Evaluation of object-based attention in mice

The deficits of attention result in significant impairment in daily life, and pharmacological intervention to improve attention is the most effective treatment in clinics. However, methods which are suitable for the large scale preclinical screening of attention-improving compounds or drugs are few in the field. In this study, we have developed object-based attention task as a simple and wherever-practical method that suitable for quick drug screening in mice. Treatment with p-chlorophenylalanine (pCPA) (200 mg/kg/day, i.p.) for three consecutive days reduced the prefrontal cortical content of serotonin and dopamine, and increased turn-over of dopamine while decreasing turn-over of norepinephrine in the prefrontal cortex on day 7. Auditory attention and working memory, but not long-term object memory after a long (10 min) object (two objects)-exposure period, were impaired on day 7 after the same treatment paradigm with pCPA. Novel object recognition ability immediately (<10 s) after a short (3 min) object (on two objects)-exposure period was not impaired after pCPA treatment. However, novel object recognition ability immediately (<10 s) after a short (3 min), but not long (6 min), object (five objects)-exposure period was impaired after pCPA treatment. For the verification, the current task, the object-based attention task, was confirmed in an attention deficit model induced by acute phencyclidine (1 mg/kg, i.p.) treatment in mice. It was implied that the object-based attention task would assist the behavioral screening process of pharmacological studies on attention-improving drugs.

Research highlights
► Treatment with p-chlorophenylalanine (pCPA) (200 mg/kg/day, i.p.) for three consecutive days reduced the prefrontal cortical content of monoamines in mice on day 7.
► Object recognition ability immediately (<10 s) after a 3-min object (two objects)-exposure period was not impaired on day 7.
► Object recognition ability immediately (<10 s) after a 3-min, but not 6-min, object (five objects)-exposure period was impaired on day 7.