Postnatal development of the basal forebrain cholinergic projections to the medial prefrontal cortex in mice

The postnatal development of basal forebrain cholinergic projections to the medial prefrontal cortex in mice was analyzed by means of the double label ing track-tracing study. The tracer was injected into the medial prefrontal cortex of mice, on the day of birth (P0) to 60 days after birth. The total number of basal forebrain neurons increased from P4 to P8, and began to de crease until P13 (52.9% vs. the maximal average (P8)). After P13, the mean average remains stable up to P60. On the other hand, differential pattern o f frontocortical projections of the anterior, intermediate, and posterior r egions can be observed. (C) 2000 Published by Elsevier Science B.V. All rig hts reserved.