Neuron a n

in CB1R KO mice. In immature slices, activation of CB1 receptors induces long-term depression of early postnatal development (Heinen et al., 2004; Luhmann and Prince, 1991) and are therefore unlikely to affect the regula-et al., 2007), attention (Mitchell et al., 2007), and plasticity (Jiang et al., 2005; Spolidoro et al., 2009). In sensory cortices, GABAergic circuits are not fully functional at birth, with matura-2008). The functional maturation of these newly formed GABAergic synapses is less understood. Curiously, evidence suggests thattion occurring slowly over development until completion at puberty. Indeed, this protracted maturation is believed to define in visual cortex the probability of release at inhibitory synapses is reduced with postnatal development (Jiang et al., 2005;inhibitory responses (iLTD) and a reduction in STD and response variability. Based on these find-ings, we propose that visually induced endocannabi-noid-dependent iLTD mediates the developmental decrease in release probability, STD, and response variability, which are characteristic of maturation of cortical GABAergic inhibition