Analysis of Ground Reaction Forces during Running Based on One-Dimensional Statistical Parametric Mapping / 医用生物力学

Objective To analyze the difference in ground reaction force (GRF) between male and female runners and between left and right limbs using the one-dimensional statistical parametric mapping (SPM). Methods Thirty male and female runners participated the running test on force treadmill at the speed of 12 km/h. GRF of consecutive five steps were recorded. The independent-sample t test and paired-sample t test in the SPM package were used to check the male vs female and right limb vs left limb differences. Results Male and female runners showed inter-limb asymmetry in vertical average loading rate (VALR), and the VALR of male runners was significantly higher than that of female runners in the left limb, while no significant differences were found in the right limb. Male and female runners showed significant differences in the right vertical GRF during push-off and medial-lateral GRF during landing, while left medial-lateral GRF presented significant differences during landing and mid stance. Male runners showed right limb vs left limb significance in the anterior-posterior GRF during push-off, vertical GRF during landing and push-off and medial-lateral GRF during landing, while female runners exhibited right limb vs left limb significance in vertical GRF during landing and push-off. Conclusions This study introduced the application of SPM in statistical analysis of GRF, elaborated the procedures and theory, compared the test of time-series data in SPM and discrete value with traditional statistics, and discussed the difference and features in SPM and SnPM, thus providing references for the application in data analysis of sports biomechanics. Comparison in the male vs female and right limb vs left limb revealed the genders and inter-limb symmetrical differences in the landing, mid-stance and push-off phases during stance. The research findings laid the foundation for future investigation of mechanism in running related injuries and strategy of prevention and treatment.

Topography of 11C-Pittsburgh compound B uptake in Alzheimer's disease: a voxel-based investigation of cortical and white matter regions

Objective: To compare results of positron emission tomography (PET) with carbon-11-labeled Pittsburgh compound B (11C-PIB) obtained with cerebellar or global brain uptake for voxel intensity normalization, describe the cortical sites with highest tracer uptake in subjects with mild Alzheimer's disease (AD), and explore possible group differences in 11C-PIB binding to white matter. Methods: 11C-PIB PET scans were acquired from subjects with AD (n=17) and healthy elderly controls (n=19). Voxel-based analysis was performed with statistical parametric mapping (SPM). Results: Cerebellar normalization showed higher 11C-PIB uptake in the AD group relative to controls throughout the cerebral cortex, involving the lateral temporal, orbitofrontal, and superior parietal cortices. With global uptake normalization, greatest cortical binding was detected in the orbitofrontal cortex; decreased 11C-PIB uptake in white matter was found in the posterior hippocampal region, corpus callosum, pons, and internal capsule. Conclusion: The present case-control voxelwise 11C-PIB PET comparison highlighted the regional distribution of amyloid deposition in the cerebral cortex of mildly demented AD patients. Tracer uptake was highest in the orbitofrontal cortex. Decreased 11C-PIB uptake in white-matter regions in this patient population may be a marker of white-matter damage in AD.

Functional MRI Characteristics in Visual Cortex (BA 17, 18 and 19) Corresponding to the Visual Field of Normal, Glaucoma Suspect (GS) and Primary Open Angle Glaucoma (POAG) Patients / Jurnal Sains Kesihatan Malaysia

The purpose of this study was to characterize, differentiate and correlate visual field and brain activation in visual cortex for normal, glaucoma suspect (GS) and primary open angle glaucoma (POAG) participants using Standard Automated Perimetry (SAP) and functional Magnetic Resonance Imaging (fMRI) respectively. The fMRI scans and SAP test were both carried out in Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM). Two types of black-and-white checkerboard pattern were displayed to the participants during the fMRI scans. The fMRI data were analyzed using WFU pickatlas toolbox targeting visual cortex area. The results showed that there was no significant difference in number of activated voxel between the three groups in visual cortex (BA 17, 18 and 19) while viewing all the given stimuli (p > 0.05). The pattern standard deviation (PSD) of SAP for visual field also revealed no significant differences (p > 0.05) in all groups of participants. However, negative correlation between PSD and fMRI activation was observed. The PSD values increased with a decrease in fMRI activation. With reference to visual field analysis, the results suggest that glaucomatous neuropathy of POAG patients has led to a gradual decrease in visual cortex activation and a gradual increase in PSD.

Statistical non-parametric mapping in sensor space

Establishing the significance of observed effects is a preliminary requirement for any meaningful interpretation of clinical and experimental Electroencephalography or Magnetoencephalography (MEG) data. We propose a method to evaluate significance on the level of sensors whilst retaining full temporal or spectral resolution. Input data are multiple realizations of sensor data. In this context, multiple realizations may be the individual epochs obtained in an evoked-response experiment, or group study data, possibly averaged within subject and event type, or spontaneous events such as spikes of different types. In this contribution, we apply Statistical non-Parametric Mapping (SnPM) to MEG sensor data. SnPM is a non-parametric permutation or randomization test that is assumption-free regarding distributional properties of the underlying data. The method, referred to as Maps SnPM, is demonstrated using MEG data from an auditory mismatch negativity paradigm with one frequent and two rare stimuli and validated by comparison with Topographic Analysis of Variance (TANOVA). The result is a time- or frequency-resolved breakdown of sensors that show consistent activity within and/or differ significantly between event or spike types. TANOVA and Maps SnPM were applied to the individual epochs obtained in an evoked-response experiment. The TANOVA analysis established data plausibility and identified latencies-of-interest for further analysis. Maps SnPM, in addition to the above, identified sensors of significantly different activity between stimulus types.

Superior Temporal Gyrus (STG) and Cerebellum Show Different Activation Profile during Simple Arithmetic Addition Task in Quiet and in Noisy Environment: An fMRI Study / Jurnal Sains Kesihatan Malaysia

Despite a vast number of studies that were focused on the roles of superior temporal gyrus (STG) and cerebellum as sensory area, little is known about their involvement in cognitive function such as attention and perception. The present fMRI study aimed to identify this cognitive role from brain activation profile of STG and cerebellum obtained from an arithmetic addition task. Eighteen healthy right hand dominance male adults participated in this study. They were instructed to solve single-digit addition tasks in quiet and noisy background during the fMRI scan. Both the in-quiet and in-noise addition tasks activated the bilateral STG and cerebellum (lobule VI and lobule VII) significantly but differentially. In both quiet and noisy conditions, STG activation is dominant in the left hemisphere while cerebellum showed a right hemisphere dominance. Bilateral STG and cerebellum (lobule VI) activation decreasedin noise, conversely cerebellum (lobule VII) activation increased in noise. These asymmetrical activation indicated hemispheric lateralization and differential behaviors of both brain areas in different environment while performing simple arithmetic addition task.

Regional Cerebral Glucose Metabolism in Novelty Seeking and Antisocial Personality: A Positron Emission Tomography Study

Novelty seeking (NS) and antisocial personality (ASP) are commonly exhibited by those who suffer from addictions, such as substance abuse. NS has been suggested to be a fundamental aspect of ASP. To investigate the neurobiological substrate of NS and ASP, we tested the relationship between regional cerebral glucose metabolism and the level of NS, determining the differences between individuals with and without ASP. Seventy-two healthy adults (43 males, mean age±SD=38.8±16.6 years, range=20~70 years; 29 females, 44.2±20.1 years, range=19~72 years) underwent resting-state brain positron emission tomography (PET) 40 minutes after 18F-fluorodeoxyglucose (FDG) injection. Within 10 days of the FDG PET study, participants completed Cloninger's 240-item Temperament and Character Inventory (TCI) to determine NS scores. Participants with and without ASP were grouped according to their TCI profiles. Statistical parametric mapping analysis was performed using the FDG PET and TCI profile data. NS scores positively correlated with metabolism in the left anterior cingulate gyrus and the insula on both sides of the brain and negatively correlated with metabolism in the right pallidum and putamen. Participants with ASP showed differences in cerebral glucose metabolism across various cortical and subcortical regions, mainly in the frontal and prefrontal areas. These data demonstrate altered regional cerebral glucose metabolism in individuals with NS and ASP and inform our understanding of the neurobiological substrates of problematic behaviors and personality disorders.

Effects of Limb Ischemic Preconditioning on Brain Metabolism of Ischemic Moyamoya Disease: A Positron Emission Tomography and Statistical Parametric Mapping Study / 中国康复理论与实践

@#Objective To observe the brain glucose metabolism after limb ischemic preconditioning (LIPC) for ischemic moyamoya disease with positron emission tomography (PET) and statistical parametric mapping (SPM). Methods 62 patients with ischemic moyamoya disease were enrolled and randomized into LIPC group (n=31) and control group (n=31). The glucose metabolism of patients was analyzed with PET before and after treatment in both groups, using the methods of radioactivity ratio and SPM. Results The glucose metabolism ratio improved more in the LIPC group than in the control group (P<0.01), and aggravated less than in the control group (P<0.001). As setting the glucose metabolism increased after treatment, there were 7 areas activated in LIPC group, including frontal, temporal and parietal lobes, and the KE=1121; while there were 5 areas activated in the control group, including frontal and parietal lobes, and the KE=292. As setting the glucose metabolism decreased after treatment, there was only frontal area activated in LIPC group, while there were 8 areas activated in the control group, including frontal, parietal, occipital lobes, and the KE=629. Conclusion LIPC may improve the brain glucose metabolism in patients with moyamoya disease, which can be observed with PET and SPM.

Effects of Limb Ischemic Preconditioning on Brain Metabolism of Ischemic Moyamoya Disease:A Positron Emis-sion Tomography and Statistical Parametric Mapping Study / 中国康复理论与实践

Objective To observe the brain glucose metabolism after limb ischemic preconditioning (LIPC) for ischemic moyamoya dis-ease with positron emission tomography (PET) and statistical parametric mapping (SPM). Methods 62 patients with ischemic moyamoya disease were enrolled and randomized into LIPC group (n=31) and control group (n=31). The glucose metabolism of patients was analyzed with PET before and after treatment in both groups, using the methods of radioactivity ratio and SPM. Results The glucose metabolism ratio improved more in the LIPC group than in the control group (P<0.01), and aggravated less than in the control group (P<0.001). As setting the glucose metabolism increased after treatment, there were 7 areas activated in LIPC group, including frontal, temporal and parietal lobes, and the KE=1121;while there were 5 areas activated in the control group, including frontal and parietal lobes, and the KE=292. As setting the glu-cose metabolism decreased after treatment, there was only frontal area activated in LIPC group, while there were 8 areas activated in the con-trol group, including frontal, parietal, occipital lobes, and the KE=629. Conclusion LIPC may improve the brain glucose metabolism in pa-tients with moyamoya disease, which can be observed with PET and SPM.

Investigating Brain Activation and Neural Effi cacy During Simple Arithmetic Addition Task in Quiet and in Noise: An fMRI Study / Jurnal Sains Kesihatan Malaysia

Knowledge about the hemodynamic model that mediates synaptic activity and measured magnetic resonance signal is essential in understanding brain activation. Neural effi cacy is a hemodynamic parameter that would change the evoked hemodynamic responses. In this work, brain activation and neural effi cacy of the activated brain areas during simple addition task in two different backgrounds were studied using fMRI. The objectives were to determine the activated areas during the performance of arithmetic addition in quiet (AIQ) and noisy (AIN) background and to investigate the relationship between neural effi cacy and height extent of activation for the respective areas. Eighteen healthy male participants performed simple arithmetic addition in quiet and in noise. Bilateral cerebellum, superior temporal gyrus (STG), temporal pole (TP) and supplementary motor area (SMA) were signifi cantly (p < 0.05) activated during AIQ and AIN. Left middle frontal gyrus (L-MFG), right superior frontal gyrus (R-SFG), right superior orbital gyrus (R-SOG) and bilateral insula were more active in quiet as compared to in noise while the left middle cingulate cortex (L-MCC), left amygdala (L-AMG), right temporal pole (R-TP) and left cerebellum (L-CER) were more active in noise as compared to in quiet. The t value for most of the activated regions was found to be inversely proportional to the neural effi cacy. Signifi cant (p < 0.05) negative relationship between t value and neural effi cacy were found for R-STG and bilateral cerebellum during AIQ, while for AIN, similar relationships were found in R-CER, R-STG and R-TP. This study suggests that while being signifi cantly activated, the hemodynamic responses of these brain regions could have been suppressed by the stimulus resulting in an intensity decrease with increasing neural efficacy

Effect of Harderian adenectomy on the statistical analyses of mouse brain imaging using positron emission tomography

Positron emission tomography (PET) using 2-deoxy-2-[18F] fluoro-D-glucose (FDG) as a radioactive tracer is a useful technique for in vivo brain imaging. However, the anatomical and physiological features of the Harderian gland limit the use of FDG-PET imaging in the mouse brain. The gland shows strong FDG uptake, which in turn results in distorted PET images of the frontal brain region. The purpose of this study was to determine if a simple surgical procedure to remove the Harderian gland prior to PET imaging of mouse brains could reduce or eliminate FDG uptake. Measurement of FDG uptake in unilaterally adenectomized mice showed that the radioactive signal emitted from the intact Harderian gland distorts frontal brain region images. Spatial parametric measurement analysis demonstrated that the presence of the Harderian gland could prevent accurate assessment of brain PET imaging. Bilateral Harderian adenectomy efficiently eliminated unwanted radioactive signal spillover into the frontal brain region beginning on postoperative Day 10. Harderian adenectomy did not cause any post-operative complications during the experimental period. These findings demonstrate the benefits of performing a Harderian adenectomy prior to PET imaging of mouse brains.

Cerebral FDG Metabolic Pattern in Pediatric Patients with Neurofibromatosis Type 1: A Retrospective Study.

Aims: Learning disabilities represent the most significant cause of lifetime morbidity in neurofibromatosis type 1 (NF1) patients. The cognitive phenotype of NF1 pediatric patients is not well understood. The purpose of this study was to examine the cerebral glucose metabolic pattern in NF1 pediatric patients. Study Design: Retrospective. Place and Duration of Study: Saint Louis University Hospital, Saint Louis, Missouri, United States, between May 2011 and May 2012. Methodology: Six NF1 pediatric patients underwent FDG PET/CT including the brain, for evaluation of extracranial neoplasm. Their brain PET images were compared with a pediatric comparison set (21 subjects) using Statistical Parametric Mapping. Significant differences between groups were examined at p<0.001, uncorrected for voxel height and p<0.05, corrected for cluster extent. Results: Compared with the comparison set, the 6 NF1 patients showed the largest cluster of reduced FDG uptake (3966 voxels) in the medial dorsal nucleus of bilateral thalami. Additional clusters of metabolism in the range from 415 to 926 voxels were noticed in the right cingulate gyrus (Brodmann area (BA) 8 and 24), left occipital lobe (BA 17 and 18) and right fronto-parietal lobe (BA 43). Conclusion: The FDG reduction of the bilateral thalami is compelling and may be most pathognomonic for NF1. This and other areas of FDG reduction found within the brain may contribute to a better understanding of the NF1 cognitive phenotype.

Functional Specialisation and Effective Connectivity During Self-paced Unimanual and Bimanual Tapping of Hand Fingers: An Extended Analysis Using Dynamic Causal Modeling and Bayesian Model Selection for Group Studies

Introduction: This multiple-subject fMRI study continue to further investigate brain activation within and effective connectivity between the significantly (p<0.001) activated primary motor area (M1), supplementary motor area (SMA) with the inclusion of BA44 during unimanual (UNIright and UNIleft) and bimanual (BIM) self-paced tapping of hand fingers. Methods: The activation extent (spatial and height) and effective connectivity were analysed using statistical parametric mapping (SPM), dynamic causal modeling (DCM) and the novel method of Bayesian model selection (BMS) for group studies. Results: Group results for UNIright and UNIleft showed contra-lateral and ipsi-lateral involvement of M1 and SMA. The results for BIM showed bilateral activation in M1, SMA and BA44. A larger activation area but with lower percentage of signal change (PSC) are observed in the left M1 due to the control on UNIright as compared to the right M1 due to the control on UNIleft. This is discussed as due to the influence of the tapping rate effects that is greater than what would be produced by the average effects of the dominant and sub-dominant hand. However, the higher PSC observed in the right M1 is due to a higher control demand used by the brain in coordinating the tapping of the sub-dominant hand fingers. Connectivity analysis indicated M1 as the intrinsic input for UNIright and UNIleft while for BIM, the inputs were both M1s. During unilateral finger tapping, the contra-lateral M1 acts as the input center which in turn triggers the propagation of signal unidirectionally to other regions of interest. The results obtained for BIM (BIMleft and BIMright) however yield a model with less number of significant connection. M1-M1 connection is unidirectional for UNIleft and UNIright originating from contra-lateral M1, and is inhibited during BIM. Conclusion: By taking into consideration the presence of outliers that could have arisen in any subject under study, BMS for group study has successfully chosen a model that has the best balance between accuracy (fit) and complexity.

Caudate Volume Change in Transient Global Amnesia Patients; Voxel-Based Morphometric Study

BACKGROUND: Transient global amnesia (TGA) is characterized by a severe disturbance of memory, lasting less than a day, and complete resolution. However, some authors have suggested the occurrence of permanent memory impairment in such cases. In this study, we investigated whether the gray-matter structure suffers degeneration in TGA, based on the assumption that TGA attacks appear to be related to underlying permanent pathology. METHODS: T1-weighted magnetic resonance imaging data for 20 TGA and 55 normal subjects were analyzed. The gray-matter volume was measured using voxel-based morphometry. The subjects also completed the Seoul Neuropsychological Screening Battery (SNSB). RESULTS: The gray-matter volume was reduced in the left superior frontal gyrus, right precentral gyrus, right superior frontal gyrus, left caudate nucleus, left precentral gyrus, left post central gyrus, and both putamens. The SNSB revealed the presence of selective neuropsychological dysfunctions after clinical recovery. Most of the cases exhibited attention deficit, and difficulties in copying of the Rey-Osterrieth Complex Figure, and in the Seoul verbal learning test. CONCLUSIONS: Left caudate nucleus atrophy could explain the attention deficit and memory impairment experienced in these TGA patients. Many patients with TGA have neuropsychological dysfunctions even after they appear to be clinically improved.

Activation Characteristics of the Primary Motor (M1) and Supplementary Motor (SMA) Areas during Robust Unilateral Finger Tapping Task / Jurnal Sains Kesihatan Malaysia

This study investigated the functional specialisation characteristics of brain in multiple right-hand dominant subjects pertaining to the activation of the cerebral motor cortices evoked by unilateral finger tapping, especially in primary motor (M1) and supplementary motor (SMA) areas. This multiple-subject study used unilateral (UNIright and UNIleft) selfpaced tapping of hand fingers to activate the M1 and SMA. Brain activation characteristics were analysed using statistical parametric mapping (SPM). Activation for UNIright and UNIleft showed the involvement of contralateral and ipsilateral M1 and SMA. A larger activation area but with a lower percentage of signal change (PSC) were observed in the left M1 due to the control on UNIright (4164 voxels at α = 0.001, PSC = 1.650) as compared to the right M1 due to the control on UNIleft (2012 voxels at α = 0.001, PSC = 2.377). This is due to the influence of the tapping rate effects which is greater than what could be produced by the average effects of the dominant and sub-dominant hands. The significantly higher PSC value observed in the right M1 (p < 0.05) is due to a higher control demand used by the brain in coordinating the tapping of the sub-dominant fingers. The findings obtained from this study showed strong evidence of the existence of brain functional specialisation and could be used as baseline references in determining the most probable motor pathways in a sample of subjects.

Development of the Multi-Parametric Mapping Software Based on Functional Maps to Determine the Clinical Target Volumes / 의학물리

To determine the clinical target volumes considering vascularity and cellularity of tumors, the software was developed for mapping of the analyzed biological clinical target volumes on anatomical images using regional cerebral blood volume (rCBV) maps and apparent diffusion coefficient (ADC) maps. The program provides the functions for integrated registrations using mutual information, affine transform and non-rigid registration. The registration accuracy is evaluated by the calculation of the overlapped ratio of segmented bone regions and average distance difference of contours between reference and registered images. The performance of the developed software was tested using multimodal images of a patient who has the residual tumor of high grade gliomas. Registration accuracy of about 74% and average 2.3 mm distance difference were calculated by the evaluation method of bone segmentation and contour extraction. The registration accuracy can be improved as higher as 4% by the manual adjustment functions. Advanced MR images are analyzed using color maps for rCBV maps and quantitative calculation based on region of interest (ROI) for ADC maps. Then, multi-parameters on the same voxels are plotted on plane and constitute the multi-functional parametric maps of which x and y axis representing rCBV and ADC values. According to the distributions of functional parameters, tumor regions showing the higher vascularity and cellularity are categorized according to the criteria corresponding malignant gliomas. Determined volumes reflecting pathological and physiological characteristics of tumors are marked on anatomical images. By applying the multi-functional images, errors arising from using one type of image would be reduced and local regions representing higher probability as tumor cells would be determined for radiation treatment plan. Biological tumor characteristics can be expressed using image registration and multi-functional parametric maps in the developed software. The software can be considered to delineate clinical target volumes using advanced MR images with anatomical images.

Diagnosis of regional cerebral blood flow abnormalities using SPECT: agreement between individualized statistical parametric maps and visual inspection by nuclear medicine physicians with different levels of expertise in nuclear neurology

INTRODUCTION: Visual analysis is widely used to interpret regional cerebral blood flow (rCBF) SPECT images in clinical practice despite its limitations. Automated methods are employed to investigate between-group rCBF differences in research studies but have rarely been explored in individual analyses. OBJECTIVES: To compare visual inspection by nuclear physicians with the automated statistical parametric mapping program using a SPECT dataset of patients with neurological disorders and normal control images. METHODS: Using statistical parametric mapping, 14 SPECT images from patients with various neurological disorders were compared individually with a databank of 32 normal images using a statistical threshold of p<0.05 (corrected for multiple comparisons at the level of individual voxels or clusters). Statistical parametric mapping results were compared with visual analyses by a nuclear physician highly experienced in neurology (A) as well as a nuclear physician with a general background of experience (B) who independently classified images as normal or altered, and determined the location of changes and the severity. RESULTS: Of the 32 images of the normal databank, 4 generated maps showing rCBF abnormalities (p<0.05, corrected). Among the 14 images from patients with neurological disorders, 13 showed rCBF alterations. Statistical parametric mapping and physician A completely agreed on 84.37 percent and 64.28 percent of cases from the normal databank and neurological disorders, respectively. The agreement between statistical parametric mapping and ratings of physician B were lower (71.18 percent and 35.71 percent, respectively). CONCLUSION: Statistical parametric mapping replicated the findings described by the more experienced nuclear physician. This finding suggests that automated methods for individually analyzing rCBF SPECT images may be a valuable resource to complement visual inspection in clinical practice.

The neural substrates underlying the writing: a second language PET study / 中华行为医学与脑科学杂志

Objective To research the neural substracts for the processing of the discourse-level English writing using PET-CT.Method Six healthy people underwent 18F-FDG PET examination in the pseudo-writing condition and the discourse-level English writing condition.statistical parametric mapping(SPM)was used to investigate the activicated focus in english writing thruugh pared-t test.Results The activated foci were observed in left inferior parietal lobule,left postcentral gyrus,left cingulate gyrus,left putamen,fight frontal precentral gyrus,right superior frontal gyrus,right thalamus medial dorsal nucleus,both cerebellum(P＜0.05).Conclusions The writing of English as a second language implicates conical and subcortical structures.Left inferior parietal lobule,right frontal and both cerebellum participate in the language production and processes,and left putamen is more engaged in English learning.

Brain Activations Evoked by Passive and Active Listening: A Preliminary Study on Multiple Subjects / Jurnal Sains Kesihatan Malaysia

A functional magnetic resonance imaging (fMRI) study was conducted on 4 healthy male and female subjects to investigate brain activation during passive and active listening. Two different experimental conditions were separately used in this study. The first condition requires the subjects to listen to a simple arithmetic instruction (e.g. one-plus-two-plus-three-plus-four) – passive listening. In the second condition, the subjects were given the same series of arithmetic instruction and were required to listen and perform the calculation – active listening. The data were then analysed using the Statistical Parametric Mapping (SPM5) and the MATLAB 7.4 (R2007a) programming softwares. The results obtained from the fixed (FFX) and random effects analyses (RFX) show that the active-state signal intensity was significantly higher (p < 0.05) than the resting-state signal intensity for both conditions. The results also indicate significant differences (p < 0.001) in brain activation between passive and active listening. The activated cortical regions during passive listening, as obtained from the FFX of the first condition is symmetrical in the left and right temporal and frontal lobes covering the cortical auditory areas. However, for the second condition, which was active listening, more activation occurs in the left hemisphere with a reduction in the number of activated voxels and their signal intensity in the right hemisphere. Activation mainly occurs in the middle temporal gyrus, precentral gyrus, middle frontal gyrus, superior temporal gyrus and several other areas in the frontal lobes. The point of maximum signal intensity has been shifted to a new coordinates during active listening. It is also observed that the magnetic resonance signal intensity and the number of activated voxel in the right and left superior temporal lobes for the second condition have been reduced as compared to that of the first condition. The results obtained strongly suggest the existence of functional specialisation. The results also indicate different networks for the two conditions. These networks clearly pertain to the existence of functional connectivity between activation areas during listening and listening while performing a simple arithmetic task.

The Acquisition, Analyses and Interpretation of fMRI Data: A Study on Functional Specialisation in Primary Auditory Cortices

In this study, functional magnetic resonance imaging (fMRI) is used to investigate func-tional specialisation in human auditory cortices during listening. A silent fMRI paradigm was used to reduce the scanner sound artefacts on functional images. The subject was instructed to pay attention to the white noise stimulus binaurally given at an inten-sity level of 70 dB higher than the hearing level for normal people. Functional speciali-sation was studied using the Matlab-based Statistical Parametric Mapping (SPM5) software by means of fixed effects (FFX), random effects (RFX) and conjunction analyses. Individual analyses on all subjects indicated asymmetrical bilateral activation of the left and right hemispheres in Brodmann areas (BA) 22, 41 and 42, involving the primary and secondary auditory cortices. The percentage of signal change is larger in the BA22, 41 and 42 on the right as compared to the ones on the left (p>0.05). The average number of activated voxels in all the respective Brodmann areas are higher in the right hemisphere than in the left (p>0.05). FFX results showed that the point of maximum intensity was in the right BA41 whereby 599±1 activated voxels were ob-served in the right temporal lobe as compared to 485±1 in the left temporal lobe. The RFX results were consistent with that of FFX. The analysis of conjunction which fol-lowed, showed that the right BA41 and left BA22 as the common activated areas in all subjects. The results confirmed the specialisation of the right auditory cortices in pro-cessing non verbal stimuli.