Explore the vast range of titles available.

The intertwining of space and time poses a significant scientific challenge, transcending disciplines from philosophy and physics to neuroscience. Deciphering neural coding, marked by its inherent spatial and temporal dimensions, has proven to be a complex task. In this paper, we present insights into temporal and spatial modes of neural coding and their intricate interplay, drawn from neuroscientific findings. We illustrate the conversion of a purely spatial input into the temporal form of a singular spike train, demonstrating storage, transmission to remote locations, and recall through spike bursts corresponding to Sharp Wave Ripples. Moreover, the converted temporal representation can be transformed back into a spatiotemporal pattern. The principles of the transformation process are illustrated using a simple feed-forward spiking neural network. The frequencies and phases of Subthreshold Membrane potential Oscillations play a pivotal role in this framework. The model offers insights into information multiplexing and phenomena such as stretching or compressing time of spike patterns.

A radiofrequency oscillation is successfully superimposed on a plasma potential of a filamented source plasma in an ion beam source while maintaining a constant plasma density, in order to investigate effects of oscillating source plasma potential on an extracted ion beam. The experiment is preliminarily performed with a positive argon ion beam source. A class-D amplifier operational over a wide range of a frequency from a few tens of kHz to several MHz is installed; leading the oscillation of the plasma potential in the plasma source for the frequency range being tested. The beam current profile downstream of the extraction grids shows an oscillation of the beam current at the peripheral region of the ion beam; implying that the oscillation of a beam halo is induced by the potential oscillation of the source plasma.

In gastropods, the function of neuropeptides has been studied primarily in the peripheral motor systems. Their functional roles in the central nervous system have received less attention. The procerebrum, the secondary olfactory center of the terrestrial slug Limax, consists of several hundred thousand interneurons, and plays a pivotal role in olfactory learning and memory. In the present study, we found that enterin, known as a myoactive peptide functioning in the enteric and vascular system of Aplysia, is expressed in the procerebrum of Limax. These enterin-expressing neurons primarily make projections within the cell mass layer of the procerebrum. The oscillatory frequency of the local field potential in the procerebrum was reduced by an exogenous application of enterin. The local field potential oscillation in the tentacular ganglion, the primary olfactory center, was also modulated by enterin. Whole-cell patch-clamp recordings revealed that the modulatory effect in the procerebrum was due to the inhibitory effect of enterin on the bursting neurons, which function as the kernels determining the oscillatory activity of the procerebrum. Our results revealed the novel role of the myoactive neuropeptide enterin in the higher olfactory function in terrestrial gastropods.

The hippocampus comprises two neural signals-place cells and θ oscillations-that contribute to facets of spatial navigation. Although their complementary relationship has been well established in rodents, their respective contributions in the primate brain during free navigation remains unclear. Here, we recorded neural activity in the hippocampus of freely moving marmosets as they naturally explored a spatial environment to more explicitly investigate this issue. We report place cells in marmoset hippocampus during free navigation that exhibit remarkable parallels to analogous neurons in other mammalian species. Although θ oscillations were prevalent in the marmoset hippocampus, the patterns of activity were notably different than in other taxa. This local field potential oscillation occurred in short bouts (approximately .4 s)-rather than continuously-and was neither significantly modulated by locomotion nor consistently coupled to place-cell activity. These findings suggest that the relationship between place-cell activity and θ oscillations in primate hippocampus during free navigation differs substantially from rodents and paint an intriguing comparative picture regarding the neural basis of spatial navigation across mammals.

A variety of autonomous oscillations in nature such as heartbeats and some biochemical reactions have been widely studied and utilized for applications in the fields of bioscience and engineering. Here, we report a unique phenomenon of moisture-induced electrical potential oscillations on polymers, poly([2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide-co-acrylic acid), during the diffusion of water molecules. Chemical reactions are modeled by kinetic simulations while system dynamic equations and the stability matrix are analyzed to show the chaotic nature of the system which oscillates with hidden attractors to induce the autonomous surface potential oscillation. Using moisture in the ambient environment as the activation source, this self-excited chemoelectrical reaction could have broad influences and usages in surface-reaction based devices and systems. As a proof-of-concept demonstration, an energy harvester is constructed and achieved the continuous energy production for more than 15,000 seconds with an energy density of 16.8 mJ/cm 2 . A 2-Volts output voltage has been produced to power a liquid crystal display toward practical applications with five energy harvesters connected in series. Moisture-induced energy generation is a potential green energy power source. Here, the authors report a moisture-induced autonomous surface potential oscillation phenomenon and apply it to the demonstration of energy harvesters with long persistence time and good energy density

Neural oscillations are prominent features of brain activity, characterized by frequency-specific power changes in electroencephalograms (EEG) and local field potentials (LFP). These oscillations also appear as rhythmic coherence across brain regions. While the identification of oscillations has primarily relied on EEG and LFP, they are also present in neuronal spiking. However, several questions remain unanswered: How do spiking oscillations relate to field potential oscillations? How are spiking oscillations correlated across brain regions? And how are they connected to other physiological and behavioral measures. In this study, we explore the potential to detect individual cycles of neural rhythms solely through the spiking activity of neurons, leveraging recent advances in the high-density recording of large neuronal populations within local networks. The pooled spiking rate of many neurons within a local population reflects shared variation in the membrane potential of nearby neurons, allowing us to identify cyclic patterns. To achieve this, we utilize a Long Short Term Memory (LSTM) network, pre-trained on synthetic data, to effectively isolate and align individual cycles of neural oscillations in the spiking of a densely recorded population of neurons. We applied this approach to robustly isolate specific neural cycles across various brain regions in mice, covering a broad range of timescales, from gamma rhythms to ultra-slow rhythms lasting up to hundreds of seconds. These ultra-slow rhythms, often underrepresented in the LFP, were also detected in behavioral measures of arousal, such as pupil size and mouse facial motion. Interestingly, these rhythms showed delayed coherence with corresponding rhythms in the population spiking activity. Using these isolated neural cycles, we addressed two key questions: 1) How can we account for biological variation in neural signal transmission timing across trials during the sensory stimulation experiments? By isolating gamma cycles driven by sensory input, we achieved a more accurate trial alignment in the sensory stimulation experiments conducted in the primary visual cortex (V1) of mice. This alignment accounts for biological variability in sensory signal transmission times from the retina to V1 across trials, enabling a clearer understanding of neural dynamics in response to sensory stimuli. 2) How do spiking correlations across brain regions vary by timescale? We used the distinct spiking cycles in simultaneously recorded brain regions to examine the correlation of spiking across brain regions, separately for different timescales. Our findings revealed that the delays in population spiking between brain regions vary depending on the brain regions involved and the timescale of the oscillations. This work demonstrates the utility of population spiking activity for isolating neural rhythms, providing insights into oscillatory dynamics across brain regions and their relationship to physiological and behavioral measures.

Scalable and high-throughput platforms to non-invasively record the Action Potentials (APs) of excitable cells are highly demanded to accelerate disease diagnosis and drug discovery. AP recordings are typically achieved with the invasive and low-throughput patch clamp technique. Non-invasive alternatives like planar multielectrode arrays cannot record APs without membrane poration, preventing accurate measurements of disease states and drug effects. Here, we disclose reliable and non-invasive recording of APs with patch clamp-like quality from human stem cell-derived cardiomyocytes using an inkjet-printed polymer semiconductor in an Electrolyte-Gated Field-Effect Transistor configuration. High sensitivity is proven by the detection of drug-induced pro-arrhythmic membrane potential oscillations as early/delayed afterdepolarizations. The higher throughput potential of this platform could significantly enhance disease modelling, drug screening, safety pharmacology and the study of abiotic/biotic interfaces. Scalable platforms for non-invasive action potential recording are needed. Here, the authors present a reliable method to capture APs with patch-clamp-like fidelity from stem cell-derived cardiomyocytes using an Electrolyte-Gated Polymer Field-Effect Transistors.

Synaptic mechanisms that contribute to human memory consolidation remain largely unexplored. Consolidation critically relies on sleep. During slow wave sleep, neurons exhibit characteristic membrane potential oscillations known as UP and DOWN states. Coupling of memory reactivation to these slow oscillations promotes consolidation, though the underlying mechanisms remain elusive. Here, we performed axonal and multineuron patch-clamp recordings in acute human brain slices, obtained from neurosurgeries, to show that sleep-like UP and DOWN states modulate axonal action potentials and temporarily enhance synaptic transmission between neocortical pyramidal neurons. Synaptic enhancement by UP and DOWN state sequences facilitates recruitment of postsynaptic action potentials, which in turn results in long-term stabilization of synaptic strength. In contrast, synapses undergo lasting depression if presynaptic neurons fail to recruit postsynaptic action potentials. Our study offers a mechanistic explanation for how coupling of neural activity to slow waves can cause synaptic consolidation, with potential implications for brain stimulation strategies targeting memory performance. Whether and how slow wave activity (SWA) and the underlying membrane potential UP and DOWN states initiate mechanisms that augment memory functions in humans are not fully understood. Here authors used multineuron patch-clamp in alive human brain tissue, resected during neurosurgeries, to show that membrane potential UP/DOWN states, which mimic neural sleep activity, modulate axonal action potentials to boost synaptic strength and plasticity.

Sinoatrial node myocytes (SAMs) act as cardiac pacemaker cells by firing spontaneous action potentials (APs) that initiate each heartbeat. The funny current (If) is critical for the generation of these spontaneous APs; however, its precise role during the pacemaking cycle remains unresolved. Here, we used the AP-clamp technique to quantify If during the cardiac cycle in mouse SAMs. We found that If is persistently active throughout the sinoatrial AP, with surprisingly little voltage-dependent gating. As a consequence, it carries both inward and outward current around its reversal potential of −30 mV. Despite operating at only 2 to 5% of its maximal conductance, If carries a substantial fraction of both depolarizing and repolarizing net charge movement during the firing cycle. We also show that β-adrenergic receptor stimulation increases the percentage of net depolarizing charge moved by If, consistent with a contribution of If to the fight-or-flight increase in heart rate. These properties were confirmed by heterologously expressed HCN4 channels and by mathematical models of If. Modeling further suggested that the slow rates of activation and deactivation of the HCN4 isoform underlie the persistent activity of If during the sinoatrial AP. These results establish a new conceptual framework for the role of If in pacemaking, in which it operates at a very small fraction of maximal activation but nevertheless drives membrane potential oscillations in SAMs by providing substantial driving force in both inward and outward directions.

The role of the hippocampus in spatial navigation has been primarily studied in nocturnal mammals, such as rats, that lack many adaptations for daylight vision. Here we demonstrate that during 3D navigation, the common marmoset, a new world primate adapted to daylight, predominantly uses rapid head-gaze shifts for visual exploration while remaining stationary. During active locomotion marmosets stabilize the head, in contrast to rats that use low-velocity head movements to scan the environment as they locomote. Pyramidal neurons in the marmoset hippocampus CA3/CA1 regions predominantly show mixed selectivity for 3D spatial view, head direction, and place. Exclusive place selectivity is scarce. Inhibitory interneurons are predominantly mixed selective for angular head velocity and translation speed. Finally, we found theta phase resetting of local field potential oscillations triggered by head-gaze shifts. Our findings indicate that marmosets adapted to their daylight ecological niche by modifying exploration/navigation strategies and their corresponding hippocampal specializations. How diurnal primates develop exploration-navigation strategy and how the physiology of primate hippocampus is shaped in navigation are not fully understood. Here authors show that marmosets adapted their navigation strategies to their diurnal ecological niche. Notably, marmoset hippocampal neurons are specialized for encoding combinations of view, head direction and place, and that theta oscillations are triggered by rapid head-gaze movements.