Machine learning for automatic prediction of the quality of electrophysiological recordings.

The quality of electrophysiological recordings varies a lot due to technical and biological variability and neuroscientists inevitably have to select "good" recordings for further analyses. This procedure is time-consuming and prone to selection biases. Here, we investigate replacing human decisions by a machine learning approach. We define 16 features, such as spike height and width, select the most informative ones using a wrapper method and train a classifier to reproduce the judgement of one of our expert electrophysiologists. Generalisation performance is then assessed on unseen data, classified by the same or by another expert. We observe that the learning machine can be equally, if not more, consistent in its judgements as individual experts amongst each other. Best performance is achieved for a limited number of informative features; the optimal feature set being different from one data set to another. With 80-90% of correct judgements, the performance of the system is very promising within the data sets of each expert but judgments are less reliable when it is used across sets of recordings from different experts. We conclude that the proposed approach is relevant to the selection of electrophysiological recordings, provided parameters are adjusted to different types of experiments and to individual experimenters.

Pharmacology and chemistry of the venoms of solitary wasps.

In this study certain activities of solitary wasp venoms collected from the Suez Canal area (Bembix oculata, Dielis collaris, and Scolia erythrocephala) were investigated. The effects of these venoms on different types of muscles were studied, and in addition, the chemical structures were studied by electrophoretic analysis. We found that the venoms affect different types of muscles (cardiac, skeletal, and smooth) in different ways. The effect of the venoms on heart muscle was rapid and led to bradycardia, an increase in R amplitude on ECG, and other cardiac disorders such as atrioventricular block. These effects were abolished by atropine, indicating they were mediated through the peripheral nervous system. All of the venoms we tested reversibly blocked the nicotinic receptors of toad skeletal muscle and the muscarinic receptors of smooth muscles. Through electrophoretic analysis, seven bands were detected in Dielis collaris venom, while five bands were detected in Bembix oculata venom.