Figure 7.

Activation of stubby dendritic spines produces a larger uEPSP in thalamorecipient neurons. a, Image of a second-order dendrite with a short stubby spine and a nearby mushroom spine on which glutamate was uncaged (yellow squares) for 0.2 ms. Scale bar, 1 μm. b, Examples of single uEPSPs evoked by a pulse of glutamate uncaging (arrow) at a short stubby dendritic spine (black) and at the neighboring mushroom (red) dendritic spine in the neuron from a. c, Filled circles represent peak uEPSP amplitudes (averaged from 5–10 uEPSPs) measured at stubby spines and neighboring mushroom spines (11 stubby-mushroom spine pairs from 7 neurons) located on second-order dendrites within 100 μm of the soma. Also shown are the means ± SEM calculated from all experiments. *p < 0.001 (paired t test).