Superior Temporal Gyrus Regions Research Articles

Cortical neuronal hypertrophy and mTOR pathway activation in CAN regions in SUDEP.

Dysfunctional connectivity and preexisting structural abnormalities of central autonomic network (CAN) regions have been shown on magnetic resonance imaging (MRI) in sudden unexpected death in epilepsy (SUDEP) and may be mechanistically relevant. In a previous postmortem study we reported increased microglia in CAN regions, including the superior temporal gyrus (STG) in SUDEP. In this current study we investigated mammalian target of rapamycin (mTOR) pathway activation and neuronal c-Fos activation in CAN regions in SUDEP compared to control groups. In a series of 59 postmortem cases (SUDEP, n=26; epilepsy controls [EPCs], n=14; and nonepilepsy controls [NECs], n=19), we quantified pS6-240/4, pS6-235/6 (markers of mTOR activation) and c-Fos neuronal densities and labeling index in the STG, anterior cingulate, insula, frontobasal, and pulvinar regions using immunohistochemistry with whole-slide automated image analysis. Significantly more pS6-positive neurons were present in the STG in cases with a history of recent seizures prior to death and also in SUDEP compared to other cause of death groups. No differences were noted for c-Fos neuronal labeling in any region between cause of death groups. Cortical neuronal hypertrophy in the STG was observed in some SUDEP cases and associated with pS6-240/4 expression. pS6-235/6 highlighted neuronal intranuclear inclusions, mainly in SUDEP cases and in the STG region. Neuronal labeling for pS6 in the STG correlated with both seizure activity in the period prior to death and SUDEP. Further investigations are required to explore the significance of this region in terms of autonomic network dysfunction that may increase the vulnerability for SUDEP.

Error in the Superior Temporal Gyrus? A Systematic Review and Activation Likelihood Estimation Meta-Analysis of Speech Production Studies.

Evidence for perceptual processing in models of speech production is often drawn from investigations in which the sound of a talker's voice is altered in real time to induce "errors." Methods of acoustic manipulation vary but are assumed to engage the same neural network and psychological processes. This paper aims to review fMRI and PET studies of altered auditory feedback and assess the strength of the evidence these studies provide for a speech error correction mechanism. Studies included were functional neuroimaging studies of speech production in neurotypical adult humans, using natural speech errors or one of three predefined speech manipulation techniques (frequency altered feedback, delayed auditory feedback, and masked auditory feedback). Seventeen studies met the inclusion criteria. In a systematic review, we evaluated whether each study (1) used an ecologically valid speech production task, (2) controlled for auditory activation caused by hearing the perturbation, (3) statistically controlled for multiple comparisons, and (4) measured behavioral compensation correlating with perturbation. None of the studies met all four criteria. We then conducted an activation likelihood estimation meta-analysis of brain coordinates from 16 studies that reported brain responses to manipulated over unmanipulated speech feedback, using the GingerALE toolbox. These foci clustered in bilateral superior temporal gyri, anterior to cortical fields typically linked to error correction. Within the limits of our analysis, we conclude that existing neuroimaging evidence is insufficient to determine whether error monitoring occurs in the posterior superior temporal gyrus regions proposed by models of speech production.

The role of left vs. right superior temporal gyrus in speech perception: An fMRI-guided TMS study

Debate continues regarding the necessary role of right superior temporal gyrus (STG) regions in sublexical speech perception given the bilateral STG activation often observed in fMRI studies. To evaluate the causal roles, TMS pulses were delivered to inhibit and disrupt neuronal activity at the left and right STG regions during a nonword discrimination task based on peak activations from a blocked fMRI paradigm assessing speech vs. nonspeech perception (N = 20). Relative to a control region located in the posterior occipital lobe, TMS to the left anterior STG (laSTG) led to significantly worse accuracy, whereas TMS to the left posterior STG (lpSTG) and right anterior STG (raSTG) did not. Although the disruption from TMS was significantly greater for the laSTG than for raSTG, the difference in accuracy between the laSTG and lpSTG did not reach significance. The results argue for a causal role of the laSTG but not raSTG in speech perception. Further research is needed to establish the source of the differences between the laSTG and lpSTG.

Pure word deafness in a patient with bilateral ischemic stroke in the superior temporal gyrus (STG)

ABSTRACT Introduction Pure word deafness is a rare neurological disorder linked with an inability to comprehend speech. The precise localization of damage is still unclear. Case presentation A 72-year-old woman presented with acute verbal contact disturbances, disorientation, and anxiety. In the neurological examination a slight right hemiparesis was found, together with a pure word deafness (PWD) in neuropsychological tests. Neuroimages confirmed bilateral ischemic lesions in the superior temporal gyrus (STG) acute in the left hemisphere. Conclusions Our case suggested that bilateral, symmetric lesions in the region of STG could cause pure world deafness. The diversity and severity of symptoms confirm the necessity of pure world deafness classification for subtypes.

Cortical auditory distance representation based on direct-to-reverberant energy ratio

Auditory distance perception and its neuronal mechanisms are poorly understood, mainly because 1) it is difficult to separate distance processing from intensity processing, 2) multiple intensity-independent distance cues are often available, and 3) the cues are combined in a context-dependent way. A recent fMRI study identified human auditory cortical area representing intensity-independent distance for sources presented along the interaural axis (Kopco et al. PNAS, 109, 11019-11024). For these sources, two intensity-independent cues are available, interaural level difference (ILD) and direct-to-reverberant energy ratio (DRR). Thus, the observed activations may have been contributed by not only distance-related, but also direction-encoding neuron populations sensitive to ILD. Here, the paradigm from the previous study was used to examine DRR-based distance representation for sounds originating in front of the listener, where ILD is not available. In a virtual environment, we performed behavioral and fMRI experiments, combined with computational analyses to identify the neural representation of distance based on DRR. The stimuli varied in distance (15–100 ​cm) while their received intensity was varied randomly and independently of distance. Behavioral performance showed that intensity-independent distance discrimination is accurate for frontal stimuli, even though it is worse than for lateral stimuli. fMRI activations for sounds varying in frontal distance, as compared to varying only in intensity, increased bilaterally in the posterior banks of Heschl’s gyri, the planum temporale, and posterior superior temporal gyrus regions. Taken together, these results suggest that posterior human auditory cortex areas contain neuron populations that are sensitive to distance independent of intensity and of binaural cues relevant for directional hearing.

A machine learning investigation of volumetric and functional MRI abnormalities in adults born preterm.

Imaging studies have characterized functional and structural brain abnormalities in adults after premature birth, but these investigations have mostly used univariate methods that do not account for hypothesized interdependencies between brain regions or quantify accuracy in identifying individuals. To overcome these limitations, we used multivariate machine learning to identify gray matter volume (GMV) and amplitude of low frequency fluctuations (ALFF) brain patterns that best classify young adults born very preterm/very low birth weight (VP/VLBW; n = 94) from those born full-term (FT; n = 92). We then compared the spatial maps of the structural and functional brain signatures and validated them by assessing associations with clinical birth history and basic cognitive variables. Premature birth could be predicted with a balanced accuracy of 80.7% using GMV and 77.4% using ALFF. GMV predictions were mediated by a pattern of subcortical and middle temporal reductions and volumetric increases of the lateral prefrontal, medial prefrontal, and superior temporal gyrus regions. ALFF predictions were characterized by a pattern including increases in the thalamus, pre- and post-central gyri, and parietal lobes, in addition to decreases in the superior temporal gyri bilaterally. Decision scores from each classification, assessing the degree to which an individual was classified as a VP/VLBW case, were predicted by the number of days in neonatal hospitalization and birth weight. ALFF decision scores also contributed to the prediction of general IQ, which highlighted their potential clinical significance. Combined, the results clarified previous research and suggested that primary subcortical and temporal damage may be accompanied by disrupted neurodevelopment of the cortex.

Hippocampal atrophy disrupts the language network but not hemispheric language lateralization.

It is still unclear how temporal lobe epilepsy (TLE) with and without hippocampal atrophy (HA) affects cortical language distribution. We aimed to investigate the role of the hippocampus on language lateralization, activation pattern, and functional connectivity (FC) in patients with TLE. We investigated 93 patients with TLE-divided into right HA (RHA), left HA (LHA), and negative magnetic resonance imaging (MRI) (non-HA)-and 101 controls using a semantic-language functional MRI (fMRI) task and the Boston Naming Test (BNT). Groups did not differ in the frequency of atypical language lateralization (LL), which correlated differently with handedness in each brain region and group. Blood-oxygen-level dependend (BOLD) activation patterns and region of interest (ROI)-to-ROI FC differed between LHA and controls, as well as between LHA and non-HA patients. In the task activation pattern analysis, there was a decrease in the activation of patients with LHA relative to controls, exactly in the left hippocampus. However, non-HA patients had increased FC relative to controls in the left superior temporal gyrus region. Seed-to-voxel FC demonstrated greater differences between patients and controls and smaller differences among patient groups. The non-HA group was similar to controls, except for increased BOLD activation and increase FC in the superior temporal gyri. RHA and LHA differed from controls in BNT. BNT correlated with fMRI activation in RHA and non-HA groups. LHA affected naming performance, fMRI semantic task activation pattern, and FC more than RHA and non-HA. Contrary to our expectations, LHA did not increase the frequency of atypical LL. Regardless of the side, HA impacts negatively on the language network but not on hemispheric language lateralization.

Aberrant DNA methylation associated with Alzheimer's disease in the superior temporal gyrus.

Abnormal DNA methylation patterns have been demonstrated to be associated with the pathogenesis of Alzheimer's disease (AD). The present study aimed to identify differential methylation in the superior temporal gyrus (STG) of patients with late-onset AD based on epigenome-wide DNA methylation data by bioinformatics analysis. The genome-wide DNA methylation data in the STG region of 34 patients with late-onset AD and 34 controls without dementia were recruited from the Gene Expression Omnibus database. Through systemic quality control, differentially methylated CpG sites were determined by the Student's t-test and mean methylation value differences between the two conditions. Hierarchical clustering analysis was applied to assess the classification performance of differentially methylated CpGs. Functional analysis was performed to investigate the biological functions of the genes associated with differentially methylated CpGs. A total of 17,895 differentially methylated CpG sites were initially identified, including 11,822 hypermethylated CpGs and 6,073 hypomethylated CpGs. Further analysis examined 2,211 differentially methylated CpGs (covering 1,991 genes). AD subjects demonstrated distinctive DNA methylation patterns when compared with the controls, with a classification accuracy value of 1. Hypermethylation was mainly detected for genes regulating the cell cycle progression, whereas hypomethylation was observed in genes involved in transcription factor binding. The present study demonstrated widespread and distinctive DNA methylation alterations in late-onset AD. Identification of AD-associated epigenetic biomarkers may allow for the development of novel diagnostic and therapeutic targets.

Planning for selective amygdalohippocampectomy involving less neuronal fiber damage based on brain connectivity using tractography.

Temporal lobe resection is an important treatment option for epilepsy that involves removal of potentially essential brain regions. Selective amygdalohippocampectomy is a widely performed temporal lobe surgery. We suggest starting the incision for selective amygdalohippocampectomy at the inferior temporal gyrus based on diffusion magnetic resonance imaging (MRI) tractography. Diffusion MRI data from 20 normal participants were obtained from Parkinson's Progression Markers Initiative (PPMI) database (www.ppmi-info.org). A tractography algorithm was applied to extract neuronal fiber information for the temporal lobe, hippocampus, and amygdala. Fiber information was analyzed in terms of the number of fibers and betweenness centrality. Distances between starting incisions and surgical target regions were also considered to explore the length of the surgical path. Middle temporal and superior temporal gyrus regions have higher connectivity values than the inferior temporal gyrus and thus are not good candidates for starting the incision. The distances between inferior temporal gyrus and surgical target regions were shorter than those between middle temporal gyrus and target regions. Thus, the inferior temporal gyrus is a good candidate for starting the incision. Starting the incision from the inferior temporal gyrus would spare the important (in terms of betweenness centrality values) middle region and shorten the distance to the target regions of the hippocampus and amygdala.

Neural networks mediating sentence reading in the deaf.

The present work addresses the neural bases of sentence reading in deaf populations. To better understand the relative role of deafness and spoken language knowledge in shaping the neural networks that mediate sentence reading, three populations with different degrees of English knowledge and depth of hearing loss were included—deaf signers, oral deaf and hearing individuals. The three groups were matched for reading comprehension and scanned while reading sentences. A similar neural network of left perisylvian areas was observed, supporting the view of a shared network of areas for reading despite differences in hearing and English knowledge. However, differences were observed, in particular in the auditory cortex, with deaf signers and oral deaf showing greatest bilateral superior temporal gyrus (STG) recruitment as compared to hearing individuals. Importantly, within deaf individuals, the same STG area in the left hemisphere showed greater recruitment as hearing loss increased. To further understand the functional role of such auditory cortex re-organization after deafness, connectivity analyses were performed from the STG regions identified above. Connectivity from the left STG toward areas typically associated with semantic processing (BA45 and thalami) was greater in deaf signers and in oral deaf as compared to hearing. In contrast, connectivity from left STG toward areas identified with speech-based processing was greater in hearing and in oral deaf as compared to deaf signers. These results support the growing literature indicating recruitment of auditory areas after congenital deafness for visually-mediated language functions, and establish that both auditory deprivation and language experience shape its functional reorganization. Implications for differential reliance on semantic vs. phonological pathways during reading in the three groups is discussed.

Effective connectivity associated with auditory error detection in musicians with absolute pitch

It is advantageous to study a wide range of vocal abilities in order to fully understand how vocal control measures vary across the full spectrum. Individuals with absolute pitch (AP) are able to assign a verbal label to musical notes and have enhanced abilities in pitch identification without reliance on an external referent. In this study we used dynamic causal modeling (DCM) to model effective connectivity of ERP responses to pitch perturbation in voice auditory feedback in musicians with relative pitch (RP), AP, and non-musician controls. We identified a network compromising left and right hemisphere superior temporal gyrus (STG), primary motor cortex (M1), and premotor cortex (PM). We specified nine models and compared two main factors examining various combinations of STG involvement in feedback pitch error detection/correction process. Our results suggest that modulation of left to right STG connections are important in the identification of self-voice error and sensory motor integration in AP musicians. We also identify reduced connectivity of left hemisphere PM to STG connections in AP and RP groups during the error detection and corrections process relative to non-musicians. We suggest that this suppression may allow for enhanced connectivity relating to pitch identification in the right hemisphere in those with more precise pitch matching abilities. Musicians with enhanced pitch identification abilities likely have an improved auditory error detection and correction system involving connectivity of STG regions. Our findings here also suggest that individuals with AP are more adept at using feedback related to pitch from the right hemisphere.

A novel PBL-McRBFN-RFE approach for identification of critical brain regions responsible for Parkinson’s disease

In this paper, we present a novel approach for the identification of critical brain regions responsible for Parkinson’s disease (PD) based on magnetic resonance images (MRI) using meta-cognitive radial basis function network (McRBFN) classifier with Recursive Feature Elimination (RFE). The McRBFN classifier uses voxel based morphometric (VBM) features extracted from MRI and employs a projection based learning (PBL) algorithm. The meta-cognitive learning present in PBL-McRBFN helps in selecting proper samples to learn based on its current knowledge and evolve the architecture automatically. Since, the classifier developed using PBL-McRBFN is efficient, we propose recursive feature elimination approach (called PBL-McRBFN-RFE) to identify most relevant brain regions responsible for PD prediction.The study has been conducted using the Parkinson’s Progression Markers Initiative (PPMI) data set. First, we conducted the study on PD prediction using the PBL-McRBFN classifier on the PPMI data set. We have also compared the results of the PBL-McRBFN classifier with the support vector machine (SVM) classifier. The study results clearly show that the PBL-McRBFN classifier produces better generalization performance on PD prediction. Finally, we use RFE approach with PBL-McRBFN to identify the brain regions responsible for PD. The PBL-McRBFN-RFE selected features indicate that the loss of gray matter in the superior temporal gyrus region may be responsible for the onset of PD, and is consistent with the earlier findings from medical research studies.

Towards a fronto-temporal neural network for the decoding of angry vocal expressions

Vocal expressions commonly elicit activity in superior temporal and inferior frontal cortices, indicating a distributed network to decode vocally expressed emotions. We examined the involvement of this fronto-temporal network for the decoding of angry voices during attention towards (explicit attention) or away from emotional cues in voices (implicit attention) based on a reanalysis of previous data (Frühholz, S., Ceravolo, L., Grandjean, D., 2012. Cerebral Cortex 22, 1107-1117). The general network revealed high interconnectivity of bilateral inferior frontal gyrus (IFG) to different bilateral voice-sensitive regions in mid and posterior superior temporal gyri. Right superior temporal gyrus (STG) regions showed connectivity to the left primary auditory cortex and secondary auditory cortex (AC) as well as to high-level auditory regions. This general network revealed differences in connectivity depending on the attentional focus. Explicit attention to angry voices revealed a specific right-left STG network connecting higher-level AC. During attention to a nonemotional vocal feature we also found a left-right STG network implicitly elicited by angry voices that also included low-level left AC. Furthermore, only during this implicit processing there was widespread interconnectivity between bilateral IFG and bilateral STG. This indicates that while implicit attention to angry voices recruits extended bilateral STG and IFG networks for the sensory and evaluative decoding of voices, explicit attention to angry voices solely involves a network of bilateral STG regions probably for the integrative recognition of emotional cues from voices.

Auditory object salience: human cortical processing of non-biological action sounds and their acoustic signal attributes

Whether viewed or heard, an object in action can be segmented as a distinct salient event based on a number of different sensory cues. In the visual system, several low-level attributes of an image are processed along parallel hierarchies, involving intermediate stages wherein gross-level object form and/or motion features are extracted prior to stages that show greater specificity for different object categories (e.g., people, buildings, or tools). In the auditory system, though relying on a rather different set of low-level signal attributes, meaningful real-world acoustic events and “auditory objects” can also be readily distinguished from background scenes. However, the nature of the acoustic signal attributes or gross-level perceptual features that may be explicitly processed along intermediate cortical processing stages remain poorly understood. Examining mechanical and environmental action sounds, representing two distinct non-biological categories of action sources, we had participants assess the degree to which each sound was perceived as object-like versus scene-like. We re-analyzed data from two of our earlier functional magnetic resonance imaging (fMRI) task paradigms (Engel et al., 2009) and found that scene-like action sounds preferentially led to activation along several midline cortical structures, but with strong dependence on listening task demands. In contrast, bilateral foci along the superior temporal gyri (STG) showed parametrically increasing activation to action sounds rated as more “object-like,” independent of sound category or task demands. Moreover, these STG regions also showed parametric sensitivity to spectral structure variations (SSVs) of the action sounds—a quantitative measure of change in entropy of the acoustic signals over time—and the right STG additionally showed parametric sensitivity to measures of mean entropy and harmonic content of the environmental sounds. Analogous to the visual system, intermediate stages of the auditory system appear to process or extract a number of quantifiable low-order signal attributes that are characteristic of action events perceived as being object-like, representing stages that may begin to dissociate different perceptual dimensions and categories of every-day, real-world action sounds.

Combining fiber tracking and functional brain imaging for revealing brain networks involved in auditory–visual integration in humans

Previous functional magnetic resonance imaging (MRI) found various brain areas in the temporal and occipital lobe involved in integrating auditory and visual object information. Fiber tracking based on diffusion-weighted MRI suggested neuroanatomical connections between auditory cortex and sub-regions of the temporal and occipital lobe. However, the relationship between functional activity and white-matter tracks remained unclear. Here, we combined probabilistic tracking and functional MRI in order to reveal the structural connections related to auditory–visual object perception. Ten healthy people were examined by diffusion-weighted and functional MRI. During functional examinations they viewed either movies of lip or body movements, listened to corresponding sounds (phonological sounds or body action sounds), or a combination of both. We found that phonological sounds elicited stronger activity in the lateral superior temporal gyrus (STG) than body action sounds. Body movements elicited stronger activity in the lateral occipital cortex than lip movements. Functional activity in the phonological STG region and the lateral occipital body area were mutually modulated (sub-additive) by combined auditory–visual stimulation. Moreover, bimodal stimuli engaged a region in the posterior superior temporal sulcus (STS). Probabilistic tracking revealed white-matter tracks between the auditory cortex and sub-regions of the STS (anterior and posterior) and occipital cortex. The posterior STS region was also found to be relevant for auditory–visual object perception. The anterior STS region showed connections to the phonological STG area and to the lateral occipital body area. Our findings suggest that multisensory networks in the temporal lobe are best revealed by combining functional and structural measures.

Sound localization difficulty affects early and late processing of auditory spatial information: Investigation using the dipole tracing method

To understand the functional roles of brain regions related in the auditory spatial localization, we recorded auditory event-related potentials (ERPs) and estimated their source generators using the dipole tracing method. Target sound stimuli perceived as coming from two directions (-90 degrees, +90 degrees where 0 degrees was straight behind the subject within the azimuth in the interaural plane) were randomly presented with two distracter stimuli for providing difficulty of detection. The distracter stimuli were 75 degrees behind the target stimuli (easy task) and 45 degrees behind the target stimuli (difficult task). Compared with the passive listening tasks, distinct potentials appeared in the easy task at the early (110-150 ms: N1-late) time windows of ERPs and in the difficult task at the late (450-800 ms: slow wave, SW) time windows of ERPs. Dipoles were estimated to be at the posterior auditory cortex, precuneus and thalamus for N1-late, and the middle/inferior frontal gyrus, anterior region of superior temporal gyrus and parahippocampal gyrus for SW for both tasks. Difficulty of sound localization may affect brain function related to analyzing features of the spatial cue, eventually identifying the spatial location, and attention. Brain regions responsible for sound localization may show different activity patterns depending on the functional roles of each brain region.

Attentional Modulation in the Detection of Irrelevant Deviance: A Simultaneous ERP/fMRI Study

Little is known about the neural mechanisms that control attentional modulation of deviance detection in the auditory modality. In this study, we manipulated the difficulty of a primary task to test the relation between task difficulty and the detection of infrequent, task-irrelevant deviant (D) tones (1,300 Hz) presented among repetitive standard (S) tones (1,000 Hz). Simultaneous functional magnetic resonance imaging (fMRI)/event-related potentials (ERPs) were recorded from 21 subjects performing a two-alternative forced-choice duration discrimination task (short and long tones of equal probability). The duration of the short tone was always 50 msec. The duration of the long tone was 100 msec in the easy task and 60 msec in the difficult task. As expected, response accuracy decreased and response time (RT) increased in the difficult compared with the easy task. Performance was also poorer for D than for S tones, indicating distraction by task-irrelevant frequency information on trials involving D tones. In the difficult task, an amplitude increase was observed in the difference waves for N1 and P3a, ERP components associated with increased attention to deviant sounds. The mismatch negativity (MMN) response, associated with passive deviant detection, was larger in the easy task, demonstrating the susceptibility of this component to attentional manipulations. The fMRI contrast D > S in the difficult task revealed activation on the right superior temporal gyrus (STG) and extending ventrally into the superior temporal sulcus, suggesting this region's involvement in involuntary attention shifting toward unattended, infrequent sounds. Conversely, passive deviance detection, as reflected by the MMN, was associated with more dorsal activation on the STG. These results are consistent with the view that the dorsal STG region is responsive to mismatches between the memory trace of the standard and the incoming deviant sound, whereas the ventral STG region is activated by involuntary shifts of attention to task-irrelevant auditory features.

Dorsolateral prefrontal and superior temporal volume deficits in first–episode psychoses that evolve into schizophrenia

Regions with a likely involvement in schizophrenia may differ between patients with first-episodes of psychosis respectively with and without evolution into schizophrenia following the initial episode. We have used magnetic resonance imaging (MRI) to assess the volumes of dorsolateral prefrontal (DLPF) and superior temporal gyrus (STG) in a group of 37 first-episode psychotic patients. After an initial MRI study performed by the time of the first episode, the subjects were followed for two years. After this period 22 cases were diagnosed with schizophrenia, while the other 15 did not show clinical evidence for this illness. A Talairach-based tool was used for segmentation and volumetry of the MRI scans. A group of 44 healthy controls was used for comparison and, using lineal regression, to control for the normal effects of age and intracranial volume on the regional parameters of the patients. By the time of their first episode, patients with schizophrenia had significantly less grey matter in the right DLPF and STG regions as compared to both controls and FE without schizophrenia. Nevertheless, these parameters could not predict final diagnosis in a discriminant analysis model. Our findings indicate that subtle structural defects are already found by the time of the first psychotic break in schizophrenia, although clinical implications for these differences seem unclear.

Response of anterior temporal cortex to syntactic and prosodic manipulations during sentence processing

Previous research has implicated a portion of the anterior temporal cortex in sentence-level processing. This region activates more to sentences than to word-lists, sentences in an unfamiliar language, and environmental sound sequences. The current study sought to identify the relative contributions of syntactic and prosodic processing to anterior temporal activation. We presented auditory stimuli where the presence of prosodic and syntactic structure was independently manipulated during functional magnetic resonance imaging (fMRI). Three "structural" conditions included normal sentences, sentences with scrambled word order, and lists of content words. These three classes of stimuli were presented either with sentence prosody or with flat supra-lexical (list-like) prosody. Sentence stimuli activated a portion of the left anterior temporal cortex in the superior temporal sulcus (STS) and extending into the middle temporal gyrus, independent of prosody, and to a greater extent than any of the other conditions. An interaction between the structural conditions and prosodic conditions was seen in a more dorsal region of the anterior temporal lobe bilaterally along the superior temporal gyrus (STG). A post-hoc analysis revealed that this region responded either to syntactically structured stimuli or to nonstructured stimuli with sentence-like prosody. The results suggest a parcellation of anterior temporal cortex into 1) an STG region that is sensitive both to the presence of syntactic information and is modulated by prosodic manipulations (in nonsyntactic stimuli); and 2) a more inferior left STS/MTG region that is more selective for syntactic structure.

Aberrant localization of synchronous hemodynamic activity in auditory cortex reliably characterizes schizophrenia

BackgroundAmong the most prominent features of schizophrenic brains are abnormalities in auditory cortex structure and function, particularly in the superior temporal gyrus (STG). In this study, we attempted to examine auditory cortex function using an intrinsic, task-uncorrelated measure. MethodsUsing functional magnetic resonance imaging data, we calculated synchronous hemodynamic independent maps (SHIMs) of auditory cortex in patients with schizophrenia and matched healthy control subjects while they performed an auditory oddball task. ResultsPatient SHIMs revealed greater synchrony in ventral and medial STG regions (including auditory association Brodmann area [BA] 42); control SHIMs had greater synchrony in dorsal and lateral STG regions (which did not include BA 42). A within-participant subtractive comparison of these two sets of regions differentiated schizophrenic from healthy control subjects with 97% accuracy initially (further validated by a retest of the healthy control subjects) and performed with 94% accuracy in a confirmatory study of new subjects scanned at a different site. ConclusionsThese results shed new light on STG functional differences in schizophrenia, suggest that aberrant patterns of coherence in temporal lobe cortical regions are a cardinal abnormality in schizophrenia, and have the potential to provide a powerful, quantitative clinical tool for the assessment of schizophrenia.