Probing adaptation and spontaneous firing in human auditory-nerve fibers with far-field peri-stimulus time responses

Information in sound stimuli is conveyed from sensory hair cells to the cochlear nuclei by the firing of auditory nerve fibers (ANFs). For obvious ethical reasons, single unit recordings from the cochlear nerve have never been performed in human, thus functional hallmarks of ANFs are unknown. By filtering and rectifying the electrical signal recorded at the round window of gerbil cochleae, we reconstructed a peri-stimulus time response (PSTR), with a waveform similar to the peri-stimulus time histograms (PSTHs) recorded from single ANFs. Pair-by-pair analysis of simultaneous PSTR and PSTH recordings in gerbil provided a model to predict the rapid adaptation and spontaneous discharge rates (SR) in a population of ANFs according to their location in the cochlea. We then probed the model in the mouse, in which the SR-based distribution of ANFs differs from the gerbil. We show that the PSTR-based predictions of the rapid adaptation time constant and mean SR across frequency again matched those obtained by recordings from single ANFs. Using PSTR recorded from the human cochlear nerve in 8 normal-hearing patients who underwent cerebellopontine angle surgeries for a functional cranial-nerve disorders (trigeminal neuralgia or hemifacial spasm), we predicted a rapid adaptation of about 3 milliseconds and a mean SR of 23 spikes/s in the 4 kHz frequency range in human ANFs. Together, our results support the use of PSTR as a promising diagnostic tool to map the auditory nerve in humans, thus opening new avenues to better understanding neuropathies, tinnitus, and hyperacusis.

Research on subliminal visual messages based on EEG signal and convolutional neural network

The visual information that can't be detected by consciousness but can affect individual's behavior and attitude under specific conditions is called subliminal visual messages. In order to better apply subliminal visual messages to commercial advertising, education and other fields, this paper studied the process of subliminal visual messages in the brain. First, this paper designed a experiment to allow the subjects to see a series of pictures stimulation of different durations and collect the EEG signals, then analyzed the impact of stimulation time on classification accuracy. The experimental results showed that when the stimulus time is short, the classification accuracy increases with the increase of time, resulting in subliminal visual effects. However, with the increase of stimulus time, the classification accuracy began to decline. We speculated that the visual information changed from subthreshold to suprathreshold. The subliminal visual effects were disturbed until disappeared.

Time

Within the traditional notion of the senses, the perception of time is especially puzzling. There is no specific physical energy carrying information about time, and hence no sensory receptors can transduce a ‘temporal stimulus.’ Time-related properties of events can instead be shown to emerge from specific perceptual processes involving multisensory interactions. In this chapter, we will examine five such properties: the awareness that two events occur at the same time (simultaneity) or one after the other (succession); the coherent time-stamping of events despite inaccuracies and imprecisions in coding simultaneity and succession (temporal coherence); the awareness of the temporal extent occupied by events (duration); the organization of events in regular temporal units (rhythm).