Electrical activation of the pedunculopontine tegmental nucleus modulates the neuronal activities of the subthalamic nucleus and the substantia nigra pars reticulata in anesthetized rats.

The subthalamic nucleus (STN), substantia nigra pars reticulata (SNr), and pedunculopontine tegmental nucleus (PPTg) are reciprocally connected brain regions that play significant roles in the motor control. However, the electrophysiological relationship among the STN, SNr, and PPTg remains controversial. The present study was designed to further explore the mutual electrophysiological relationship of these brain regions from the perspective of the PPTg-STN-SNr neural circuit. The neuronal activities in the STN and SNr were simultaneously recorded while the PPTg was stimulated in anesthetized rats. The activation of PPTg induced excitatory responses of both the STN and SNr neurons. Comparisons of excitation latencies between the STN and SNr were made to distinguish the excitation evoked from the PPTg-STN-SNr pathway. Additionally, two types of excitatory responses and various inhibitory responses with different latencies in the SNr were recorded. The SNr responses could also be classified into five different response categories, which might attribute to projections within different neural circuits. Neuronal recordings were analyzed in different electrophysiological features (i.e., interspike interval [ISI] mode, ISI asymmetry index, ISI coefficient of variance, firing rate, burst index, and trough peak duration), and different response patterns of neurons had their specific features in neuronal activities. These findings indicated the complex interactions among the STN, SNr, and PPTg electrophysiologically, and provided insights into exploring information transmission mechanisms underlying these circuits.

Simultaneous Multisite Extracellular Electrophysiological Recordings During Electrical Stimulation in Anesthetized Rats.

Analyzing neuronal activities is essential to deciphering the function of neural circuits. In anesthetized rodents, simultaneous multisite recording of extracellular electrophysiological activity with defined electrical stimulation is a powerful tool to dissect reciprocal relationships between brain structures. Here, we present a protocol to simultaneously record from the subthalamic nucleus and substantia nigra pars reticulata while stimulating the pedunculopontine tegmental nucleus in anesthetized rats. This protocol describes the preparation of recording and stimulating electrodes, surgery setup, and detailed recording techniques. Basic post-recording data analysis methods are included as well. This protocol can be adapted to other brain areas of interest following the outlined procedures. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Assembly of recording and stimulating electrodes Basic Protocol 2: Implantation of recording and stimulating electrodes in an anesthetized rat Basic Protocol 3: Simultaneous recording from the STN and SNr with PPTg stimulation Basic Protocol 4: Histological verification of recording sites Basic Protocol 5: Analysis of electrophysiological data.

Enhancing catalytic ozonation activity of MCM-41 via one-step incorporating fluorine and iron: The interfacial reaction induced by hydrophobic sites and Lewis acid sites.

Fe-MCM-41 had been widely used as ozonation catalyst, however, the existence of large amount of hydrophilic silanol hindered its interfacial reaction with O3 and pollutants. To solve this problem, F-Fe-MCM-41 was synthesized by co-doping F and Fe into the framework of MCM-41 to replace silanol with Si-F groups through a one-step hydrothermal method. F introduced hydrophobic sites which contributed to more ibuprofen (IBP) chemisorption on the surface of F-Fe-MCM-41. Moreover, doping F also enhanced the acidity, which accelerated O3 decomposition into •OH. F-Fe-MCM-41/O3 exhibited notably activity with 96.6% IBP removal efficiency within 120 min, while only 78.5% and 80.9% in O3 alone and Fe-MCM-41/O3, respectively. Surface Lewis acid sites and metal hydroxyl groups were considered as important factors for O3 activation and •OH generation. F-Fe-MCM-41 exhibited excellent catalytic performance under acidic and alkaline conditions. Comparative experiments revealed that F doping improved the interfacial reaction, especially the interfacial electron transfer, which resulted in the high catalytic activity of F-Fe-MCM-41. F-Fe-MCM-41 possessed good stability and reusability, with only 5.7% decline for IBP removal in five successive cycles. Furthermore, the possible degradation path of IBP was proposed according to DFT calculation and GC-MS analysis.