Letters, foundational units of alphabetic writing systems, are quintessential to human culture. The ability to read, indispensable to perform in today’s society, necessitates a reorganization of visual cortex for fast letter recognition, but the developmental course of this process has not yet been characterized. Here, we show the emergence of visual sensitivity to letters across five electroencephalography measurements from kindergarten and throughout elementary school and relate this development to emerging reading skills. We examined the visual N1, the electrophysiological correlate of ventral occipito-temporal cortex activation in 65 children at varying familial risk for dyslexia. N1 letter sensitivity emerged in first grade, when letter sound knowledge gains were most pronounced and decayed shortly after when letter knowledge is consolidated, showing an inverted U-shaped development. This trajectory can be interpreted within an interactive framework that underscores the influence of top-down predictions. While the N1 amplitudes to letters correlated with letter sound knowledge at the beginning of learning, no association between the early N1 letter response and later reading skills was found. In summary, the current findings provide an important reference point for our neuroscientific understanding of learning trajectories and the process of visual specialization during skill learning.

Social bonds reflect specific and enduring relationships among conspecifics. In some group living animals they have been found to generate immediate and long-term fitness benefits. It is currently unclear how important and how widespread social bonds are in animals other than primates. It has been hypothesized that social bonds may help establishing stable levels of reciprocal cooperation. Norway rats (Rattus norvegicus) reciprocate received help to an unrelated social partner. It is hitherto unknown, however, whether this cooperative behaviour is based on the establishment of social bonds among involved individuals. Norway rats live in social groups that can be very large, hence without bonds it may be difficult to keep track of other individuals and their previous behaviour, which is a precondition for generating evolutionarily stable levels of cooperation based on direct reciprocity. Here we tested whether wild-type female rats form bonds among each other, which are stable both over time and across different contexts. In addition, we scrutinized the potential influence of social rank on the establishment of bonds. Despite the fact that the hierarchy structure within groups remained stable over the study period, no stable social bonds were formed between group members. Apparently, social information from consecutive encounters with the same social partner is not accumulated. The lack of long-term social bonds might explain why rats base their decisions to cooperate primarily on the last encounter with a social partner, which may differ from other animals where cooperation is based on the existence of long-term social bonds.

Prävalenz und Charakterisierung von Methicillin-resistenten Macrococcus spp. bei Nutztieren und Fleisch in der Schweiz im Jahr 2019 Die Prävalenz von Methicillin-resistenten Macrococcus spp. bei Kälbern und Schweinen wurde anhand von Proben aus dem Schlachthof und Fleisch aus dem Einzelhandel bestimmt. Für die Studie wurden Proben verwendet, welche im Rahmen der nationalen Überwachung auf Methicillin-resistenten Staphylococcus aureus bei Lebensmittelliefernden Tieren sowie Fleisch entnommen wurden. Die Isolate wurden einer antimikrobiellen Empfindlichkeitsprüfung für 19 Antibiotika unterzogen. Mittels molekularen Techniken (z. B. PCR, Microarray, WGS) wurden Sequenztyp (ST), Resistenzgene und die Elemente, welche ein Methicillin-Resistenzgen mec tragen, identifiziert.

Number processing abilities are important for academic and personal development. The course of initial specialization of ventral occipito-temporal cortex (vOTC) for visual number processing is crucial for the development of numeric and arithmetic skills. We examined the visual N1, the electrophysiological correlate of vOTC activations across five time points in kindergarten (T1), middle and end of first grade (T2, T3), second (T4) and fifth grade (T5). 62 children (35 female) performed a target detection task which included visual presentation of digits, false fonts, and letters. Arithmetic skills were measured at T4 and T5 with standardized math tests. Stronger N1 amplitudes for digits than false fonts were found across all 5 measurements. Arithmetic skills correlated negatively with visual N1 sensitivity to digits at T4 (2nd grade, mean age 8.3 yrs) over the left hemisphere, possibly reflecting allocation of more attentional or cognitive resources with poorer arithmetic skills. Our main result shows persistent visual N1 sensitivity to digits that is already present early on in pre-school and remains stable until fifth grade. This differs from the relatively sharp rise and fall of the visual N1 sensitivity to words or letters between kindergarten and middle of elementary school. The present study thus indicates different trajectories in the development of visual processing for written characters that are relevant to numeracy and literacy.