Infant rats received either lesions of the septal nuclei or control operations at 7 days of age. Following weaning at 21 days, the infant rats were trained to leverpress for food. A DRL 20-secschedule was then used, with the rats being tested in either a conventional operant chamber or one which contained wooden balsa blocks. DRL training continued for 40 daily 60-min sessions. The infant rats successfully leverpressed for food. The presence of the wooden blocks facilitated the development of efficient DRL behavior in the rats with septal lesions, but not in the controls. With training, the juvenile rats with septal lesions trained in conventional chambers showed an improvement in their DRL behavior.

No abstract

No abstract

Symptoms of Attention Deficit Hyperactive Disorder (ADHD) include hyperactivity, inattentiveness, and impulsivity, which are caused by dopamine dysfunction in the medial prefrontal cortex.  A six-hydroxydopamine lesion model of ADHD was used to examine response accuracy on an attentional task under one of three conditions: cue only, methylphenidate only (MPH), and MPH with cue.  Results indicated rats injected with methylphenidate and exposed to an external cue showed a significant increase in response accuracy compared to the MPH and cue only groups.  Also, the results indicate animals in the cue only condition had an increase performance in response accuracy compared to just methylphenidate group.  This study provides evidence that combination of a stimulant and external cue would have a stronger affect than a stimulant or external cue was given alone. Keywords: dopamine, hyperactivity, methylphenidate, external cue, medial prefrontal cortex

Autism is a common neurodevelopmental disorder that affects communication and social behavior.  To reduce the social deficits characteristic of autism, the compounds oxytocin, arginine vasopressin, D-cycloserine, and D-cycloserine + oxytocin were explored as therapeutic agents.  Twenty-one Long Evans Hooded rats underwent a bilateral amygdala lesion, which reduced the time of social interactions between the pairs of animals.  Upon administration of D-cycloserine, the social deficits induced by the lesions were significantly reversed in both sexes.  In addition, it was observed that the efficacy of the treatments was affected by the sex of the subjects.  Male rats had the largest increase in social behavior when given D-cycloserine.  However, female rats experienced the largest reduction in social impairment when administered oxytocin.  Thus, sexually dimorphic treatments should be further investigated for individuals with autism spectrum disorders.