Depression is a common and severely debilitating neuropsychiatric disorder. Multiple studies indicate a strong correlation between the occurrence of immunological inflammation and the presence of depression. The basolateral amygdala (BLA) is crucial in the cognitive and physiological processing and control of emotion. However, due to the lack of detection tools, the neural activity of the BLA during depression is not well understood. In this study, a microelectrode array (MEA) based on the shape and anatomical location of the BLA in the brain was designed and manufactured. Rats were injected with lipopolysaccharide (LPS) for 7 consecutive days to induce depressive behavior. We used the MEA to detect neural activity in the BLA before modeling, during modeling, and after LPS administration on 7 consecutive days. The results showed that after LPS treatment, the spike firing of neurons in the BLA region of rats gradually became more intense, and the local field potential power also increased progressively. Further analysis revealed that after LPS administration, the spike firing of BLA neurons was predominantly in the theta rhythm, with obvious periodic firing characteristics appearing after the 7 d of LPS administration, and the relative power of the local field potential in the theta band also significantly increased. In summary, our results suggest that the enhanced activity of BLA neurons in the theta band is related to the depressive state of rats, providing valuable guidance for research into the neural mechanisms of depression.

The globus pallidus internus (GPi) was considered a common target for stimulation in Parkinson’s disease (PD). Located deep in the brain and of small size, pinpointing it during surgery is challenging. Multi-channel microelectrode arrays (MEAs) can provide micrometer-level precision functional localization, which can maximize the surgical outcome. In this paper, a 64-channel MEA modified by platinum nanoparticles with a detection site impedance of 61.1 kΩ was designed and prepared, and multiple channels could be synchronized to cover the target brain region and its neighboring regions so that the GPi could be identified quickly and accurately. The results of the implant trajectory indicate that, compared to the control side, there is a reduction in local field potential (LFP) power in multiple subregions of the upper central thalamus on the PD-induced side, while the remaining brain regions exhibit an increasing trend. When the MEA tip was positioned at 8,700 μm deep in the brain, the various characterizations of the spike signals, combined with the electrophysiological characteristics of the β-segmental oscillations in PD, enabled MEAs to localize the GPi at the single-cell level. More precise localization could be achieved by utilizing the distinct characteristics of the internal capsule (ic), the thalamic reticular nucleus (Rt), and the peduncular part of the lateral hypothalamus (PLH) brain regions, as well as the relative positions of these brain structures. The MEAs designed in this study provide a new detection method and tool for functional localization of PD targets and PD pathogenesis at the cellular level.

Effective and precise neural modulation with real-time detection in the brain is of great importance and represents a significant challenge. Nanoliposome-encapsulated light-sensitive compounds have excellent characteristics such as high temporal and spatial resolution, delayed drug clearance, and restricted drug biodistribution for neural modulation. In this study, we developed a nanoliposome-based delivery system for ruthenium-based caged GABA compounds (Nanolipo-Ru) to modulate neural activity and allow for real-time monitoring using the microelectrode arrays (MEAs). The Nanolipo-Ru nanoparticles had an average size of 134.10 ± 4.30 nm and exhibited excellent stability for seven weeks. For the in vivo experiment in the rat, release of GABA by Nanolipo-Ru under blue light illumination resulted in an average firing rate reduction in interneurons and pyramidal neurons in the same brain region of 79.4% and 81.6%, respectively. Simultaneously, the average power of local field potentials in the 0-15 Hz range degraded from 4.34 to 0.85 mW. In addition, the Nanolipo-Ru nanoparticles have the potential to provide more flexible timing of modulation than unencapsulated RuBi-GABA in the experiments. These results indicated that Nanolipo-Ru could be an effective platform for regulating neuronal electrophysiology. Furthermore, nanoliposomes with appropriate modifications would render promising utilities for targeting of specific types of neurons in the future.