Acoustic radiation
Radiatio acustica
- Latin synonym: Fibrae geniculotemporales
- Synonym: Geniculotemporal fibers
Definition
The acoustic radiation (a.k.a. auditory radiation) is an important thalamocortical component of the auditory pathway. It carries auditory information from the medial geniculate body of the thalamus to the primary auditory cortex, located in the transverse temporal (Heschl) gyri and associated mainly with Brodmann areas 41 and 42. These small transverse gyri lie on the superior surface of the superior temporal gyrus, deeply within the lateral (Sylvian) fissure.
The acoustic radiation is classically associated with the inferior thalamic peduncle and passes through the sublenticular part of the internal capsule on its way to the auditory cortex.
Clinical correlate
Above the level of the cochlear nuclei, auditory information from each ear is represented bilaterally because of extensive crossing and bilateral projections within the auditory pathway. Consequently, a unilateral lesion of the acoustic radiation or primary auditory cortex usually causes partial impairment of hearing rather than complete deafness, because auditory information can still reach the opposite cerebral hemisphere.
Key pathway
Medial geniculate body → acoustic radiation → sublenticular part of internal capsule → primary auditory cortex (Heschl gyri).
References
Snell, R.S. (2010). ‘Chapter 8: The Structure and Functional Localization of the Cerebral Cortex’, in Clinical Neuroanatomy. (7th ed.) Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, pp. 261-262.
George K, Das JM. Neuroanatomy, Thalamocortical Radiations. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546699/
Giampiccolo, D., Duncan, J.S., van Dijk, J., Baruteau, K.P., Davagnanam, I. (2025). Inferior Thalamic Radiation. In: Duncan, J.S., Giampiccolo, D. (eds) MRI Neuroanatomy. Springer, Cham. https://doi.org/10.1007/978-3-031-76696-1_57
Vanderah, T.W. and Gould, D.J. (2021). ‘Chapter 22: Cerebral Cortex’ in Nolte’s The Human Brain: An Introduction to its Functional Anatomy (8th ed.) Elsevier 1600 John F. Kennedy Blvd. Ste 1800 Philadelphia, PA 19103-2899 (link)
