Chronic Fluoxetine Treatment Suppresses Plasticity (Long-Term Potentiation) in the Mature Rodent Primary Auditory Cortex In Vivo

Figure 3

Amplitude of the first (a) and second (b) peak of field postsynaptic potentials (fPSPs) in the auditory cortex of rats treated with water (𝑛=11) or fluoxetine (𝑛=14), and the effect of theta-burst stimulation (TBS, at arrow) of the medial geniculate nucleus. Two episodes of TBS resulted in significant increases of amplitude of both the first (a) and second (b) fPSP peak in both groups of rats. However, for the second fPSP peak, fluoxetine-treated rats showed significantly less LTP than that seen in water animals. ANOVA results for (a) effect of time, 𝐹(14,322)=10.4, 𝑃<0.0001; effect of group, 𝐹(1,23)=0.8, 𝑃=0.4; interaction, 𝐹(14,322)=0.5, 𝑃=0.9. ANOVA results for (b) effect of time, 𝐹(14,252)=10.0, 𝑃<0.0001; effect of group, 𝐹(1,18)=3.6, 𝑃=0.08; interaction, 𝐹(14,252)=2.2, 𝑃=0.007; * indicates significant (𝑃<0.05) simple effects tests comparing the two treatment groups. (Note that group sizes for the analysis of the second peak were 𝑛=9 and 𝑛=11 for water and fluoxetine rats, resp., since this peak could not be consistently resolved in all animals.)

(a)

(b)