P3-5. Altered motion perception in mild cognitive impairment and Alzheimer’s disease: An fMRI study

• Published in: Clinical neurophysiology Vol. 124; no. 8; p. e37
• Main Authors: Yamasaki, Takao, Muranaka, Hiroyuki, Kaseda, Yumiko, Mimori, Yasuyo, Torii, Tsuyoshi, Ohshita, Tomohiko, Matsumoto, Masayasu, Tobimatsu, Shozo
• Format: Journal Article
• Language: English
• Published: Elsevier Ireland Ltd 01.08.2013
• Subjects: Neurology
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2013.02.108

Motion perceptual deficits are frequently observed in patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Information of coherent motion is mainly processed by the two distinct dorsal streams: the ventro-dorsal including inferior parietal lobule (IPL) and dorso-dorsal including superior parietal lobule (SPL) pathways. The former conveys radial optic flow (OF) information while the latter deals with horizontal (HO) motion information. To elucidate how the two dorsal streams are functionally altered, BOLD responses were measured during OF and HO perception in patients with MCI ( n = 10) and mild AD ( n = 8) and healthy elderly controls ( n = 3) by using fMRI. In healthy elderly controls, OF predominantly increased the IPL signal whereas the SPL was more strongly activated by HO. In contrast, in both MCI and mild AD patients, there was a significant activation of the SPL by HO. However, no significant activation of the IPL was observed by OF. These findings indicate that the function of the ventro-dorsal (IPL) stream is selectively impaired in MCI and mild AD, while dorso-dorsal (SPL) function appears to be preserved. Therefore, we conclude that fMRI measurement of visual perception can be used as in vivo biomarkers for early functional brain changes in MCI and AD patients.