Conclusions
A significant reduction between the baseline and experimental recording, in amplitude (30%) in both theta I and theta II (p<0.001) were observed, while the frequencies were not statistically significant. No abnormal activity in these traces (i.e. gamma waves) was observed. Our results illustrate that the observed reduction of theta rhythm was always associated with 75% loss of MS/DB GABAergic neurons. Thus, MS/BD GABAergic neurons play an important role in theta rhythm amplitude modulation. Ongoing studies are dedicated to determine if there is a correlation between destruction of a wider area of the MS/DB GABAergic neurons and its subsequent functional changes in hippocampal theta rhythm.