Extended Data Fig. 9: Untagged neurons in the tagging experiments are no different than generic recordings, and optical inhibition of terminals of the two cell types replicates cell body inactivation.
From: Thalamic circuits for independent control of prefrontal signal and noise
a, (Top Left) Schematic of optogenetic tagging and identification of MDD2 and MDGRIK4 neurons. MDD2 or MDGRIK4 neurons are tagged with NpHR3.0 and identified via light activated spike rate suppression. (Bottom) Example tagged neuronal response to NpHR3.0 activation. (Right) Tagged neurons from one mouse (red) are identified using k-means clustering (features: change in firing rate, proportion of trials suppressed, and half-time to recover from suppression (n = 262 total number of neurons). b, Relative fraction of all MD neurons from GRIK4-cre mice that are conflict-preferring vs. non-preferring are comparable to that of wild-type animals (Fig. 3g) (n = 91 neurons from 3 mice; p = 0.429 (NS), chi-squared test). Note that tagged MDGRIK4 neurons are significantly more conflict-preferring compared to the whole population (Fig. 4b) (p = 0.0175; chi-squared test). c, Relative fraction of all MD neurons from D2-cre mice that are conflict-preferring vs. non-preferring, are also comparable to that of wild-type animals (Fig. 3g) (n = 95 neurons from 3 mice; p = 0.166 (NS), chi-squared test). Note, that tagged MDD2 neurons are significantly more conflict-non-preferring (Fig. 4d) (p=1.34 x 10-4; chi-squared test). d, Optical inhibition of MDGRIK4 terminals in the PL recapitulates the loss in task accuracy across low and high conflict trials as seen with optical MDGRIK4 inactivation (Fig. 4e; n = 20 sessions over 4 GRIK4-cre mice, *p = 0.0199, ***p = 0.0002; Mann-Whitney U test). e, Optical inhibition of MDD2 terminals in the PL enhances performance accuracy on trials with high cueing conflict, similar to the effect of optical MDD2 inactivation (Fig. 4f; n = 20 sessions over 4 D2-cre mice, p = 0.3941 (NS), **p = 0.0023; Mann-Whitney U test. f, Schematic of micro-drive bottom piece and the 3x3 grid organization of the tetrode array for MD recordings. g, Summary of the density of tagged neurons on the medial-lateral axis separated by animal. We show the result for 2 Grik4-cre (top and bottom) and 2 D2-cre animals ((top and bottom rows) that have enough numbers of tagged neurons. All statistical tests are two-tailed. For box plots b – e boundaries, 25–75th percentiles; midline, median; whiskers, minimum–maximum
