Abstract: There many studies have demonstrated that anterior cingulate cortex (ACC) and the level of dopamine (DA) in this brain area play a critical role in effort-based decision-making, a kind of cost-benefit decision-making. It has been found that haloperidol, a DA D2 receptor-antagonist, could disrupt the performance of rats in effort-based decision-making tasks. The present experimental study used on-line multi-channel neuronal recording technique to record both the neuronal firing frequency and local field potentials (LFPs) in ACC when rats were performing effort-based decision-making tasks. We further investigate the effects of haloperidol on performance of rats.
All rats (10 Wistar rats) were surgically implanted with a 2×8 microelectrode array in ACC before they learned behavioral task. After 1 week of recovery, rats were introduced to T-maze for training periods. There were two choices in this task, rats could choose to get two food pellets at the end of one arm without any barrier (low cost-low reward, LCLR) or by climbing a barrier (high cost-high reward, HCHR) to get four pellets at the end of the other arm.
After training for a period of time (about 2 weeks), eight of ten rats preferred choosing HCHR. Electrophysiological research found five characteristic types of neuronal firing, and a great majority of ACC neurons showed significantly higher firing when to choose HCHR. Compared to control group (saline, 0.5ml, i.p), injection of haloperidol (0.1mg/kg, i.p) significantly decreased the ratio of choosing HCHR, which made the characteristic firing of ACC neurons disappear and reduced LFPs of ACC. This indicates that haloperidol impaired the function of effort-based decision-making. No movement disorders or decreased appetite were observed through out experiments.
In conclusion, the present study recorded activities of individual neurons in ACC when rats were performing decision-making tasks. We also studied the impact of haloperidol on the performance of rats. This study confirmed that ACC and actions of D2 receptor are very important in modulating effort-based decision-making.

Key words: cost-benefit decision making, anterior cingulate cortex, dopamine, T-maze