Disconnection in a left-hemispheric temporo-parietal network impairs multiplication fact retrieval.

Arithmetic fact retrieval has been suggested to recruit a left-lateralized network comprising perisylvian language areas, parietal areas such as the angular gyrus (AG), and non-neocortical structures such as the hippocampus. However, the underlying white matter connectivity of these areas has not been evaluated systematically so far. Using simple multiplication problems, we evaluated how disconnections in parietal brain areas affected arithmetic fact retrieval following stroke. We derived disconnectivity measures by jointly considering data from n = 73 patients with acute unilateral lesions in either hemisphere and a white-matter tractography atlas (HCP-842) using the Lesion Quantification Toolbox (LQT). Whole-brain voxel-based analysis indicated a left-hemispheric cluster of white matter fibers connecting the AG and superior temporal areas to be associated with a fact retrieval deficit. Subsequent analyses of direct gray-to-gray matter disconnections revealed that disconnections of additional left-hemispheric areas (e.g., between the superior temporal gyrus and parietal areas) were significantly associated with the observed fact retrieval deficit. Results imply that disconnections of parietal areas (i.e., the AG) with language-related areas (i.e., superior and middle temporal gyri) seem specifically detrimental to arithmetic fact retrieval. This suggests that arithmetic fact retrieval recruits a widespread left-hemispheric network and emphasizes the relevance of white matter connectivity for number processing.

Stoneflies left over from a mining disaster: new species and records of Perlidae (Plecoptera) from the Doce River basin, southeastern Brazil.

Seven years after a mudflow reached an important area of the Doce River basin, southeastern Brazil, and with the objective of reporting the current Plecoptera fauna, specimens of Anacroneuria Klaplek, 1909 (Plecoptera: Perlidae) were studied. Three new records from this basin are included: A. mineira Novaes & Bispo, 2014; A. atrifrons Klaplek, 1922; and Anacroneuria itatiaiensis Baldin, Bispo & Novaes, 2013. A new species is described: A. piranga sp. nov. Castillo-Velsquez, Gonalves & Salles. The new species is morphologically similar to A. annulicauda Stark & Kondratieff, 2004 and A. atrifrons, but can be distinguished by the keel of the penial armature, which is flat and pointed at the apex. In addition to its description, photographs of all species are included, as well as a detailed description of the habitat of the new species.

Ethanol fuel improves pitfall traps through rapid sinking and death of captured orthopterans.

The choice of killing solutions for pitfall traps can influence sampling and is highly dependent on the objectives of each study. It is becoming increasingly common, however, and is more environmentally friendly, to use the same organisms to extract information for different kinds of studies. The killing solution should, therefore, be able to sample local active organisms, as well as maintain the integrity of their organs, tissues, and macromolecules. In a previous work, we showed that using ethanol fuel as a killing solution maintains the integrity of the specimens and enhances the Orthoptera richness and abundance of samples. In the current study, we evaluated two explanations for this pattern. We set up a field experiment to test whether ethanol fuel is attractive for orthopterans, and we investigated in the laboratory whether individuals of Gryllus sp. sink or die faster in ethanol fuel than in other killing solutions. Our results allowed us to refute the hypotheses of attraction caused by ethanol fuel and showed that the higher sampling efficiency of ethanol fuel is directly linked to the specimens sinking and dying faster than in other killing solutions. Thus, in addition to taxonomic, anatomical, and molecular studies, we recommend ethanol fuel for sampling organisms active in the litter in ecological studies.