Various mechanisms of interaction which are intrinsic to neuronal populations exert profound influences on the dynamic behaviour of individual elements within the population and may markedly affect the behavior of such elements in response to pharmacological agents, af ferent inhibitory or excitatory drive, or other treatments that affect neu ronal activity.
A computational model was developed in which GPe neurons are represented as coupled phase oscillators influenced by experimentally derived phase-response curves and extrinsic inputs, showing that while the model captures general trends, discrepancies exist in peak amplitude and decay rates, suggesting that key biological details of the GPe are not represented in the model.
This manuscript distil theoretical approaches to emergence into a practical framework for assessing system behaviour focussed on “novelty” as a necessary condition for emergence and identifies a range of ways in which novelty can arise.
K. C. A. Wedgwood, Patrick McGivern, Alexander R. Harris· Frontiers in Neuroscience· 0 citations
The effects of stimulation are dependent on the baseline state of the network, with the level of beta suppression dependent on the level of inhibition and the external drive, and networks with higher inhibition and lower drive show greater disruption of beta oscillations.
Spandan Sengupta, Shervin Safavi, T. Knösche et al.· bioRxiv· 0 citations
The corticothalamic neurons from layer 6 (L6CT) of primary sensory cortices provide extensive input to the thalamus in addition to projecting within the cortex, positioning them to play a key hypothesized role in shaping thalamocortical signaling. With the expansion of tools for precise functional identification of L6CT neurons for in-vivo electrophysiology, increasing evidence highlights L6CT neurons as dynamic gain modulators of thalamocortical sensory responses. However much of the work to date has been conducted under anesthesia and not in the context of awake and/or behaving animals. In this study, we show that L6CT neurons in the awake mouse convey information about ascending sensory inputs, the timing of which is fast enough to contribute to the sensory response of neurons throughout the thalamocortical circuit. Overall, L6CT neurons robustly encode the presence vs absence of a sensory stimulus but are relatively weak encoders of the fine details. Benchmarked against the activity of other excitatory cortical neuron, we also provide evidence for L6CT neurons as predictors of the behavioral outcome during a trained detection task. Taken together, the results in this study tie L6CT neurons to behavior in tactile detection, one of the most fundamental functional roles of the pathway.
Elaida D. Dimwamwa, Nelson Chang, C. Waiblinger et al.· bioRxiv· 0 citations
Determining the amount of information a neuron receives per unit of time is key to understanding brain connectivity and how neural networks encode and transmit information. In particular, estimating this information flow by distinguishing between excitatory and inhibitory synaptic contributions is critical to understanding neural network function, as maintaining the excitation-inhibition (E/I) balance regulates neuronal excitability and circuit stability, whereas its disruption can lead to a plethora of brain disorders, including neurodegenerative and psychiatric conditions. However, because synaptic conductances cannot be measured directly, inverse methods are required to infer them from the membrane potential —a readily measurable quantity. Although partial solutions have been proposed, accurately estimating these conductances remains a significant challenge due to the complexity and diversity of the inputs. This is particularly true in the spiking regime, where neurons actively fire. In this work, we introduce a novel computational strategy that combines two critical metrics extracted from the time course of the membrane potential recording: the amplitude of the spike and the interspike interval. By using these quantities, the proposed method enables the accurate separation of excitatory and inhibitory contributions, yielding highly favorable results in the spiking regime. Author summary Quantifying the continuous stream of inputs a neuron receives is key to understanding brain connectivity. Inside the brain, individual cells must maintain a tight balance between excitation and inhibition (E/I) to process information correctly, as any disruption in this equilibrium can impair its functionality. However, directly measuring the underlying excitatory and inhibitory synaptic conductances is technically challenging, and existing mathematical tools often fail when neurons enter their active firing regime. In this work, we introduce a novel computational strategy designed to extract and separate these time-varying conductances directly from the neuron’s spiking activity. By dynamically tracking just two accessible metrics – the amplitude of the spikes and the time intervals between them – our algorithm estimates both conductance profiles with high precision. Furthermore, we demonstrate that this procedure is highly robust against realistic experimental noise and data variability, providing an accessible framework that does not require complex hardware or an unfeasible number of repetitive experimental trials. By tracking changes in the E/I ratio of the synaptic input, this method provides an efficient approach to detecting pathological imbalances and understanding how local connectivity shapes cellular functionality.
R.M. Delicado-Moll, A. Guillamón, A. E. Teruel et al.· bioRxiv· 0 citations
Interoceptive signals reflecting internal bodily states influence emotional processing. The paraventricular thalamus (PVT) constitutes a key node within the interoceptive network, monitoring circulating humoral factors in the ventricles, and is thus considered to link interoceptive signals to emotion-related behaviors. Here, we demonstrate that the vagus nerve (VN), a principal afferent pathway for interoceptive signaling, also affects PVT neuronal activity in mice. Left vagus nerve stimulation (VNS) induced pronounced c-Fos expression in PVT neurons and elicited transient increases and decreases in neuronal spike rates across all PVT subregions. These VNS-responsive neuronal populations were distinct from those exhibiting transient-to-sustained delayed responses following lipopolysaccharide injection after vagotomy, which selectively activates VN-independent pathways, including humoral factors. VNS-responsive PVT neurons projected to limbic structures and modulated anxiety-like behavior. Taken together, these findings demonstrate that PVT neuronal populations integrate and relay interoceptive signals across multiple pathways and timescales, thereby playing a pivotal role in linking vagus nerve-related bodily states to emotional responses.
Zi-Yan Xie, Musashi Yamakawa, Tasuku Kayama et al.· Frontiers in Neural Circuits· 0 citations
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