The implementation of verbal instructions: Dissociating motor preparation from the formation of stimulus-response associations

Only recently, brain imaging research has started to investigate the transformation of verbal instructions into efficient behavior. A frontal-parietal network has been consistently shown to be involved in this context. The existing studies, however do not allow distinguishing brain regions that are involved in creating the stimulus response link (S-R link) and brain areas involved in response preparation proper. The aim of the current study was to dissociate brain regions associated with these different functions. In order to do so, we adopted a paradigm in which instructions were given using two successive instruction cues. Each cue instructing one component of an S-R mapping, enabling the identification of areas that are involved in representing response information and areas that play a role in setting up the link between stimulus and response information. Results show that premotor cortices, pre-supplementary motor area (pre-SMA) and anterior intraparietal sulcus (IPS) are engaged in representing and preparing the instructed response. Importantly, the left inferior frontal sulcus (IFS, including the inferior frontal junction (IFJ)) was engaged in the formation of the stimulus and response link. It is concluded that during the implementation of verbal instructions IFS/IFJ transforms these instructions to guide modality specific areas needed to perform the upcoming task.

► Examined brain areas involved in implementation of instructed behavioral rules. ► Dissociated areas involved in S-R link formation and response preparation. ► IFS/IFJ crucial for integrating stimulus response information based on instructions. ► Anterior IPS, premotor areas and pre-SMA involved in preparing instructed response. ► IFS/IFJ could guide modality-specific areas needed to perform the upcoming task.