Spatial working memory (SWM) involves both simultaneous and sequential encoding, but the differences in their neural correlates are unclear. We investigated the differences in prefrontal cortex activity related to these SWM encoding types. We also examined the patterns of brain activity influencing individual visuospatial abilities (VSA). We conducted SWM tasks with two different conditions, sequential and simultaneous encoding, and examined hemodynamic activity in 39 healthy adults using near-infrared spectroscopy. The bilateral dorsolateral prefrontal cortex was activated more strongly in the sequential condition compared with the simultaneous condition. This suggests that prefrontal cortex activity underlying SWM is modulated by the type of encoding. We also found that individuals with high VSA showed weaker activation in the right-dorsolateral prefrontal cortex compared with those with lower VSA during the simultaneous condition. This hypoactivation is thought to reflect neural efficiency in the individuals with high ability. These findings are expected to lead to a better understanding of neural substrates for SWM.
aDepartment of Special Needs Education, Faculty of Education, Tokyo Gakugei University
bJapan Society for the Promotion of Science
cDepartment of Developmental Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry (NCNP)
dDepartment of Clinical Psychology, Faculty of Psychology, Rissho University, Tokyo, Japan
* Yuhei Oi, Yosuke Kita, and Kota Suzuki contributed equally to the writing of this article.
Correspondence to Yosuke Kita, Department of Developmental Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8553, Japan Tel: +81 42 341 2711; fax: +81 42 346 2158; e-mail: firstname.lastname@example.org
Received January 20, 2017
Accepted February 9, 2017