Induction of c-Fos expression by electrical stimulation of the nucleus basalis magnocellularis.

The present study examined the expression of the immediate-early gene c-fos in different brain regions following a single 20-min session of unilateral electrical stimulation of the nucleus basalis magnocellularis (NBM). Current findings confirm that NBM stimulation provides specific activation of several cortical and subcortical regions closely related to the NBM and involved in learning and memory processes, such as the cingulate, parietal, piriform and perirhinal cortices, dorsal subiculum, and the parafascicular, central lateral and central medial nuclei of the thalamus. In contrast, NBM stimulation did not increase c-Fos expression in some expected areas that receive direct NBM projections such as the entorhinal cortex or amygdala nuclei.

Differential effects of muscarinic receptor blockade in prelimbic cortex on acquisition and memory formation of an odor-reward task.

The present experiments determined the consequences of blocking muscarinic cholinergic receptors of the prelimbic (PL) cortex in the acquisition and retention of an odor-reward associative task. Rats underwent a training test (five trials) and a 24-h retention test (two retention trials and two relearning trials). In the first experiment, rats were bilaterally infused with scopolamine (20 or 5 microg/site) prior to training.

Muscarinic cholinergic receptor blockade in the rat prelimbic cortex impairs the social transmission of food preference.

Previous findings demonstrate the involvement of the cholinergic NBM in the acquisition of the social transmission of food preference (STFP), a relational associative odor-guided learning task. There is also evidence that muscarinic receptors in the medial prefrontal cortex, an important NBM target area, may modulate olfactory associative memory. The present experiment determined the consequences of blocking muscarinic cholinergic receptors in a component of the medial prefrontal region (the prelimbic cortex) on the STFP task.

Effects of nucleus basalis magnocellularis stimulation on a socially transmitted food preference and c-Fos expression.

Experiment 1 examined the effects of electrical stimulation of nucleus basalis magnocellularis (NBM) on a relational odor-association task--the social transmission of food preference (STFP). Rats were stimulated unilaterally in the NBM for 20 min (100 microA, 1 Hz) immediately before the social training. They were tested on their ability to remember preference for the trained food either immediately or following a 24-h delay.