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Heining, K.

Publications and source records attributed to Heining, K..

5 recordsLinked to original sources

Capturing Spatially Organized Oscillatory Cliques as Signatures of Neuronal Assemblies

State-of-the-art neural recording technologies now enable dense sampling of neuronal activity, demonstrating meaningful spiking variability from moment to moment. Yet spiking activity is sparse by nature and allows only partial access to collective neuronal dynamics. Local field potentials (LFPs) provide complementary information by capturing coordinated activity from large neuronal populations, but methods to characterize the fine-scale spatio-temporal organization of LFPs are lacking. Starting from the notion that neural oscillations are brief and burst-like, we introduce a framework to detect and analyze SPatially Organized Oscillatory Cliques (SPOOCs), oscillatory events that are cohesive in space, time, and frequency. SPOOCs displayed diverse dynamics in space and frequency and were differentially modulated during stimulus processing. Linking SPOOCs to local spiking, we demonstrate that these events index rapid reconfigurations of neuronal assemblies. With SPOOChunter, we provide an open-source toolbox that enables systematic detection and analysis of transient, spatially organized population dynamics in high-density electrophysiological recordings.

neuroscience↗

A Prefrontal Cortex Map based on Single Neuron Activity

The intrinsic organization underlying the central cognitive role of the prefrontal cortex (PFC) is poorly understood. The work to date has been dominated by cytoarchitecture as a canvas for studies on the PFC, constraining concepts, analyses, results, and their interpretations to pre-configured delimitations that might not be relevant to function. We approached organization by profiling the activity and spatial location of >23,000 neurons recorded in awake mice. Regularly firing neurons were over-represented in most PFC subregions, yet a fine-grained activity map of the PFC did not align with cytoarchitecturally defined subregions. Instead, we observed a robust relationship between spontaneous activity patterns and intra-PFC hierarchy, suggesting internal organization principles transcending cytoarchitecture. Single neuron responses to sounds did not reflect intra-PFC hierarchy but were linked to spontaneous firing rate, indicating that responsiveness increases with excitability and is decoupled from the PFCs intrinsic operational structure. Our data-driven approach provides a scalable roadmap to explore functional organizations in diverse brain regions and species, opening avenues to link activity, structure, and function in the brain.

neuroscience↗

PEACOC - Detecting and classifying a wide range of epileptiform activity patterns in rodents

Epileptiform activity (EA) manifests in diverse patterns of hypersynchronous network activity. Fundamental research mostly addresses two extreme patterns, individual epileptiform spikes and seizures. We developed PEACOC to detect and classify a wide range of EA patterns in local field potentials. PEACOC delimits EA patterns as bursts of epileptiform spikes, and classifies these bursts according to spike load. In EA from kainate-injected mice, burst patterns displayed a continuum of spike loads. With PEACOC, we partitioned this continuum into bursts of high, medium and low spike load. High-load bursts resembled electrographic seizures. The EA patterns automatically retrieved by PEACOC were reproducible and comparable across animals and laboratories. PEACOC has been employed to diagnose the overall burden of EA in individual mice, and to describe epileptic dynamics at multiple time-scales. We here further report that the rate of high-load bursts was anti-correlated to granule cell dispersion in the dentate gyrus.

neuroscience↗

On-demand low-frequency stimulation for seizure control: efficacy and behavioral implications

Mesial temporal lobe epilepsy (MTLE), the most common form of focal epilepsy in adults, is often refractory to medication and associated with hippocampal sclerosis. Deep brain stimulation represents an alternative treatment option for drug-resistant patients who are ineligible for resective brain surgery. In clinical practice, closed-loop stimulation at high frequencies is applied to interrupt ongoing seizures, yet with a high incidence of false detections, the drawback of delayed seizure-suppressive intervention and limited success in sclerotic tissue. More recently, hippocampal low-frequency stimulation (LFS) has been shown to reduce excitability in clinical settings and prevent seizures in experimental MTLE when applied continuously. However, as the hippocampus is important for navigation and memory, it would be beneficial to stimulate it only on-demand to reduce its exposure to LFS pulses, and to investigate LFS-related effects on cognition. Using the intrahippocampal kainate mouse model, which recapitulates the key features of MTLE, we developed an on-demand LFS setup and investigated its effects on spontaneous seizure activity and hippocampal function. Specifically, our online detection algorithm monitored epileptiform activity in hippocampal local field potential recordings and identified short epileptiform bursts preceding focal seizure clusters, triggering hippocampal LFS to stabilize the network state. In addition, we investigated the acute influence of LFS on behavioral performance, including anxiety-like behavior in the light-dark box test, spatial and non-spatial memory in the object location memory and novel object recognition test, as well as spatial navigation and long-term memory in the Barnes maze. Compared to open-loop stimulation protocols, on-demand LFS was more efficient in preventing focal seizure clusters, as the strong anti-epileptic effect was achieved with a reduced stimulation load. In behavioral tests, chronically epileptic mice were as mobile as healthy controls but showed increased anxiety, an altered spatial learning strategy and impaired memory performance. Most importantly, our experiments ruled out deleterious effects of hippocampal LFS on cognition and even showed alleviation of deficits in long-term memory recall. Taken together, our findings may provide a promising alternative to current therapies, overcoming some of their major limitations, and inspire further investigation of LFS for seizure control in MTLE.

neuroscience↗

Optogenetic low-frequency stimulation of dentate granule cells prevents seizure generation in experimental epilepsy

Mesial temporal lobe epilepsy (MTLE) is the most common form of focal epilepsy in adults and is typically associated with hippocampal sclerosis and drug-resistant seizures. As an alternative to curative epilepsy surgery, brain stimulation evolves as a promising approach for seizure-interference. However, particularly in MTLE with severe hippocampal sclerosis, current stimulation protocols are often not effective. Here, we show that optogenetic low-frequency stimulation (oLFS) of entorhinal afferents exhibits unprecedented anti-ictogenic effects in chronically epileptic mice. Photostimulation at 1 Hz resulted in an almost complete suppression of focal seizures, independent of the degree of hippocampal sclerosis. Furthermore, by performing oLFS for 30 min before a pro-convulsive stimulus, seizure generalization was successfully prevented. Finally, acute slice experiments revealed a decreased excitability upon oLFS, which may partially explain the observed anti-epileptic effects. Taken together, our results suggest that oLFS of entorhinal afferents constitutes a promising approach for seizure control in MTLE.

physiology↗