target selection (reviewed in (Role and Berg, 1996). In addition, signaling through nAChRs is also important for establishing critical periods for activity-dependent shaping of visual cortical function (Morishita et al., 2010) and maturation of thalamocortical (Aramakis and Metherate, 1998; Aramakis et al., 2000; Hsieh et al., 2002) and corticothalamic (Heath et al., 2010; Horst et al., 2012; King et al., 2003; Picciotto et al., 1995) glutamatergic synapses. It appears likely that ACh release, potentially in response to salient stimuli, potentiates glutamatergic synapses during development through an LTP-like mechanism (Aramakis and Metherate, 1998), highlighting another important role for cholinergic signaling in synaptic plasticity. Several neurotrophic factors are also involved in the development and maturation cholinergic neurons, but the dependence on neurotrophins is not homogenous throughout the CNS (for reviews, see (Angelucci et al., 2005; Schindowski et al., 2008)). Although a comprehensive review of the developmental effects of ACh is beyond the scope of this article, it is important to note that various developmental processes can be affected by ACh signaling (for more comprehensive reviews, see (Heath and Picciotto, 2009; Liu et al., 2007; Metherate and Hsieh, 2003; Role and Berg, 1996)).
