Biology subjects

Aroso, M.

Publications and source records attributed to Aroso, M..

6 recordsLinked to original sources

bioRxiv2026

Closed-loop control of in vitro neuronal activity using reinforcement learning after in silico pre-training

Controlling specific neuronal dynamics with electrical stimulation is critical for therapeutic neuromodulation, yet deriving optimal control policies remains challenging due to the complex and non-stationary nature of biological neuronal networks. While reinforcement learning (RL) offers a powerful closed-loop control framework, its reliance on prolonged stimulus-driven exploration is difficult to reconcile with the physiological limits of living tissue. Here, we demonstrate an in silico-to-in vitro transfer strategy that achieves efficient state-dependent control of network bursting in cultured neurons. The transferred policy outperforms heuristic controls, while maintaining constrained stimulation usage. Concurrent calcium imaging reveals the mechanistic basis of the learned policy: the agent optimizes stimulation spatially and temporally, exploiting local network topology and intrinsic physiological temporal dynamics. These results establish in vitro brain-on-chip cultures as a tractable stepping stone for RL-based neuromodulation and demonstrate that effective control policies can be derived in biophysically calibrated digital twins and transferred directly to living networks.

neuroscience↗

bioRxiv2024

Influence of asymmetric microchannels in the structure and function of engineered neuronal circuits

Understanding the intricate structure-function relationships of neuronal circuits is crucial for unraveling how the brain sustains efficient information transfer. In specific brain regions, like the hippocampus, neurons are organized in layers and form unidirectional connectivity, which is thought to help ensure controlled signal flow and information processing. In recent years, researchers have tried emulating these structural principles by providing cultured neurons with asymmetric environmental cues, namely microfluidics microchannels that promote directed axonal growth. Even though a few reports have claimed achieving unidirectional connectivity of in vitro neuronal circuits, given the lack of functional characterization, whether this structural connectivity correlates with functional connectivity remains unknown. We have replicated and tested the performance of asymmetric microchannel designs previously reported in the literature to be successful in the promotion of directed axonal growth, as well as other custom variations. A new variation of "Arrowhead", termed "Rams", was the best-performing motif with a [~]76% probability per microchannel of allowing strictly unidirectional connections at 14 days in vitro. Importantly, we assessed the functional implications of these different asymmetric microchannel designs. For this purpose, we combined custom microfluidics with microelectrode array (MEA) technology to record the electrophysiological activity of two segregated populations of hippocampal neurons ("Source" and "Target"). This functional characterization revealed that up to [~]94% of the spiking activity recorded along microchannels with the "Rams" motif propagates towards the "Target" population. Moreover, our results indicate that these engineered circuits also tended to exhibit network-level synchronizations with defined directionality. Overall, this characterization of the structure-function relationships promoted by asymmetric microchannels has the potential to provide insights into how neuronal circuits use specific network architectures for effective computations. Moreover, the here-developed devices and approaches may be used in a wide range of applications, such as disease modeling or preclinical drug screening.

neuroscience↗

bioRxiv2024

Bringing astrocytes into the spotlight of electrical brain stimulation

Astrocytes, primarily viewed only as supportive units, are now emerging as active players in the information processing of the brain. Accumulated evidence supports that the bidirectional communication between astrocytes and neurons maintains complex animal behaviours such as memory formation and decision-making. The lack of characterisation of astrocytic electrophysiology is, in our opinion, associated with the early idea of a passive electrical nature of astrocytes, in opposition to the electrically active neurons. A better understanding of the effect of electrical stimulation on astrocytes physiology and activity will greatly strengthen the current knowledge in neural biology. Here, we assessed if astrocytes may have a role in therapies based on electrical brain stimulation by being able to respond to the same electrical stimulus used to modulate neuronal activity. To do so, we took advantage of microelectrode arrays (MEAs) capability to simultaneously record and deliver extracellular electrical signals. Additionally, we synchronized the recording of electrophysiological data with the recording of calcium activity, a hallmark of astrocytic activity. Here, we show that astrocytes respond to electrical stimulation with the generation of strong membrane voltage oscillations and simultaneous production of calcium waves, demonstrating, unequivocally, that astrocytes respond to electrical stimulation in the same range as neurons do. Importantly, these responses are dependent on the stimuli amplitude. Furthermore, membrane voltage oscillations are significantly reduced in the absence of extracellular calcium, but not abolished, while calcium activity is not detected.

neuroscience↗

bioRxiv2022

A novel closed-loop control algorithm to disrupt pathological neuronal oscillations - implementation and validation in vitro

Adaptive neuronal stimulation has a strong therapeutic potential for neurological disorders such as Parkinsons disease and epilepsy. However, standard stimulation protocols mostly rely on continuous open-loop stimulation. We implement here, for the first time in neuronal populations, two different Delayed Feedback Control (DFC) algorithms and assess their efficacy in disrupting unwanted neuronal oscillations. DFC is a well-established closed-loop control technique but its use in neuromodulation has been limited so far to models and computational studies. Leveraging on the high spatiotemporal monitoring capabilities of specialized in vitro platforms, we show that standard DFC in fact worsens the neuronal population oscillatory behaviour and promotes faster bursting, which was never reported in silico. Alternatively, we present adaptive DFC (aDFC) that monitors ongoing oscillation periodicity and self-tunes accordingly. aDFC disrupts collective neuronal oscillations and decreases network synchrony. Furthermore, we show that the intrinsic population dynamics have a strong impact in the susceptibility of networks to neuromodulation. Experimental data was complemented with computer simulations to show how this network controllability might be determined by specific network properties. Overall, these results support aDFC as a better candidate for therapeutic neurostimulation and provide new insights regarding the controllability of neuronal systems.

neuroscience↗

bioRxiv2021

A memristor-based neuromodulation device for real-time monitoring and adaptive control of in vitro neuronal populations

Neurons are specialized cells in information transmission and information processing. Following this, many neurologic disorders are directly linked not to cellular viability/homeostasis issues but rather to specific anomalies in electrical activity dynamics. Acknowledging this fact, therapeutic strategies based on direct modulation of neuronal electrical activity have been producing remarkable results, with successful examples ranging from cochlear implants to deep brain stimulation. Development on these implantable devices are hindered, however, by important challenges: power requirements, size factor, signal transduction, and adaptability/computational capabilities. Memristors, nanoscale electronic components able to emulate natural synapses, provide unique properties to address these constraints and their use in neuroprosthetic devices is being actively explored. Here we demonstrate for the first time the use of memristive devices in a clinically relevant setting where communication between two neuronal populations is conditioned to specific activity patterns in the source population. In our approach, the memristor device performs a simple pattern detection computation and acts as a synapstor capable of reversible short-term plasticity. Using in vitro hippocampal neuronal cultures, we show real-time adaptive control with a high degree of reproducibility using our monitor-compute-actuate paradigm. We envision very similar systems being used for automatic detection and suppression of seizures in epileptic patients.

neuroscience↗

bioRxiv2021

In vitro neuronal networks show bidirectional axonal conduction with antidromic action potentials effectively depolarizing the soma

Recent technological advances are revealing the complex physiology of the axon and challenging long-standing assumptions. Namely, while most action potential (AP) initiation occurs at the axon initial segment in central nervous system neurons, initiation in distal parts of the axon has been shown to occur in both physiological and pathological conditions. However, such ectopic action potential (EAP) activity has not been reported yet in studies using neuronal cultures and its functional role, if exists, is still not clear. Here, we show the spontaneous occurrence of EAPs and effective antidromic conduction in hippocampal neuronal cultures. We also observe a significant fraction of bidirectional axonal conduction in dorsal root ganglia neuronal cultures. We investigate and characterize this antidromic propagation via a combination of microfluidics, microelectrode arrays, advanced data analysis and in silico studies. We show that EAPs and antidromic conduction can occur spontaneously, and after distal axotomy or physiological changes in the axon biochemical environment. Conduction velocity is asymmetrical, with antidromic conduction being slower than orthodromic. Importantly, EAPs may carry information and can have a functional impact on the neuron, as they consistently depolarize the soma. Thus, plasticity or gene transduction mechanisms triggered by soma depolarization can also be affected by these antidromic APs. Altogether these findings have important implications for the study of neuronal function in vitro, reshaping our understanding on how information flows in neuronal cultures.

neuroscience↗