Biology subjects

Tan, A. Y. Y.

Publications and source records attributed to Tan, A. Y. Y..

3 recordsLinked to original sources

bioRxiv2025

Graphene nanoedge electronics for monolithic and chronic recording of local microcircuits at neuronal density

High-density single-unit recording among closely spaced neurons over long durations is crucial for understanding the cellular-level functional architecture of the brain. Existing brain probes, however, either laterally sample neurons far more sparsely than neuronal density in the same cortical layer or suffer from long-term instability due to electrode modification, preventing precise neuron-to-neuron interrogation in local microcircuits. Here, we report a monolithic graphene-edge probe (NeuroEdge) that achieves single-unit recording at neuronal density (16 electrodes within 100 {micro}m diameter). We fabricate NeuroEdge using self-assembled reduced graphene oxide nanoflakes to form an electrochemically active tip consisting of exposed graphene nanoedges and electrolyte-filling nanotunnels, achieving an ultralow specific impedance of 20 M{Omega} {micro}m2. In vivo experiments over 5 months demonstrate recording at a high signal-to-noise ratio (>20 dB) and reliable interrogation of neighboring neurons. We also show that NeuroEdge can record from a single auditory cortical layer and reveal heterogeneities in the acoustic frequency response and dynamic connectivity among neighboring neurons. NeuroEdge provides a tool for precisely interrogating local microcircuits at the density of neurons in the brain.

bioengineering↗

bioRxiv2025

Agonistic interactions between slender mudskippers (Periophthalmus gracilis) in Singapore

Mudskippers engage in frequent territorial interactions. Few studies of mudskipper agonistic behavioral sequences exist. The slender mudskipper (Periophthalmus gracilis) inhabits intertidal zones of mangrove forests across Southeast Asia. Here, we describe common behavioral sequences of winners and losers among unmanipulated, wild slender mudskipper interactions in Singapore. Winning mudskippers showed more approach behaviors than losers, such as "Crawl towards", and more behaviors that may indicate aggression, such as "Pectoral wave", "Flag", and "Head up". Losers showed more evasive behaviors, like "Jump" and "Crawl away". We found evidence of agonistic behavioral matching. Larger mudskippers won contests more frequently than smaller mudskippers.

animal behavior and cognition↗

bioRxiv2021

Different excitation-inhibition correlations between spontaneous and tone-evoked activity in primary auditory cortex neurons

Tone-evoked synaptic excitation and inhibition are highly correlated in many neurons with V-shaped tuning curves in the primary auditory cortex of pentobarbital-anesthetized rats. In contrast, there is less correlation between spontaneous excitation and inhibition in visual cortex neurons under the same anesthetic conditions. However, it was not known whether the primary auditory cortex resembles visual cortex in having spontaneous excitation and inhibition that is less correlated than tone-evoked excitation and inhibition. Here we report whole-cell voltage-clamp measurements of spontaneous excitation and inhibition in primary auditory cortex neurons of pentobarbital-anesthetized rats. The larger excursions of both spontaneous excitatory and inhibitory currents appeared to consist of distinct events, with the inhibitory event rate typically lower than the excitatory event rate. We use the ratio of the excitatory event rate to the inhibitory event rate, and the assumption that the excitatory and inhibitory synaptic currents can each be reasonably described as a filtered Poisson process, to estimate the maximum spontaneous excitatory-inhibitory correlation for each neuron. In a subset of neurons, we also measured tone-evoked excitation and inhibition. In neurons with V-shaped tuning curves, although tone-evoked excitation and inhibition were highly correlated, the spontaneous inhibitory event rate was typically sufficiently lower than the spontaneous excitatory event rate to indicate a lower excitatory-inhibitory correlation for spontaneous activity than for tone-evoked responses.

neuroscience↗