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Geiger, J. R. P.

Publications and source records attributed to Geiger, J. R. P..

2 recordsLinked to original sources

Intra-individual Physiomic Landscape of Pyramidal Neurons in the Human Neocortex

Understanding the functional principles of the human brain requires deep insight into the neuronal and network physiology. To what extent such principles of cellular physiology and synaptic interactions are common across different human individuals is unknown. We characterized the physiology of ~1200 pyramidal neurons and ~1400 monosynaptic connections using advanced multineuron patch-clamp recordings in slices from human temporal cortex. To disentangle within and between individual sources of heterogeneity, we recorded up to 100 neurons per single subject. We found that neuronal, but not synaptic physiology varied with laminar depth. Connection probability was ~15% throughout layer 2-3. Synaptic amplitudes exhibited heavy-tailed distributions with an inverse power law relationship to short term plasticity. Neurons could be classified into four functional subtypes. These general principles of microcircuit physiology were common across individuals. Our study advances the understanding of human neuron and synaptic diversity from an individual and phenotypic perspective.

neuroscience↗

Network-specific synchronization of electrical slow-wave oscillations regulates sleep in Drosophila

Slow-wave rhythms characteristic of deep sleep oscillate in the delta band (0.5-4 Hz) and can be found across various brain regions in vertebrates. Across systems it is however unclear how oscillations arise and whether they are the causal functional unit steering behavior. Here, for the first time in any invertebrate, we discover sleep-relevant delta oscillations in Drosophila. We find that slow-wave oscillations in the sleep-regulating R2 network increase with sleep need. Optical multi-unit voltage recordings reveal that single R2 neurons get synchronized by sensory and circadian input pathways. We show that this synchronization depends on NMDA receptor (NMDARs) coincidence detector function and on an interplay of cholinergic and glutamatergic inputs setting a resonance frequency. Genetically targeting the coincidence detector function of NMDARs in R2, and thus the uncovered mechanism underlying synchronization, abolished network-specific slow-wave oscillations. It also disrupted sleep and facilitated light-induced wakening, directly establishing a causal role for slow-wave oscillations in regulating sleep and sensory gating. We therefore propose that the synchronization-based increase in oscillatory power likely represents an evolutionarily conserved, potentially optimal, strategy for constructing sleep-regulating sensory gates.

neuroscience↗