Identification of a respiratory related area in the rat insular cortex

2000 ◽  
Vol 78 (7) ◽  
pp. 582-586 ◽  
Author(s):  
Vjacheslav G Aleksandrov ◽  
Nina P Aleksandrova ◽  
Vitaly A Bagaev
Keyword(s):  
Gastric Motility ◽  
Anterior Commissure ◽  
Insular Cortex ◽  
Respiratory Cycle ◽  
Cycle Duration ◽  
Related Area ◽  
Excitatory Responses ◽  
Histological Location ◽  
Respiratory Area ◽  
Respiratory Responses

The aim of this study was to map areas within the rat insular cortex from which respiratory responses originate and compare those sites with gastrointestinal control regions. The insular cortex was systematically microstimulated and histological location of responsive sites determined. Increased inspiratory airflow and decreased respiratory cycle duration were considered to be respiratory excitatory responses. The responses were localized in dysgranular and agranular insular cortex at levels caudal to the joining of the anterior commissure. More rostrally, respiratory inhibitory responses were elicited: these were manifested as a decrease in inspiratory airflow without a significant alteration in respiratory cycle duration. Respiratory inhibitory responses were usually accompanied by changes in gastric motility. These results suggest that the respiratory area in the rat insular cortex consist of two distinct zones which overlap a region modulating the gastrointestinal activity.Key words: rats, insular cortex, respiration, gastrointestinal motility.

scholarly journals Manganese-enhanced MRI depicts a reduction in brain responses to nociception upon mTOR inhibition in chronic pain rats

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Myeounghoon Cha ◽  
Songyeon Choi ◽  
Kyeongmin Kim ◽  
Bae Hwan Lee
Keyword(s):  
Chronic Pain ◽  
Nerve Injury ◽  
Pain Perception ◽  
Imaging Techniques ◽  
Insular Cortex ◽  
Pain Modulation ◽  
Anterior Cingulate ◽  
Related Area ◽  
Mtor Inhibition ◽  
The Brain

AbstractNeuropathic pain induced by a nerve injury can lead to chronic pain. Recent studies have reported hyperactive neural activities in the nociceptive-related area of the brain as a result of chronic pain. Although cerebral activities associated with hyperalgesia and allodynia in chronic pain models are difficult to represent with functional imaging techniques, advances in manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) could facilitate the visualization of the activation of pain-specific neural responses in the cerebral cortex. In order to investigate the alleviation of pain nociception by mammalian target of rapamycin (mTOR) modulation, we observed cerebrocortical excitability changes and compared regional Mn2+ enhancement after mTOR inhibition. At day 7 after nerve injury, drugs were applied into the intracortical area, and drug (Vehicle, Torin1, and XL388) effects were compared within groups using MEMRI. Therein, signal intensities of the insular cortex (IC), primary somatosensory cortex of the hind limb region, motor cortex 1/2, and anterior cingulate cortex regions were significantly reduced after application of mTOR inhibitors (Torin1 and XL388). Furthermore, rostral-caudal analysis of the IC indicated that the rostral region of the IC was more strongly associated with pain perception than the caudal region. Our data suggest that MEMRI can depict pain-related signal changes in the brain and that mTOR inhibition is closely correlated with pain modulation in chronic pain rats.

Relaxin counteracts the altered gastric motility of dystrophic (mdx) mice: functional and immunohistochemical evidence for the involvement of nitric oxide

2011 ◽  
Vol 300 (2) ◽  
pp. E380-E391 ◽  
Author(s):  
M. G. Vannucchi ◽  
R. Garella ◽  
G. Cipriani ◽  
M. C. Baccari
Keyword(s):  
Nitric Oxide ◽  
Gastric Motility ◽  
Electrical Field Stimulation ◽  
Gastric Fundus ◽  
Mdx Mice ◽  
No Production ◽  
Contractile Responses ◽  
Lower Amplitude ◽  
Immunohistochemical Evidence ◽  
Excitatory Responses

Impaired gastric motility ascribable to a defective nitric oxide (NO) production has been reported in dystrophic (mdx) mice. Since relaxin upregulates NO biosynthesis, its effects on the motor responses and NO synthase (NOS) expression in the gastric fundus of mdx mice were investigated. Mechanical responses of gastric strips were recorded via force displacement transducers. Evaluation of the three NOS isoforms was performed by immunohistochemistry and Western blot. Wild-type (WT) and mdx mice were distributed into three groups: untreated, relaxin pretreated, and vehicle pretreated. In strips from both untreated and vehicle-pretreated animals, electrical field stimulation (EFS) elicited contractile responses that were greater in mdx than in WT mice. In carbachol-precontracted strips, EFS induced fast relaxant responses that had a lower amplitude in mdx than in WT mice. Only in the mdx mice did relaxin depress the amplitude of the neurally induced excitatory responses and increase that of the inhibitory ones. In the presence of l-NNA, relaxin was ineffective. In relaxin-pretreated mdx mice, the amplitude of the EFS-induced contractile responses was decreased and that of the fast relaxant ones was increased compared with untreated mdx animals. Responses to methacholine or papaverine did not differ among preparations and were not influenced by relaxin. Immunohistochemistry and Western blotting showed a significant decrease in neuronal NOS expression and content in mdx compared with WT mice, which was recovered in the relaxin-pretreated mdx mice. The results suggest that relaxin is able to counteract the altered contractile and relaxant responses in the gastric fundus of mdx mice by upregulating nNOS expression.

scholarly journals Responses of Neurons in the Insular Cortex to Gustatory, Visceral, and Nociceptive Stimuli in Rats

1998 ◽  
Vol 79 (5) ◽  
pp. 2535-2545 ◽  
Author(s):  
Takamitsu Hanamori ◽  
Takato Kunitake ◽  
Kazuo Kato ◽  
Hiroshi Kannan
Keyword(s):  
Electrical Stimulation ◽  
Intravenous Injection ◽  
Anterior Commissure ◽  
Insular Cortex ◽  
Inhibitory Response ◽  
Inhibitory Neurons ◽  
Excitatory Response ◽  
Tail Pinch ◽  
Posterior Tongue ◽  
Stimulation Of

Hanamori, Takamitsu, Takato Kunitake, Kazuo Kato, and Hiroshi Kannan. Responses of neurons in the insular cortex to gustatory, visceral, and nociceptive stimuli in rats. J. Neurophysiol. 79: 2535–2545, 1998. Extracellular unit responses to baroreceptor and chemoreceptor stimulation, gustatory stimulation of the posterior tongue, electrical stimulation of the superior laryngeal (SL) nerve, and tail pinch were recorded from the insular cortex of anesthetized and paralyzed rats. Forty-three neurons identified responded to stimulation by at least one of the stimuli used in the present study. Of the 43 neurons, 33 responded to tail pinch, and the remaining 10 had no response; 18 showed an excitatory response, and 15 showed an inhibitory response. Of the 43 neurons, 35 responded to electrical stimulation of the SL nerve; 27 showed an excitatory response, and 8 showed an inhibitory response. Of the 20 neurons that responded to baroreceptor stimulation by an intravenous injection of methoxamine hydrochloride (Mex), 11 were excitatory and 9 were inhibitory. Twenty-seven neurons were responsive to an intravenous injection of sodium nitroprusside (SNP); 10 were excitatory and 17 were inhibitory. Ten neurons were excited and 16 neurons were inhibited by arterial chemoreceptor stimulation by an intravenous injection of sodium cyanide (NaCN). Twenty-six neurons were responsive to at least one of the gustatory stimuli (1.0 M NaCl, 30 mM HCl, 30 mM quinine HCl, and 1.0 M sucrose): four to six excitatory neurons and three to nine inhibitory neurons for each stimulus. A large number of the neurons (42/43) received convergent inputs from more than one stimulus among the nine stimuli used in the present study. Most neurons (38/43) were responsive to two or more stimulus groups when the natural stimuli used in the present study are grouped into three, gustatory, visceral, and nociceptive stimuli. The neurons recorded were located in the insular cortex between 2.8 mm anterior and 1.1 mm posterior to the anterior edge of the joining of the anterior commissure (AC); the mean location was 1.0 mm ( n = 43) anterior to the AC. This indicates that most of the neurons identified in the present study were located in the region posterior to the taste area and anterior to the visceral area in the insular cortex. These results indicate that the insular cortex neurons distributing between the taste area and the visceral area receive convergent inputs from baroreceptor, chemoreceptor, gustatory, and nociceptive organs and may have roles in taste aversion or in regulation of visceral responses.

Visceral-related area in the rat insular cortex

2006 ◽  
Vol 125 (1-2) ◽  
pp. 16-21 ◽  
Author(s):  
V. Bagaev ◽  
V. Aleksandrov
Keyword(s):  
Insular Cortex ◽  
Related Area

scholarly journals Respiration during feeding on solid food: alterations in breathing during mastication, pharyngeal bolus aggregation, and swallowing

2008 ◽  
Vol 104 (3) ◽  
pp. 674-681 ◽  
Author(s):  
Koichiro Matsuo ◽  
Karen M. Hiiemae ◽  
Marlis Gonzalez-Fernandez ◽  
Jeffrey B. Palmer
Keyword(s):  
Healthy Volunteers ◽  
Solid Food ◽  
Respiratory Cycle ◽  
Cycle Duration ◽  
Healthy Individuals ◽  
Expiratory Phase ◽  
Solid Foods ◽  
Respiratory Airflow ◽  
Food Transport ◽  
Better Than

During feeding, solid food is chewed and propelled to the oropharynx, where the bolus gradually aggregates while the larynx remains open and breathing continues. The aggregated bolus in the valleculae is exposed to respiratory airflow, yet aspiration is rare in healthy individuals. The mechanism for preventing aspiration during bolus aggregation is unclear. One possibility is that alterations in the pattern of respiration during feeding could help prevent inhalation of food from the pharynx. We hypothesized that respiration was inhibited during bolus aggregation in the valleculae. Videofluorography was performed on 10 healthy volunteers eating solid foods with barium. Respiration was monitored concurrently with plethysmography and nasal air pressure. The timing of events during mastication, food transport, pharyngeal bolus aggregation, and swallowing were measured in relation to respiration. Respiratory cycle duration decreased during chewing ( P < 0.001) but increased with swallowing ( P < 0.001). During 66 recordings of vallecular bolus aggregation, there was inspiration in 8%, expiration in 41%, a pause in breathing in 17%, and multiple phases (including inspiration) in 35%. Out of 98 swallows, 47% started in the expiratory phase and 50% started during a pause in breathing, irrespective of bolus aggregation in the valleculae. Plethysmography was better than nasal manometry for determining the end of active expiration during feeding and swallowing with solid food. The hypothesis is rejected in that respiration was not inhibited during bolus aggregation. These findings suggest that airflow through the pharynx does not have a role in preventing aspiration during bolus aggregation in the oropharynx.

Microstimulation of the medullary reticular formation during fictive locomotion

1994 ◽  
Vol 71 (1) ◽  
pp. 229-245 ◽  
Author(s):  
M. C. Perreault ◽  
S. Rossignol ◽  
T. Drew
Keyword(s):  
Reticular Formation ◽  
Afferent Feedback ◽  
Medial Longitudinal Fasciculus ◽  
Cycle Duration ◽  
Fictive Locomotion ◽  
Medullary Reticular Formation ◽  
Locomotor Rhythm ◽  
Locomotor Pattern ◽  
Latency Response ◽  
Excitatory Responses

1. The present study was designed to determine the effects of microstimulation of the medullary reticular formation (MRF) on the locomotor activity of the cat in the absence of phasic afferent feedback from the limbs. To this end, both short (33 ms) and long (200 ms) trains of stimuli (trains of 0.2-ms pulses at 330 Hz, 35 microA) were applied at 43 loci in the MRF (P:6–12 mm; L:0.5–1.5 mm), and in 3 loci in the medial longitudinal fasciculus (P7.5, L < 0.5 mm) during fictive locomotion in the decerebrate and paralyzed cat. The locomotor pattern was monitored by recording the activity of representative flexor and extensor muscle nerves from each of the four limbs. 2. Short trains of stimuli evoked transient excitatory and/or inhibitory responses in extensor and flexor nerves of each limb that were incorporated into the locomotor pattern. In the majority of sites, excitatory responses were obtained in the motor nerves to both flexor and extensor muscles of the fore- and hindlimbs. The exception to this rule was the ipsilateral triceps, in which the predominant response was inhibitory. The amplitude of these responses was dependent on the time of the locomotor cycle at which the stimulus was delivered, and it was always maximum during the period of activity of the respective nerve. 3. The shortest latency response in the nerves to different muscles of the forelimb averaged between 5.6 and 7.3 ms; for the hindlimbs the values were between 6.9 and 9.3 ms. 4. Changing the depth at which the stimulation was applied in any one trajectory usually produced changes only in the amplitude of the evoked responses but occasionally also caused a change in the sign of these responses, especially in the most ventral regions of the MRF. 5. At 72% of the loci (31/43), short trains of stimulation also changed the duration of the activity in the recorded nerves. These changes were often (20/31 loci) sufficiently strong to alter the duration of the overall locomotor cycle. If one considers only the largest changes produced at each locus, stimulation during the period of ipsilateral extensor activity produced an average reduction in the ipsilateral locomotor cycle duration of 12.8 +/- 8.8% (mean +/- SD), whereas stimulation when the ipsilateral flexor nerve was active produced an average increase in locomotor cycle duration of 27.1 +/- 20.8%. 6. Long trains of stimuli produced similar but larger effects than the shorter trains and always reset the locomotor rhythm.(ABSTRACT TRUNCATED AT 400 WORDS)

Retrofacial lesions: effects on CO2-sensitive phrenic and sympathetic nerve activity

1992 ◽  
Vol 73 (4) ◽  
pp. 1317-1325 ◽  
Author(s):  
E. E. Nattie ◽  
C. Blanchford ◽  
A. Li
Keyword(s):  
Blood Pressure ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Respiratory Cycle ◽  
Ventrolateral Medulla ◽  
Cycle Duration ◽  
Nerve Activity ◽  
Retrotrapezoid Nucleus ◽  
Predominant Effect

We made unilateral chemical (10- or 50-nl microinjections; 4.7 mM kainic acid) or electrolytic (5–15 mA; 15 s) lesions in a region of the rostral ventrolateral medulla (VLM) caudal to the retrotrapezoid nucleus in 10 decerebrate, paralyzed, vagotomized, and servo-ventilated cats. The lesions were 3.0–4.2 mm lateral to the midline, within 2 mm caudal to the facial nucleus, and within 2.5 mm of the VLM surface. Four control injections (mock cerebrospinal fluid and fluorescent beads alone) produced small and inconsistent effects over 3–5 h. The predominant effect of the lesions was a significant decrease in baseline integrated phrenic nerve amplitude (PNA) (apnea in 2 cases), total respiratory cycle duration, and the response to increased CO2 (slope < 15% of control in 3 cases). The respiratory-related peak amplitude of the integrated sympathetic signal, blood pressure, and the sympathetic nerve activity response to CO2 were also decreased after the majority of lesions. Not all lesions produced all effects, and some lesions resulted in increased PNA and respiratory cycle duration. The lesioned region appears functionally to represent a caudal extension of the retrotrapezoid nucleus containing neurons necessary for normal baseline PNA and CO2 sensitivity. In addition, it contains neurons involved in the determination of resting respiratory frequency and normal sympathetic activity and blood pressure. The pattern of mixed responses among animals suggests that a heterogeneity of function is present within a relatively small VLM region.

Bifurcations of the respiratory pattern produced with phasic vagal stimulation in the rat

1993 ◽  
Vol 75 (2) ◽  
pp. 912-926 ◽  
Author(s):  
M. Sammon ◽  
J. R. Romaniuk ◽  
E. N. Bruce
Keyword(s):  
Time Window ◽  
Respiratory Cycle ◽  
Respiratory Pattern ◽  
Cycle Duration ◽  
Return Maps ◽  
Inspiratory Activity ◽  
Dynamic Processing ◽  
Low Dimensional ◽  
Electrical Stimuli ◽  
Low Amplitude

Geometric methods from nonlinear dynamics are employed to evaluate dynamic processing of vagal afferent information by the respiratory central pattern generator (RCPG). While measuring airflow and diaphragm EMG, we applied brief electrical stimuli (40- to 130-ms duration) to one afferent vagus of bilaterally vagotomized urethan-anesthetized rats during every breath at various phases of the respiratory cycle. Stimuli applied during early or late inspiration of every breath evoke highly predictable one-dimensional responses: reversible (graded inhibition) or irreversible (off-switching) inhibition of inspiratory activity, respectively. Stimulation during midinspiration produces higher-dimensional oscillations that wander unpredictably over a continuum of graded inhibition and off-switching; "spiral" attractors and "horseshoe" return maps at this phase are characteristic of Silnikov's bifurcation. Stimuli applied during early expiration always prolonged expiratory duration, but those delivered during midexpiration evoked unpredictable wandering between prolongations and shortening of expiratory duration. A narrow time window surrounds the expiratory-inspiratory (E-I) transition, where stimuli elicit either breaths of short duration and low amplitude (irreversible E-I transition, decreased total respiratory cycle duration) or transient bursts of inspiratory activity at the E-I transition followed by a prolonged breath (reversible E-I transition, increased total respiratory cycle duration). We conclude that RCPG "gating" of and adaptation to vagal feedback combine to produce complex breath-to-breath dynamics in the rat that are consistent with low-dimensional chaos.

Retrotrapezoid nucleus glutamate injections: long-term stimulation of phrenic activity

1994 ◽  
Vol 76 (2) ◽  
pp. 760-772 ◽  
Author(s):  
E. E. Nattie ◽  
A. Li
Keyword(s):  
Blood Pressure ◽  
Firing Rate ◽  
Single Unit ◽  
Respiratory Cycle ◽  
Cycle Duration ◽  
Retrotrapezoid Nucleus ◽  
Nerve Signal ◽  
Subsequent Response ◽  
Blood Pressure Responses

In chloralose-urethan anesthetized, paralyzed, vagotomized, glomectomized, and servo-ventilated cats we examined the effects of 10 nl of glutamate (10 mM, 100 mM, and 1 M) injected unilaterally over 60 s into the region of the retrotrapezoid nucleus (RTN). Seven 10 mM glutamate injections produced no consistent effects on the amplitude of the integrated phrenic nerve signal, respiratory cycle duration, or blood pressure. Ten 100 mM injections consistently increased integrated phrenic amplitude significantly from a baseline average of 31 +/- 2% (SE) of maximum to a peak response average of 50 +/- 3% of maximum. This effect was long lasting (45.6 +/- 8.6 min). Blood pressure responses were variable. Seven 1 M glutamate injections consistently decreased integrated phrenic amplitude significantly from a baseline average for all injections of 29 +/- 3% of maximum to a peak average of 20 +/- 5% of maximum. Respiratory cycle duration and blood pressure responses were variable. Prior injection into the RTN of 10 nl of 100 mM kynurenic acid attenuated the subsequent response of the integrated phrenic amplitude to injection of 10 nl of glutamate at the same site. Comparison of glutamate (10 nl, 100 mM) injected over 60 s vs. 30 ms showed that the prolonged increase in phrenic activity was related to the longer-duration (60-s) injections and that RTN single units were stimulated for up to 5 min on average after the 60-s injection with one unit showing an increase in firing rate over 40 min. After the 30-ms injection, integrated phrenic amplitude and RTN unit mean firing rate were increased for the first two breaths and at 5 min after the injection. We conclude that glutamate injected into the RTN increases local single-unit firing rate and the amplitude of the integrated phrenic activity. Injections made over 60 s result in prolonged phrenic stimulation and, in some cases, in RTN single-unit firing rate.

Definition of a Stereotactic 3-Dimensional Magnetic Resonance Imaging Template of the Human Insula

2012 ◽  
Vol 72 (1) ◽  
pp. ons35-ons46 ◽  
Author(s):  
Afif Afif ◽  
Guillaume Becq ◽  
Patrick Mertens
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Morphometric Analysis ◽  
Reference System ◽  
Anterior Commissure ◽  
Insular Cortex ◽  
Close Correlation ◽  
Resonance Imaging ◽  
Posterior Commissure ◽  
3 Dimensional

Abstract Background: This study proposes a 3-dimensional (3-D) template of the insula in the bicommissural reference system with posterior commissure (PC) as the center of coordinates. Objective: Using the bicommissural anterior commissure (AC)-PC reference system, this study aimed to define a template and design a method for the 3-D reconstruction of the human insula that may be used at an individual level during stereotactic surgery. Methods: Magnetic resonance imaging (MRI)-based morphometric analysis was performed on 100 cerebral cortices with normal insulae based on a 3-step procedure: Step 1: AC-PC reference system-based reconstruction of the insula from the 1-mm thick 3-D T1-weighted MRI slices. Step 2: Digitalization and superposition of the data obtained in the 3 spatial planes. Step 3: Representation of pixels as colors on a scale corresponding to the probability of localization of each insular anatomic component. Results: The morphometric analysis of the insula confirmed our previously reported findings of a more complex shape delimited by 4 peri-insular sulci. A very significant correlation between the coordinates of the main insular structures and the length of AC-PC was demonstrated. This close correlation allowed us to develop a method that allows the 3-D reconstruction of the insula from MRI slices and only requires the localization of AC and PC. This process defines an area deemed to contain insula with 100% probability. Conclusion: This 3-D reconstruction of the insula should be useful to improve its localization and other cortical areas and allow the differentiation of insular cortex from opercular cortex.

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