Coordinated electrical activity in the olfactory bulb gates the oscillatory entrainment of entorhinal networks in neonatal mice
Fig 6
Effects of pharmacological blockade of neuronal firing in OB on patterns of oscillatory activity in OB–LEC circuits.
(A) Schematic drawing of experimental protocol. (B) Photograph of the brain of a P10 mouse showing the confinement of injections to one hemisphere of the OB. For visualization, the same volume of methylene blue was used. (C) Characteristic LFP traces (black, filtered 1–100 Hz) recorded in OB (top) and LEC (bottom) of a P9 mouse before (left) and after (right) lidocaine infusion, displayed together with the wavelet spectrograms of the LFP and simultaneously recorded MUA. (D) Top, mean MUA firing rate in OB (left) and LEC (right) before and after lidocaine infusion. The time of infusion is considered 0. Bottom, box plots displaying the mean MUA in OB (left) and LEC (right) before and after lidocaine infusion (Friedmann test, Wilxocon signed-rank test with Bonferroni correction for post hoc comparison, *p < 0.0071). (E) Box plots displaying the power of RR activity in OB and LEC in the RR band before and after lidocaine infusion. Gray dots and lines correspond to individual animals (Wilcoxon signed-rank test, *p < 0.05; **p < 0.01). (F) Same as E for the theta burst activity in neonatal OB and LEC. (G) Scatterplot displaying the relationship between the occurrence changes (percent of baseline) of OB and LEC theta bursts (r = 0.008, p = 0.0039, Pearson correlation). Data are available in S1 Data. LEC, lateral entorhinal cortex; LFP, local field potential; MUA, multiunit activity; OB, olfactory bulb; P, postnatal day; RR, respiration-related rhythm.