Neural Representations of Courtship Song in the Drosophila Brain

Acoustic communication in drosophilid flies is based on the production and perception of courtship songs, which facilitate mating. Despite decades of research on courtship songs and behavior in Drosophila, central auditory responses have remained uncharacterized. In this study, we report on intracellular recordings from central neurons that innervate the Drosophila antennal mechanosensory and motor center (AMMC), the first relay for auditory information in the fly brain. These neurons produce graded-potential (nonspiking) responses to sound; we compare recordings from AMMC neurons to extracellular recordings of the receptor neuron population [Johnston's organ neurons (JONs)]. We discover that, while steady-state response profiles for tonal and broadband stimuli are significantly transformed between the JON population in the antenna and AMMC neurons in the brain, transient responses to pulses present in natural stimuli (courtship song) are not. For pulse stimuli in particular, AMMC neurons simply low-pass filter the receptor population response, thus preserving low-frequency temporal features (such as the spacing of song pulses) for analysis by postsynaptic neurons. We also compare responses in two closely related Drosophila species, Drosophila melanogaster and Drosophila simulans, and find that pulse song responses are largely similar, despite differences in the spectral content of their songs. Our recordings inform how downstream circuits may read out behaviorally relevant information from central neurons in the AMMC

Judith P. Coen to Mr. Meredith (2 October 1962)

https://egrove.olemiss.edu/mercorr_pro/1446/thumbnail.jp

Figli della memoria

Figli della memoria, primo numero della collana di studi "Il tempo, la storia e la memoria", raccoglie contributi che affrontano il tema della Shoah e della memoria con approcci di tipo letterario, filosofico, artistico, storico, linguistico, politico e giuridico. Molti degli autori fanno parte della Rete Universitaria per il Giorno della Memoria e sono responsabili dei Corsi di Storia e didattica della Shoah istituiti dalla Rete in Italia e all'estero. Figli della memoria sintetizza la volont\ue0 di tenere uniti il mondo dell\u2019Universit\ue0, della Scuola e del Museo, senza facili strabismi e anzi mantenendo ferma l\u2019istanza civile, scientifica e didattica

Ideology and culture

This chapter evaluates the role of culture and ideology in relation to journalism. Journalists cannot ignore that they are not operating in a vacuum, immune to environmental influences. A “western” (or any ideological) approach to journalism is not a neutral norm to which others need to adhere. Journalists can keep themselves and each other in check by questioning the approach taken to a story and identifying the lens they employ. Secondly, diverse recruitment within media organisations is key, not just in terms of ethnic, gender or national backgrounds but also in terms of value profiles. There is no one Nation which holds the gold standard for journalism and can be used as a reference point for all others. In other words, there is no such thing as Greenwich Mean Time journalism

A Bi-Directional Refinement Algorithm for the Calculus of (Co)Inductive Constructions

The paper describes the refinement algorithm for the Calculus of (Co)Inductive Constructions (CIC) implemented in the interactive theorem prover Matita. The refinement algorithm is in charge of giving a meaning to the terms, types and proof terms directly written by the user or generated by using tactics, decision procedures or general automation. The terms are written in an "external syntax" meant to be user friendly that allows omission of information, untyped binders and a certain liberal use of user defined sub-typing. The refiner modifies the terms to obtain related well typed terms in the internal syntax understood by the kernel of the ITP. In particular, it acts as a type inference algorithm when all the binders are untyped. The proposed algorithm is bi-directional: given a term in external syntax and a type expected for the term, it propagates as much typing information as possible towards the leaves of the term. Traditional mono-directional algorithms, instead, proceed in a bottom-up way by inferring the type of a sub-term and comparing (unifying) it with the type expected by its context only at the end. We propose some novel bi-directional rules for CIC that are particularly effective. Among the benefits of bi-directionality we have better error message reporting and better inference of dependent types. Moreover, thanks to bi-directionality, the coercion system for sub-typing is more effective and type inference generates simpler unification problems that are more likely to be solved by the inherently incomplete higher order unification algorithms implemented. Finally we introduce in the external syntax the notion of vector of placeholders that enables to omit at once an arbitrary number of arguments. Vectors of placeholders allow a trivial implementation of implicit arguments and greatly simplify the implementation of primitive and simple tactics

Superfast vocal muscles control song production in songbirds

Journal ArticleBirdsong is a widely used model for vocal learning and human speech, which exhibits high temporal and acoustic diversity. Rapid acoustic modulations are thought to arise from the vocal organ, the syrinx, by passive interactions between the two independent sound generators or intrinsic nonlinear dynamics of sound generating structures. Additionally, direct neuromuscular control could produce such rapid and precisely timed acoustic features if syringeal muscles exhibit rare superfast muscle contractile kinetics. However, no direct evidence exists that avian vocal muscles can produce modulations at such high rates