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The anterior cingulate cortex (ACC) has been shown to be critical to many aspects of executive function including filtering irrelevant information, updating response contingencies when reinforcement contingencies change and stabilizing task sets. Nonspecific lesions to this region in rats produce a vulnerability to distractors that have gained salience through prior associations with reinforcement. These lesions also exacerbate cognitive fatigue in tests of sustained attention but do not produce global attentional impairments nor do they produce distractibility to novel distractors that do not have a prior association with reinforcement. To determine the neurochemical basis of these cognitive impairments, dopaminergically selective lesions of the ACC were made in both male and female Long-Evans, hooded rats prior to assessment in two attentional tasks. Dopaminergic lesions of the ACC increase the vulnerability of subjects to previously reinforced distractors and impede formation of an attentional set. Lesioned rats were not more susceptible to the effects of novel, irrelevant stimuli in a test of sustained attention as has been previously shown. Additionally, the effects of dopaminergic lesions were found to differ based on sex. Lesioned female, but not male, rats were more vulnerable than sham-lesioned females to the effects of prolonged testing and the removal of reinforcement during a test of sustained attention. Together, these data support the hypothesis that dopamine in the ACC is critical to filtering distractors whose salience has been gained through reinforcement., (© 2024 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Background: Sitophilus zeamais is one of the most economically impactful pests, attacking various grains and processed foods. Control of this insect has been achieved using synthetic insecticides, exacerbated and careless use of which has led to the development of resistant insect populations, toxicity to non-target organisms and environmental contamination. In this study, Piper corcovadensis leaf essential oil (PcLEO) and its major compound, 1-butyl-3,4-methylenedioxybenzene (BMDB), were investigated as alternative insecticidal agents against S. zeamais., Results: Characterization of PcLEO showed the presence of 40 compounds. The major components were the phenylpropanoid BMDB (35.77%) and the monoterpenes α-pinene (14.95%) and terpinolene (6.23%). PcLEO and BMDB were toxic by fumigation (half-maximal lethal concentration [LC 50 ]: 9.46 and 0.85 μl L -1 of air, respectively), by contact (half-maximal lethal dose [LD 50 ]: 9.38 and 6.16 μg g -1 of insect, respectively) and ingestion (LC 50 : 16.04 and 14.30 mg g -1 , respectively). In the ingestion test, both PcLEO and BMDB promoted the loss of insect biomass and had a strong deterrent effect. In addition, both were able to inhibit trypsin and α-amylase activities., Conclusion: PcLEO and BMDB exhibited insecticidal activity against S. zeamais, with a toxic effect by fumigation, contact and ingestion, in addition to food deterrence and inhibiting trypsin and α-amylase activities, suggesting their potential for use in the control of this pest., (© 2021 Society of Chemical Industry.)