Availability and safety assessment of infrared neural stimulation at high repetition rate through an implantable optrode

Abstract

An implantable optrode with micro-thermal detectors was designed to investigate the availability and safety of INS using high repetition rates. Optical auditory brainstem responses (oABRs) were recorded in normal-hearing guinea pigs, and the energy thresholds, pulse durations, and amplitudes evoked by the varied stimulus repetitions were analyzed. Stable oABRs could be evoked through INS even as the repetition rate of stimulation reached 19[Formula: see text]kHz. The energy threshold of oABRs was elevated, the amplitudes decreased as pulse durations increased and repetition rates were higher, and the latencies were delayed as the pulse durations increased. The temperature variation curves on the site of stimulation significantly increased as the pulse duration increased to 400 [Formula: see text]s. INS elevated the temperature around the stimulus site area via thermal accumulation during radiation, especially when higher repetition stimuli were used. Our results demonstrate that high repetition infrared stimulations can safely evoke stable and available oABRs in normal-hearing guinea pigs.

All-fiber-transmission photometry for simultaneous optogenetic stimulation and multi-color neuronal activity recording

“…Few studies have attempted to combine optogenetic manipulation and neuronal activity recording into a single system 24−28 . The optrode, which integrates electrophysiological recording 29 with the optogenetic stimulations 24,30 , is the most widely used method to record and manipulate neurons, but it cannot directly monitor neurotransmitter activities. Enabled by the development of genetically encoded fluorescent indicators (GEFI) 31−35 , optical imaging technologies including the miniature fluorescence microscope 18,27 and the miniaturized two-photon microscope 17,36 are capable of imaging and manipulating neurons at the same time.…”