our study provides first evidence for an FLE with non-linear motion in general and with biological motion in particular. Our results suggest that predictive coding within the sensorimotor system alone cannot explain the FLE. Our findings are compatible with visual prediction (Nijhawan, 2008) which assumes that extrapolated motion representations within the visual system generate the FLE. These representations are modulated by sudden visual input (e.g. offset signals) or by input from other systems (e.g. sensorimotor) that can boost or attenuate overshooting representations in accordance with biased neural competition (Desimone & Duncan, 1995).