Age-dependent plasticity in the superior temporal sulcus in deaf humans: a functional MRI study

Norihiro Sadato¹^,2 , Hiroki Yamada² , Tomohisa Okada¹ , Masaki Yoshida⁴ , Takehiro Hasegawa⁴ , Ken-Ichi Matsuki⁴ , Yoshiharu Yonekura⁵ and Harumi Itoh³

¹National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, 444-8585, Japan

²JST/RISTEX, 2-5-1, Atago, Minato-ku, Tokyo, 105-6218, Japan

³Fukui University School of Medicine, Fukui, 910-1193, Japan

⁴Fukui University School of Education, Fukui, 910-1193, Japan

⁵Biomedical Imaging Research Center, Fukui University School of Medicine, Fukui, 910-1193, Japan

author email corresponding author email

BMC Neuroscience 2004, 5:56doi:10.1186/1471-2202-5-56


Published:	8 December 2004

Abstract

Background

Sign-language comprehension activates the auditory cortex in deaf subjects. It is not known whether this functional plasticity in the temporal cortex is age dependent. We conducted functional magnetic-resonance imaging in six deaf signers who lost their hearing before the age of 2 years, five deaf signers who were >5 years of age at the time of hearing loss and six signers with normal hearing. The task was sentence comprehension in Japanese sign language.

Results

The sign-comprehension tasks activated the planum temporale of both early- and late-deaf subjects, but not that of hearing signers. In early-deaf subjects, the middle superior temporal sulcus was more prominently activated than in late-deaf subjects.

Conclusions

As the middle superior temporal sulcus is known to respond selectively to human voices, our findings suggest that this subregion of the auditory-association cortex, when deprived of its proper input, might make a functional shift from human voice processing to visual processing in an age-dependent manner.