1. Volume 115, Issue 6, Pages 1353-1362 (December 1998)
Identification and characterization of cerebral cortical response to esophageal mucosal acid exposure and distention 
Mark K. Kern*,‡, Rasmus M. Birn*,§, Safwan Jaradeh*,∥, Andrzej Jesmanowicz*,§, Robert W. Cox§, James S. Hyde§, Reza Shaker*,‡¶ 
Gastroenterology 
Volume 115, Issue 6, Pages (December 1998)
DOI: /S (98)
Copyright © 1998 American Gastroenterological Association Terms and Conditions

2. Fig. 1
Comparison of an idealized waveform representing alternating intervals of no esophageal distention and distention. (A) An example of a lack of FMRI signal changes in an inactive area of the cerebral cortex during esophageal balloon distention. (B) An example of FMRI signal changes in an activated area of the cerebral cortex during esophageal balloon distention.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

3. Fig. 2
Three examples of the phase shifting method of determining the correlation of stimulus with cerebral cortical FMRI activity. (A) An idealized waveform in exact synchrony with intervals of esophageal balloon distention is used for correlation with all FMRI time series. With a correlation threshold of 0.7, little signal activity is correlated to the idealized waveform, as illustrated by the small number of activated (colored) pixels in the sagittal, axial, and coronal anatomic images. (B) Result of correlations of all FMRI time series with an idealized waveform temporally shifted 5 seconds after the initiation of esophageal distention. Distinct regions of activation are seen as overlaid colored areas on the anatomic images. (C) Correlations at the 0.7 threshold for a 20-second phase shifted idealized waveform show no correlated regions of activation.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

4. Fig. 3
Schematic representation of the cerebral cortical FMRI temporal characteristics measured in our study. A to B, Activation latency; B to C, activation to maximum signal; D to E, deactivation latency; E to F, deactivation to baseline.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

5. Fig. 4
(A) Regions of activation for normalized brain volume using the Talairach coordinate system in the midsagittal, midaxial, and midcoronal planes for all acid perfusion scans in all subjects. (B) An average (mean ± SE) response time course with the signal intensity data normalized to the minimum intensity value of each activated pixel time course. Esophageal acidification elicited an average increase of 7.1% ± 1.4% above the baseline FMRI signal intensity in those regions shown as active in the anatomic images in A.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

6. Fig. 5
Regions of activation for normalized brain volume using the Talairach coordinate system in the midsagittal, midaxial, and midcoronal planes are shown in A for all esophageal distention preperfusion scans in all subjects. An average (mean ± SE) response time course is shown in B with the signal intensity data normalized to the minimum intensity value of each activated pixel time course. Esophageal distention elicited an average increase of 7.6% ± 1.5% above the baseline FMRI signal intensity in those regions shown as active in the anatomic images shown in A.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

7. Fig. 6
Temporal characteristics of FMRI response to esophageal balloon distention were significantly different than those of intraluminal esophageal acidification. In all measured parameters, i.e., activation latency, activation to peak, and deactivation periods for esophageal acidification, were significantly longer than those of balloon distention (+P < 0.05). Saline perfusion did not elicit an identifiable FMRI signal change.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

8. Fig. 7
Effect of esophageal mucosal acid exposure on FMRI response to esophageal balloon distention. Among the measured parameters, the activation latency for post–acid perfusion, esophageal balloon distention was significantly different from that of pre–acid perfusion activation latency (*P < 0.05). On the contrary, saline perfusion did not alter the temporal characteristics of the FMRI response to esophageal balloon distention compared with pre–saline perfusion values.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions