On the Daguerre plate: About the Daguerrean excursions

Primera traducción al español del ensayo que Rodolphe Töppfer dedicó al daguerrotipo en 1841, apenas dos años después de su presentación oficial. Sobre el trasfondo de esta nueva experiencia visual, el texto traza una reflexión sobre la fotografía partiendo de la diferencia entre la identidad y la semejanza. El abordaje trasciende la problemática del realismo en fotografía para expandirse hacia el campo de la caricatura, principal línea de producción estética de Töpffer, y el valor espiritual del arte.First translation into Spanish of the essay that Rodolphe Töppfer dedicated to the daguerreotype in 1841, just two years after its official presentation. On the background of this new visual experience, the text traces a reflection on photography based on the difference between identity and similarity. The approach transcends the problematic of realism in photography to expand towards the field of caricature, Töpffer's main aesthetic production line, and the spiritual value of art.Fil: Tell, Verónica. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Departamento de Artes; Argentina. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hakel, Laura. Universidad del Museo Social Argentino; Argentin

Non-invasive vagus nerve stimulation in epilepsy patients enhances cooperative behavior in the prisoner's dilemma task

The vagus nerve constitutes a key link between the autonomic and the central nervous system. Previous studies provide evidence for the impact of vagal activity on distinct cognitive processes including functions related to social cognition. Recent studies in animals and humans show that vagus nerve stimulation is associated with enhanced reward-seeking and dopamine-release in the brain. Social interaction recruits similar brain circuits to reward processing. We hypothesize that vagus nerve stimulation (VNS) boosts rewarding aspects of social behavior and compare the impact of transcutaneous VNS (tVNS) and sham stimulation on social interaction in 19 epilepsy patients in a double-blind pseudo-randomized study with cross-over design. Using a well-established paradigm, i.e., the prisoner's dilemma, we investigate effects of stimulation on cooperative behavior, as well as interactions of stimulation effects with patient characteristics. A repeated-measures ANOVA and a linear mixed-effects model provide converging evidence that tVNS boosts cooperation. Post-hoc correlations reveal that this effect varies as a function of neuroticism, a personality trait linked to the dopaminergic system. Behavioral modeling indicates that tVNS induces a behavioral starting bias towards cooperation, which is independent of the decision process. This study provides evidence for the causal influence of vagus nerve activity on social interaction

Transcutaneous auricular vagus nerve stimulation influences gastric motility: A randomized, double-blind trial in healthy individuals

Background: Transcutaneous auricular vagus nerve stimulation (taVNS) has been investigated regarding its therapeutic properties in several several conditions such as epilepsy, migraine and major depressive disorder and was shown to access similar neural pathways as invasive vagus nerve stimulation. While the vagus nerve's role in gut motility is physiologically established, the effect of taVNS has scarcely been investigated in humans and yielded conflicting results. Real-time gastric magnetic resonance imaging (rtMRI) is an established reproducible method to investigate gastric motility non-invasively. Objective: To investigate the influence of taVNS on gastric motility of healthy participants using rtMRI. Methods: We conducted a randomized, double-blind study using high-frequency (HF) stimulation at 25Hz or low-frequency (LF) taVNS at 1Hz after ingestions of a standardized meal in 57 healthy participants. The gastric motility index (GMI) was determined by measuring the amplitude and velocity of the peristaltic waves using rtMRI. Results: After HF taVNS, GMI was significantly higher than after LF stimulation (p = 0.005), which was mainly attributable to a higher amplitude of the peristaltic waves (p = 0.003). Conclusion: We provide evidence that 4-h of taVNS influences gastric motility in healthy human participants for the first time using rtMRI. HF stimulation is associated with higher amplitudes of peristaltic waves in the gastric antrum compared to LF stimulation. Further studies are needed to investigate the effect of different frequencies of taVNS and its therapeutic properties in conditions with impaired gastric motility