Where is heschls area

That portion of the superior temporal gyrus that lies inside the banks of the lateral fissure the temporal operculum. This area is also referred to as the transverse gyri of Heschl as the individual gyri are oriented in a lateral—medial plane within the operculum as opposed to a more anterior—posterior or inferior—superior plane of most of the cortical gyri.

This region is the primary cortical projection area for auditory information coming from the medial geniculates, the specific auditory relay nuclei of the thalamus. While quite rare, bilateral lesions to this structure could result in deafness. Brain Lang : 1 — 10 , Friederici AD : The brain basis of language processing: from structure to function. Physiol Rev 91 : — , Hickok G , Poeppel D : Dorsal and ventral streams: a framework for understanding aspects of the functional anatomy of language.

Cognition 92 : 67 — 99 , Neuroimage 84 : — , Psychol Rev 74 : — , Cognition 21 : 1 — 36 , Brain Struct Funct : — , Cereb Cortex 19 : — , Cortex 46 : — , Fiber dissection and diffusion tensor imaging tractography study of the temporoparietal fiber intersection area. Neurosurgery 72 1 Suppl Operative : ons87 — ons98 , J Anat : — , J Neurosurg : — , New insights into the anatomic dissection of the temporal stem with special emphasis on the inferior fronto-occipital fasciculus: implications in surgical approach to left mesiotemporal and temporoinsular structures.

Neurosurgery 66 3 Suppl Operative : 4 — 12 , Eur J Radiol 82 : — , Front Evol Neurosci 4 : 9 , Hum Brain Mapp 37 : — , Ventral and dorsal pathways for language.

Neuroimage 49 : — , J Neurosci 32 : — , Neurosurgery 65 6 Suppl : 1 — 36 , Wernicke C : The aphasic symptom-complex: a psychological study on an anatomical basis. Arch Neurol 22 : — , Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Sign in Sign up. Advanced Search Help. Free access. Download PDF. RESULTS Five tracts were observed to pass through the HGFIA: the anterior segment of the arcuate fasciculus, the middle longitudinal fasciculus, the acoustic radiation, the inferior fronto-occipital fasciculus, and the optic radiation. Methods Cortex-Sparing Fiber Dissection A total of 8 human cerebral hemispheres 4 left sides and 4 right sides; mean age of the subjects 73 years, range 63—82 years were dissected by J.

Statistical Analysis The side of the hemisphere right vs left was selected as the independent variable. TABLE 1. FD performed in 8 cadaveric specimens; DTI tractography performed in 4 healthy volunteers.

Superficial Layer Within the superficial layer Fig. Surgical Implications Intraoperative electrical stimulation of the HGFIA elicited language disturbances in all cases at the cortical and subcortical level.

Limitations The results presented here have the following limitations. Conclusions This anatomical study delineated the HGFIA, a region where 5 fiber tracts intersect in a relationship with the primary auditory area. Neurology 85 : — , Binder JR : The Wernicke area: modern evidence and a reinterpretation. Neurology 85 : — , false.

Neuroimage 29 : — , false. Ann Neurol 57 : 8 — 16 , false. Cortex 44 : — , Catani M , Mesulam M : The arcuate fasciculus and the disconnection theme in language and aphasia: history and current state. Cortex 44 : — , false. Cortex 44 : — , Catani M , Thiebaut de Schotten M : A diffusion tensor imaging tractography atlas for virtual in vivo dissections.

Hum Brain Mapp 32 : — , false. This is because of the way that FreeSurfer and thus TASH defines gyri; gyri are defined as corresponding to vertices having negative curvature values. Second, during manual labelling, as mentioned above, the medial two-thirds of HG was selected, while in FreeSurfer and TASH, the entire gyrus was selected. As described above, however, despite this, due to the more liberal definition of the anterior border of the full extent of HG during manual labeling, in many cases the antero-lateral border corresponding to the medial two-thirds during manual labeling was actually similar to the lateral border of HG as considered within Freesurfer, and thus also within TASH see Supplementary Fig.

Due to the above differences between these approaches, the correlations between manually labelled HG volumes and those obtained using TASH and FreeSurfer thus somewhat underestimate the strength of existing relationships, whereas the strength of the relationship between HG volumes obtained using FreeSurfer and TASH should not be affected.

Note also that in all three methods, the grey matter volumes surface areas, etc. We used TASH to obtain left HG volumes in the brain structural data of participants in whom we have previously shown, using manual labelling and VBM, positive relationships between left HG volumes and phonetic learning scores i.

As previously noted, this subset of the data was used to develop the TASH toolbox, however, none of these data were used for the validation of TASH described in section 2. Here, we aimed to replicate the previous findings of larger left HG in faster compared to slower learners, using TASH. Part of these data has previously been used to show, using manual labelling of HG, that musicians, whether professional or amateur, have larger HG volumes bilaterally than non-musicians 16 , 39 , 56 , 65 , 66 ; here we aimed to replicate these findings 16 , 39 , 56 , 65 , 66 and extend them 67 to a larger dataset, using HG volumes obtained automatically with TASH.

For this, we combined the three musicianship datasets i. The relatively weaker correlation in the right hemisphere suggests that TASH and FreeSurfer differ more in terms of how they segment HG in the right compared to the left hemisphere see Discussion for possible explanations for this. Figure 2 provides examples of the TASH and the FreeSurfer segmentations of the right HG in three representative participants: one with a single transverse temporal gyrus top row , one with a common-stem duplication middle row and one with a full posterior duplication bottom row.

It can be seen in these examples that the FreeSurfer transverse temporal gyrus ROIs see yellow outlines, in the middle column erroneously exclude the most medial part of this gyrus. Examples of TASH left, in blue and FreeSurfer middle, yellow outlines HG segmentations in the right hemispheres of three representative participants, and the overlays of these right. Light grey regions depict gyri and dark grey ones depict sulci. Red squares on the right of each panel show zoomed-in views of the auditory cortex.

We did this in the data acquired on the three different scanners and thus at both field strengths and in the left and right hemispheres separately, in order to explore the relative strength of the relationships in these different data.

Table 2 provides an overview of the correlations, and of significance testing. As a first application of our method, we tested to see if HG volumes obtained using TASH correlate with phonetic learning scores, as has previously been shown using manual labeling and voxel-based morphometry VBM in these same participants see Methods.

Partial correlations were performed between left HG grey matter volumes obtained using different methods manual labeling, TASH and FreeSurfer and phonetic learning scores, controlling for mean left hemisphere cortical volumes. We analyzed the volumes using a mixed ANCOVA, with group non-musicians, amateurs and professional musicians as the between-subjects factor and with hemisphere as the within-subjects factor, controlling for the covariates of age, sex, whole brain cortical volume and scanner.

Average HG grey matter volumes for professionals, amateurs and non-musicians in the left blue and right red hemispheres. We analyzed surface area using a mixed ANCOVA, with group non-musicians, amateurs and professional musicians as the between-subjects factor and with hemisphere as the within-subjects factor, controlling for the covariates of age, sex, whole brain cortical area and scanner.

Furthermore, we also tested for an overall asymmetry in HG surface area i. We also analyzed HG cortical thickness measures using a mixed ANCOVA, with group non-musicians, amateurs and professional musicians as the between-subjects factor and with hemisphere as the within-subjects factor, controlling for the covariates of age, sex, whole brain mean thickness and scanner. Furthermore, we also tested for an overall asymmetry in the mean HG cortical thickness i. This toolbox makes use of and builds upon the FreeSurfer pipeline in order to perform fine segmentation of the first transverse temporal gyrus i.

HG , including existing CSDs. Thus, we show replication in our validation of TASH, demonstrating that it is robust to differences in scanner and field strength. Manual delineation for the labeling of cortical regions is still the gold standard for the fine segmentation of the auditory cortex, despite its drawbacks regarding reproducibility.

Indeed, manual labelling of cortical regions is not only monotonous and time consuming, but in addition, the high anatomical variability of small structures such as HG and its existing duplications results in labelling errors and lack of reproducibility 40 , 52 , Given that our method is automated, it allows for fully reproducible feature selection, and is not subject to arbitrary and subjective decisions regarding the location of a boundary or regarding the presence of a gyrus, based, for example, on its apparent height as seen on a particular view of the brain.

In particular, certain systematic errors arising from the FreeSurfer pipeline in the labelling of such a small and variable structure as HG are rectified by our pipeline. TASH can thus be used as a complementary tool to Freesurfer, in studies where there is specific interest in the detailed and accurate segmentation of HG.

This might be due to several reasons, one being that the most anterior HG tends to be shallower in the right compared to the left hemisphere 65 , 72 , 73 , possibly making it more difficult for a segmentation tool that is not fine-tuned for such a small and variable structure as HG to accurately segment the region.

Another reason for the relatively weaker convergence between right HG segmentations with TASH vs with FreeSurfer may be related to the fact that there tends to be greater morphological variability in the STG in the right compared to the left hemisphere in healthy populations 27 , Our validation dataset included data from healthy controls and also from musicians; it has been shown that also in musicians, the gyrification index tends to be higher in the right compared to the left HG, even when only considering CSD morphotypes We also applied TASH to two datasets which have previously been used to show relationships, using manual labelling, between HG volumes and a phonetic learning 9 and b musicianship status 16 , In the first application of our method, we showed that, as expected, left HG volumes obtained using TASH correlate positively with phonetic learning skill, replicating previous findings 9.

We also extended these findings to show a significant positive relationship between phonetic learning and left HG surface area. In the second application, TASH revealed larger HG volumes bilaterally in professional and amateur musicians compared to non-musicians, again replicating previous findings 16 , 56 and extending them to a larger dataset. TASH also revealed group differences in HG surface area and cortical thickness; for surface area, only the professionals had higher values than non-musicians, and for thickness both professionals and amateurs had higher values than non-musicians.

In one of the original manual labeling studies on this topic, it had been shown that professional and amateur musicians have larger HG volumes in the medial two-thirds of the first transverse temporal gyrus with the border of the full extent of the transverse temporal gyrus being relatively liberally defined 16 , however, in a later such study these volume differences were shown for both the medial and also for the lateral HG A larger volume of a gyrus or of gyri, in the case of common stem duplications is associated with a relatively larger surface area, as also shown in our results, and thus also with a relatively greater overall presence of superficial cortical layers compared to what can be expected to exist in smaller gyri.

Interestingly, it has recently been shown that within the primary auditory cortex i. Thus, a speculative explanation for larger bilateral HG in musicians and of a larger left HG in faster phonetic learners is that there may be a relatively greater presence of superficial layers in the HG of these populations, and this might underlie a capacity for better processing of complex or subtle musical and linguistic sounds these groups.

It remains to be established how differences in the relative proportion of different cortical layers in gyri versus sulci 76 might relate to overall gyrification patterns and to macroscopic differences in volume or surface area observed across people with different degrees of musical or linguistic skill.

These questions can be explored in future, laminar resolution functional and structural imaging studies not only of cases with single transverse temporal gyri or with common stem duplications but also of more complex gyrification patterns. As described above see Methods , in the current study the manual labeling considered the medial two-thirds of HG i.

Despite this apparent difference across methods, the way that the lateral border of medial HG was defined during manual labeling actually corresponded relatively well to the lateral border of HG as determined by TASH this was due to differences in how the full extent of HG is defined across methods, see the Methods section. Given, however, that during manual labeling the lateral border of the medial two-thirds of HG was defined using a fixed distance spanning laterally along the direction of HG, we expect that the correlations that we report between HG volumes obtained using TASH compared to manual labelling actually underestimate the strength of the true relationship between the two i.

Our replications of previous findings of larger HG volumes in relation to language learning and to musicianship using our fully automated approach further validate our method in showing that it can be used to uncover brain structure—behaviour relationships in a fully automated and replicable manner. This opens doors to numerous applications for studies where fine assessment of HG volumes or surface area, thickness, etc is needed, and in particular in studies where large sample sizes are involved.

As such, it relies only on macroscopic structural landmarks for auditory cortex feature selection. Thus, it is complementary to functional imaging studies in terms of helping to localize functional responses in and around HG 26 , and also to DTI studies, where it can for example be used to determine seeds for tracking of auditory cortex white matter fibers We are currently also extending TASH to allow a more flexible approach to feature selection, one that can be decided upon by researchers based on their research goals and hypotheses.

Thus, there is a need for automated and reliable methods to allow the segmentation not only of HG but also of fully duplicated second and third, etc. FPDs , in individual subjects.

Thus, future developments of TASH will include versions of the pipeline which will allow the selection of: a both CSDs and FPDs; b only the most anterior gyrus, even in the case of CSDs; c the medial two-thirds of the most anterior gyrus, region which corresponds most closely to the auditory core 2 , 33 , 37 ; d HG plus anterior secondary auditory regions i.

Thus, more generally, different implementations of TASH can allow to run several different feature selection versions on the same data, allowing comparison of HG volumes or of other measures i. Studies involving manual labelling have also done this 16 , 22 , but at the cost of many hours of work, and of not fully reproducible segmentations.

It should be noted that the HG volumes and other measures e. If multiple dependent measures such as HG volume, surface area, thickness, and curvature are extracted and assessed conjointly, then machine learning can serve to pinpoint which of those anatomical measures most clearly differentiate individuals with respect to the effects of interest i. Normative studies i. We have replicated this finding using our automated TASH toolbox in a large dataset, further validating our method.

TASH can be extended to a wide range of applications. For example, initiatives exist to study the development of the auditory cortex and of other brain structures more generally, from infancy to adulthood 23 , 69 , 81 , 82 , and to study the brains of bilingual adults 13 and children Molecular genetic studies have also been done in search of genes which affect auditory cortex structural features 25 , 84 , and heritability studies have explored the possible contribution of auditory cortex morphology to dyslexia Our method will allow to perform further such studies in much larger sample sizes using a comparable approach across datasets, allowing for more robust and generalizable findings.

Other applications of our method include further exploration of relationships between auditory cortex structure and basic auditory processing 5 , 12 , 86 , 87 , 88 as well as with higher-level linguistic or musical processing and expertise 8 , 12 , 13 , 39 , 89 , Clinical applications include extension and replication of studies having examined the auditory cortex structure in dyslexia 21 , 22 , 91 , in deafness 72 , 92 , 93 , in autism 82 and in schizophrenia 30 , 94 , 95 , the latter likely in relation to auditory hallucinations Our approach can also be adapted for auditory cortex feature selection in the non-human primate brain 97 , TASH allows finer auditory cortex segmentation than is currently possible using existing automated software, with the option of selecting specific auditory cortex subregions and combinations thereof.

Perspectives for new developments of TASH include the implementation of regular updates and improvements to this toolbox in order to adapt and optimize its performance in the context of the changing and variable demands that will likely arise in relation to the anatomical measures required to better explain brain structural phenotypes.

Moreover, given evidence for higher myelination within gray matter regions of the PAC 36 , 37 , 99 , future developments of TASH can include extensions allowing the integration of data from different imaging modalities e. Heschl, R. Von Economo, C. Uber windungsrelief mabe und Rindenarchitektonic der supratemparalflache, ihre individuellen und seitenunterschiede.

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Sutherland, M. Anatomical correlates of dynamic auditory processing: Relationship to literacy during early adolescence. Ressel, V. However, the organization and function of these cortical areas and the underlying fiber tracts connecting them remain unclear. The goal of this study was to analyze the area formed by the organization of the intersection of Heschl's gyrus-related fiber tracts, which the authors have termed the "Heschl's gyrus fiber intersection area" HGFIA.