scholarly journals Spontaneous activity synchronizes whisker-related sensorimotor networks prior to their maturation in the developing rat cortex

2017 ◽  
Author(s):  
David A. McVea ◽  
Timothy H. Murphy ◽  
Majid H. Mohajerani

AbstractA prominent feature of the cortical systems controlling the whiskers in the adult rodent is tight coupling between sensory and motor systems. Stimulation of the whiskers evokes activation of discrete motor regions of cortex shortly after activation of the sensory cortex. To explore the factors that direct the development of sensorimotor functional connectivity, we recorded spontaneous and whisker-evoked cortical activity using voltage-sensitive imaging over a large (7X7 mm) craniotomy in postnatal rats (day 5-12) under anesthesia. We found that spontaneous bursts of activity in the barrel cortex were correlated predominantly with activity in motor (anterio-medial) cortex, at ages before whisker stimulation evoked activation in this area. Intracortical microstimulation and anatomical tracing experiments confirmed there were no functional or anatomical intracortical sensorimotor connections. We interpret these results as evidence that the spontaneous patterns of activity in the cortex synchronize functionally related regions of the brain prior to their maturation.Author ContributionsD.A.M, T.H.M., and M.H.M. designed the study. D.A.M, and M.H.M performed the experiments and analyzed the data and wrote the manuscript, which all authors commented on and edited. T.H.M. and M.H.M. supervised the study.

2019 ◽  
Author(s):  
Yi Chen ◽  
Filip Sobczak ◽  
Patricia Pais-Roldán ◽  
Cornelius Schwarz ◽  
Alan P. Koretsky ◽  
...  

ABSTRACTThe optogenetically driven manipulation of circuit-specific activity enabled functional causality studies in animals, but its global effect on the brain is rarely reported. Here, we applied simultaneous fMRI with calcium recording to map brain-wide activity by optogenetic activation of fibers running in one orientation along the corpus callosum(CC) connecting the barrel cortex(BC). Robust positive BOLD signals were detected in the ipsilateral BC due to antidromic activity, which spread to ipsilateral motor cortex(MC) and posterior thalamus(PO). In the orthodromic target (contralateral barrel cortex), positive BOLD signals were reliably evoked by 2Hz light pulses, whereas 40Hz light pulses led to a reversed sign of BOLD - indicative of CC-mediated inhibition. This presumed optogenetic CC-mediated inhibition was further elucidated by pairing light with peripheral whisker stimulation at varied inter-stimulus intervals. Whisker induced positive BOLD, and calcium signals were reduced at inter-stimulus intervals of 50/100ms. The calcium-amplitude modulation (AM)-based correlation with whole-brain fMRI signal revealed that the inhibitory effects spread to contralateral BC as well as ipsilateral MC and PO. This work raises the need of fMRI to elucidate the brain-wide network activation in response to projection-specific optogenetic stimulation.


2005 ◽  
Vol 94 (3) ◽  
pp. 2004-2018 ◽  
Author(s):  
Hiroyuki Kida ◽  
Satoshi Shimegi ◽  
Hiromichi Sato

Cells in the rat barrel cortex exhibit stimulus-specific response properties. To understand the network mechanism of direction selectivity in response to facial whisker deflection, we examined direction selectivity of neuronal responses to single- and multiwhisker stimulations. In the case of regular-spiking units, i.e., putative excitatory cells, direction preferences were quite similar between responses to single-whisker stimulation of the principal and adjacent whiskers. In multiwhisker stimulation at short (≤5 ms) interstimulus intervals (ISIs), response facilitation was evoked only when the whiskers were deflected to the preferred direction of the response to the single whisker stimulation. These results suggest that there are neuronal networks among cells with different whisker preferences but with a common direction preference that could be the neuronal basis of the direction-selective facilitation of the response to multiwhisker stimulation. In contrast, multiwhisker stimulation at long (≥6 ms) ISIs caused non–direction-selective suppression of the response to the second stimulus. In the case of fast-spiking units, i.e., putative inhibitory cells, poor direction selectivity was exhibited. Thus stimulus direction is represented as the direction-selective responses to the single- and multiwhisker stimulations of putative excitatory cells rather than those of putative inhibitory cells.


2012 ◽  
Vol 112 (7) ◽  
pp. 1215-1222 ◽  
Author(s):  
Takashi Suzuki ◽  
Yasuhiro Ooi ◽  
Junji Seki

The present study aims to validate the applicability of infrared (IR) thermal imaging for the study of brain function through experiments on the rat barrel cortex. Regional changes in neural activity within the brain produce alterations in local thermal equilibrium via increases in metabolic activity and blood flow. We studied the relationship between temperature change and neural activity in anesthetized rats using IR imaging to visualize stimulus-induced changes in the somatosensory cortex of the brain. Sensory stimulation of the vibrissae (whiskers) was given for 10 s using an oscillating whisker vibrator (5-mm deflection at 10, 5, and 1 Hz). The brain temperature in the observational region continued to increase significantly with whisker stimulation. The mean peak recorded temperature changes were 0.048 ± 0.028, 0.054 ± 0.036, and 0.097 ± 0.015°C at 10, 5, and 1 Hz, respectively. We also observed that the temperature increase occurred in a focal spot, radiating to encompass a larger region within the contralateral barrel cortex region during single-whisker stimulation. Whisker stimulation also produced ipsilateral cortex temperature increases, which were localized in the same region as the pial arterioles. Temperature increase in the barrel cortex was also observed in rats treated with a calcium channel blocker (nimodipine), which acts to suppress the hemodynamic response to neural activity. Thus the location and area of temperature increase were found to change in accordance with the region of neural activation. These results indicate that IR thermal imaging is viable as a functional quantitative neuroimaging technique.


2021 ◽  
Vol 15 ◽  
Author(s):  
Benedetta Mariani ◽  
Giorgio Nicoletti ◽  
Marta Bisio ◽  
Marta Maschietto ◽  
Roberto Oboe ◽  
...  

Since its first experimental signatures, the so called “critical brain hypothesis” has been extensively studied. Yet, its actual foundations remain elusive. According to a widely accepted teleological reasoning, the brain would be poised to a critical state to optimize the mapping of the noisy and ever changing real-world inputs, thus suggesting that primary sensory cortical areas should be critical. We investigated whether a single barrel column of the somatosensory cortex of the anesthetized rat displays a critical behavior. Neuronal avalanches were recorded across all cortical layers in terms of both multi-unit activities and population local field potentials, and their behavior during spontaneous activity compared to the one evoked by a controlled single whisker deflection. By applying a maximum likelihood statistical method based on timeseries undersampling to fit the avalanches distributions, we show that neuronal avalanches are power law distributed for both multi-unit activities and local field potentials during spontaneous activity, with exponents that are spread along a scaling line. Instead, after the tactile stimulus, activity switches to a transient across-layers synchronization mode that appears to dominate the cortical representation of the single sensory input.


2008 ◽  
Vol 99 (2) ◽  
pp. 787-798 ◽  
Author(s):  
J. Berwick ◽  
D. Johnston ◽  
M. Jones ◽  
J. Martindale ◽  
C. Martin ◽  
...  

The spatial resolution of hemodynamic-based neuroimaging techniques, including functional magnetic resonance imaging, is limited by the degree to which neurons regulate their blood supply on a fine scale. Here we investigated the spatial detail of neurovascular events with a combination of high spatiotemporal resolution two-dimensional spectroscopic optical imaging, multichannel electrode recordings and cytochrome oxidase histology in the rodent whisker barrel field. After mechanical stimulation of a single whisker, we found two spatially distinct cortical hemodynamic responses: a transient response in the “upstream” branches of surface arteries and a later highly localized increase in blood volume centered on the activated cortical column. Although the spatial representation of this localized response exceeded that of a single “barrel,” the spread of hemodynamic activity accurately reflected the neural response in neighboring columns rather than being due to a passive “overspill.” These data confirm hemodynamics are capable of providing accurate “single-condition” maps of neural activity.


1975 ◽  
Vol 20 (12) ◽  
pp. 923-924
Author(s):  
MADGE E. SCHEIBEL ◽  
ARNOLD B. SCHEIBEL

2020 ◽  
Vol 44 (3) ◽  
pp. 241-249
Author(s):  
Yoshiaki Omura

While a visiting Professor at the University of Paris, VI (formerly Sorvonne) more than 40 years ago, the Author became very good friends with Dr. Paul Nogier who periodically gave seminars and workshops in Paris. After the author diagnosed his cervical problem & offered him simple help, Dr. Nogier asked the Author to present lectures and demonstrations on the effects of ear stimulation, namely the effects of acupuncture & electrical stimulation of the ear lobules. It is only now, in 2019 that we have discovered 2–5 minute high frequency stimulation of the ear lobule inhibits cancer activity for 1– 4 hours post stimulation. Although the procedure is extremely simple. First take optimal dose of Vitamin D3, which has the most essential 10 unique beneficial factors required for every human cell activity. Next, apply high frequency stimulation to ear lobule while the worst ear lobule is held by all fingers with vibrator directly touching the surface of the worst ear lobule, preferably after patient repeatedly takes optimal dose of Vitamin D3. When the worst ear lobule is held between thumb & index fingers and applying mechanical stimulation of 250 ~ 500 mechanical vibration/second for 2 ~ 5 minutes using an electrical vibrator, there is rapid disappearance of cancer activity in both the brain and rest of the body for short time duration 1 ~ 4 hours. The effect often increases by additional pressure by holding fingers. As of May 2019, the Author found that many people from various regions of the world developed early stages of multiple cancers. For evaluation of this study, U. S. patented Bi-Digital O-Ring Test (BDORT) was used which was developed by the Author while doing his Graduate experimental physics research at Colombia University. BDORT was found to be most essential for determining the beneficial effects as well as harmful effects of any substance or treatment. Using BDORT, Author was the first to recognize severe increasing mid-backache was an early sign of pancreatic cancer of President of New York State Board of Medicine after top pain specialists failed to detect the cause after 3 years of effort, while the BDORT showed early stages of cancer whereas conventional X-Ray of the pancreas did not show any cancer image until 2 months after Author detected with BDORT. For example, the optimal dose of the banana is usually about 2.0 - 2.5 millimeters cross section of the banana. A whole banana is more than 50 ~ 100 times the optimal dose. Any substance eaten in more than 25 times of its optimal dose becomes highly toxic and creates DNA mutations which can cause multiple malignancies in the presence of strong electro-magnetic field. With standard medication given by doctor, patients often become sick and they are unable to reduce body weight, unless medication is reduced or completely stopped. When the amount of zinc is very high, DNA often becomes unstable and multiple cancers can grow rapidly in the presence of strong electromagnetic field. Large amount of Vitamin C from regular orange or orange juice inhibit the most important Vitamin D3 effects. At least 3 kinds of low Vitamin C oranges will not inhibit Vitamin D3. Since B12 particularly methyl cobalamin which is a red small tablet is known to improve brain circulation very significantly we examined its effect within 20 seconds of oral intake we found the following very significant changes. Acetylcholine in both sides of the brain often increases over 4,500 ng. Longevity gene Sirtuin 1 level increases significantly for short time of few hours. Thymosin α1 and Thymosinβ4 both increase to over 1500 ng from 20 ng or less.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Danilo Reymão Moreira ◽  
Ana Carolina Musa Gonçalves Uberti ◽  
Antonio Rafael Quadros Gomes ◽  
Michelli Erica Souza Ferreira ◽  
Aline da Silva Barbosa ◽  
...  

AbstractThe present study aimed to evaluate the effects of dexamethasone on the redox status, parasitemia evolution, and survival rate of Plasmodium berghei-infected mice. Two-hundred and twenty-five mice were infected with Plasmodium berghei and subjected to stimulation or inhibition of NO synthesis. The stimulation of NO synthesis was performed through the administration of L-arginine, while its inhibition was made by the administration of dexamethasone. Inducible NO synthase (iNOS) inhibition by dexamethasone promoted an increase in the survival rate of P. berghei-infected mice, and the data suggested the participation of oxidative stress in the brain as a result of plasmodial infection, as well as the inhibition of brain NO synthesis, which promoted the survival rate of almost 90% of the animals until the 15th day of infection, with possible direct interference of ischemia and reperfusion syndrome, as seen by increased levels of uric acid. Inhibition of brain iNOS by dexamethasone caused a decrease in parasitemia and increased the survival rate of infected animals, suggesting that NO synthesis may stimulate a series of compensatory redox effects that, if overstimulated, may be responsible for the onset of severe forms of malaria.


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