Intracellular simulated biophoton stimulation and transsynaptic signal transmission

" The traditional theory holds that the information transmission between nerve cells includes electrical and chemical transmission; however, these known functional features do face some difficulties to explain the fast and efficient information processing and cognitive processes in the brain due to the existing functional limitations of neuronal networks, such as the dendritic and axonal propagation delays as well as the chemical synaptic transmission time delay that have been debated for a long time. We generated three kinds of ultraweak lasers, called as simulated biophotons, with different spectra and intensities to implement intracellular stimulation in a single nerve cell of the hippocampal areas in mouse brain slices combined with intracellular membrane potential recording and biophoton imaging techniques. We found that the simulated biophoton stimulation can lead to transsynaptic biophotonic activities and transmission in the ipsilateral and contralateral projection circuits in the hippocampus. The activity and transmission characteristics were related to the spectra and intensities of the simulated biophotons but not to the levels of membrane potentials before stimulation. These findings present specific characteristics of neural biophoton signal transmission, which may be involved in the mechanisms of processing, encoding, and storage of neural signals." {Credits 1}

" Unexpectedly, we found that the simulated biophoton stimulation of some nerve cells with relatively small membrane potential could also lead to obvious biophotonic activities and transmission, suggesting that the biophotonic activity and transmission induced by the simulated biophoton stimulation in a single nerve cell may have no relationship with its membrane potential state. It has been traditionally believed that the generation and conduction of action potentials are directly related to the membrane potential; however, previous studies demonstrated that it is very sparse or silent for most of the neurons in the hippocampus, neocortex, and cerebellum under the appropriate behavioral conditions." {Credits 1}

" Interestingly, in this study, we found that the patterns of biophotonic activities and transmission in the hippocampal neural circuit caused by different simulated biophoton stimulations were related to their spectra and intensities. Under the same intensity, red light stimulation resulted in stronger and wider effects of activities and transmission than green and blue light stimulation. It is unknown whether such effects are related to the biological characteristics of the targeted nerve cells. Our previous research found that the biophotons emitted from brain slices of various species induced by glutamate presented spectral redshift from low to high species, and the red laser wavelength (650 nm) used in this study was similar to the average wavelength of the biophoton (647 nm) in mouse brain slices induced by glutamate [28]. In addition, blue light stimulation could not effectively induce biophotonic activity and transmission in the contralateral neural circuit of the mouse hippocampus. These findings suggest that simulated red biophotons may be more conducive to transmission and are more suitable and effective for the processing of neural information in mouse neural circuits than simulated blue biophotons." {Credits 1}

{Credits 1} 🎪 Na Liu, Zhuo Wang, and Jiapei Dai , "Intracellular simulated biophoton stimulation and transsynaptic signal transmission", Appl. Phys. Lett. 121, 203701 (2022) https://doi.org/10.1063/5.0128956. © 2022 Author(s). This is an open access article distributed under the terms of the Creative Creative Commons Attribution 4.0 International License.