Similar additive effects were also observed in rats 17 and 18 and pigeons [13]. The similarity of
the dual-task interference effects in humans and animals suggests the presence of common cognitive processes related to dual-task interference. This could make it possible to apply a variety of neurobiological techniques to nonhuman primates to investigate the neural mechanisms related to dual-task interference effects. fMRI studies have shown that the lateral prefrontal cortex (LPFC) is involved in dual-task interference effects 3, 22, 23, 24, 25 and 26. The precise roles of the LPFC in dual-task interference PLX-4720 price effects and their neural mechanisms remain largely unknown 22 and 27. However, since the cognitive capacity limitations in humans and monkeys have similar characteristics 28 and 29, it is expected that a common neural mechanism for the flexible allocation of cognitive resource is present in both humans and monkeys while they perform dual tasks. Therefore, neurophysiological selleck kinase inhibitor studies using monkeys could provide some important evidence for understanding the neural mechanisms of dual-task interference. Single-neuron recordings
from monkeys performing dual tasks are beginning to reveal the neural mechanisms responsible for dual-task interference 30, 31•, 32 and 33•• (Table 1). In the monkey’s lateral prefrontal cortex (LPFC), Wise and colleagues 30 and 31• examined the neural mechanisms related to interference effects using a dual-task-like paradigm (Figure 2a). In their task, while monkeys looked at a fixation point at the center of a screen, a visual cue was first presented at one position and then revolved around the fixation point to a second position. The brightness selleck products of the visual cue then either increased or decreased after the end of the delay period (1.0–2.5 s), and this informed the monkeys to make a saccade to the first or second position, respectively. Therefore, monkeys were required to attend to the visual cue at the second position to
detect the change in brightness while remembering the fist position during the delay period. The authors found ‘specialized’ neurons that encoded either the remembered or attended position (Figure 2b). They also found a substantial number of ‘multi-tasking’ neurons that encoded both the remembered and attended positions (Figure 2c). Multi-tasking neurons exhibited several computational advantages over specialized neurons in resolving dual-task interference effects. For example, multi-tasking neurons encoded different (often diametrically opposite) positions for both attention and memory and exhibited stronger spatial tunings than specialized neurons, thereby representing a larger amount of information than specialized neurons (Figure 2d).