Neuronal correlates of early social behaviour in visually naive domestic chicks (Gallus gallus)

The detection of animate creatures, such as conspecifics, preys
or predators, is crucial for survival of animals already at the onset of life.
Behavioural studies conducted in newly hatched, visually-naive domestic
chicks (Gallus gallus), demonstrated preferences for visual stimuli that re-
semble conspecifics (e.g. a stuffed fowl over a less naturalistic one) or that
display static and dynamic features typical of animate objects (e.g., face-like
or biologically-moving stimuli). However, the neuronal mechanisms mediat-
ing this phenomenon are mostly unknown. We conducted a series of ex-
periments to investigate this issue in chicks (hatched in dark incubators and
tested directly after birth), by mapping neuronal activity through immediate
early genes expression. The experiments revealed that exposure to the static
configuration of features or to the natural motion typical of conspecifics
stimulated differential activation in the amygdaloid, septal and preoptic nu-
clei. These areas are part of the so-called ‘‘social behaviour network”, which
is shared among all vertebrates and comprises interconnected areas rich in
sex steroid receptors and implicated in adult social behaviours. Overall, the
results of my works demonstrate that important nodes of the social behav-
iour network are already engaged in social responses at birth: previous
learning experiences associated with social companions are not needed for
their involvement in this function.