Social affiliation relates to tyrosine hydroxylase immunolabeling in male and female zebra finches (Taeniopygia guttata)

Abstract

The catecholamines dopamine and norepinephrine are implicated in affiliative behaviors, yet few studies have addressed the extent to which affiliative behaviors within distinct social settings rely upon similar or distinct catecholaminergic mechanisms. To explore the role of catecholamines in affiliative behavior within distinct long-term social contexts, we examined the density of the catecholamine synthetic enzyme tyrosine hydroxylase (TH) in brain regions within both the mesolimbic dopaminergic system and “social behavior network” in male and female zebra finches (Taeniopygia guttata) paired for 21 days with either a same- or opposite-sex conspecific. On days 16-21 after pairing, members of both same- and mixed-sex pairs produced similar rates of affiliative behaviors. Measures of affiliation related to TH labeling in the ventral tegmental area (VTA), nucleus accumbens (Ac), medial preoptic nucleus (POM), and ventromedial nucleus of the hypothalamus (VMH). Relationships between TH labeling density and specific measures of affiliative behavior differed in rostral compared to caudal subregions of Ac and VTA, suggesting distinct roles for these subregions in the regulation of affiliative behavior. Finally, TH labeling density in the VMH and rostral VTA were positively related to the amount of courtship received from the partner and TH labeling in Ac was denser in opposite-sex pairs compared to same-sex pairs, indicative of socially-induced brain plasticity. Overall, results highlight a complex region- and behavior-specific role for catecholamines in vertebrate affiliation.

Gene expression correlates of social evolution in coral reef butterflyfishes

“…Our comparative results suggest that dopamine neurotransmission within the mesolimbic reward network is important for pair bonding in C. lunulatus, as appears to be the case in the zebra finch T. guttata 99,100,186,187 and in M. ochrogaster rodents [30][31][32] . A notable brain region of this network that appears to be targeted by DA in all three taxa is the striatal Vc/ striatal NAcc 31,32,100,186 . In addition, DA appears to act within the TPp (mammalian and avian VTA) and the POA in both C. lunulatus and T. guttata 99,186 , but whether it targets these regions in mammals remains untested.…”

“…A notable brain region of this network that appears to be targeted by DA in all three taxa is the striatal Vc/ striatal NAcc 31,32,100,186 . In addition, DA appears to act within the TPp (mammalian and avian VTA) and the POA in both C. lunulatus and T. guttata 99,186 , but whether it targets these regions in mammals remains untested. Finally, our study further implicated that DA-D1R-and -D2R signaling within the Dm, Dl, and Vs might also regulate C. lunulatus pair bonding, but their involvement within homologous regions (i.e., the blAMY, HIP, and meAMY/BNST, respectively) remain untested in other taxa.…”

Functional interactions of dopamine cell groups reflect personality, sex, and social context in highly social finches

“…Consistent with these functions, A10 neurons exhibit immediate early gene responses to sexual interactions in both birds and rodents [18,[46][47][48]. Numerous studies in birds also demonstrate an involvement in sexually motivated song [7,39,49].…”

“…Furthermore, optical density of TH in the A14 cell group negatively correlates with clumping behavior (non-sexual affiliation) in zebra finches [48]. Such negative correlations are difficult to interpret given that other findings suggest an involvement of A14 DA in sexual and social behaviors, but the decreased TH-immunolabeling may be the result of end-product inhibition of TH by consistent high DA concentrations [48,59].…”

“…However, studies in songbirds have demonstrated that A14 neurons in the medial preoptic nucleus (POM) respond to singing behavior in a context-dependent manner [58], and examination of TH labeling reveals a negative relationship between breeding context song and indices of TH immunoreactivity [59]. Furthermore, optical density of TH in the A14 cell group negatively correlates with clumping behavior (non-sexual affiliation) in zebra finches [48]. Such negative correlations are difficult to interpret given that other findings suggest an involvement of A14 DA in sexual and social behaviors, but the decreased TH-immunolabeling may be the result of end-product inhibition of TH by consistent high DA concentrations [48,59].…”