Cranial irradiation impairs intrinsic excitability and synaptic plasticity of hippocampal CA1 pyramidal neurons with implications for cognitive function

Radiation therapy is a standard treatment for head and neck tumors.However,patients often exhibit cognitive impairments following radiation therapy.Previous studies have revealed that hippocampal dysfunction,specifically abnormal hippocampal neurogenesis or neuroinflammation,plays a key role in radiation-induced cognitive impairment.However,the long-term effects of radiation with respect to the electrophysiological adaptation of hippocampal neurons remain poorly characterized.We found that mice exhibited cognitive impairment 3 months after undergoing 10 minutes of cranial irradiation at a dose rate of 3 Gy/min.Furthermore,we observed a remarkable reduction in spike firing and excitatory synaptic input,as well as greatly enhanced inhibitory inputs,in hippocampal CA1 pyramidal neurons.Corresponding to the electrophysiological adaptation,we found reduced expression of synaptic plasticity marker VGLUT1 and increased expression of VGAT.Furthermore,in irradiated mice,long-term potentiation in the hippocampus was weakened and GluR1 expression was inhibited.These findings suggest that radiation can impair intrinsic excitability and synaptic plasticity in hippocampal CA1 pyramidal neurons.

Self-screening of the polarized electric field in wurtzite gallium nitride along[0001]direction

The strong polarization effect of GaN-based materials is widely used in high-performance devices such as white-lightemitting diodes(white LEDs),high electron mobility transistors(HEMTs),and GaN polarization superjunctions.However,the current researches on the polarization mechanism of GaN-based materials are not sufficient.In this paper,we studied the influence of polarization on electric field and energy band characteristics of Ga-face GaN bulk materials by using a combination of theoretical analysis and semiconductor technology computer-aided design(TCAD) simulation.The selfscreening effect in Ga-face bulk GaN under ideal and non-ideal conditions is studied respectively.We believe that the formation of high-density two-dimensional electron gas(2 DEG) in GaN is the accumulation of screening charges.We also clarify the source and accumulation of the screening charges caused by the GaN self-screening effect in this paper and aim to guide the design and optimization of high-performance GaN-based devices.

Discrete solitons in azimuthally modulated Bessel lattices:An introduction to solitons in quasi-periodic structure

The investigation of discrete solitons in quasi-periodic structure,namely azimuthally modulated Bessel lattices imprinted in photorefractive crystal,is introduced.It is shown that the discrete solitons centralize more energy in the internal layers than the Bessel lattice and moreover,the effect of centralization of discrete solitons in focusing media is stronger than that in defocusing media.The discrete solitons are unstable in some propagation constant windows and they are absolutely stable when the propagation constant is large enough.The stable solitons perform long-distance and periodic oscillation of intensity and shape under the perturbation of intrinsic excitation.

Roles of somatic A-type K^+ channels in the synaptic plasticity of hippocampal neurons

In the mammalian brain, information encoding and storage have been explained by revealing the cellular and molecular mechanisms of synaptic plasticity at various levels in the central nervous system, including the hippocampus and the cerebral cortices. The modulatory mechanisms of synaptic excitability that are correlated with neuronal tasks are fundamental factors for synaptic plasticity, and they are dependent on intracellular Ca2＋-mediated signaling. In the present review, the A-type K＋ （IA） channel, one of the voltage-dependent cation channels, is considered as a key player in the modulation of Ca2＋ influx through synaptic NMDA receptors and their correlated signaling pathways. The cellular functions of IA channels indicate that they possibly play as integral parts of synaptic and somatic complexes, completing the initiation and stabilization of memory.