Biology subjects

Kurikawa, T.

Publications and source records attributed to Kurikawa, T..

4 recordsLinked to original sources

bioRxiv2024

Different timescales of neural activities introduce different representations of task-relevant information

Recent findings indicate significant variations in neuronal activity timescales across and within cortical areas, yet their impact on cognitive processing remains inadequately understood. This study explores the role of neurons with different timescales in information processing within the neural system, particularly during the execution of context-dependent working memory tasks. Especially, we hypothesized that neurons with varying timescales contribute distinctively to task performance by forming diverse representations of task-relevant information. To test this, the model was trained to perform a context-dependent working memory task with a machine-learning technique. Results revealed that slow timescale neurons maintained stable representations of contextual information throughout the trial, whereas fast timescale neurons responded transiently to immediate stimuli. This differentiation in neuronal function suggests a fundamental role for timescale diversity in supporting the neural systems ability to integrate and process information dynamically. Our findings contribute to understanding how neural timescale diversity underpins cognitive flexibility and task-specific information processing, highlighting implications for both theoretical neuroscience and practical applications in designing artificial neural networks.

neuroscience↗

bioRxiv2024

Decomposed frontal corticostriatal ensemble activity changes across trials, revealing distinct features relevant to outcome-based decision making

The frontal cortex-striatum circuit plays a pivotal role in adaptive goal-directed behaviours. However, the mediation of decision-related signals through cross-regional transmission between the medial frontal cortex and the striatum by neuronal ensembles remains unclear. We analysed neuronal ensemble activity obtained through simultaneous multiunit recordings in the secondary motor cortex (M2) and dorsal striatum (DS) while the rats performed an outcome-based choice task. Tensor component analysis (TCA), an unsupervised dimensionality reduction approach at the single-trial level, was adopted for concatenated ensembles of M2 and DS neurons. We identified distinct three spatiotemporal neural dynamics (TCA components) at the single-trial level specific to task-relevant variables. Choice-position selective neural dynamics was correlated with the trial-to-trial fluctuation of behavioural variables. This analytical approach unveiled choice-pattern selective neural dynamics distinguishing whether the incoming choice was a repetition or switch from the previous choice. Other neural dynamics was selective to outcome. Choice-pattern selective within-trial activity increased before response choice, whereas outcome selective within-trial activity increased following response. These results suggest that the concatenated ensembles of M2 and DS process distinct features of decision-related signals at various points in time. The M2 and DS may collaboratively monitor action outcomes and determine the subsequent choice, whether to repeat or switch, for coordinated action selection.

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↗

bioRxiv2017

Individual Differences In Perceptual Decision Making Reflect Neural Variability In Medial Frontal Cortex

Decision making obeys common neural mechanisms, but there is considerable variability in individuals decision making behavior particularly under uncertainty. How individual differences arise within common decision making brain systems is not known. Here, we explored this question in the medial frontal cortex (MFC) of rats performing a sensory-guided choice task. When rats trained on familiar stimuli were exposed to unfamiliar stimuli, choice responses varied significantly across individuals. We examined how variability in MFC neural processing could mediate this individual difference and constructed a network model to replicate this. Our model suggested that susceptibility of neural trajectories is a crucial determinant of the observed choice variability. The model predicted that trial-by-trial variability of trajectories are correlated with the susceptibility, and hence also correlated with the individual difference. This prediction was confirmed by experiment. Thus, our results suggest that variability in neural dynamics in MFC networks underlies individual differences in decision making.

neuroscience↗