scholarly journals Regional brain stem activations during capsaicin inhalation using functional magnetic resonance imaging in humans

2019 ◽  
Vol 121 (4) ◽  
pp. 1171-1182 ◽  
Author(s):  
Tara G. Bautista ◽  
Jennifer Leech ◽  
Stuart B. Mazzone ◽  
Michael J. Farrell
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Brain Stem ◽  
Animal Studies ◽  
Functional Brain Imaging ◽  
Ventrolateral Medulla ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Airway Irritation

Coughing is an airway protective behavior elicited by airway irritation. Animal studies show that airway sensory information is relayed via vagal sensory fibers to termination sites within dorsal caudal brain stem and thereafter relayed to more rostral sites. Using functional magnetic resonance imaging (fMRI) in humans, we previously reported that inhalation of the tussigenic stimulus capsaicin evokes a perception of airway irritation (“urge to cough”) accompanied by activations in a widely distributed brain network including the primary sensorimotor, insular, prefrontal, and posterior parietal cortices. Here we refine our imaging approach to provide a directed survey of brain stem areas activated by airway irritation. In 15 healthy participants, inhalation of capsaicin at a maximal dose that elicits a strong urge to cough without behavioral coughing was associated with activation of medullary regions overlapping with the nucleus of the solitary tract, paratrigeminal nucleus, spinal trigeminal nucleus and tract, cardiorespiratory regulatory areas homologous to the ventrolateral medulla in animals, and the midline raphe. Interestingly, the magnitude of activation within two cardiorespiratory regulatory areas was positively correlated ( r2 = 0.47, 0.48) with participants’ subjective ratings of their urge to cough. Capsaicin-related activations were also observed within the pons and midbrain. The current results add to knowledge of the representation and processing of information regarding airway irritation in the human brain, which is pertinent to the pursuit of novel cough therapies. NEW & NOTEWORTHY Functional brain imaging in humans was optimized for the brain stem. We provide the first detailed description of brain stem sites activated in response to airway irritation. The results are consistent with findings in animal studies and extend our foundational knowledge of brain processing of airway irritation in humans.

Functional MRI: Finally, a Textbook for All of Us

2005 ◽  
Vol 11 (4) ◽  
pp. 498-499
Author(s):  
Stephen M. Rao
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Recovery Of Function ◽  
Mri Contrast Agents ◽  
Functional Brain Imaging ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Functional Brain ◽  
Medical Centers

Functional Magnetic Resonance Imaging, by Scott A. Huettel, Allen W. Song and Gregory McCarthy. 2004. Sunderland, MA: Sinauer Associates, Inc. 492 pp., $79.95.Imaging the human brain at work was revolutionized by the discovery of functional magnetic resonance imaging (fMRI) in the early 1990s. Prior to this, functional brain mapping was limited to a handful of medical centers capable of conducting positron emission tomography (PET) scans of regional cerebral blood flow. With the discovery of the endogenous blood oxygen level dependent (BOLD) contrast method in 1992, fMRI “democratized” the field by expanding the number of medical centers capable of functional brain imaging. Today, over a thousand peer-reviewed fMRI articles are published each year, many in high profile scientific journals that receive additional attention by the popular press. This explosion of scientific research is relatively easy to understand: fMRI can be conducted on the majority of the 6,600 MRI scanners installed in the US alone, the technique is completely noninvasive since it does not require injection of MRI contrast agents or radiopharmaceuticals, and, as an added benefit, fMRI provides a unique combination of high spatial and temporal resolution. Not surprisingly, fMRI is the imaging technique of choice for mapping cognitive and emotional systems in the healthy brain. More recently, fMRI has been applied to clinical populations to identify the brain mechanisms governing recovery of function from stroke and head trauma, detect early brain changes in neurodegenerative conditions, and measure the effects of psychoactive medications on neurodevelopmental disorders, as examples. fMRI provides a complementary method for testing neuropsychological models of brain function derived from other methods (lesion, electrophysiology).

Functional Magnetic Resonance Imaging Measures of Blood Flow Patterns in the Human Auditory Cortex in Response to Sound

1998 ◽  
Vol 41 (3) ◽  
pp. 538-548 ◽  
Author(s):  
Sean C. Huckins ◽  
Christopher W. Turner ◽  
Karen A. Doherty ◽  
Michael M. Fonte ◽  
Nikolaus M. Szeverenyi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Speech Stimuli ◽  
Complex Stimuli ◽  
Scanning Session ◽  
Auditory Research

Functional Magnetic Resonance Imaging (fMRI) holds exciting potential as a research and clinical tool for exploring the human auditory system. This noninvasive technique allows the measurement of discrete changes in cerebral cortical blood flow in response to sensory stimuli, allowing determination of precise neuroanatomical locations of the underlying brain parenchymal activity. Application of fMRI in auditory research, however, has been limited. One problem is that fMRI utilizing echo-planar imaging technology (EPI) generates intense noise that could potentially affect the results of auditory experiments. Also, issues relating to the reliability of fMRI for listeners with normal hearing need to be resolved before this technique can be used to study listeners with hearing loss. This preliminary study examines the feasibility of using fMRI in auditory research by performing a simple set of experiments to test the reliability of scanning parameters that use a high resolution and high signal-to-noise ratio unlike that presently reported in the literature. We used consonant-vowel (CV) speech stimuli to investigate whether or not we could observe reproducible and consistent changes in cortical blood flow in listeners during a single scanning session, across more than one scanning session, and in more than one listener. In addition, we wanted to determine if there were differences between CV speech and nonspeech complex stimuli across listeners. Our study shows reproducibility within and across listeners for CV speech stimuli. Results were reproducible for CV speech stimuli within fMRI scanning sessions for 5 out of 9 listeners and were reproducible for 6 out of 8 listeners across fMRI scanning sessions. Results of nonspeech complex stimuli across listeners showed activity in 4 out of 9 individuals tested.

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