Reproducibility of swallow-induced cortical BOLD positive and negative fMRI activity.
ABSTRACT Functional MRI (fMRI) studies have demonstrated that a number of brain regions (cingulate, insula, prefrontal, and sensory/motor cortices) display blood oxygen level-dependent (BOLD) positive activity during swallow. Negative BOLD activations and reproducibility of these activations have not been systematically studied. The aim of our study was to investigate the reproducibility of swallow-related cortical positive and negative BOLD activity across different fMRI sessions. We studied 16 healthy volunteers utilizing an fMRI event-related analysis. Individual analysis using a general linear model was used to remove undesirable signal changes correlated with motion, white matter, and cerebrospinal fluid. The group analysis used a mixed-effects multilevel model to identify active cortical regions. The volume and magnitude of a BOLD signal within each cluster was compared between the two study sessions. All subjects showed significant clustered BOLD activity within the known areas of cortical swallowing network across both sessions. The cross-correlation coefficient of percent fMRI signal change and the number of activated voxels across both positive and negative BOLD networks were similar between the two studies (r ≥ 0.87, P < 0.0001). Swallow-associated negative BOLD activity was comparable to the well-defined "default-mode" network, and positive BOLD activity had noticeable overlap with the previously described "task-positive" network. Swallow activates two parallel cortical networks. These include a positive and a negative BOLD network, respectively, correlated and anticorrelated with swallow stimulus. Group cortical activity maps, as well as extent and amplitude of activity induced by volitional swallowing in the cortical swallowing network, are reproducible between study sessions.
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ABSTRACT: Background and Objectives: Central and peripheral neural regulation of swallowing and aero-digestive reflexes is unclear in human neonates. Functional near infrared spectroscopy (NIRS) is a noninvasive method to measure changes in oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbD). Pharyngo-esophageal manometry permits evaluation of aero-digestive reflexes. Modalities were combined to investigate feasibility and to test neonatal fronto-parietal cortical changes during pharyngo-esophageal (visceral) stimulation and/or swallowing. Methods: Ten neonates (45.6±3.0wks PMA, 4.1±0.5kg) underwent novel pharyngo-esophageal manometry concurrent with NIRS. To examine esophagus-brain interactions, we analyzed cortical hemodynamic response (HDR) latency and durations during aerodigestive provocation and esophageal reflexes. Data are presented as mean ± SE or %. Results: HDR rates were 8.84 times more likely with basal spontaneous deglutition compared to sham stimuli (P=0.004). Of 182 visceral stimuli, 95% were analyzable for esophageal responses, 38% for HDR, and 36% for both. Of analyzable HDR (N=70): a) HbO concentration (µmol/L) baseline 1.5±0.7 vs. 3.7±0.7 post- stimulus was significant (P=0.02) b) HbD concentration (µmol/L) between baseline 0.1±0.4 vs. post-stimulus -0.5±0.4 was not significant (P=0.73). c) Hemispheric lateralization was 21% left only, 29% right only, and 50% bilateral. During concurrent esophageal and NIRS responses (N=66): a) Peristaltic reflexes were present in 74% and HDR in 61%. b) HDR was 4.75 times more likely with deglutition reflex vs. secondary peristaltic reflex (P=0.016). Conclusions: Concurrent NIRS with visceral stimulation is feasible in neonates, and fronto-parietal cortical activation is recognized. Deglutition contrasting with secondary peristalsis is related to cortical activation; thus, implicating higher hierarchical aerodigestive protective functional neural networks.AJP Gastrointestinal and Liver Physiology 05/2014; 307(1). DOI:10.1152/ajpgi.00350.2013 · 3.74 Impact Factor
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ABSTRACT: We speculate that cortical reactions evoked by swallowing activity may be abnormal in patients with central infarction with dysphagia. The present study aimed to detect functional imaging features of cerebral cortex in central dysphagia patients by using blood oxygen level-dependent functional magnetic resonance imaging techniques. The results showed that when normal controls swallowed, primary motor cortex (BA4), insula (BA13), premotor cortex (BA6/8), supramarginal gyrus (BA40), and anterior cingulate cortex (BA24/32) were activated, and that the size of the activated areas were larger in the left hemisphere compared with the right. In recurrent cerebral infarction patients with central dysphagia, BA4, BA13, BA40 and BA6/8 areas were activated, while the degree of activation in BA24/32 was decreased. Additionally, more areas were activated, including posterior cingulate cortex (BA23/31), visual association cortex (BA18/19), primary auditory cortex (BA41) and parahippocampal cortex (BA36). Somatosensory association cortex (BA7) and left cerebellum in patients with recurrent cerebral infarction with central dysphagia were also activated. Experimental findings suggest that the cerebral cortex has obvious hemisphere lateralization in response to swallowing, and patients with recurrent cerebral infarction with central dysphagia show compensatory recombination phenomena of neurological functions. In rehabilitative treatment, using the favorite food of patients can stimulate swallowing through visual, auditory, and other nerve conduction pathways, thus promoting compensatory recombination of the central cortex functions.Neural Regeneration Research 03/2015; 10(3):490-7. DOI:10.4103/1673-5374.153701 · 0.23 Impact Factor
Clinical Gastroenterology and Hepatology 09/2014; 12(12). DOI:10.1016/j.cgh.2014.08.031 · 6.53 Impact Factor