Auditory cortical volumes and musical ability in Williams syndrome

Individuals with Williams syndrome (WS) have been shown to have atypical morphology in the auditory cortex, an area associated with aspects of musicality. Some individuals with WS have demonstrated specific musical abilities, despite intellectual delays. Primary auditory cortex and planum temporale volumes were manually segmented in 25 individuals with WS and 25 control participants, and the participants also underwent testing of musical abilities. Left and right planum temporale volumes were significantly larger in the participants with WS than in controls, with no significant difference noted between groups in planum temporale asymmetry or primary auditory cortical volumes. Left planum temporale volume was significantly increased in a subgroup of the participants with WS who demonstrated specific musical strengths, as compared to the remaining WS participants, and was highly correlated with scores on a musical task. These findings suggest that differences in musical ability within WS may be in part associated with variability in the left auditory cortical region, providing further evidence of cognitive and neuroanatomical heterogeneity within this syndrome.     

Planum temporale and Heschl gyrus volume reduction in schizophrenia: a magnetic resonance imaging study of first-episode patients

BACKGROUND: Magnetic resonance imaging studies in schizophrenia have revealed abnormalities in temporal lobe structures, including the superior temporal gyrus. More specifically, abnormalities have been reported in the posterior superior temporal gyrus, which includes the Heschl gyrus and planum temporale, the latter being an important substrate for language. However, the specificity of the Heschl gyrus and planum temporale structural abnormalities to schizophrenia vs affective psychosis, and the possible confounding roles of chronic morbidity and neuroleptic treatment, remain unclear. METHODS: Magnetic resonance images were acquired using a 1.5-T magnet from 20 first-episode (at first hospitalization) patients with schizophrenia (mean age, 27.3 years), 24 first-episode patients with manic psychosis (mean age, 23.6 years), and 22 controls (mean age, 24.5 years). There was no significant difference in age for the 3 groups. All brain images were uniformly aligned and then reformatted and resampled to yield isotropic voxels. RESULTS: Gray matter volume of the left planum temporale differed among the 3 groups. The patients with schizophrenia had significantly smaller left planum temporale volume than controls (20.0%) and patients with mania (20.0%). Heschl gyrus gray matter volume (left and right) was also reduced in patients with schizophrenia compared with controls (13.1%) and patients with bipolar mania (16.8%). CONCLUSIONS: Compared with controls and patients with bipolar manic psychosis, patients with first-episode schizophrenia showed left planum temporale gray matter volume reduction and bilateral Heschl gyrus gray matter volume reduction. These findings are similar to those reported in patients with chronic schizophrenia and suggest that such abnormalities are present at first episode and are specific to schizophrenia.     

Morphometry of the superior temporal plane in schizophrenia: relationship to clinical correlates

A magnetic-resonance-imaging-based method of cortical parcellation was used to evaluate the morphology of the superior temporal plane and its subregions (Heschl's gyrus [HG], planum temporale [PT], and planum polare [PP]) in a group of 30 patients with schizophrenia versus a matched group of healthy subjects. Right HG volume was significantly reduced in patients compared with control subjects. Each subregion showed a unique set of structure/function relationships: reduced volumes of the HG were associated with greater duration of illness; reduced volumes of the PT were associated with positive symptoms; and in most contrast, elevated volumes of the PP were associated with cumulative neuroleptic exposure.     

Does the definition of borders of the planum temporale influence the results in schizophrenia?

OBJECTIVE: The planum temporale, a highly asymmetric neocortical area of the temporal lobe, has a possible role in schizophrenia. The authors used three different anatomical definitions of the planum temporale to examine the anterior, posterior, and total planum temporale gray matter volumes simultaneously. METHOD: Magnetic resonance imaging was used to examine 30 male schizophrenic patients and 30 healthy male comparison subjects. The total planum temporale was identical in all three anatomical definitions applied to determine the border between the anterior and posterior planum temporale regions. RESULTS: No significant differences between men with and without schizophrenia were detected with regard to planum temporale volumes and asymmetry coefficients for any of the three definitions. CONCLUSIONS: The authors could not prove the hypothesis that the definition of planum temporale borders influences the results concerning possible disturbances of planum temporale asymmetry in patients with schizophrenia.     

Progressive decrease of left Heschl gyrus and planum temporale gray matter volume in first-episode schizophrenia: a longitudinal magnetic resonance imaging study

BACKGROUND: The Heschl gyrus and planum temporale have crucial roles in auditory perception and language processing. Our previous investigation using magnetic resonance imaging (MRI) indicated smaller gray matter volumes bilaterally in the Heschl gyrus and in left planum temporale in patients with first-episode schizophrenia but not in patients with first-episode affective psychosis. We sought to determine whether there are progressive decreases in anatomically defined MRI gray matter volumes of the Heschl gyrus and planum temporale in patients with first-episode schizophrenia and also in patients with first-episode affective psychosis. METHODS: At a private psychiatric hospital, we conducted a prospective high spatial resolution MRI study that included initial scans of 28 patients at their first hospitalization (13 with schizophrenia and 15 with affective psychosis, 13 of whom had a manic psychosis) and 22 healthy control subjects. Follow-up scans occurred, on average, 1.5 years after the initial scan. RESULTS: Patients with first-episode schizophrenia showed significant decreases in gray matter volume over time in the left Heschl gyrus (6.9%) and left planum temporale (7.2%) compared with patients with first-episode affective psychosis or control subjects. CONCLUSIONS: These findings demonstrate a left-biased progressive volume reduction in the Heschl gyrus and planum temporale gray matter in patients with first-episode schizophrenia in contrast to patients with first-episode affective psychosis and control subjects. Schizophrenia but not affective psychosis seems to be characterized by a postonset progression of neocortical gray matter volume loss in the left superior temporal gyrus and thus may not be developmentally fixed.     

Temporal lobe abnormalities in first-episode psychosis

OBJECTIVE: The nature and time course of temporal lobe abnormalities in psychotic illness remain controversial. Confounds include disease chronicity, gender, and handedness. The present study investigated temporal substructures in right-handed male patients experiencing their first episode of psychotic illness. METHOD: Magnetic resonance imaging scans were obtained for 25 minimally treated patients experiencing their first psychotic episode and 16 healthy comparison subjects. Group differences in volumes of the hippocampus, amygdala, planum temporale, and Heschl's gyrus were tested. RESULTS: The patients had smaller bilateral hippocampal and left planum temporale volumes than the comparison subjects. Paranoid and nonparanoid patients differed in left amygdala volume. CONCLUSIONS: The authors conclude that bilateral hippocampal and left planum temporale abnormalities are present near the onset of psychosis.     

Left planum temporale volume reduction in schizophrenia

BACKGROUND: The planum temporale, located on the posterior and superior surface of the temporal lobe, is a brain region thought to be a biological substrate of language and possibly implicated in the pathophysiology of schizophrenia. To investigate further the role of planum temporale abnormalities in schizophrenia, we measured gray matter volume underlying the planum temporale from high spatial resolution magnetic resonance imaging techniques. METHODS: Sixteen male patients with chronic schizophrenia and 16 control subjects were matched for age, sex, handedness, and parental socioeconomic status. Magnetic resonance imaging images were obtained from a 1.5-T magnet. RESULTS: Gray matter volume was significantly reduced in the left planum temporale (28.2%) in schizophrenic patients compared with normal controls. Schizophrenic patients showed a reversal of the left greater than right planum temporale asymmetry found in normal controls. Heschl's gyrus (primary auditory cortex) showed no differences between the left and right sides in either group. Of note, the Suspiciousness/Persecution subscale score of the Positive and Negative Syndrome Scale was associated with reduced left planum temporale volume in schizophrenic patients. CONCLUSIONS: Patients with schizophrenia have reduced left planum temporale gray matter and a reversal of planum temporale asymmetry, which may underlie an impairment in language processing and symptoms of suspiciousness or persecution characteristic of schizophrenia.     

Gray and white matter asymmetries in healthy individuals aged 21-29 years: a voxel-based morphometry and diffusion tensor imaging study

The hemispheres of the human brain are functionally and structurally asymmetric. The study of structural asymmetries provides important clues to the neuroanatomical basis of lateralized brain functions. Previous studies have demonstrated age-related changes in morphology and diffusion properties of brain tissue. In this study, we simultaneously explored gray and white matter asymmetry using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) in 109 young healthy individuals (58 females and 51 males). To eliminate the potential confounding effects of aging and handedness, we restricted the study to right-handed subjects aged 21-29 years. VBM and voxel-based analysis of fractional anisotropy (FA) maps derived from DTI revealed a number of gray matter volume asymmetries (including the right frontal and left occipital petalias and leftward asymmetry of the planum temporale) and white matter FA asymmetries (including leftward asymmetry of the arcuate fasciculus, cingulum, and corticospinal tract). There was no significant effect of sex on gray and white matter asymmetry. Leftward volume asymmetry of the planum temporale and leftward FA asymmetry of the arcuate fasciculus were simultaneously demonstrated. Post hoc analysis showed that the gray matter volume of the planum temporale and FA of the arcuate fasciculus were positively related (Pearson correlation coefficient, 0.43; P < 0.0001). The results of our study demonstrate gray and white matter asymmetry in right-handed healthy young adults and suggest that leftward volume asymmetry of the planum temporale and leftward FA asymmetry of the arcuate fasciculus may be related.     

Smaller left Heschl's gyrus volume in patients with schizotypal personality disorder

OBJECTIVE: Individuals with schizophrenia spectrum disorders evince similar genetic, neurotransmitter, neuropsychological, electrophysiological, and structural abnormalities. Magnetic resonance imaging (MRI) studies have shown smaller gray matter volume in patients with schizotypal personality disorder than in matched comparison subjects in the left superior temporal gyrus, an area important for language processing. In a further exploration, the authors studied two components of the superior temporal gyrus: Heschl's gyrus and the planum temporale. METHOD: MRI scans were acquired from 21 male, neuroleptic-naive subjects recruited from the community who met DSM-IV criteria for schizotypal personality disorder and 22 male comparison subjects similar in age. Eighteen of the 21 subjects with schizotypal personality disorder had additional comorbid, nonpsychotic diagnoses. The superior temporal gyrus was manually delineated on coronal images with subsequent identification of Heschl's gyrus and the planum temporale. Exploratory correlations between region of interest volumes and neuropsychological measures were also performed. RESULTS: Left Heschl's gyrus gray matter volume was 21% smaller in the schizotypal personality disorder subjects than in the comparison subjects, a difference that was not associated with the presence of comorbid axis I disorders. There were no between-group volume differences in right Heschl's gyrus or in the right or left planum temporale. Exploratory analyses also showed a correlation between poor logical memory and smaller left Heschl's gyrus volume. CONCLUSIONS: Smaller left Heschl's gyrus gray matter volume in subjects with schizotypal personality disorder may help to explain the previously reported abnormality in the left superior temporal gyrus and may be a vulnerability marker for schizophrenia spectrum disorders.     

Association between smaller left posterior superior temporal gyrus volume on magnetic resonance imaging and smaller left temporal P300 amplitude in first-episode schizophrenia

BACKGROUND: In chronic schizophrenia, the P300 is broadly reduced and shows a localized left temporal deficit specifically associated with reduced gray matter volume of the left posterior superior temporal gyrus (STG). In first-episode patients, a similar left temporal P300 deficit is present in schizophrenia, but not in affective psychosis. The present study investigated whether the left temporal P300-left posterior STG volume association is selectively present in first-episode schizophrenia. METHOD: P300 was recorded as first-episode subjects with schizophrenia (n = 15) or affective psychosis (n = 18) or control subjects (n = 18) silently counted infrequent target tones amid standard tones. High-resolution spoiled gradient-recalled acquisition magnetic resonance images provided quantitative measures of temporal lobe gray matter regions of interest. RESULTS: Patients with first-episode schizophrenia displayed a reversed P300 temporal area asymmetry (smaller on the left), while magnetic resonance imaging showed smaller gray matter volumes of left posterior STG relative to control subjects and patients with affective psychosis (15.4% and 11.0%, respectively), smaller gray matter volumes of left planum temporale (21.0% relative to both), and a smaller total Heschl's gyrus volume (14.6% and 21.1%, respectively). Left posterior STG and the left planum temporale, but not other regions of interest, were specifically and positively correlated (r>0.5) with left temporal P300 voltage in patients with schizophrenia but not in patients with affective psychosis or in control subjects. CONCLUSION: These results suggest that the left temporal P300 abnormality specifically associated with left posterior STG gray matter volume reduction is present at the first hospitalization for schizophrenia but is not present at the first hospitalization for affective psychosis.     

Cerebral volumetric asymmetries in non-human primates: a magnetic resonance imaging study

Magnetic resonance images (MRI) were collected in a sample of 23 apes, 14 Old World monkeys, and 8 New World monkeys. The total area or volume of the anterior and posterior cerebral regions of each hemisphere of the brain was measured. The results indicated that a rightward frontal and leftward occipital pattern of asymmetry was present at a population level in the great ape sample. Population-level cerebral asymmetries were not revealed in the sample of New or Old World monkeys. The total area or volume of the planum temporale, which was localised only in the great apes, was also measured in both hemispheres. A leftward planum temporale asymmetry was evident at the population level in the great apes. It was hypothesised that the rightward frontal and leftward occipital asymmetries would correlate with leftward planum temporale asymmetries. This hypothesis was based on the assumption that, similar to development of the human brain, the nonhuman primate brain 'torques' during development due to a growth gradient which progresses anterior to posterior, ventral to dorsal, and right to left. The results of this study confirmed the predicted relationship between cerebral volume and the planum temporale asymmetries. This supports the hypothesis that the great ape brain may develop in a 'torquing' manner, producing similar anatomical asymmetries as reported in humans.     

Significant relation between MR measures of planum temporale area and dichotic processing of syllables in dyslexic children

In the present study, we investigated differences between dyslexic and normal reading children in asymmetry of the planum temporale area in the upper posterior part of the temporal lobe and dichotic listening performance to consonant-vowel syllables. The current study was an extension of previous studies in our laboratory on the same participants, now including also girls and left-handers. There were 20 boys and 3 girls in the dyslexic group and 19 boys and 4 girls in the normal reading group. The age of the participants was 10-12 years for both groups. The participants were screened from a population of 950 students in the fourth school grade in the greater Bergen district. The planum temporale area was measured in sagittal magnetic resonance (MR) images. Mean left and right area and asymmetry index were compared between the groups. Dichotic presentations of consonant-vowel syllables made it possible to separately probe left and right hemisphere phonological function, and to correlate this with planum temporale area. The results showed a significantly larger left than right planum temporale area for both groups. However, while the right planum temporale area was similar for the dyslexic and control groups, the left planum temporale was significantly (one-tailed t-test) smaller in the dyslexic group. Both groups also showed a significant right ear advantage to the consonant-vowel syllables in the dichotic listening test. The relation between planum temporale and dichotic listening asymmetry showed a significant correlation for the dyslexic group only, indicating a positive relation between brain structure and function in dyslexic children. The results are discussed in terms of important subject characteristics with regard to brain markers of dyslexia.     

Age-Related Changes in the Anatomy of Language Regions in Autism Spectrum Disorder

Impairments in language and communication are core features of autism spectrum disorder (ASD). The anatomy of critical language areas has been studied in ASD with inconsistent findings. We used MRI to measure gray matter volume and asymmetry of Heschl’s gyrus, planum temporale, pars triangularis, and pars opercularis in 40 children and adolescents with ASD and 40 typically developing individuals, each divided into younger (7–11 years) and older (12–19 years) cohorts. The older group had larger left planum temporale volume and stronger leftward asymmetry than the younger group, regardless of diagnosis. The pars triangularis and opercularis together were larger in ASD than controls. Correlations between frontal language areas with language and symptom severity scores were significant in younger ASD children. Results suggest similar developmental changes in planum temporale anatomy in both groups, but group differences in pars triangularis and opercularis that may be related to language abilities and autism symptom severity.     

The left human speech-processing cortex is thinner but longer than the right

We present histological data from 21 post-mortem, adult human cases that indicate the neocortex on the left planum temporale (secondary auditory cortex) is thinner but longer than that on the right side. The volumes of the left and right regions are approximately equal. Thus, the left planum temporale cortex is long and thin and the right short and thick. The present data fit excellently with previous studies of the volume, surface area, cytoarchitectonics, and neuronal structures of these areas. From these studies we suggest that the hemispheric differences arise from a so-called "balloon model" of cortical development. In this the cortex is extended and stretched by white matter growth. The stretching is greater on the left side, leaving greater distances between neuronal columns and more tangentially (to the pial surface) oriented dendrites on that side. This difference in fine structure can result in more independent activity of individual columns on the left, and could be an anatomical factor in the usual dominance of the left hemisphere for speech perception (Seldon, 1982, 1985).     

Cingulate cortex anatomical abnormalities in children and adolescents with bipolar disorder

OBJECTIVE: In vivo imaging studies have suggested anatomical and functional abnormalities in the anterior cingulate in adults with mood disorders. This anatomical magnetic resonance imaging study examined the cingulate cortex in children and adolescents with bipolar disorder and matched healthy comparison subjects. METHOD: Sixteen patients (mean age=15.5 years, SD=3.4) with DSM-IV bipolar disorder and 21 matched healthy comparison subjects (mean age=16.9 years, SD=3.8) were studied. Three-dimensional gradient echo imaging was performed (TR=25 msec, TE=5 msec, slice thickness=1.5 mm) in a 1.5-T GE Signa magnet. Cingulate volumes were compared by using analysis of covariance, with age and intracranial volume as covariates. RESULTS: The patients with bipolar disorder had significantly smaller mean volumes relative to the healthy subjects in the left anterior cingulate (mean=2.49 cm(3 [SD=0.28] versus 3.60 cm3 [SD=0.12], respectively), left posterior cingulate (2.53 cm3 [SD=0.32] versus 2.89 cm3 [SD=0.09]), and right posterior cingulate (2.19 cm3 [SD=0.13] versus 2.28 cm3 [SD=0.08]). No significant between-group difference was found for the right anterior cingulate (2.64 cm3 [SD=0.21] versus 2.71 cm3 [SD=0.10]). CONCLUSIONS: The findings indicate smaller cingulate volumes in children and adolescents with bipolar disorder, suggesting that such abnormalities may be present early in the illness course.     

Brain morphology in normal and dyslexic children: The influence of sex and age

Morphometric magnetic resonance imaging techniques were used to compare the convolutional surface area of the planum temporale, temporal lobe volume and superior surface area, and an estimate of overall brain volume in a homogeneous sample of 17 dyslexic children (7 girls) and 14 nonimpaired children (7 girls). Substantial sex differences were apparent for all measured regions, with all the measurements in boys being significantly larger. Age, even within the narrow range employed here (7.5–9.7 years), was positively correlated with the size of each brain region. While initial analyses suggested smaller left hemisphere structures in dyslexics compared to control subjects, subsequent analyses controlling for age and overall brain size revealed no significant differences between dyslexics and nonimpaired children on a variety of measures, in particular surface area and symmetry of the planum temporale. We suggest that differences in subject characteristics (i.e., sex, age, handedness, and definition of dyslexia) as well as procedural variations in the methods used to acquire images and to define and measure anatomical regions of interest such as the planum temporale all may play an important role in explaining apparent discrepant results in the neuroimaging literature on dyslexia.     

The left human speech-processing cortex is thinner but longer than the right

We present histological data from 21 post-mortem, adult human cases that indicate the neocortex on the left planum temporale (secondary auditory cortex) is thinner but longer than that on the right side. The volumes of the left and right regions are approximately equal. Thus, the left planum temporale cortex is long and thin and the right short and thick. The present data fit excellently with previous studies of the volume, surface area, cytoarchitectonics, and neuronal structures of these areas. From these studies we suggest that the hemispheric differences arise from a so-called "balloon model" of cortical development. In this the cortex is extended and stretched by white matter growth. The stretching is greater on the left side, leaving greater distances between neuronal columns and more tangentially (to the pial surface) oriented dendrites on that side. This difference in fine structure can result in more independent activity of individual columns on the left, and could be an anatomical factor in the usual dominance of the left hemisphere for speech perception (Seldon, 1982, 1985).     

Volume reduction of the left planum temporale gray matter associated with long duration of untreated psychosis in schizophrenia: a preliminary report

A longer duration of untreated psychosis (DUP) in schizophrenia is reported to lead to a poorer clinical outcome, possibly reflecting a neurodegenerative process after the onset of overt psychosis. However, the effect of DUP on brain morphology in schizophrenia is still poorly understood. In this study, we used magnetic resonance imaging to investigate the relation between DUP and volumetric measurements for the superior temporal sub-regions (Heschl's gyrus, planum temporale, and caudal superior temporal gyrus), the medial temporal lobe structures (hippocampus and amygdala), and the frontal lobe regions (prefrontal area and anterior cingulate gyrus) in a sample of 38 schizophrenia patients (20 males and 18 females) whose illness duration was less than five years. We found a significant negative correlation between DUP and the volume of gray matter in the left planum temporale even after controlling for age, age at illness onset, and duration and dosage of neuroleptic medication. There was no such correlation for the other brain regions including each sub-region of the prefrontal cortex (the superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus, ventral medial prefrontal cortex, orbitofrontal cortex, and straight gyrus). When subjects were divided into two groups around the median DUP, the long-DUP group had a significantly smaller planum temporale gray matter than the short-DUP group. These findings may reflect a progressive pathological process in the gray matter of the left planum temporale during the initial untreated phase of schizophrenia, whereas abnormalities in the medial temporal regions might be, as has been suggested from previous longitudinal findings, relatively static at least during the early course of the illness.     

Planum temporale asymmetry and ear advantage in dichotic listening in Developmental Dyslexia and Attention-Deficit/Hyperactivity Disorder (ADHD).

The planum temporale is clearly involved in language processing, for it serves as the auditory association cortex. Research has consistently demonstrated that 60 to 70% of the population has leftward asymmetry of the planum temporale. Research has also suggested that dyslexic individuals tend to have either rightward asymmetry or symmetrical plana. Moreover, many studies have found a relationship between the presence of dyslexia and/or language impairment and deficits in the normal right ear advantage found in dichotic listening paradigms. In this context, this study examined the relationship between planum temporale asymmetry and ear preference in dichotic listening performance in children with Developmental Dyslexia and Attention-Deficit/Hyperactivity Disorder (ADHD). Subjects included 19 children with dyslexia (10 of whom had a comorbid diagnosis of ADHD), 23 children with ADHD, and 12 diagnosed normal control children. Dichotic listening data were not collected for 8 of the 12 normal control children and for 3 of the 23 ADHD children. Results revealed no significant difference between ADHD and dyslexic subjects in regard to ear advantage on the free recall dichotic listening task. In addition, although the directed dichotic listening tasks were not related to degree of planum asymmetry, as predicted, results indicated that subjects who consistently displayed an atypical left ear advantage tended to have larger right bank lengths than those who consistently displayed a typical right ear advantage. These findings support the notion that some individuals with dyslexia or language deficits tend to have a larger right planum temporale and that performance on dichotic listening tasks may reflect this relatively unusual pattern.     

Hemispheric specialization for language: Brain volume matters

Increasing brain volume may impose constraints, through longer information transfer delays, on the distributed networks supporting language. Here, we assessed the relative effects of brain volume and other putative predictors of the functional variability of perisylvian language areas, as probed with PET, during both a language comprehension and a language production task. In the case of language comprehension (story listening), a linear combination of planum temporale surface, brain volume and handedness could explain almost 60% of the functional asymmetry observed in the perisylvian area. Without brain volume, the goodness of fit was significantly decreased (39%, P < 0.05), and furthermore, the effect of handedness was not detected anymore. This was due to the fact that in our sample, left-handers (n = 12) had a significantly larger brain volume as compared to right-handers (n = 8, P = 0.03). As for language production (verb generation), brain volume and the planum temporale also played a role. However, in this case, the main predictor of functional variability was handedness, where a greater degree of right-handedness was associated with larger activation of left inferior frontal regions. Depending on the language component of interest, these results support different (yet compatible) theories on hemispheric specialization. Left specialization for comprehension could be attributed to the constraints of processing speech stimuli, while a gestural origin of language is mostly supported by the relation we observed between left specialization for production and right-handedness.