Comparison of fMRI data from passive listening and active-response story processing tasks in children

PURPOSE

To use functional MRI (fMRI) methods to visualize a network of auditory and language-processing brain regions associated with processing an aurally-presented story. We compare a passive listening (PL) story paradigm to an active-response (AR) version including online performance monitoring and a sparse acquisition technique.

MATERIALS AND METHODS

Twenty children (ages 11-13 years) completed PL and AR story processing tasks. The PL version presented alternating 30-second blocks of stories and tones; the AR version presented story segments, comprehension questions, and 5-second tone sequences, with fMRI acquisitions between stimuli. fMRI data was analyzed using a general linear model approach and paired t-test identifying significant group activation.

RESULTS

Both tasks showed activation in the primary auditory cortex, superior temporal gyrus bilaterally, and left inferior frontal gyrus (IFG). The AR task demonstrated more extensive activation, including the dorsolateral prefrontal cortex and anterior/posterior cingulate cortex. Comparison of effect size in each paradigm showed a larger effect for the AR paradigm in a left inferior frontal region-of-interest (ROI).

CONCLUSION

Activation patterns for story processing in children are similar in PL and AR tasks. Increases in extent and magnitude of activation in the AR task are likely associated with memory and attention resources engaged across acquisition intervals.

Language networks in children: evidence from functional MRI studies

OBJECTIVE

The purpose of our study was to review functional MRI and other neuroimaging studies of language skills in children from infancy to adulthood.

CONCLUSION

Functional MRI (fMRI) and other neuroimaging studies show developmental changes in the networks of brain regions supporting language, which can be affected by brain injuries or neurologic disorders. Particular aspects of language rely on networks that lateralize to the dominant hemisphere; others rely on bilateral or nondominant mechanisms. Multiple fMRI tasks for pediatric patients characterize functional brain reorganization that may accompany language deficits.

DEVELOPMENTAL SEX DIFFERENCES IN THE RELATION OF NEUROANATOMICAL CONNECTIVITY TO INTELLIGENCE

Recent neuroimaging research has shown sex-related differences in the relationship between brain structure and cognitive function. Anatomical studies have shown a greater reliance for cognitive function on white matter structure in adult females, and a greater reliance on gray matter structure in adult males. Functional neuroimaging studies have also shown a greater correlation between brain connectivity and cognitive function in females. However, this relationship is not present in young childhood (5 years old) but appears during the developmental period. Here sex differences in structure-function relationships and their developmental trajectory are investigated using diffusion tensor imaging (DTI) on a large cohort of over 100 normal children ages 5-18. Significant sex-X-IQ interactions on fractional anisotropy (FA), a marker for white matter organization, were seen in the left frontal lobe, in fronto-parietal areas bilaterally, and in the arcuate fasciculus bilaterally, with girls showing positive correlations of FA with IQ, and boys showing a negative correlation. Significant sex-X-IQ-X-age interactions on FA were also seen in the left frontal lobe and in fronto-parietal areas bilaterally, showing a developmental effect. These results strongly corroborate previous findings regarding sex differences in structure-function relationships regarding intelligence. Results also indicate that a naïve interpretation of "more is better" with respect to FA may not be accurate, especially in adult males.

Developmental differences in white matter architecture between boys and girls

Previous studies have found developmental differences between males and females in brain structure. During childhood and adolescence, relative white matter volume increases faster in boys than in girls. Sex differences in the development of white matter microstructure were investigated in a cohort of normal children ages 5-18 in a cross-sectional diffusion tensor imaging (DTI) study. Greater fractional anisotropy (FA) in boys was shown in associative white matter regions (including the frontal lobes), while greater FA in girls was shown in the splenium of the corpus callosum. Greater mean diffusivity (MD) in boys was shown in the corticospinal tract and in frontal white matter in the right hemisphere; greater MD in girls was shown in occipito-parietal regions and the most superior aspect of the corticospinal tract in the right hemisphere. Significant sex-age interactions on FA and MD were also shown. Girls displayed a greater rate of fiber density increase with age when compared with boys in associative regions (reflected in MD values). However, girls displayed a trend toward increased organization with age (reflected in FA values) only in the right hemisphere, while boys displayed this trend only in the left hemisphere. These results indicate differing developmental trajectories in white matter for boys and girls and the importance of taking sex into account in developmental DTI studies. The results also may have implications for the study of the relationship of brain architecture with intelligence.

Chronic isolated hemifacial spasm as a manifestation of epilepsia partialis continua

The objective of this case study was to describe the clinical and electroencephalography (EEG)/functional magnetic resonance imaging (fMRI) data of a case of isolated hemifacial spasm due to epilepsia partialis continua in a 59-year-old man with abnormal hemifacial movements that disappeared during voluntary tasks, were absent during sleep, and responded to carbamazepine. His neurological examination was normal; EEG revealed right inferior frontal epileptiform discharges. EEG/fMRI demonstrated increased blood oxygenation level-dependent contrast in the right inferior and middle frontal gyri corresponding to the contralateral motor and premotor cortex responsible for facial movements (BA 44, 45, 45, 9), with widespread BOLD signal deactivations suggestive of epileptic network involvement despite a very focal epileptogenic process. We hypothesize that the response of some cases of hemifacial spasm to carbamazepine, a first-line treatment in the pre-botulinum toxin era, may have been due to its antiepileptic effects, rather than to modulation of facial nerve hyperexcitability.

Sirolimus for angiomyolipoma in tuberous sclerosis complex or lymphangioleiomyomatosis

BACKGROUND

Angiomyolipomas in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis are associated with mutations in tuberous sclerosis genes resulting in constitutive activation of the mammalian target of rapamycin (mTOR). The drug sirolimus suppresses mTOR signaling.

METHODS

We conducted a 24-month, nonrandomized, open-label trial to determine whether sirolimus reduces the angiomyolipoma volume in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis. Sirolimus was administered for the first 12 months only. Serial magnetic resonance imaging of angiomyolipomas and brain lesions, computed tomography of lung cysts, and pulmonary-function tests were performed.

RESULTS

Of the 25 patients enrolled, 20 completed the 12-month evaluation, and 18 completed the 24-month evaluation. The mean (+/-SD) angiomyolipoma volume at 12 months was 53.2+/-26.6% of the baseline value (P<0.001) and at 24 months was 85.9+/-28.5% of the baseline value (P=0.005). At 24 months, five patients had a persistent reduction in the angiomyolipoma volume of 30% or more. During the period of sirolimus therapy, among patients with lymphangioleiomyomatosis, the mean forced expiratory volume in 1 second (FEV1) increased by 118+/-330 ml (P=0.06), the forced vital capacity (FVC) increased by 390+/-570 ml (P<0.001), and the residual volume decreased by 439+/-493 ml (P=0.02), as compared with baseline values. One year after sirolimus was discontinued, the FEV1 was 62+/-411 ml above the baseline value, the FVC was 346+/-712 ml above the baseline value, and the residual volume was 333+/-570 ml below the baseline value; cerebral lesions were unchanged. Five patients had six serious adverse events while receiving sirolimus, including diarrhea, pyelonephritis, stomatitis, and respiratory infections.

CONCLUSIONS

Angiomyolipomas regressed somewhat during sirolimus therapy but tended to increase in volume after the therapy was stopped. Some patients with lymphangioleiomyomatosis had improvement in spirometric measurements and gas trapping that persisted after treatment. Suppression of mTOR signaling might constitute an ameliorative treatment in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis. (ClinicalTrials.gov number, NCT00457808.)

Object identification and lexical/semantic access in children: a functional magnetic resonance imaging study of word-picture matching

Theoretical models for lexical access to visual objects have been based mainly on adult data. To investigate the developmental aspects of object recognition and lexical access in children, a large-scale functional MRI (fMRI) study was performed in 283 normal children ages 5-18 using a word-picture matching paradigm in which children would match an aurally presented noun to one of two pictures (line drawings). Using group Independent Component Analysis (ICA), six task-related components were detected, including (a) the posterior superior temporal gyrus bilaterally; (b) the fusiform, inferior temporal, and middle occipital gyri bilaterally; (c) the dorsal aspect of the inferior frontal gyrus bilaterally, the left precuneus, the left superior/middle temporal gyrus, and the anterior cingulate; (d) the right medial fusiform gyrus; (e) a left-lateralized component including the inferior/middle frontal, middle temporal, medial frontal, and angular gyri, as well as the thalamus and the posterior cingulate; and (f) the ventral/anterior aspect of the inferior frontal gyrus bilaterally. Increased activation associated with age was seen in the components (b) and (d) (ventral visual pathway) for object recognition, and (c) and (f) likely associated with semantic maintenance and response selection. Increased activation associated with task performance was seen in components (b) and (d) (ventral visual pathway) while decreased activation associated with task performance was seen in component (f) (ventral/anterior inferior frontal gyrus). The results corroborate the continued development of the ventral visual pathway throughout the developmental period.

Development of effective connectivity for narrative comprehension in children

A large-scale study of narrative comprehension using functional MRI was performed involving children of ages 5-18 years old using a recently published method, multivariate autoregressive modeling, modified for multi subject analyses to investigate effective connectivity and its development with age. Feedback networks were found during a narrative processing task and involved effective connectivity from Broca's area and the medial aspect of the superior frontal gyrus to the posterior aspects of the superior temporal gyrus bilaterally. The effective connectivity from Broca's area to the superior temporal gyrus in the left hemisphere was shown to increase with age. The results demonstrate the feasibility of performing multi subject multivariate autoregressive modeling analyses to investigate effective connectivity in the absence of an a priori model.

Diffusion tensor MR imaging reveals persistent white matter alteration after traumatic brain injury experienced during early childhood

BACKGROUND AND PURPOSE

Diffusion tensor imaging (DTI) can noninvasively quantify white matter (WM) integrity. Although its application in adult traumatic brain injury (TBI) is common, few studies in children have been reported. The purposes of this study were to examine the alteration of fractional anisotropy (FA) in children with TBI experienced during early childhood and to quantify the association between FA and injury severity.

MATERIALS AND METHODS

FA was assessed in 9 children with TBI (age = 7.89 +/- 1.00 years; Glasgow Coma Scale [GCS] = 10.11 +/- 4.68) and a control group of 12 children with orthopedic injuries without central nervous system involvement (age = 7.51 +/- 0.95 years). All of the subjects were at minimum 12 months after injury. We examined group differences in a series of predetermined WM regions of interest with t test analysis. We subsequently conducted a voxel-wise comparison with Spearman partial correlation analysis. Correlations between FA and injury severity were also calculated on a voxel-wise basis.

RESULTS

FA values were significantly reduced in the TBI group in genu of corpus callosum (CC), posterior limb of internal capsule (PLIC), superior longitudinal fasciculus (SLF), superior fronto-occipital fasciculus (SFO), and centrum semiovale (CS). GCS scores were positively correlated with FA in several WM areas including CC, PLIC, SLF, CS, SFO, and inferior fronto-occipital fasciculus (IFO).

CONCLUSION

This DTI study provides evidence that WM integrity remains abnormal in children with moderate-to-severe TBI experienced during early childhood and that injury severity correlated strongly with FA.

Functional MRI of language lateralization during development in children

Changes in the distribution of language function in the brain have been documented from infancy through adulthood. Even macroscopic measures of language lateralization reflect a dynamic process of language development. In this review, we summarize a series of functional MRI studies of language skills in children ages of five to 18 years, both typically-developing children and children with brain injuries or neurological disorders that occur at different developmental stages with different degrees of severity. These studies used a battery of fMRI-compatible language tasks designed to tap sentential and lexical language skills that develop early and later in childhood. In typically-developing children, lateralization changes with age are associated with language skills that have a protracted period of development, reflecting the developmental process of skill acquisition rather than general maturation of the brain. Normative data, across the developmental period, acts as a reference for disentangling developmental patterns in brain activation from changes due to developmental or acquired abnormalities. This review emphasizes the importance of considering age and child development in neuroimaging studies of language.

A combined bootstrap/histogram analysis approach for computing a lateralization index from neuroimaging data

Cerebral hemispheric specialization has traditionally been described using a lateralization index (LI). Such an index, however, shows a very severe threshold dependency and is prone to be influenced by statistical outliers. Reliability of this index thus has been inherently weak, and the assessment of this reliability is as yet not possible as methods to detect such outliers are not available. Here, we propose a new approach to calculating a lateralization index on functional magnetic resonance imaging data by combining a bootstrap procedure with a histogram analysis approach. Synthetic and real functional magnetic resonance imaging data was used to assess performance of our approach. Using a bootstrap algorithm, 10,000 indices are iteratively calculated at different thresholds, yielding a robust mean, maximum and minimum LI and thus allowing to attach a confidence interval to a given index. Taking thresholds into account, an overall weighted bootstrapped lateralization index is calculated. Additional histogram analyses of these bootstrapped values allow to judge reliability and the influence of outliers within the data. We conclude that the proposed methods yield a robust and specific lateralization index, sensitively detect outliers and allow to assess the underlying data quality.

Age-related connectivity changes in fMRI data from children listening to stories

The way humans comprehend narrative speech plays an important part in human development and experience. A group of 313 children with ages 5-18 were subjected to a large-scale functional magnetic resonance imaging (fMRI) study in order to investigate the neural correlates of auditory narrative comprehension. The results were analyzed to investigate the age-related brain activity changes involved in the narrative language comprehension circuitry. We found age-related differences in brain activity which may either reflect changes in local neuroplasticity (of the regions involved) in the developing brain or a more global transformation of brain activity related to neuroplasticity. To investigate this issue, Structural Equation Modeling (SEM) was applied to the results obtained from a group independent component analysis (Schmithorst, V.J., Holland, S.K., et al., 2005. Cognitive modules utilized for narrative comprehension in children: a functional magnetic resonance imaging study. NeuroImage) and the age-related differences were examined in terms of changes in path coefficients between brain regions. The group Independent Component Analysis (ICA) had identified five bilateral task-related components comprising the primary auditory cortex, the mid-superior temporal gyrus, the most posterior aspect of the superior temporal gyrus, the hippocampus, the angular gyrus and the medial aspect of the parietal lobule (precuneus/posterior cingulate). Furthermore, a left-lateralized network (sixth component) was also identified comprising the inferior frontal gyrus (including Broca's area), the inferior parietal lobule, and the medial temporal gyrus. The components (brain regions) for the SEM were identified based on the ICA maps and the results are discussed in light of recent neuroimaging studies corroborating the functional segregation of Broca's and Wernicke's areas and the important role played by the right hemisphere in narrative comprehension. The classical Wernicke-Geschwind (WG) model for speech processing is expanded to a two-route model involving a direct route between Broca's and Wernicke's area and an indirect route involving the parietal lobe.

Cerebral ischemia-hypoxia induces intravascular coagulation and autophagy

Hypoxia is a critical factor for cell death or survival in ischemic stroke, but the pathological consequences of combined ischemia-hypoxia are not fully understood. Here we examine this issue using a modified Levine/Vannucci procedure in adult mice that consists of unilateral common carotid artery occlusion and hypoxia with tightly regulated body temperature. At the cellular level, ischemia-hypoxia produced proinflammatory cytokines and simultaneously activated both prosurvival (eg, synthesis of heat shock 70 protein, phosphorylation of ERK and AKT) and proapoptosis signaling pathways (eg, release of cytochrome c and AIF from mitochondria, cleavage of caspase-9 and -8). However, caspase-3 was not activated, and very few cells completed the apoptosis process. Instead, many damaged neurons showed features of autophagic/lysosomal cell death. At the tissue level, ischemia-hypoxia caused persistent cerebral perfusion deficits even after release of the carotid artery occlusion. These changes were associated with both platelet deposition and fibrin accumulation within the cerebral circulation and would be expected to contribute to infarction. Complementary studies in fibrinogen-deficient mice revealed that the absence of fibrin and/or secondary fibrin-mediated inflammatory processes significantly attenuated brain damage. Together, these results suggest that ischemia-hypoxia is a powerful stimulus for spontaneous coagulation leading to reperfusion deficits and autophagic/lysosomal cell death in brain.

Functional MRI evidence for disparate developmental processes underlying intelligence in boys and girls

Previous research has shown evidence for sex differences in the neuroanatomical bases for intelligence in adults. Possible differences in the neuroanatomical correlates of intelligence and their developmental trajectories between boys and girls were investigated using functional MRI (fMRI). A large cohort of over 300 children, ages 5-18, performed the semantic processing task of silent verb generation. Regions were found in the left hemisphere exhibiting positive correlations of blood-oxygenation-level-dependent (BOLD) activation with IQ, including the middle temporal gyrus, prefrontal cortex (Broca's area), medial frontal gyrus, precuneus, and cingulate gyrus, while the superior temporal gyrus in the right hemisphere displayed a negative correlation of BOLD activation with IQ. Significant sex-X-IQ and sex-X-IQ-X-age interaction effects were also seen in the left middle temporal gyrus and left inferior frontal gyrus. Using a data-driven analysis procedure, a sex-X-IQ-X-age interaction was also demonstrated in the functional connectivity between regions in the left hemisphere, parameterized as a weighted sum of pairwise covariances between fMRI time courses. While young girls (<13 years) exhibited no correlation of connectivity with intelligence, older girls (>13 years) demonstrated a positive association of functional connectivity with intelligence. Boys, however, demonstrated the opposite developmental trajectory, from a positive association of connectivity with intelligence in young boys (ages <9 years), to a negative association in older boys (ages >13 years). Our results provide evidence for disparate neuroanatomical trajectories underlying intelligence in boys and girls.

A longitudinal functional magnetic resonance imaging study of language development in children 5 to 11 years old

OBJECTIVE

Language skills continue to develop rapidly in children during the school-age years, and the "snapshot" view of the neural substrates of language provided by current neuroimaging studies cannot capture the dynamic changes associated with brain development. The aim of this study was to conduct a 5-year longitudinal investigation of language development using functional magnetic resonance imaging in healthy children.

METHODS

Thirty subjects enrolled at ages 5, 6, or 7 were examined annually for 5 years using a 3-Tesla magnetic resonance imaging scanner and a verb generation task. Data analysis was conducted based on a general linear model that was modified to investigate developmental changes whereas minimizing the potential for missing data.

RESULTS

With increasing age, there is progressive participation in language processing by the inferior/middle frontal, middle temporal, and angular gyri of the left hemisphere and the lingual and inferior temporal gyri of the right hemisphere and regression of participation of the left posterior insula/extrastriate cortex, left superior frontal and right anterior cingulate gyri, and left thalamus.

CONCLUSION

The age-related changes observed in this study provide evidence of increased neuroplasticity of language in this age group and may have implications for further investigations of normal and aberrant language development.

Making memories: a cross-sectional investigation of episodic memory encoding in childhood using FMRI

In adults, the neural substrate associated with encoding memories connected to a specific time and place include the prefrontal cortex and medial temporal lobe (MTL). Using functional magnetic resonance imaging, this research studied the developmental trajectory of this frontal-MTL system by comparing 7- and 8-year-old children to those who were 10 or older in conditions that promoted episodic encoding. In 1 condition, participants generated verbs from nouns heard; in another, they listened to short stories for comprehension. Regions in which brain activation predicted subsequent recognition memory performance were identified. These included the left prefrontal cortex, but not MTL, in the verb generation condition for both age groups. In the story comprehension condition, activation in left posterior MTL predicted subsequent memory performance in both age groups, and activation in left anterior MTL (including the hippocampus proper) and left prefrontal cortex predicted subsequent memory only for the older children. These results illustrate both similarities and differences in how brain systems interact in development to mediate the formation of episodic memories.

fMRI shows atypical language lateralization in pediatric epilepsy patients

PURPOSE

The goal of this study was to compare language lateralization between pediatric epilepsy patients and healthy children.

METHODS

Two groups of subjects were evaluated with functional magnetic resonance imaging (fMRI) by using a silent verb-generation task. The first group included 18 pediatric epilepsy patients, whereas the control group consisted of 18 age/gender/handedness-matched healthy subjects.

RESULTS

A significant difference in hemispheric lateralization index (LI) was found between children with epilepsy (mean LI =-0.038) and the age/gender/handedness-matched healthy control subjects (mean LI=0.257; t=6.490, p<0.0001). A dramatic difference also was observed in the percentage of children with epilepsy (77.78%) who had atypical LI (right-hemispheric or bilateral, LI<0.1) when compared with the age/gender/handedness-matched group (11.11%; chi(2)=16.02, p<0.001). A linear regression analysis showed a trend toward increasing language lateralization with age in healthy controls (R(2)=0.152; p=0.108). This association was not observed in pediatric epilepsy subjects (R(2)=0.004, p=0.80). A significant association between language LI and epilepsy duration also was found (R(2)=0.234, p<0.05).

CONCLUSIONS

This study shows that epilepsy during childhood is associated with neuroplasticity and reorganization of language function.

fMRI study of language lateralization in children and adults

Language lateralization in the brain is dependent on family history of handedness, personal handedness, pathology, and other factors. The influence of age on language lateralization is not completely understood. Increasing left lateralization of language with age has been observed in children, while the reverse has been noted in healthy young adults. It is not known whether the trend of decreasing language lateralization with age continues in the late decades of life and at what age the inflection in language lateralization trend as a function of age occurs. In this study, we examined the effect of age on language lateralization in 170 healthy right-handed children and adults ages 5-67 using functional MRI (fMRI) and a verb generation task. Our findings indicate that language lateralization to the dominant hemisphere increases between the ages 5 and 20 years, plateaus between 20 and 25 years, and slowly decreases between 25 and 70 years.

Functional magnetic resonance imaging reveals atypical language organization in children following perinatal left middle cerebral artery stroke

We used verb generation and story listening tasks during fMRI to study language organization in children (7, 9 and 12 years old) with perinatal left MCA infarctions. Healthy, age-matched comparison children (n = 39) showed activation in left Broca's area during the verb generation task; in contrast, stroke subjects showed activation either bilaterally or in the right hemisphere homologue during both tasks. In Wernicke's area, comparison subjects showed left lateralization (verb generation) and bilateral activation (L > R) (story listening). Stroke subjects instead showed bilateral or right lateralization (verb generation) and bilateral activation (R > L) (story listening). Language is distributed atypically in children with perinatal left hemisphere stroke.

Cognitive functions correlate with white matter architecture in a normal pediatric population: a diffusion tensor MRI study

A possible relationship between cognitive abilities and white matter structure as assessed by magnetic resonance diffusion tensor imaging (DTI) was investigated in the pediatric population. DTI was performed on 47 normal children ages 5-18. Using a voxelwise analysis technique, the fractional anisotropy (FA) and mean diffusivity (MD) were tested for significant correlations with Wechsler full-scale IQ scores, with subject age and gender used as covariates. Regions displaying significant positive correlations of IQ scores with FA were found bilaterally in white matter association areas, including frontal and occipito-parietal areas. No regions were found exhibiting correlations of IQ with MD except for one frontal area significantly overlapping a region containing a significant correlation with FA. The positive direction of the correlation with FA is the same as that found previously with age, and indicates a positive relationship between fiber organization and/or density with cognitive function. The results are consistent with the hypothesis that regionally specific increased fiber organization is a mechanism responsible for the normal development of white matter tracts.

Sound blending in the brain: a functional magnetic resonance imaging investigation

The presence of high levels of background noise is a serious concern for functional magnetic resonance imaging studies of phonological processing using conventional methods. As a result, many such studies have focused on phonological units larger than phonemes (e.g. syllables) or used stimuli presented in the visual (e.g. printed letters) rather than the auditory domain. We used a recently developed functional magnetic resonance imaging method to present spoken stimuli without the scanner's background noise. Young adult participants mentally blended phonemes in a series (e.g. /b/, /ae/, /t/), counted the number of discrete tones, or rested. Relative to tone counting, sound blending elicited activation in bilateral temporal and prefrontal cortices with left asymmetry. Activation within the dorsoposterior inferior frontal gyrus, a subregion of Broca's area, was negatively correlated with sound-blending accuracy. Our findings are consistent with prior studies ascribing a role of general sequencing, motor and articulatory programming, and vocal or subvocal articulatory rehearsal to this brain region.

Cognitive modules utilized for narrative comprehension in children: a functional magnetic resonance imaging study

The ability to comprehend narratives constitutes an important component of human development and experience. The neural correlates of auditory narrative comprehension in children were investigated in a large-scale functional magnetic resonance imaging (fMRI) study involving 313 subjects ages 5-18. Using group independent component analysis (ICA), bilateral task-related components were found comprising the primary auditory cortex, the mid-superior temporal gyrus, the hippocampus, the angular gyrus, and medial aspect of the parietal lobule (precuneus/posterior cingulate). In addition, a right-lateralized component was found involving the most posterior aspect of the superior temporal gyrus, and a left-lateralized component was found comprising the inferior frontal gyrus (including Broca's area), the inferior parietal lobule, and the medial temporal gyrus. Using a novel data-driven analysis technique, increased task-related activity related to age was found in the components comprising the mid-superior temporal gyrus (Wernicke's area) and the posterior aspect of the superior temporal gyrus, while decreased activity related to age was found in the component comprising the angular gyrus. The results are discussed in light of recent hypotheses involving the functional segregation of Wernicke's area and the specific role of the mid-superior temporal gyrus in speech comprehension.

Cortical reorganization in children with unilateral sensorineural hearing loss

Previous studies have shown evidence of cortical reorganization following unilateral sensorineural hearing loss (USNHL). In addition, study participants with right USNHL have shown greater deficits in academic and language performance compared with those with left USNHL. A preliminary functional magnetic resonance imaging investigation was performed on a small cohort of participants, four with left USNHL and four with right USNHL, using the paradigm of listening to random tones. While the participants with left USNHL displayed greater activation in the right superior temporal gyrus, those with right USNHL displayed greater activation in the left inferior frontal area immediately anterior to the superior temporal gyrus. The results provide preliminary evidence of disparate neural circuitry supporting auditory processing in participants with left and right USNHL.

Separate cortical networks involved in music perception: preliminary functional MRI evidence for modularity of music processing

Music perception is a quite complex cognitive task, involving the perception and integration of various elements including melody, harmony, pitch, rhythm, and timbre. A preliminary functional MRI investigation of music perception was performed, using a simplified passive listening task. Group independent component analysis (ICA) was used to separate out various components involved in music processing, as the hemodynamic responses are not known a priori. Various components consistent with auditory processing, expressive language, syntactic processing, and visual association were found. The results are discussed in light of various hypotheses regarding modularity of music processing and its overlap with language processing. The results suggest that, while some networks overlap with ones used for language processing, music processing may involve its own domain-specific processing subsystems.