Neuroanatomical correlates of musicianship in left-handers.

BACKGROUND: Left-handedness is a condition that reverses the typical left cerebral dominance of motor control to an atypical right dominance. The impact of this distinct control - and its associated neuroanatomical peculiarities - on other cognitive functions such as music processing or playing a musical instrument remains unexplored. Previous studies in right-handed population have linked musicianship to a larger volume in the (right) auditory cortex and a larger volume in the (right) arcuate fasciculus. RESULTS: In our study, we reveal that left-handed musicians (n = 55), in comparison to left-handed non-musicians (n = 75), exhibit a larger gray matter volume in both the left and right Heschl's gyrus, critical for auditory processing. They also present a higher number of streamlines across the anterior segment of the right arcuate fasciculus. Importantly, atypical hemispheric lateralization of speech (notably prevalent among left-handers) was associated to a rightward asymmetry of the AF, in contrast to the leftward asymmetry exhibited by the typically lateralized. CONCLUSIONS: These findings suggest that left-handed musicians share similar neuroanatomical characteristics with their right-handed counterparts. However, atypical lateralization of speech might potentiate the right audiomotor pathway, which has been associated with musicianship and better musical skills. This may help explain why musicians are more prevalent among left-handers and shed light on their cognitive advantages.

Retrieval of Ossicles by Cobbler’s Cut

As the ossicles are the smallest bones, they are well protected in temporals and pose difficulty in their retrieval. For the retrieval of the ossicles we require a method which does not disturb the normal anatomy of the tympanum along which intact bones can be taken out. Two hundred fifty temporal bones were dissected by Cobbler's cut technique to assess its efficacy and reasonability for the retrieval of the ossicles. This technique quickly exposes the middle ear cavity and helps in easy retrieval of the the ossicles with preservation of the normal anatomy of the tympanic cavity. The complete sets of ossicles were successfully retrieved in about 86-89% of cases; whereas, in only 11-14% cases we could not be able to collect the complete set of ossicles. The Cobbler’s cut technique proves to be a reasonably good method for the retrieval of intact ossicles

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Avances en corteza auditiva / Advances in auditory cortex

El sistema auditivo nos permite detectar e interpretar las señales acústicas del medio ambiente y así modificar nuestro comportamiento. En humanos la corteza auditiva se ubica en el giro temporal superior del lóbulo temporal. Esta corteza presenta una organización estructural y funcional característica, que se ha identificado en muchas especies de mamíferos. Las áreas de organización de la corteza auditiva son: (i) una región central denominada corteza auditiva primaria o core, que corresponde al primer nivel de procesamiento, cuyas características cito-arquitectónicas y funcionales principales son poseer una capa IV prominente y presentar una organización tonotópica especular. Además, (ii) una región circundante conocida como cinturón o belt, que corresponde a las cortezas secundarias que participan de la localización espacial y reconocimiento del sonido, como también en el procesamiento del habla. Por último, (iii) las áreas de asociación auditiva integran la información auditiva con la de otros sistemas sensoriales. En este artículo se revisan las bases neuroanatómicas y las propiedades funcionales de la corteza auditiva, las que constituyen pilares fundamentales para el desarrollo de métodos diagnósticos y terapéuticos del procesamiento auditivo central.

The auditory system allows us to detect and interpret the acoustic signals of the environment and thus change our behavior. In humans, the auditory cortex is located in the superior temporal gyrus of the temporal lobe. This cortex has a characteristic structural organization and functionality that have been identified in many mammalian species. The auditory cortex has different organizational areas: (i) a core called "primary auditory cortex," which corresponds to the first level of processing, and its cyto-architectural and physiological main features are to present a prominent layer IV and to display a mirror-tonotopic organization. In addition, (ii) a surrounding region known as belt that corresponds to the secondary auditory cortices and participates in the location and recognition of sound, as well as in speech processing. Finally, (iii) auditory association areas that integrate auditory information with other sensory systems. In this article, the neuroanatomical bases and functional properties of auditory cortex processing are reviewed. These topics constitute the foundations for the development of diagnostic tools and therapeutic procedures of central auditory processing.