Past events

From detecting food to locating lurking predators, visual search -- the ability to find an object of interest against a background -- needs to be accurate and fast to ensure survival. In mammals, this led to the development of a parallel search mode, pop-out, which enables fast detection time that is not dependent on the number of distracting objects. Although it may be beneficial to most animals, pop-out behavior has been observed only in mammals, where its neural correlates are found as early as V1 in contextually modulated cells that encode aspects of saliency. I will describe our recent findings of pop-out visual search in the archer fish and discuss possible implications about universality of visual search among vertebrates.

Bats have a unique view of the world: ‘seeing’ their environment with their ears through echolocation. They use this active sensing system to master their predominantly dark world, e.g. for detecting and targeting of small insect prey, navigating through complex vegetation or interaction with other individuals. Over the last decades we have developed a solid understanding of how bats apply echolocation to achieve this. However, many questions are still unsolved, e.g. assessment of larger objects like trees or even whole habitats. In my talk, I will show how bats recognize and deal with water surfaces. My results demonstrate that a recognition pattern can be very simple: for bats any smooth surface is perceived as a water surface. Likely through a long evolutionary consolidation without any contradicting experiences, this is phylogenetically wide spread among bats, extremely hardwired and even innate. In addition I will talk about the integration of varying sensory input, the role of spatial memory and potential evolutionarytraps that may arise from this. Echolocation is a rather short-ranged sensing system, which leaves the intriguing question of how bats orientate and navigate over long distances. They face this challenge not only during daily foraging trips but also on migration routes which can be over 1,000 kilometers long. Recent evidence has shown that bats can, for example, make use of the Earth’s magnetic field. However, the exact functional mechanism of this ability is as yet largely unknown. In this context, I will present data showing that our tested bat species recognizes the sky’s polarization pattern at dusk and uses it as a calibrating system for its magnetic compass. This is the only known case so far for a mammal to use this sensory light cue.

The mammalian cerebral cortex supports cognitive functions such as sensorimotor integration, memory, and social behaviors. Normal brain function relies on a diverse set of differentiated cell types, including neurons, glia, and vasculature. Here, we have used large-scale single-cell RNA sequencing (RNA-seq) to classify cells in the mouse somatosensory cortex and hippocampal CA1 region. We found 47 molecularly distinct subclasses, comprising all known major cell types in the cortex. We identified numerous marker genes, which allowed alignment with known cell types, morphology, and location.

How animals make decisions in the wild is an open key-question in biology. Our lack of knowledge on this fundamental question results from a technological gap – the difficulty to track animals over long periods while monitoring their behavior; and from a conceptual gap – how to identify animals’ decision-points outdoors? We apply innovative on-board miniature sensors, to study decision making in wild bats, focusing on one of the most fundamental contexts of decision making – foraging for food. We are interested in how different sources of information, e.g., social information and sensory information, are integrated when making foraging decisions.