Biology subjects

Ohnuki, T.

Publications and source records attributed to Ohnuki, T..

4 recordsLinked to original sources

bioRxiv2025

Behavioral expression of decision confidence engages disentangled confidence coding in the orbitofrontal cortex

Task engagement is thought to recruit subsets of neurons encoding task-relevant variables, but it remains unclear whether it also reorganizes the geometry of population codes and how such reorganization supports behavior. Here we show that, in the orbitofrontal cortex (OFC), task engagement aligns population activity along a confidence axis, thereby enabling the behavioral use of decision confidence. We recorded OFC activity while rats performed two variants of the same perceptual decision-making task that differed only in reward-timing uncertainty, which altered the utility of post-decision confidence for guiding reward waiting. OFC neurons exhibited more linear responses to confidence when confidence was more strongly expressed in behavior. Although the proportion of OFC neurons encoding confidence was similar across strategies, strategy-dependent alignment of population activity to confidence emerged under variable long delays, and this alignment predicted confidence-based waiting behavior. These findings suggest that OFC population codes flexibly adapt to the behavioral relevance of task variables, linking cognitive strategy to the geometry of neural representation.

neuroscience↗

bioRxiv2025

A neural circuit targeting technique for investigating functional input-output organization in the nervous system

Neurons communicate information across circuits and the function of cells in these circuits is determined by both the afferent inputs they receive and the efferent outputs they send to other brain regions1,2. To study the activity and function of specific neuronal populations, transneuronal anterograde3 and retrograde4-6 viral approaches have been employed to define neural circuit elements by inputs or outputs, respectively. However, what is missing is a way to study the function of neurons based on both their inputs and outputs. Applying a combination of multiple recombinases and transneuronal anterograde/retrograde viruses, we developed a technique called input-output Projection-based INtersectional Circuit-tagging Enabled by Recombinases (PINCER) to target specific neuronal cell types and investigate functional input-output organization in neural circuits. We show the logic and application of this technique with in vivo calcium imaging and optogenetic approaches to reveal the distinct functions and neural dynamics of connectivity defined neuronal populations in the amygdala for emotional processing. Specifically, PINCER allowed the parsing of valence and salience functions of the amygdala to reveal an input-output cell type selectively mediating aversive memory formation. This technique allows neuroscientists to identify novel subclasses of cells based on their combinatorial input-output anatomical connectivity, providing a tool for fine dissection of the functional properties of neural circuits.

neuroscience↗

bioRxiv2020

Accurate perceptual decision driven by distinct population dynamics in association and sensory cortex

It is widely assumed that variability in visual detection performance is attributed to the fidelity of the visual responses in visual cortical areas, which could be modulated by fluctuations of internal states such as vigilance and behavioral history. However, it is not clear what neural ensembles represent such different internal states. Here, we utilized a visual detection task, which distinguishes perceptual states to identical stimuli, while recording neurons simultaneously from the primary visual cortex (V1) and the posterior parietal cortex (PPC). We found distinct population dynamics segregating hit responses from misses despite no clear differences in visual responses. The population-level computation was significantly contributed by heterogenous non-sensory neurons in V1, whereas the contribution from non-neurons with the previous outcome selectivity was prominent in PPC. These results indicate different contributions of non-sensory neurons in V1 and PPC for the population-level computation that enables behavioral responses from visual information.

neuroscience↗

bioRxiv2019

Dynamic coding of choice targets in the perirhinal cortex

Cortical neurons show distinct firing patterns across multiple task-epochs characterized by distinct computational aspects. Recent studies suggest that such distinct patterns underly dynamic population code achieving computational flexibility, whereas neurons in some cortical areas often show coherent firing patterns across epochs. To understand how such coherent single-neuron code contribute to dynamic population code, we analyzed neural responses in the perirhinal cortex (PRC) during cue and reward epochs of a two-alternative forced-choice task. We found that the PRC neurons often encoded the opposite choice-directions between those epochs. By using principal component analysis as population-level analysis, we identified neural subspaces associated with each epoch, which reflected coordinated patterns across the neurons. The cue and reward epochs shared neural dimensions where the choice directions were consistently discriminated. Interestingly, those dimensions were supported by dynamically changing contributions of individual neurons. These results indicated heterogeneity of coherent single-neuron responses in their contribution to population code.

neuroscience↗