According to the facial feedback hypothesis, people's affective responses can be influenced by their own facial expression (e.g., smiling, pouting), even when their expression did not result from ...their emotional experiences. For example, Strack, Martin, and Stepper (1988) instructed participants to rate the funniness of cartoons using a pen that they held in their mouth. In line with the facial feedback hypothesis, when participants held the pen with their teeth (inducing a "smile"), they rated the cartoons as funnier than when they held the pen with their lips (inducing a "pout"). This seminal study of the facial feedback hypothesis has not been replicated directly. This Registered Replication Report describes the results of 17 independent direct replications of Study 1 from Strack et al. (1988), all of which followed the same vetted protocol. A meta-analysis of these studies examined the difference in funniness ratings between the "smile" and "pout" conditions. The original Strack et al. (1988) study reported a rating difference of 0.82 units on a 10-point Likert scale. Our meta-analysis revealed a rating difference of 0.03 units with a 95% confidence interval ranging from −0.11 to 0.16.
This research shows that short-term synaptic plasticity can play a critical role in shaping the behavioral response to environmental change. In Aplysia, exposure to turbulent environments produces a ...stable reduction in the duration of the siphon-withdrawal reflex (SWR) and the responsiveness of siphon motor neurons. Recovery takes >1 min after a brief (10 sec-5 min) exposure but <1 min after a long (10 min) exposure. Here we demonstrate that (1) in-turbulence and post-turbulence phases of regulation depend on different cellular processes and (2) the post-turbulence phase of regulation is mediated by augmentation (AUG), an activity-dependent form of short-term synaptic plasticity. In reduced preparations (tail, siphon, and CNS), we show that treatment with 100 microm d-tubocurarine has no effect on in-turbulence regulation but blocks up to 90% of post-turbulence regulation, indicating that these phases of regulation are mediated by distinct cellular process. We then show that (1) turbulence induces activity in L30 inhibitory interneurons, (2) this activation produces AUG that lasts 1 min after a brief exposure to turbulence, and (3) manipulations that attenuate L30 AUG also attenuate regulation after brief turbulence. We also found that long (10 min) exposures to turbulence do not produce a post-turbulence phase of regulation because L30 activity declines over the course of a long turbulence exposure, leading to the decay of AUG before turbulence offset. Our results demonstrate a specific behavioral function of AUG and show how interactions between cellular processes can confer temporal sensitivity in the network regulation of behavior.
After developing a model neuron or network, it is important to systematically explore its behavior across a wide range of parameter values or experimental conditions, or both. However, compiling a ...very large set of simulation runs is challenging because it typically requires both access to and expertise with high-performance computing facilities. To lower the barrier for large-scale model analysis, we have developed NeuronPM, a client/server application that creates a “screen-saver” cluster for running simulations in NEURON (Hines & Carnevale, 1997). NeuronPM provides a user-friendly way to use existing computing resources to catalog the performance of a neural simulation across a wide range of parameter values and experimental conditions. The NeuronPM client is a Windows-based screen saver, and the NeuronPM server can be hosted on any Apache/PHP/MySQL server. During idle time, the client retrieves model files and work assignments from the server, invokes NEURON to run the simulation, and returns results to the server. Administrative panels make it simple to upload model files, define the parameters and conditions to vary, and then monitor client status and work progress. NeuronPM is open-source freeware and is available for download at
. It is a useful entry-level tool for systematically analyzing complex neuron and network simulations.
We examined the relation between self-explaining and encoding among kindergartners. For 5 days, children (n = 27) took turns solving addition problems with an adult expert who always used an advanced ...addition strategy. During the game, children explained the expert's answers (Explain-Expert), explained their own answers (Explain-Novice), or did not generate explanations (Control). Encoding of the expert's strategy was measured each day by asking children to describe how the expert had solved the last problem. Explain-Expert children encoded more and learned more than children in the Control group; Explain-Novice children showed neither advantage. The Explain-Expert group also acquired the expert's strategy more rapidly and used it more frequently than the other groups. These results suggest that explanations enhance learning in part by facilitating encoding.
Exposure to turbulence, an environmental stimulus, produces behavioral adaptation in the
Aplysia
siphon-withdrawal response (SWR). The authors show that the duration and spatial extent of turbulence ...influence adaptation recovery. In terms of duration, recovery in whole animals and reduced preparations (tail, siphon, and CNS) was more rapid after longer exposures to turbulence (10 min) than after briefer exposures (10 s-5 min). In terms of spatial extent, recovery in reduced preparations was more rapid after diffuse turbulence (tail and siphon together) compared with focal turbulence (siphon alone). Furthermore, spatial extent and duration interact: Duration regulates recovery only when turbulence is diffuse. Results suggest that SWR adaptation reflects a composite of cellular processes, including short-term synaptic enhancement in L30 inhibitory interneurons.
Sequence analysis of the 330-kb genome of chlorella virus PBCV-1 revealed an open reading frame, A464R, which encodes a protein with 30–35% amino acid identity to ribonuclease III (RNase III) from ...many bacteria. The
a464r gene was cloned and the protein was expressed in
Escherichia coli using the chitin-binding intein system. The recombinant PBCV-1 RNase III cleaves model dsRNA substrates, in a Mg
2+-dependent manner, into a defined set of products. The substrate cleavage specificity overlaps, but is nonidentical to that of
E. coli RNase III. The
a464r gene is expressed very early during PBCV-1 infection, within 5–10 min p.i. The RNase III protein appears at 15 min p.i. and disappears by 120 min p.i. The
a464r gene is highly conserved among the chlorella viruses. Phylogenetic analyses indicate that the PBCV enzyme is most closely related to
Mycoplasma pneumoniae RNase III.
Knowledge of neuronal circuitry is foundational to the neurosciences, but no tools have been developed for cataloguing this knowledge. Part of the problem is that the concepts used to describe neural ...circuits are rapidly evolving and vary substantially across different species. The NeuronBank project (http://neuronbank.org) is developing an informatics infrastructure for managing the dynamic, domain-specific knowledge of neural circuitry, providing a reference source, an outlet for publishing new knowledge, and a useful research tool. Our solution is a federation of customizable knowledge bases, each adaptable to store knowledge of the neural circuitry of a single species. The federation is united by a common set of web services and a central portal that provides core functionality across various knowledge bases. This service-oriented architecture provides domain-specific representations of specialized scientific knowledge while maintaining interoperability across a broad discipline.
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