Fig. 6: Alpha rhythms require Mg2+-independent dendritic NMDA spikes and subthreshold potassium conductances.
From: Layer 4 pyramidal neuron dendritic bursting underlies a post-stimulus visual cortical alpha rhythm
a Pharmacological dissection of the alpha rhythm. Graph shows mean (± s.e.m.) LFP alpha power relative to the mean alpha power generated by the slice model shown in Fig. 1b. NR1-containing, NR2A-, 2B- and NR2C/D-containing NMDA receptor-mediated excitation was blocked by R-CPP, TCN201, CO101244 and PPDA, respectively. ERG channels were blocked by terfenadine (terf). Voltage-operated calcium channel subtypes N, P/Q, L and T were blocked with ω-conotoxin GIVA, ω-agatoxin, amlodipine and NNC 55-0369, respectively. *P < 0.05 cf. control alpha LFP power. b Example dendritic recordings from L4 V1 pyramids showing the effects of NR2C/D-containing NMDA receptors with PPDA. Upper trace shows dendritic activity during the initial kainate-induced gamma rhythm, middle trace shows dendritic activity during the alpha rhythm and lower trace the activity in the same dendrite in the presence of PPDA. Scale bars 10 mV, 50 ms. c Examples of reconstructed, biocytin-filled L4 V1 stellate and pyramidal neurons with overlaid somatic Kv10.2 immunopositivity. Lower traces show somatic activity in L4 V1 pyramids during the initial, kainate-induced gamma rhythm (upper), the subsequent alpha rhythm (mid) and in the presence of terfenadine (lower). Scale bars as in b.
