Transverse temporal gyrus
| Transverse temporal gyrus | |
|---|---|
 Section of brain showing upper surface of temporal lobe. ("Transverse temporal gyri" visible at center left.) | |
 Human brain view on transverse temporal and insular gyri (gyri temporales transversi are #4) | |
| Details | |
| Part of | Temporal lobe |
| Parts | Primary auditory cortex |
| Artery | Middle cerebral |
| Identifiers | |
| Latin | gyri temporales transversi |
| NeuroNames | 1520 |
| TA98 | A14.1.09.140 |
| TA2 | 5491 |
| FMA | 72016 |
| Anatomical terms of neuroanatomy | |
The transverse temporal gyri (also called Heschl's gyri or Heschl's convolutions) are found in the area of primary auditory cortex buried within the lateral sulcus of the human brain, occupying Brodmann areas 41 & 42. Transverse temporal gyri are superior to and are separated from the planum temporale (cortex involved in language production) by Heschl’s sulcus. Transverse temporal gyri are found in varying numbers in both the right and left hemispheres of the brain, and one study found that this number is not related to the hemisphere or dominance of hemisphere studied in subjects. Transverse temporal gyri can be viewed in the saggital plane as either an omega shape (if one gyrus is present) or a heart shape (if two gyri and a sulcus are present).[1]
Transverse temporal gyri are the first cortical structures to process incoming auditory information. Anatomically, the transverse temporal gyri are distinct in that they run mediolaterally (towards the center of the brain), rather than front to back as all other temporal lobe gyri run.
The transverse temporal gyri are active during auditory processing under fMRI for tone and semantic tasks. [citation needed] Transverse temporal gyri were found in one study to have significantly faster processing rates (33 Hz) in the left hemisphere compared to those in the right hemisphere (3 Hz). Additionally this difference in processing rate was found to be related to the volume of rate-related cortex in the gyri; right transverse temporal gryi were found to be more active during temporal processing, and these gryi were found to have more “rate-related cortex”.[1] White and grey matter volumes of transverse temporal gyri were not found to relate to this processing speed, although larger white matter volumes in subjects are associated with increased sensitivity to “rapid auditory input”.[2]
The role of transverse temporal gyri in auditory processing of tone is demonstrated by a study by Wong, Warrier et. al. (2008). This study revealed the following: subjects that could successfully form an association between Mandarin Chinese “pitch patterns” and word meaning were found to have transverse temporal gyri with larger volume than subjects who had “difficulty learning these associations.” Successful completion of the previous task was also found to be associated with a “greater concentration of white matter” in the left transverse temporal gyri of the subject. In general, larger transverse temporal gyri “could be associated with more efficient processing of speech-related cues which could facilitate learning and perceiving new speech sounds.”[2]
The Heschl's gyri are named after Richard L. Heschl.
References
- The peri-sylvian aphasias
- Heschl’s Gyrus: Anatomic description and methods of identification in MRI
- Relating structure to function: Heschl’s Gyrus and acoustic processing
- ^ a b "Heschl's Gyrus: Anatomic description and methods of identification in MRI" (PDF).
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