Figure 11.

DA has a greater impact on integration of signals that propagate down the dendrite compared with local signals. A, Dual recordings of the dendrite and soma of neurons were performed to examine propagation of αPSPs from the dendrite to the soma. αPSPs injected into the dendrite and recorded in the dendrite display similar features as αPSPs injected to the soma and recorded in the soma (see Fig. 3): the summation at depolarized membrane potentials is greater, and DA enhanced summation at depolarized membrane potentials. However, when examining αPSPs initiated in the dendrite while recording at the soma, the effect of DA on summation is significantly greater. B, The effect of DA on αPSPs that travel to the soma from the dendrite is much greater, indicating that DA facilitates signals that must travel down the dendrite. This figure depicts recordings at the soma and the apical dendrite, ∼200 μm from the soma. Black traces represent baseline conditions, and gray traces represent DA conditions. *p < 0.05, significant difference in a paired t test comparison between baseline and DA conditions.