The effects of bilateral and unilateral frontal lesions on visual cortical hypersynchronous bursting and behavioral activity

Microinjection of galanin into the medial preoptic nucleus facilitates copulatory behavior in the male rat

The medial preoptic area (MPOA) is an important region for masculine sexual behavior. Because galanin (GAL) immunoreactive cells within the MPOA are affected by the gonadal steroid environment and GAL binding is apparent, GAL was microinjected site specifically in 0, 10, 50, 100, and 500 ng doses in order to determine effects on copulatory behavior. Unilateral microinjection of GAL within the medial preoptic nucleus facilitated copulatory behavior in a dose-responsive fashion, evidenced by an increase in the percentage of males that displayed sexual behaviors and a decrease in mount and intromission latencies. These effects required the presence of gonadal steroids, and were not due to general arousal as measured in open field testing. The techniques of survival analysis were used to display data and for statistical analysis of intromission and mount latencies; these approaches revealed significant effects that were not evident with more commonly used procedures. The results support the suggestion that sexually dimorphic galaninergic cell groups within the MPOA are involved in gonadal steroid-induced masculine sexual behavior.

Depth distribution of frontal cortical field potential to acoustic stimulation in unrestrained non-anaesthetized rats

Intracortical depth profiles of acoustically evoked potentials (AEP) through the frontal cortex were studied with moveable electrodes in 5 freely behaving rats to identify the generators of the AEP components with current source-density analysis in pharmacologically uninfluenced relaxed wakefulness. The main negative AEP components (N21 and N38) which change their polarity across the cortical depth are generated by extracellular current sinks within the V cortical lamina. Since both components were polarity reversed in different cortical depths and have their current sources in different laminae, the participation of different generation modi are assumed for both AEP components.