Biology subjects

Gaidica, M.

Publications and source records attributed to Gaidica, M..

8 recordsLinked to original sources

bioRxiv2026

Tumbly: An Open-Source Home-Cage Device for Time-Restricted Feeding in Mice

Time-restricted feeding (TRF) is a common tool for studying metabolism, circadian rhythms, aging, and neurodegeneration. Here, we describe a new device called Tumbly, an automated device for performing TRF studies in mouse home-cages. Tumbly controls access to rodent diets at user-set times via a programmable servo-driven food hopper. Tumbly is also battery powered and compatible with multiple types of vivarium home-cages, due to a removable faceplate that can be customized to fit different cage dimensions without modification. Finally, Tumbly is open-source and affordable, with all design files available online, allowing researchers to build and customize it. As a validation test, we deployed Tumbly in two labs at separate institutions, one with singly housed mice (n = 6, within-subject) and one with group-housed mice (n = 22, between-group). We measured daily body weight and food intake. In both labs, mice on an 8-hour TRF schedule maintained their body weight and ate similar amounts of food compared to ad libitum feeding. Our quantified error rates were also low, with no device failures over >1000 hours of operation. We conclude that Tumbly provides a reliable, low-cost option for running TRF studies in mice.

neuroscience↗

bioRxiv2026

FLEX-DBS: a flexible wireless platform for bilateral constant-current deep brain stimulation in freely moving rodents

Background: Preclinical deep brain stimulation (DBS) in rodents is central to understanding how DBS works, but most rodent DBS is delivered through a tether, which constrains behavior, home-cage experiments and uninterrupted stimulation. Most long-runtime wireless mouse stimulators achieve their runtimes by setting stimulation parameters before or around implantation and operating from supplies of about 3 V. New method: FLEX-DBS (Flexible Deep Brain Stimulation) is a head-mounted, battery-powered stimulator that delivers bilateral constant-current stimulation from improved Howland current pumps on +/-5 V rails. Amplitude, pulse width and frequency are programmable in continuous and burst modes from an iOS application over Bluetooth Low Energy, and stimulation continues autonomously after the phone disconnects. The device measures 19.5 x 22.5 x 8.72 mm, weighs 3.71 g in operation and runs on two size-13 zinc-air cells, which are exchanged by briefly detaching the device, pausing stimulation only for the exchange. Results: Into a 1 k{Omega} bench load, delivered current increased approximately linearly with the amplitude setting and was repeatable from pulse to pulse, with an asymmetric biphasic waveform whose recovery phase ran at about one fifth of the stimulating amplitude. Battery current was 1.47-1.89 mA in standby and 3.15-3.42 mA during stimulation at amplitude settings of 60-400 A, giving a projected three days of continuous stimulation per pair of cells. Firmware v0.5 left a net charge of 26-35 % of the stimulating-phase charge per pulse into 1 k{Omega}. Into 47 k{Omega}, within the in vivo load range, stimulating current was compliance-limited at 93 A. Pulse-derived estimates of the effective load presented by five implanted platinum electrodes in three mice had weekly means of 43-54 k{Omega} over eight weeks (32-80 k{Omega} across individual sessions), placing the maximum regulated current near 90 A (81-101 A at the weekly means). Analysis of the current-pump network bounds load-dependent current error at 3-8% for these loads. In vivo, we delivered cingulate FLEX-DBS at high amplitude settings intended to evoke a robust stimulation-associated behavioral phenotype in six mice. Time spent immobile in an open field rose from 46.5% at baseline to 75.7% during stimulation (a 62.7% increase in the group mean) and remained elevated after stimulation ended; without a sham control, this increase cannot be separated from within-session habituation. Comparison with existing methods: Among the published wireless rodent stimulators compared here, several offer some of these capabilities, but none combines bilateral constant current output, real-time wireless control that continues as autonomous stimulation after disconnect, and both continuous and burst modes; FLEX-DBS does so at the cost of runtime measured in days rather than weeks. Conclusions: FLEX-DBS is designed for untethered DBS experiments in which parameters must be set, changed and verified at the cage. Its measured power consumption permits a projected three days of continuous operation per cell pair; firmware v0.5 requires improved charge balancing before prolonged in vivo stimulation. The electrode load, rather than the programmable range, sets the usable stimulation amplitude in vivo. In vivo, stimulation at high amplitude settings was associated with increased immobility, consistent with effective stimulation through implanted electrodes; electrode impedance and delivered current were not measured in these mice.

bioengineering↗

bioRxiv2026

Biocosm: A Simulation Environment for Designing Energy-Constrained Ethological Sensors

Long-duration ethological sensing increasingly depends on miniaturized, battery-constrained devices that must decide when to observe, transmit, store, compute, or sleep. These policy decisions shape not only device lifetime, but also which biological events are ultimately available for inference. This manuscript presents BO_SCPLOWIOCOSMC_SCPLOW, a measurement-process simulation framework for energy-constrained ethological instrumentation. BO_SCPLOWIOCOSMC_SCPLOW separates the latent biological world from the observation model, sensing policy, energy model, and analysis layer, allowing researchers to evaluate how alternative sensing strategies transform true behavioral interactions into observed data. Although motivated by wireless proximity logging, the framework is hardware-agnostic: beaconing, listening, sensing, storage, and computation are represented as parameterized state/action costs rather than as fixed properties of one device architecture. This structure supports reproducible design-space exploration, policy comparison, and sensitivity analysis before field deployment. BO_SCPLOWIOCOSMC_SCPLOW is grounded in prior work on animal proximity loggers, low-power wireless discovery and energy modeling, agent-based ethological simulation, and digital twin-inspired methods in medicine and neurotechnology. Framing measurement as a coupled world-observation-policy system makes instrumentation choices explicit and quantifiable.

animal behavior and cognition↗

bioRxiv2026

Sex differences in exploration-exploitation strategies during home-cage decision making

The exploration-exploitation trade-off refers to the conflict between using known strategies that reliably yield reward (exploitation) and sampling uncertain options that might yield better outcomes (exploration). Dysregulation of this balance is implicated in neuropsychiatric disease, and while sex differences in this balance have been described, the biological bases remain unclear. To quantify sex differences in this trade-off, we tested mice (n=74 male, 62 female) on four home-cage based foraging tasks with an operant pellet dispensing device, Feeding Experimentation Device 3 (FED3). Mice completed the tasks continuously over multiple days and the tasks were their only source of food. Across multiple tasks, males showed higher win-stay behaviour than females, indicating greater exploitation of previously rewarded actions, an effect that was modest in size but highly significant. Power analyses revealed that >30 mice per sex were needed to detect these modest but significant sex differences with 80% power. No consistent sex differences were observed in pellet intake, suggesting that differences in exploitation did not reflect differences in hunger drive or demand for pellets. Exploitation is a more efficient strategy when environmental parameters are fixed, while exploration can be more advantageous when parameters such as reward locations are changing and uncertain. We tested this idea by re-running our mice in a probabilistic foraging task, where actions led to uncertain probabilities of reward. While males continued to show higher levels of win-stay behaviour on this task, this no longer led to increases in accuracy. Behavioural modelling also supported this framework, demonstrating that stronger win-stay behaviour was most advantageous in deterministic models, and less advantageous in probabilistic models. Together, our findings demonstrate that male and female mice have small but significant differences in their exploration-exploitation balance, which leads to more accurate foraging in certain, but not uncertain, environments.

neuroscience↗

bioRxiv2024

A Wireless Wearable Ecosystem for Social Network Analysis in Free-living Animals

Understanding the dynamics of animal social systems requires studying variation in contact and interaction, which is influenced by environmental conditions, resource availability, and predation risk, among other factors. Traditional (direct) observational methods have limitations, but advancements in sensor technologies and data analytics provide unprecedented opportunities to study these complex systems in naturalistic environments. Proximity logging and tracking devices, capturing movement, temperature, and social interactions, offer non-invasive means to quantify behavior and develop empirical models of animal social networks. However, challenges remain in integrating different data types, incorporating more sensor modalities, and addressing logistical constraints. To address these gaps, we developed a wireless wearable sensor system with novel features (called "Juxta"), including modular battery packs, memory management for combining data types, reconfigurable deployment modes, and a smartphone app for data collection. We present data from a pilot study on prairie voles (Microtus ochrogaster), which is a small mammal species that exhibits relatively complex social behavior. We demonstrate the potential for Juxta to increase our understanding of the social networks and behavior of free-living animals. Additionally, we propose a framework to guide future research in merging temporal, spatial, and event-driven data. By leveraging wireless technology, battery efficiency, and smart sensing modalities, our wearable ecosystem offers a scalable solution for real-time, high-resolution data capture and analysis in animal social network studies, opening new avenues for exploring complex social dynamics across species and environments.

animal behavior and cognition↗

bioRxiv2021

Using a Homeogram to Detect Sleep in Free-living Animals

O_LISleep is appreciated as a behavior critical to homeostasis, performance, and fitness. Yet, most of what we know about sleep comes from humans or controlled laboratory experiments. Assessing sleep in wild animals is challenging, as it is often hidden from view, and electrophysiological recordings that define sleep states are difficult to obtain. Accelerometers have offered great insight regarding gross movement, although ambiguous quiescent states like sleep have been largely ignored, limiting our understanding of this ubiquitous behavior. C_LIO_LIWe developed a broadly applicable sleep detection method called a homeogram that can be applied to accelerometer data collected from wild animals. We applied our methodology to detect sleep in free-ranging North American red squirrels (Tamiasciurus hudsonicus) in a region that experiences drastic seasonal shifts in light, temperature, and behavioral demands. C_LIO_LIOur method characterized sleep in a manner consistent with limited existing studies and expanded those observations to provide evidence that red squirrels apply unique sleep strategies to cope with changing environments. C_LIO_LIApplying our analytical strategy to accelerometer data from other species may open new possibilities to investigate sleep patterns for researchers studying wild animals. C_LI

animal behavior and cognition↗

bioRxiv2020

Precisely-timed dopamine signals establish distinct kinematic representations of skilled movements

Brain dopamine is critical for normal motor control, as evidenced by its importance in Parkinson Disease and related disorders. Current hypotheses are that dopamine influences motor control by "invigorating" movements and regulating motor learning. Most evidence for these aspects of dopamine function comes from simple tasks (e.g., lever pressing). Therefore, the influence of dopamine on motor skills requiring multi-joint coordination is unknown. To determine the effects of precisely-timed dopamine manipulations on the performance of a complex, finely coordinated dexterous skill, we optogenetically stimulated or inhibited midbrain dopamine neurons as rats performed a skilled reaching task. We found that reach kinematics and coordination between gross and fine movements progressively changed with repeated manipulations. However, once established, rats transitioned abruptly between aberrant and baseline reach kinematics in a dopamine-dependent manner. These results suggest that precisely-timed dopamine signals have immediate and long-term influences on motor skill performance, distinct from simply "invigorating" movement.

neuroscience↗

bioRxiv2019

Interactions between motor thalamic field potentials and single unit spiking predict behavior in rats

The thalamus plays a central role in generating circuit-level neural oscillations believed to coordinate brain activity over large spatiotemporal scales. Such thalamic influences are well-documented for sleep rhythms and in sensory systems, but the relationship between thalamic activity, motor circuit local field potential (LFP) oscillations, and behavior is unknown. We recorded wideband motor thalamic (Mthal) electrophysiology as healthy rats performed a two-alternative forced choice task. The power of delta (1-4 Hz), beta (13-30 Hz), low gamma (30-70 Hz), and high gamma (70-200 Hz) oscillations were strongly modulated by task performance. As in cortex, delta phase predicted beta/low gamma power and reaction time. Furthermore, delta phase differentially predicted spike timing in functionally distinct populations of Mthal neurons, which also predicted task performance and beta power. These complex relationships suggest mechanisms for commonly observed LFP-LFP and spike-LFP interactions, as well as subcortical influences on motor output.

neuroscience↗