the LA, which presumably form axon collaterals to innervate other spiny neurons in the LA. The proportion of LA spines targeted by other LA neurons is a measurement that has not yet been examined, nor has it been determined whether excitatory axons originating from LA neurons target spines lacking GluR1 immunoreactivity. The idea that spines express different levels of GluR1, depending on their afferent partner, is novel but not impossible, because a substantial amount of evidence indicates that spines can undergo extensive biophysical and biochemical changes locally, independent of the parent dendritic shaft or soma (Carter et al., 2007; Matsuzaki et al., 2004; Yuste and Denk, 1995).
