The neural substrates of delayed match and non-match saccades;an fMRI investigation

Abstract

The current fMRI study investigated the neural substrates of saccadic inhibition in humans using a delayed-match-to-sample (DMS) / delayed-non-match-to-sample (DNMS) paradigm adapted from Hasegawa et al.’s (2004) study of single-cell activity in monkeys. Fourteen normal subjects performed alternating blocks of DMS/DNMS tasks while fMRI data was acquired and eye-movements were recorded. Imaging results revealed increased activation associated with DMS in two areas of prefrontal cortex (BA 8 and BA 10) which may have contributed to prospective memory and working memory of a planned motor act, respectively. DNMS activation was observed in the circuitry known to support saccade generation including the right medial frontal eye field (FEF), supplementary eye fields, and posterior parietal cortex. The DNMS-related activity observed in the FEF may be the human analogue of the “don’t look” signal described in the pre-FEF and FEF by Hasegawa et al. (2004).