Implication of Auditory Confounding in Interpreting Somatosensory and Motor Responses in Low-Intensity Transcranial Focused Ultrasound Stimulation

Low-intensity transcranial focused ultrasound (LI-tFUS) stimulation is a non-invasive neuromodulation tool that demonstrates high target localization accuracy and depth penetration. It has been shown to modulate activities in the primary motor and somatosensory cortex. Previous studies in animals and humans acknowledged the possibility of indirect stimulation of the peripheral auditory pathway that could confound the somatosensory and motor responses observed with LI-tFUS stimulation. Here, we discuss the implications and interpretations of auditory confounding in the context of neuromodulation.

Deficits of Hippocampal RNA Editing and Social Interaction Resulting from Prenatal Stress are Mitigated by Clozapine

BackgroundNeurodevelopmental deficits resulting from prenatal stress are associated with neurological disorders that include deficits of social behavior, such as schizophrenia1 and autism2–7. Studies of human brain and animal models indicate that an epitranscriptomic process known as ‘RNA editing’ contributes to the pathophysiology of these disorders, which occur more frequently in males than in females8–20. RNA editing plays an important role in brain development through its modification of excitatory and inhibitory neurotransmission21.MethodsWe exposed pregnant mice to restraint stress three times daily during gestational weeks 2 and 3. We treated the adult male offspring with haloperidol (1mg/kg), clozapine (5mg/kg) or saline twice daily for 5 days. Subsequently we measured social interaction behavior (SI) and locomotor activity, followed by next-generation sequencing analyses of hippocampal RNA editing.ResultsMice exposed to PRS exhibited reduced SI, which correlated with hippocampal RNA editing of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluA2, GluA3 and GluA4, the potassium channel Kv1.1, the calcium channel subunit Cav1.3, calcium-dependent secretion activator (CAPS-1) and the calcium-dependent cell adhesion protein, cadherin 22 (CDH22). Treatment with clozapine, but not haloperidol, normalized SI behavior, and selectively reduced the deficits in GluA2 RNA editing in PRS mice.ConclusionsRNA editing may contribute to impaired hippocampal function after exposure to PRS. The efficacy of clozapine in improving SI behavior may include indirect stimulation of GluA2 RNA editing in the hippocampus. Although these data are from male mice and not humans, the results suggest a new molecular pathway by which PRS leads to life-long impairments of hippocampal function.

Nonlinear response characteristics of neural networks and single neurons undergoing optogenetic excitation

Optogenetic stimulation has become the method of choice for investigating neural computation in populations of neurons. Optogenetic experiments often aim to elicit a network response by stimulating specific groups of neurons. However, this is complicated by the fact that optogenetic stimulation is nonlinear, more light does not always equal to more spikes, and neurons that are not directly but indirectly stimulated could have a major impact on how networks respond to optogenetic stimulation. To clarify how optogenetic excitation of some neurons alters the network dynamics, we studied the temporal and spatial response of individual neurons and recurrent neural networks. In individual neurons, we find that neurons show a monotonic, saturating rate response to increasing light intensity and a nonmonotonic rate response to increasing pulse frequency. At the network level, we find that Gaussian light beams elicit spatial firing rate responses that are substantially broader than the stimulus profile. In summary, our analysis and our network simulation code allow us to predict the outcome of an optogenetic experiment and to assess whether the observed effects can be attributed to direct or indirect stimulation of neurons.

A STUDY ON COGNITIVE RESPONSE TENDENCY AND DAMAGE THRESHOLD OF ABSORBING MEDIUM BY LASER-INDUCED INDIRECT STIMULATION

Laser-based research can be used in biology, medicine, engineering and many other industries. The use of pulsed laser can induce thermoelastic effect in a short time and give mechanical stimulation to the human body. When the elastic medium is attached to the human body and the laser is irradiated, the mechanical stimulus induced in the elastic medium can be transferred to the human body, which may cause tactile sensation. In this study, we investigated the effects of laser-induced indirect stimulation on cognitive response and damage to absorbing medium. Through the human body experiment, we studied the laser parameter condition that most subjects feel touch. In addition, thermal analysis simulations were performed to predict the condition of the laser pulse energy, the laser frequency and the temperature at the damage threshold of the absorption medium. The results of this study are expected to be useful for conducting non-contact tactile sensation using laser, and this technique can be widely used in laser biomedical stimulation, haptic technology, and other biological and medical fields.

MORPHOLOGICAL RESPONSE OF THE RUMINAL AND OMASAL MUCOSAE TO THE VARIATION IN DIET ENERGY

ABSTRACT The absorption capacity of the rumen responds positively to direct and indirect stimulation by VFA; there is also evidence that the wall of the omasum also responds to these stimuli. To further investigate these reports, we compared the tissue morphologies of rumen and omasum biopsy samples. Four cows surgically fitted with ruminal cannulas were sequentially fed two diets. These diets included corn silage (S) and a combination of corn silage and commercial concentrate (CS). The animals were fed S for the first 18 days of the experiment, followed by CS for the next 18 days. They were then fasted for 72 h (F), and then had at least 18 days of re-feeding. Biopsy samples were taken from the blade of the omasum and the ventral sac of the rumen at different time points during each diet: samples were taken from S-diet animals at day 18; CS, at days 4 and 18; F, at the end of the 72 h; and re-fed animals, at days 4, 12, and 18. The mitotic index of the basal layers of the ruminal and omasal epithelia and the VFA concentration in the rumen were higher after 4 days of CS diet. There was a positive correlation between the mitotic indices of the rumen and omasum. The width of the ruminal papillae varied with different diets, and was highest on day 18 of the CS diet. Our results indicate that stimulation of cell division due to increased dietary energy simultaneously affected both compartments of the stomach.