A nervous system requires a precise network of connections between cells called neurons to work properly. Within the brain, the fiber-like connections between pairs of neurons are not running crisscross like a pile of spaghetti. Instead, connected partner neurons are organized into distinct layers and columns. Many questions remain about how these partner neurons find each other and how the layers of fiber-like connections form. To answer these questions, scientists often study the part of the fruit fly nervous system that controls the insect’s vision. This brain-like structure is simple and can be easily manipulated with genetic engineering. Fruit fly studies have helped identify some molecules that play a role in helping partner cells find one another and connect. These studies have also shown that the timing of brain cell development appears to play a role. But the role that layer formation plays in the process is still a mystery. Now, Kulkarni et al. show that the birthdate of neurons in the fruit fly visual system helps organize them into layers. These neurons are generated early in the development of the fly. Shortly after birth, a molecular clock under the control of a protein called Sequoia starts within each newly generated neuron. The Sequoia protein is a transcription factor and controls the activity of many genes, and the molecular clock provides the growing neuron fibers with information about where and when to look for its partner neurons. By manipulating the amount and time that Sequoia is produced in the fly visual system, Kulkarni et al. show that this clock helps arrange the growing cells into layers. Cells with similar birthdates connect and are arranged into layers. How much and when Sequoia is produced dictates where each new layer begins. The next steps for the research will be to learn more about how the clock works and identify any intermediaries between the clock and cell growth patterns.

Birth order dependent growth cone segregation determines synaptic layer identity in the Drosophila visual system

Abstract Research driven solely by curiosity and the desire to understand fundamental principles of brain function. The freedom to address important questions with bold, sometimes risky experiments. A platform for open scientific exchange and discussions at highest academic level to provide new impulses to the field. And a growing number of scientists who share the passion for neuroscience and who join forces to tackle some of the big mysteries that surround the brain. These visions together with the deep conviction that basic research is the fundament needed for any progress in applied science motivated Dr. Armin Schram to create the foundation that carries his name. They are also the ideals that the foundation still pursues, and to date, 26 research proposals designed by individual researchers or small teams have been, or are, supported in this spirit. Here, we introduce the reader to the individual scientists who were awarded grants by the Schram Foundation over the years, highlight some of the many discoveries made in the course of their studies and list some of the key publications that arose from this work.

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Dorothea Schulte

Papers

Synapses, networks, brain development – funding basic neuroscience research in Germany by the Schram Foundation