Neural circuits underlying nest building in male zebra finches

Nest building consists of a series of motor actions, which are concomitant with activity in regions of the anterior motor pathway, the social behaviour network and the reward circuity in nest building adult male zebra finches (Taeniopygia guttata). It is not clear, however, whether this activity is due to nest building, collection and/or manipulation of nest material. To identify which areas of the brain are specifically involved, we used immunohistochemistry to quantify the immediate early gene c-fos in male zebra finches that were nest building (Building), birds given a nestbox but could interact only with tied down nest material (Fixed), and birds that were not given a nestbox or nest material (Control). We investigated the following brain regions: the anterior motor pathway (anterior ventral mesopallium (AMV), anterior nidopallium (AN), anterior striatium (ASt)), areas of the social behaviour network (bed nucleus of the stria terminalis, dorsomedial sub division (BSTmd), lateral septum (LS)), the dopaminergic reward circuitry (ventral tegmental area (VTA)) and the cerebellum. We found that there was greater Fos-ir expression in the BSTmd, LS and AMV with increased material deposition; in LS, AMV ASt and folia VI with increased material carrying; in LS, AMV and ASt with increased nest material tucking; and in LS and all folia (except folium VIII) with increased tugging at tied down material. These data confirm a functional role for areas of the anterior motor pathway, social behaviour network and the cerebellum in nest material collection and manipulation by birds