It is not easy to attribute the changes in GluR1 at axo-shaft synapses to any specific pathway within the LA, because we did not perform experiments to determine whether the postsynaptic cells were excitatory or inhibitory or whether the population of synapses showing increased GluR1 with paired or unpaired training overlap. These experiments are planned for the future. However, it is most likely that cells postsynaptic to asymmetric axo-shaft synapses are inhibitory interneurons. This supposition is based on the synaptic pattern described for the cortex, where aspiny and sparsely spiny neurons receive excitatory inputs directly on dendritic shafts, whereas spiny neurons receive most of their excitatory inputs at spine heads (White, 1989). Moreover, previous anatomical studies indicate that spines in the lateral and basal nuclei of amygdala are more likely to belong to pyramidal-like cells, because these are very spiny and also more numerous, whereas the aspiny and sparsely spiny neurons belong to the inhibitory interneurons (Millhouse and DeOlmos, 1983; McDonald, 1996; McDonald et al., 2002; Muller et al., 2007, 2009; Pinard et al., 2008). In contrast, excitatory neurons, defined
