A5017967974- Neural dynamics and brain function
- Photoreceptor and optogenetics research
- Neuroscience and Neural Engineering
- Neuroscience and Neuropharmacology Research
- EEG and Brain-Computer Interfaces
- Cognitive and developmental aspects of mathematical skills
- Receptor Mechanisms and Signaling
- Molecular Communication and Nanonetworks
- Advanced Memory and Neural Computing
- Memory and Neural Mechanisms
- Visual perception and processing mechanisms
- Light effects on plants
- Zebrafish Biomedical Research Applications
- Mathematics Education and Teaching Techniques
- Neurotransmitter Receptor Influence on Behavior
- Anesthesia and Sedative Agents
- Reinforcement Learning in Robotics
- Neurobiology and Insect Physiology Research
- Education Methods and Practices
- Neural Networks and Applications
- stochastic dynamics and bifurcation
- Health Systems, Economic Evaluations, Quality of Life
- Anesthesia and Pain Management
- Circadian rhythm and melatonin
- Cell Image Analysis Techniques
University of Freiburg
2017-2024
Bernstein Center for Computational Neuroscience Freiburg
2017-2024
Brain (Germany)
2019-2024
Ernst Strüngmann Institute for Neuroscience
2012-2021
Stanford University
2010-2019
University of Tübingen
2006-2009
Hertie Institute for Clinical Brain Research
2006-2007
Cholinergic neurons are widespread, and pharmacological modulation of acetylcholine receptors affects numerous brain processes, but such entails side effects due to limitations in specificity for receptor type target cell. As a result, causal roles cholinergic circuits have been unclear. We integrated optogenetics, freely moving mammalian behavior, vivo electrophysiology, slice physiology probe the interneurons nucleus accumbens by direct excitation or inhibition. Despite representing less...
Humans and animals can nonverbally enumerate visual items across time in a sequence or rapidly estimate the set size of spatial dot patterns at single glance. We found that temporal enumeration processes engaged different populations neurons intraparietal sulcus behaving monkeys. Once process was completed, however, another neuronal population represented cardinality irrespective whether it had been cued layout time. These data suggest distinct neural processing stages for numerical formats,...
The utilization of symbols such as words and numbers mental tools endows humans with unrivalled cognitive flexibility. In the number domain, a fundamental first step for acquisition numerical is semantic association signs cardinalities. We explored primitives mapping process by recording single-cell activity in monkey prefrontal parietal cortices, brain structures critically involved cognition. Monkeys were trained to associate visual shapes varying items matching task. After this long-term...
Studying brain function and its local circuit dynamics requires neural interfaces that can record stimulate the with high spatiotemporal resolution. Optogenetics, a technique genetically targets specific neurons to express light-sensitive channel proteins, provides capability control central nervous system neuronal activity in mammals millisecond time precision. This enables precise optical stimulation of simultaneous monitoring response by electrophysiological means, both vicinity distant...
Cognition requires the dynamic modulation of effective connectivity, i.e., postsynaptic neuronal response to a given input. If neurons are rhythmically active, this might entail rhythmic gain modulation, such that inputs synchronized phases high benefit from enhanced connectivity. We show visually induced gamma-band activity in awake macaque area V4 modulates responses unpredictable stimulus events. This exceeded simple additive superposition constant onto ongoing gamma-rhythmic firing,...
The primate prefrontal cortex (PFC) plays a cardinal role in forming abstract categories and concepts. However, it remains elusive how this is accomplished to what extent the interaction of functionally distinct neuron classes underlies representation. Here, we inferred major cortical cell types, putative pyramidal cells, interneurons by characterizing waveforms action potentials recorded monkeys performing cognitively demanding numerosity categorization task. Putative responded much faster...
Abstract The rich repertoire of skilled mammalian behavior is the product neural circuits that generate robust and flexible patterns activity distributed across populations neurons. Decades associative studies have linked many behaviors to specific population activity, but association alone cannot reveal dynamical mechanisms shape those patterns. Are local high-dimensional reservoirs able arbitrary superpositions with appropriate excitation? Or might circuit dynamics be shaped in response...
Abstract The increasing awareness of the impact spontaneous movements on neuronal activity has raised need to track behavior. We present FreiPose, a versatile learning-based framework directly capture 3D motion freely definable points with high precision (median error < 3.5% body length, 41.9% improvement compared state-of-the-art) and reliability (82.8% keypoints within 5% length boundary, 72.0% improvement). versatility FreiPose is demonstrated in two experiments: (1) By tracking moving...
Synchronization has been implicated in neuronal communication, but causal evidence remains indirect. We use optogenetics to generate depolarizing currents pyramidal neurons of the cat visual cortex, emulating excitatory synaptic inputs under precise temporal control, while measuring spike output. The cortex transforms constant excitation into strong gamma-band synchronization, revealing well-known cortical resonance. Increasing with ramps increases strength and frequency synchronization....
This paper presents the system architecture for an implant concept called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">NeuroBus</i> . Tiny distributed direct digitizing neural recorder ASICs on ultra-flexible polyimide substrate are connected in a bus-like structure, allowing short connections between electrode and recording front-end with low wiring effort high customizability. The small size (344 μm x 294 μm) of ultraflexible allow...
Abstract Simultaneous large-scale recordings and optogenetic interventions may hold the key to deciphering fast-paced multifaceted dialogue between neurons that sustains brain function. Here we have taken advantage of thin, cell-sized, optical fibers for minimally invasive optogenetics flexible implantations. We describe a simple procedure making those side-emitting with Lambertian emission distribution. combined silicon probes achieve high-quality ultrafast multichannel inhibition....
Optogenetic tools have opened a rich experimental landscape for understanding neural function and disease. Here, we present the first validation of eight optogenetic constructs driven by recombinant adeno-associated virus (AAV) vectors WGA-Cre based dual injection strategy projection targeting in widely-used New World primate model, common squirrel monkey Saimiri sciureus. We observed opsin expression around local site axonal projections to downstream regions, as well transduction thalamic...
Abstract Neural oscillations as important information carrier in the brain, are increasingly interpreted transient bursts rather than sustained oscillations. Short (<150 ms) of beta-waves (15–30 Hz) have been documented humans, monkeys and mice. These events were correlated with memory, movement perception, even suggested primary ingredient all beta-band activity. However, a method to measure these short-lived real-time investigate their impact on behaviour is missing. Here we present...