Principal sulcus

Brozoski et al. (1979) performed a landmark study on the role of PFC DA in working memory function in monkeys. These investigators used a delayed response type procedure to show that 6-OHDA-induced depletion of DA in the principal sulcus of the dorsolateral prefrontal cortex in macaques produced an impairment as profound as ablation by aspiration of the region itself. In contrast, depletion of either noradrenaline or 5-HT in the prefrontal cortex had little effect. Convincing evidence for a specific role of DA came from... 

The no-go potentials of monkeys appears with a latency of 85-150 ms after the onset of the no-go stimulus in the dorsal bank of the principal sulcus and in the rostroventral corner of the prefrontal cortex on both hemispheres contra- and ipsi-lateral to the operant hand. When a monkey was first trained to use the right hand the no-go potential was more predominant in the contralateral (left) prefrontal loci than in the ipsilateral (right). After the operant hand was switched to the left, the no-go potential in the right hemisphere gradually increased in size and that in the left hemisphere remained much the same as before, or decreased slightly. 

Fig. 1 Monkey brain and principal sulcus, (a) Schematic of the lateral view of the monkey cortex showing the approximate location (dotted black line) of the prefrontal cortex (RFC) tissue sections used for the figures, (b) Schematic view of the left hemisphere RFC coronal tissue section designating the dorsal (46-D) and ventral (46-V) banks of the principal sulcus. The dashed lines on the gray area designate the total gray matter area spanning area 46...

Tsujimoto et aL (1997) mapped regions of monkey brain involved in go/ no-go reaction time tasks with positron emission tomography. In the control task only go signals were presented. In the go/ no-go task, when compared with the control task, a signifcant increase in rCBF was noted in the following areas (1) then principal sulci (2) the anterodorsal frontal pole (3) the anterior part of the inferior occipital sulcus which appeared to be the V4 and (4) then parieto- occipital region. The increase in the principal sulci was related to the the no-go decision and motor suppression in the area. 

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