Neurons

  • Deep Inside the Brain: Unraveling the Dense Networks in the Cerebral Cortex

    Small fraction of dendrites (gray) and synapses (orange) in a piece of mouse cortex, reconstructed from 3D electron microscopy data. Motta, Wissler (c) MPI for Brain Research

    Mammalian brains, with their unmatched number of nerve cells and density of communication, are the most complex networks known. While methods to analyze neuronal networks sparsely have been available for decades, the dense mapping of neuronal circuits is a major scientific challenge. Researchers from the MPI for Brain Research have now succeeded in the dense connectomic mapping of brain tissue from the cerebral cortex, and quantify the possible imprint of learning in the circuit.

  • How much information can we get from a spike?

    In many situations it is sufficient to consider the space of pairwise spike correlations (blue) to understand neural information, without the need to evaluate all possible spike combinations (gray). Tatjana Tchumatchenko / Max Planck Institute for Brain Research

    Neurons communicate via spikes but how they use those short pulses to code information is still an open question. Recent work at the Max Planck Institute for Brain Research (Theory of Neural Dynamics Group) reveals that by determining temporal pairwise correlations one can get closer to answering this question.

    A key to understanding how the brain works is revealing the set of rules neurons use to communicate information between one another. The main means of neural communication are spikes, which are brief electrical pulses send out at some specific times.

  • Locomotion Control with Photopigments

    Mechanoreceptors of the drosophila larva. Photo: University of Göttingen

     

    (pug) Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an additional function: They not only exist in eyes, but also in mechanoreceptors along the body, where they control body movements. The results were published in Neuron. Coordinated locomotion requires mechanoreceptors that inform animals about their body movements. By analyzing locomotion in Drosophila fruit fly larvae, the scientists found that this locomotion control requires visual opsins, the visual photopigment proteins.

  • Making spintronic neurons sing in unison

    Johan Åkerman. Photo: Johan Wingborg

    What do fire flies, Huygens’s wall clocks, and even the heart of choir singers, have in common? They can all synchronize their respective individual signals into one single unison tone or rhythm. Now researchers at University of Gothenburg have taught two different emerging classes of nano-scopic microwave signal oscillators, which can be used as future spintronic neurons, to sing in unison with their neighbours. Earlier this year, they announced the first successful synchronization of five so-called nano-contact spin torque oscillators. In that system, one of the nano-contacts played the role of the conductor, deciding which note to sing, and the other nano-contacts happily followed her lead.

  • Master of the Tree – Novel Form of Dendritic Inhibition Discovered

    The distal dendrites of pyramidal neurons (red) are controlled by a specialized set of interneurons (white) in layer 1 of neocortex. Artwork by Julia Kuhl (http://somedonkey.com/).

    A unique feature that sets neurons apart from all other cells are their beautiful, highly elaborate dendritic trees. These structures have evolved to receive the vast majority of information entering a neuron, which is integrated and processed by virtue of the dendrites’ geometry and active properties. Higher brain functions such as memory and attention all critically rely on dendritic computations, which are in turn controlled by inhibitory synaptic input. A team of scientists, led by Johannes J. Letzkus (MPI for Brain Research), now has identified a novel form of inhibition that dominantly controls dendritic function and strongly depends on previous experiences.

  • New Contents: Neuronal Parkinson Inclusions are Different than Expected

    Content of Lewy bodies: The inclusions in the neurons contain mainly a membranous medley instead of the anticipated protein fibrils. University of Basel, Biozentrum

    An international team of researchers involving members of the University of Basel’s Biozentrum challenges the conventional understanding of the cause of Parkinson’s disease. The researchers have shown that the inclusions in the brain’s neurons, characteristic of Parkinson‘s disease, are comprised of a membranous medley rather than protein fibrils. The recently published study in “Nature Neuroscience” raises new questions about the etiology of Parkinson’s disease.

  • Novel Sensor Implant Radically Improves Significance of NMR Brain Scans

    Illustration of the nuclear magnetic resonance (NMR) needle in the brain tissue. © whitehoune - stock.adobe.com, Max Planck Institute for Biological Cybernetics, University of Stuttgart. Montage: Martin Vötsch (design-galaxie.de)

     

    A team of neuroscientists and electrical engineers from Germany and Switzerland developed a highly sensitive implant that enables to probe brain physiology with unparalleled spatial and temporal resolution. Now published in Nature Methods, they introduce an ultra-fine needle with an integrated chip that is capable of detecting and transmitting nuclear magnetic resonance (NMR) data from nanoliter volumes of brain oxygen metabolism. The breakthrough design will allow entirely new applications in the life sciences.

  • Rabies viruses reveal wiring in transparent brains

    Transplant of human neurons in the hippocampus of a mouse: the surrounding nerve cells in the mouse brain have connected to engrafted neurons.  © Photo: Dr. Jonas Doerr

    Scientists under the leadership of the University of Bonn have harnessed rabies viruses for assessing the connectivity of nerve cell transplants: coupled with a green fluorescent protein, the viruses show where replacement cells engrafted into mouse brains have connected to the host neural network. A clearing procedure which turns the brain into a ‘glass-like state’ and light sheet fluorescence microscopy are used to visualize host-graft connections in a whole-brain preparation. The approach opens exciting prospects for predicting and optimizing the ability of neural transplants to functionally integrate into a host nervous system. The results have been published in “Nature Communications”.

  • Researchers Take a Step Towards Light-based, Brain-like Computing Chip

    Schematic illustration of a light-based, brain-inspired chip. The chip contains an artificial network of neurons and synapses that works with light. Johannes Feldmann

    Researchers from the Universities of Münster (Germany), Oxford and Exeter (both UK) have succeeded in developing a piece of hardware which could pave the way for creating computers which resemble the human brain. The scientists produced a chip containing a network of artificial neurons that works with light and can imitate the behaviour of neurons and their synapses. The network is able to “learn” information and use this as a basis for computing and recognizing patterns. As the system functions solely with light and not with electrons, it can process data many times faster than traditional systems. The study is published in “Nature”.

  • Synapses in 3d: Scientists Develop New Method to Map Brain Structures

    An x–y view of a section 2.5 mm from the top surface of a Thy1-eGFP PEGASOS-cleared brain. Close-up of the box with a rendered neuron. Insets provide magnified views of synaptic spines. Reto Fiolka

    Our brain consists of countless nerve cells that transmit signals from one cell to the next. The connections between these cells, the synapses, provide a key to understanding how our memory works. An American research team in collaboration with Rainer Heintzmann from the Leibniz Institute of Photonic Technology (Leibniz IPHT) and the Friedrich Schiller University Jena has now succeeded in identifying these switching points in millimeter-sized tissue with a light microscope on the basis of their structure. The scientists published their results on 31 October 2019 in Nature Methods.

  • Walking is bound hand and foot: How long projecting neurons couple the movement of our limbs

    Netzwerk menschlicher Neuronen.

    We humans walk with our feet. This is true, but not entirely. Walking, as part of locomotion, is a coordinated whole-body movement that involves both the arms and legs. Researchers at the Biozentrum of the University of Basel and the Friedrich Miescher Institute for Biomedical Research have identified different subpopulations of neurons in the spinal cord with long projections. Published in Neuron, the results show that these neurons coordinate movement of arms and legs and ensure a stable body posture during locomotion.

  • Working the Switches for Axon Branching

    In neuronal cells, the protein SSNA1 (pink) accumulates at branching sites in axons (top). The SSNA1 fibrils attach to the microtubules (green) and trigger branching (bottom). © Naoko Mizuno, MPI of Biochemistry

    Our brain is a complex network with innumerable connections between cells. Neuronal cells have long thin extensions, so-called axons, which are branched to increase the number of interactions. Researchers at the Max Planck Institute of Biochemistry (MPIB) have collaborated with researchers from Portugal and France to study cellular branching processes. They demonstrated a novel mechanism that induces branching of microtubules, an intracellular support system. The newly discovered dynamics of microtubules has a key role in neuronal development. The results were recently published in the journal Nature Cell Biology.