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Objective To investigate the changes and features of firing activities of interneurons in dorsal hippocampus during the acquisition and consolidation of associative memory. Methods Trace eyeblink conditioning (tEBC) was utilized as a behavioral model of associative memory.A total of 18 wild-type C57BL/6 mice (male, 10~12 weeks old, weighing 22~25 g) were randomly divided into a paired group (n=9) and an unpaired group (n=9).Paired presentations of conditioned stimulus (CS) and unconditioned stimulus (US) were utilized to train these mice.The mice from the paired group were given US training in 250 ms after CS training, and those from the unpaired group received similar doses of CS and US training, but with no paired relationship in time.After 4 consecutive days'training, the mice of the paired group acquired tEBC, manifesting conditioned eyeblink responses (CR).Tetrode arrays were applied to record neuronal activity in dorsal hippocampus during both tEBC training epoch and the 1.5 h epoch after training.The putative interneurons (n=105) were identified according to their firing rate and spike width from trough to peak.Specific changes in hippocampal interneurons activity during tEBC training and post-training slow wave sleep were analyzed respectively. Results ① At the early stage of CR acquisition (the 1st and 2nd days), CS could evoke significantly greater activity of dorsal hippocampal interneurons in the paired group (P < 0.05).During sharp wave ripples (SWR) in the post-training slow wave sleep, the firing rate of dorsal hippocampal interneurons was significantly lower in the paired group than the unpaired group (P < 0.05).②At the late stage of CR acquisition (the 3rd and 4th days), no significant differences in CS evoked activity of dorsal hippocampal interneurons were observed between the paired group and unpaired group, neither in the firing rate of dorsal hippocampal interneurons during SWR in the post-training slow wave sleep between the 2 groups. Conclusion The dorsal hippocampal interneurons show opposite changes in firing activity during the acquisition and consolidation of associative memory.

BACKGROUND: Previous studies have confirmed that the neurotrophic factor 3-chitosan carrier can support the survival and proliferation of neural stem cells, and can efficiently induce neural stem cells to differentiate into neurons. OBJECTIVE: To observe the effects of neurotrophic factor 3-chitosan carrier on neuronal development and its electrophysiological properties at various stages of development and the subtypes of mature neurons. METHODS: Passage 3 spinal cord neural stem cells of neonatal rats were collected and cultured in four groups. The blank control group was added with neural stem cell culture medium. Chitosan group was added with neural stem cell culture medium containing chitosan. Neurotrophic factor 3 group was added with neural stem cell medium containing neurotrophic factor 3. Neurotrophic factor 3-chitosan group was added with neural stem cell medium containing neurotrophic factor 3-chitosan carrier. Immunofluorescence staining was performed to observe the development of neurons at various stages. The changes in electrophysiological properties during neural stem cell development were evaluated by whole-cell patch-clamp technology. Interneuron subtypes were visualized by immunofluorescence staining 21 days after neural stem cell differentiation. RESULTS AND CONCLUSION: (1) Immunofluorescence staining for Nestin, DCX, Tuj1 and MAP2 showed that the neurotrophic factor 3-chitosan carrier maintained the homeostasis of the neural stem cell pool and promoted neuronal maturation by accelerating the developmental process of neuroblasts. (2) Whole-cell patch-clamp technology results demonstrated that the neurotrophic factor 3 and neurotrophic factor 3-chitosan promoted cell membrane function and the maturation of ion channels on the cell membrane early in development. However, only neurotrophic factor 3-chitosan can maintain this advantage to the middle and late stages of development, that is, 7-14 days after differentiation. (3) Immunofluorescence staining exhibited that after 21 days of neural stem cell differentiation, mature neurons in the neurotrophic factor 3-chitosan group could express the motor neuron specific marker HB9, V1 type interneuron FOXP1, V2 type interneuron specific marker LHX3, and regulate a specific marker VGLUT3 that regulates mechanical pain sensory interneurons. (4) These results have verified that the neurotrophic factor 3-chitosan carrier can promote the development of neural stem cells to neuroblasts, and the function of the cell membrane and the maturation of ion channels on the cell membrane in the early stage of development to a certain degree, and can induce the diversification of mature neuronal subtypes. [ABSTRACT FROM AUTHOR]

DBS is an effective therapy in treatment of Parkinson’s diseases. To address the problem that the parameters of DBS cannot be adjusted automatically, this paper proposed a closed loop control scheme of Terminal sliding mode based on l lie model of thalamic interneuron to eliminate the Parkinsonian state, firstly, it presented the model of thalamic interneuron and its pathological activity patterns. And then it tested the effectiveness of the controller by simulations. Simulation results show that the Terminal sliding mode controller can modulate the output of DBS, eliminate the pathological firing patterns and restore the relay ability of thalamic interneuron. In addition, this control scheme is robust to noise. These results may provide an alternative method to control Parkinson’s diseases in a closed-loop DBS. [ABSTRACT FROM AUTHOR]