Qualitative and Quantitative Measurement of Human Brain Activity Using Pixel Subtraction Algorithm

PURPOSE: To develop an automated quantification program, which is called FALBA (Functional & Anatomical Labeling of Brain Activation), and to provide information on the brain centers, brain activity (%) and hemispheric lateralization index on the basis of a brain activation map obtained from functional MR imaging. MATERIALS AND METHODS: The 3-dimensional activation MR images were processed by a statistical parametric mapping program (SPM99, The Wellcome Department of Cognitive Neurology, University College London, UK) and MRIcro software (www.mricro.com). The 3-dimensional images were first converted into 2-dimensional sectional images, and then overlapped with the corresponding T1-weighted images. Then, the image dataset was extended to -59 mm to 83 mm with a 2 mm slice-gap, giving 73 axial images. By using a pixel subtraction method, the differences in the R, G, B values between the T1-weighted images and the activation images were extracted, in order to produce black & white (B/W) differentiation images, in which each pixel is represented by 24-bit R, G, B true colors. Subsequently, another pixel differentiation method was applied to two template images, namely one functional and one anatomical index image, in order to generate functional and anatomical differentiation images containing regional brain activation information based on the Brodmann's and anatomical areas, respectively. In addition, the regional brain lateralization indices were automatically determined, in order to evaluate the hemispheric predominance, with the positive (+) and negative (-) indices showing left and right predominance, respectively. RESULTS: The manual counting method currently used is time consuming and has limited accuracy and reliability in the case of the activated cerebrocortical regions. The FALBA program we developed was 240 times faster than the manual counting method: -10 hours for manual accounting and -2.5 minutes for the FALBA program using a Pentium IV processor. Compared with the FALBA program, the manual quantification method showed an average error of 0.334+/-0.007 (%). Thus, the manual counting method gave less accurate quantitative information on brain activation than the FALBA program. CONCLUSION: The FALBA program is capable of providing accurate quantitative results, including the identification of the brain activation region and lateralization index with respect to the functional and anatomical areas. Also, the processing time was dramatically shortened in comparison with the manual counting method.

Qualitative and Quantitative Measurement of Brain Activity Associated with Visual Sexual Arousal in Males and Females: 3.0 Tesla Functional MR Imaging

PURPOSE: The present study utilized 3.0 Tesla functional MR imaging to identify and quantify the activated brain regions associated with visually evoked sexual arousal, and also to discriminate the gender differences between the cortical activation patterns in response to sexual stimuli. MATERIALS AND METHODS: A total of 24 healthy, right-handed volunteers, 14 males (mean age: 24) and 10 females (mean age: 23), with normal heterosexual function underwent functional MRI on a 3.0T MR scanner (Forte, Isole technique, Korea). The sexual stimulation consisted of a 1-minute rest with black screen, followed by a 3-minute stimulation by an erotic video film, and concluded with a 1-minute rest. The fMRI data was obtained from 20 slices (5 mm slice thickness, no gap) parallel to the AC-PC (anterior commissure and posterior commissure) line on the sagittal plane, giving a total of 2,100 images. The brain activation maps and the resulting quantification were analyzed by the statistical parametric mapping program, SPM 99. The mean-activated images were obtained from each individual activation map using one sampled t-test. The FALBA program, which is a new algorithm based on the pixel differentiation method, was used to identify and quantify the brain activation and lateralization indices with respect to the functional and anatomical terms. RESULTS: In both male and female volunteers, significant brain activation showed in the limbic areas of the parahippocampal gyrus, septal area, cingulate gyrus and thalamus. It is interesting to note that the septal areas gave a relatively lower activation ratio with high brain activities. On the contrary, the putamen, insula cortex, and corpus callosum gave a higher activation ratio with low brain activities. In particular, brain activation in the septal area, which was not reported in the previous fMRI studies under 1.5 Tesla, represents a distinct finding of this study using 3.0 T MR scanner. The overall lateralization index of activation shows left predominance (LI=35.3%) in the limbic system during sexual stimulation. The gender differences of brain activation in response to sexual arousal were characterized as follows. The activation area observed in males was the hypothalamus in the limbic system, whereas in females it was the cingulate gyrus, head of caudate nucleus, insula and corpus callosum. These findings reveal dissimilarities between males and females in neuronal responses to sexual arousal. As for the overall lateralization of activation in the limbic system, male volunteers gave a lateralization index that was greater than that of females by 300%. CONCLUSION: Our findings confirmed that neuroanatomical regions are associated with visually evoked sexual arousal and also with gender differences in response to sexual stimulation. Given that data from time-course traces of activation pattern and findings are observed by different stimuli, such as tactile and olfactory sense, it might be helpful to evaluate the neurophysiological mechanism for sexual arousal, and furthermore, to develop new diagnostic tools for sexual dysfunction and disorder.

The Effects of Bone Morphogenetic Protein and Epidermal Growth Factor on the Periodontal Tissue Regeneration / 대한치주과학회지

The 3 beagle dogs aged over one and half years and weighed 14 to 16 Kg were utilized in this study. Horizontal furcation defects were induced around 3rd, and 4th premolars bilaterally. BMP-4 in conjunction with EGF and BMP-4 only were applied in the right and left premolars respectively. 1 animal was sacrificed at 2nd week, 4th week, and 8th week, after regenerative surgery respectively. Semi-thin sections using glass-knife were stained with hematoxylin-eosin and trichrome for light microscopic study. The results were as follows : 1. The long junctional epithelial down-growth was observed in both area applied with BMP-4 and with BMP-4 and EGF at 2nd week after the surgery. 2. The extensive regeneration of new bone and cementum was appeared at 4th week and the maturation of bone was observed at 8th week in both area applied with BMP-4 and with BMP-4 and EGF. 3. The root ankylosis and resorption was presented along the exposed root surface at the coronal 1/3 of defect in the BMP-4 applied site, but it was not shown in the site applied with BMP-4 in conjunction with EGF at the 4th week. At 8th week, the root ankylosis was apparently appeared in the BMP-4 and EGF applied site as well as in the BMP-4 applied site. 4. The periodontal ligament tissue including Sharpey's fiber inserted into cementum and alveolar bone, was formed along the exposed root surface in the area applied with BMP-4 only, but in the site applied with BMP-4 and EGF, the collagen fiber running parallel to the root surface without Sharpey's fiber, was observed in the periodontal ligament space at 4th and 8th week. Within the above results, BMP-4 had the remarkable capability to regenerate the periodontal tissue and EGF had possibility to prevent from the root ankylosis. Therefore, growth factors including BMP-4 and EGF may have the strong possibility to be utilized in the clinical periodontal treatments.