The Japanese journal of neuropsychology

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ArticleTitle	The brain region activated during routes recalling -A study using functional magnetic resonance imaging-
Language	J
AuthorList	Tadashi Ino¹⁾, Yumiko Ishikawa¹⁾, Makoto Kage¹⁾, Toru Kimura¹⁾, Hidenao Fukuyama²⁾
Affiliation	1) Department of Neurology, Rakusakai-Otowa Hospital 2) Human Brain Research Center, Kyoto University Graduate School of Medicine
Publication	Japanese Journal of Neuropsychology: 18 (2), 111-119, 2002
Received	Sep 4, 2001
Accepted	Dec 28, 2001
Abstract	Using functional MRI, we investigated the neural substrates of recalling routes. Each of 16 right handed male volunteers was given aurally two familiar places every 15 sec and was asked to navigate mentally between them and to count numbers successively without phonation every time he turned to the right or left during mental navigation. In the control task, the subject listened to two successive numbers consisted of three figures every 15 sec and was required to count numbers silently following these given numbers successively. Eight control and seven mental navigation tasks, both of which continued 30 sec, were done alternately. Gradient echo, single shot, echo-planar images were obtained in 16 axial slices utilizing Siemens Vision Plus (FOV 200× 200 mm; matrix 64× 64; slice thickness 6 mm; gap 1.2 mm; TR 5 sec). A three-dimensional structural image was also obtained (FOV 220× 220 mm; matrix 256× 256; slice thickness 2 mm; TR 11.6 msec; TE 4.9 msec). The data were analyzed with Statistical Parametric Mapping 99. When route recalling task was compared with control task, significantly activated regions and the number of subjects who showed significant activation in the respective regions were as follows; retrosplenial area: 16 (bilateral: 15, left: 1, right: 0), angular gyrus/occipital cortex junction: 14 (bilateral: 10, left: 4, right: 0), superior premotor area: 12 (bilateral: 7, left: 3, right: 2), precuneus: 12 (bilateral: 9, left: 2, right: 1), and medial temporal lobe: 8 (bilateral: 1, left: 4, right: 3). Using random effect model, we disclosed common activated brain regions across 16 subjects. Significant activation was observed in the bilateral retrosplenial regions, bilateral angular gyrus/occipital cortex junction, the left superior premotor area, the right parahippocampal cortex and the right cerebellum. Retrosplenial areas were activated most significantly, and among them the most significantly activated region on the left side was in the retrosplenial cortex, but on the right side was in the deeply seated region of the calcarine or parieto-occipital sulcus. Retrosplenial region collaborating with parieto-occipital association cortex and hippocampal region apperar to consititute the neural framework associated with spatial cognition. On the other hand, premotor area and cerebellum seem to be related to spatial working memory.
Keywords	routes recalling, functional magnetic resonance imaging, retrosplenial region