Supplementary Figure 5: Whole-cell patch-clamp recordings in layer II MEC stellate cells confirm that Cre-mediated knockout of HCN1 reduced Ih.
From: Grid scale drives the scale and long-term stability of place maps
Whole-cell recordings from n = 13 cells from 8 iWT mice and 13 cells from 8 iCre-KO mice. (a) Image of a representative virus-infected stellate neuron targeted for whole-cell patch clamp recording. Top: GFP expression is visible in the MEC; scale bar: 1 mm. Bottom: higher magnification view; scale bar: 0.1 mm. A red arrow marks the recorded neuron. (b-c) In MEC, the absence of HCN1 leads to a higher input resistance (Rin) and a more hyperpolarized resting membrane potential5. Consistent with a decrease in I(h), infected neurons in iCre-KO mice had a significantly higher input resistance (b) and lower resting membrane potential (c) compared to infected neurons in iWT mice (mean ± standard deviation [SD]; input resistance: iWT = 47.02 ± 15.81 mΩ, iCre-KO = 69.05 ± 17.89 mΩ, unpaired two-tailed t-test, t(24) = 3.33, p = 0.0028; resting membrane potential iWT = −64.23 ± 2.35 mV, iCre-KO = −69.23 ± 7.67 mV, t(24) = 2.25, p = 0.041). Colored bars indicate the mean ± SEM and individual data points are shown in black. *p<0.05, **p<0.01, ***p<0.001. (d) We held the membrane potential at −70 mV and applied 1 s long hyperpolarizing current steps that, in the presence of I(h), result in a slow depolarizing shift in the membrane potential (sag)6. Examples of sag potential from iWT (blue) and iCre-KO (red) infected stellate neurons (top) in response to current injections (bottom; black). (e) Cre-mediated knockout of HCN1 significantly decreased the sag ratio (mean ± SD; iWT = 1.44 ± 0.41, iCre-KO = 1.13 ± 0.07, unpaired two-tailed t-test t(24) = 7.17, p = 2.1e-7). Colored bars indicate the mean ± SEM and individual data points are shown in black. *p<0.05, **p<0.01, ***p<0.001.
5. Nolan, M.F., Dudman, J.T., Dodson, P.D. & Santoro, B. HCN1 channels control resting and active integrative properties of stellate cells from layer II of the entorhinal cortex. J Neurosci 27, 12440–12451 (2007).
6. Dickson, C.T., et al. Properties and role of I(h) in the pacing of subthreshold oscillations in entorhinal cortex layer II neurons. J Neurophysiol 83, 2562–2579 (2000).
