Biology subjects

Mizuseki, K.

Publications and source records attributed to Mizuseki, K..

9 recordsLinked to original sources

bioRxiv2024

Synchronicity transitions determine connection fluctuations in a model of coupled oscillators with plasticity

Sleep and rest, characterized by synchronized neuronal activity that emerges under large shifts in the excitation-inhibition balance, are crucial for synaptic reorganization in the brain. However, the network dynamics that permit rewiring without erasing stable connections remain unclear. To address this question, we extended a Kuramoto framework with excitation-inhibition balance by adding Hebbian and homeostatic plasticity. The resulting model showed that networks with robust inhibition consistently exhibited desynchronized dynamics and stable couplings. In contrast, networks with weaker inhibition exhibited a bistable regime, in which couplings of intermediate strengths fluctuated while strong couplings remained stable. These findings suggest that the dynamic interplay between network activity and plasticity selectively stabilizes stronger connections while permitting flexible reorganization of weaker ones, providing a potential mechanism for network reorganization during sleep and rest.

neuroscience↗

bioRxiv2023

Acquisition of Auditory Discrimination Mediated by Different Processes through Two Distinct Circuits Linked to the Lateral Striatum

The striatum, the central hub of cortico-basal ganglia loops, contains functionally heterogeneous subregions distinguished by the topographic patterns of structural connectivity. These subregions mediate various processes of procedural learning. However, it remains unclear when and how striatal subregions engage in the acquisition of sensory stimulus-based decision-making. A neuroimaging of regional brain activity shows that the anterior dorsolateral striatum (aDLS) and posterior ventrolateral striatum (pVLS) in rats are activated in a different temporal pattern during the acquisition phase of auditory discrimination. Chronic and transient pharmacologic manipulations show that the aDLS promotes the behavioral strategy driven by the stimulus- response association while suppressing that by the response-outcome association, and that the pVLS contributes to forming and maintaining the stimulus-response strategy. Electrophysiological recording indicates that subpopulations of aDLS neurons predominantly represent the outcome of specific behaviors at the initial period of discrimination learning, and that pVLS subpopulations encode the beginning and ending of each behavior according to the progress of learning. In addition, other subpopulations of striatal neurons indicate sustained activation after obtaining reward with distinct patterns reflecting the stimulus-response associations. Our findings demonstrate that aDLS and pVLS neurons integrate the new learning of auditory discrimination in spatiotemporally and functionally different manners.

animal behavior and cognition↗

bioRxiv2023

CA3 circuit model compressing sequential information in theta oscillation and replay

The hippocampus compresses the sequential information in a theta oscillation cycle and short-term sequential activities during sharp-wave ripple while sleeping or resting; these processes are known as theta sequence and replay, respectively. The theta sequence is based on theta phase precession patterns of individual neurons. However, how these sequential neuronal activities are generated and how they store information about the outside environment remains unknown. We developed a hippocampal cornu ammonis (CA)3 computational model based on the biological CA3 circuits anatomical and electrophysiological evidence to address these. The model comprises theta rhythm inhibition, place input, and CA3-CA3 plastic recurrent connection. The model could compress the sequence of the external inputs and reproduce theta phase precession and replay, learn additional sequences, and reorganize previously learned sequences. A gradual increase in synaptic inputs, controlled by interactions between theta-paced inhibition and place inputs, explained the mechanism for sequence acquisition. This model highlights the crucial role of plasticity in the CA3 recurrent connection and theta oscillational dynamics, and hypothesizes how the CA3 circuit acquires, compresses, and replays sequential information.

neuroscience↗

bioRxiv2022

A novel micro-ECoG recording method for recording multisensory neural activity from the parietal to temporal cortexes in mice

Characterization of inter-regional interactions in brain is essential for understanding the mechanism relevant to normal brain function and neurological disease. The recently developed flexible micro ()-electrocorticography (ECoG) device is one prominent method used to examine large-scale cortical activity across multiple regions. The sheet-shaped ECoG electrodes arrays can be placed on a relatively wide area of cortical surface beneath the skull by inserting the device into the space between skull and brain. Although rats and mice are useful tools for neuroscience, current ECoG recording methods in these animals are limited to the parietal region of cerebral cortex. Recording cortical activity from the temporal region of cortex in mice has proven difficult because of surgical barriers created by the skull and surrounding temporalis muscle anatomy. Here, we developed a sheet-shaped 64-channel ECoG device that allows access to the mouse temporal cortex, and we determined the factor determining the appropriate bending stiffness for the ECoG electrode array. We also established a surgical technique to implant the electrode arrays into the epidural space over a wide area of cerebral cortex covering from the barrel field to olfactory (piriform) cortex, which is the deepest region of the cerebral cortex. Using histology and computed tomography (CT) images, we confirmed that the tip of the ECoG device reached to the most ventral part of cerebral cortex without causing noticeable damage to the brain surface. Moreover, the device simultaneously recorded somatosensory and odor stimulus-evoked neural activity from dorsal and ventral parts of cerebral cortex in awake and anesthetized mice. These data indicate that our ECoG device and surgical techniques enable the recording of large-scale cortical activity from the parietal to temporal cortex in mice, including somatosensory and olfactory cortices. This system will provide more opportunities for the investigation of physiological functions from wider areas of the mouse cerebral cortex than those currently available with existing ECoG techniques.

neuroscience↗

bioRxiv2021

Intersectional, anterograde transsynaptic targeting of the neurons receiving monosynaptic inputs from two upstream regions

A brain region typically receives inputs from multiple upstream areas. However, currently, no method is available to selectively access neurons that receive monosynaptic inputs from two upstream regions. Here, we devised a method to genetically label such neurons in mice by combining the anterograde transsynaptic spread of adeno-associated virus serotype 1 (AAV1) with intersectional gene expression. Injections of AAV1s expressing either Cre or Flpo recombinases and the Cre/Flpo double-dependent AAV into two upstream regions and the downstream region, respectively, were used to label the postsynaptic neurons receiving inputs from the two upstream regions. We demonstrated this labelling in two distinct circuits: the retina/primary visual cortex to the superior colliculus and the bilateral motor cortex to the dorsal striatum. Systemic delivery of the intersectional AAV allowed for unbiased detection of the labelled neurons throughout the brain. This strategy may help analyse the interregional integration of information in the brain.

neuroscience↗

bioRxiv2021

De novo inter-regional coactivations of pre-configured local ensembles support memory

Neuronal ensembles in the amygdala, ventral hippocampus, and prefrontal cortex are involved in fear memory; however, how the inter-regional ensemble interactions support memory remains elusive. Using multi-regional large-scale electrophysiology in the afore-mentioned structures of fear-conditioned rats, we demonstrated that local ensembles activated during fear memory acquisition were inter-regionally coactivated during subsequent sleep, which relied on brief bouts of fast network oscillations. During memory retrieval, coactivations reappeared, accompanying fast oscillations. Ensembles contributing to inter-regional coactivation were configured prior to memory acquisition in the amygdala and prefrontal cortex but developed through experience in the hippocampus. Our observation suggests that elements of a given memory are instantly encoded within various brain regions in a pre-configured manner, whereas hippocampal ensembles and the network for inter-regional integration of the distributed information develop in an experience-dependent manner to form a new memory, which is consistent with hippocampal memory index hypothesis.

neuroscience↗

bioRxiv2020

Robust information routing by dorsal subiculum neurons

The hippocampus conveys various information associated with spatial navigation; yet, information distribution to multiple downstream areas remains unknown. We investigated this by identifying axonal projections using optogenetics during large-scale recordings from the rat subiculum, the major hippocampal output structure. Subicular neurons demonstrated a noise-resistant representation of place, speed, and trajectory, which was as accurate as that of hippocampal CA1 neurons. Speed and trajectory information was most prominently sent to the retrosplenial cortex and nucleus accumbens, respectively. Place information was distributed uniformly to the retrosplenial cortex, nucleus accumbens, anteroventral thalamus, and medial mammillary body. Information transmission by projection neurons was tightly controlled by theta oscillations and sharp-wave/ripples in a target region-specific manner. In conclusion, the subiculum robustly routes diverse navigation-associated information to downstream areas. One Sentence SummaryThe subiculum accurately and robustly represents diverse information and routes it in a target region-specific manner.

neuroscience↗

bioRxiv2019

Oscillation-driven memory encoding, maintenance and recall in an entorhinal-hippocampal circuit model

During the execution of working memory tasks, task-relevant information is processed by local circuits across multiple brain regions. How this multi-area computation is conducted by the brain remains largely unknown. To explore such mechanisms in spatial working memory, we constructed a neural network model involving parvalbumin-positive, somatostatin-positive and vasoactive intestinal polypeptide-positive interneurons in the hippocampal CA1 and the superficial and deep layers of medial entorhinal cortex (MEC). Our model is based on a hypothesis that cholinergic modulations differently regulate information flows across CA1 and MEC at memory encoding, maintenance and recall during delayed nonmatching-to-place tasks. In the model, theta oscillation coordinates the proper timing of interactions between these regions. Furthermore, the model predicts that MEC is engaged in decoding as well as encoding spatial memory, which we confirmed by experimental data analysis. Thus, our model accounts for the neurobiological characteristics of the cross-area information routing underlying working memory tasks.

neuroscience↗

bioRxiv2018

Reconstructing Neuronal Circuitry from Parallel Spike Trains

State-of-the-art techniques allow researchers to record large numbers of spike trains parallel for many hours. With enough such data, we should be able to infer the connectivity among neurons. Here we develop a computationally realizable method for reconstructing neuronal circuitry by applying a generalized linear model (GLM) to spike crosscorrelations. Our method estimates interneuronal connections in units of postsynaptic potentials and the amount of spike recording needed for verifying connections. The performance of inference is optimized by counting the estimation errors using synthetic data from a network of Hodgkin-Huxley type neurons. By applying our method to rat hippocampal data, we show that the numbers and types of connections estimated from our calculations match the results inferred from other physiological cues. Our method provides the means to build a circuit diagram from recorded spike trains, thereby providing a basis for elucidating the differences in information processing in different brain regions.

neuroscience↗