Skip to main content
. 2018 Feb 28;7:e34976. doi: 10.7554/eLife.34976

Figure 2. Behavioral and neural effects of explicit learning.

(A) Experimental design for explicit learning (S: Sacrifice, Test:Habituation/Cross Habituation Task). (B) From D1 to D5 of training, the percentage of correct choices increased in conditioned (Cond) but not pseudo-conditioned animals (PC) indicating that learning occurred only in the conditioned animals (C) Adult-born cell (BrdU-positive cell) density is increased after explicit learning (D) The percentage of odor-responsive adult-born cells (expressing Zif268) is increased after explicit learning. (E). Spine density of the apical domain decreased after explicit learning. (F) Spine density of the basal domain is unchanged after explicit learning. (G) Representative traces of sIPSC for Cond and PC (up). sIPSC frequency and amplitude are decreased after explicit learning (down). (H) Percentage of mitral cells exhibiting a significant response to light stimulation of adult-born granule cells. (I) The percentage of mitral cells (Tbx21) expressing Zif268 is higher in Cond versus PC animals. *p<0.05; the data are expressed as mean values ± SEM.

Figure 2—source data 1. Raw Data Figure 2.
elife-34976-fig2-data1.xlsx (25KB, xlsx)
DOI: 10.7554/eLife.34976.015

Figure 2.

Figure 2—figure supplement 1. Improvement in discrimination after explicit learning.

Figure 2—figure supplement 1.

At the end of the associative learning, the habituation/cross habituation task indicated that +lim and -lim were not discriminated in the pseudo-conditioned (PC) group (n = 10; Friedman test for Habituation, p=0.02; Wilcoxon test for discri- mination p=0.44). In contrast, conditioning allowed discrimination as observed by the significant increase of investigation time between the last habituation trial (OHab4) and the presentation of the second odorant of the pair (Otest) (n = 10; Friedman test for Habituation, p=0.00073; Wilcoxon test for discrimination p=0.005).
Figure 2—figure supplement 2. Long-term delay after explicit learning A.

Figure 2—figure supplement 2.

The percentage of correct choices returned to the control level in conditioned animals (Cond D60, Mann-Whitney p=0.36, n = 5) and remained low in pseudo-conditioned animals (PC D60, Mann-Whitney p=0.42, n = 5). (B) 42 days after explicit learning, no difference in spine density in the apical domain was observed between Conditioned (Cond) and Pseu- do-conditioned (PC) animals (Mann-Whitney p=0.07; Cond: 82 dendritic segments n = 4 mice and PC: 93 dendritic segments n = 4 mice).
Figure 2—figure supplement 3. Effect of light stimulation of adult-born neuron on mitral cell activity.

Figure 2—figure supplement 3.

(A) IPSC frequency (PC n = 23; Cond n = 22 cells; No-light versus Light in PC group p=0.015; No-light versus Light in Cond group p=0.01; PC light versus Cond light p=0.0015) and (B) amplitude (PC n = 22; Cond n = 18 cells; No-light versus Light in PC group p=0.15; No-light versus Light in Cond group p=0.0076; PC light versus Cond light p=0.25) were recorded on mitral cells in OB slices in response to light stimulation of adult-born granule cells in PC and Cond groups. Unilateral paired t-test for comparison between No-light and Light conditions and permutation tests for comparisons between Non-Enr and Enr animals, *p<0.05.
Figure 2—figure supplement 4. The biophysical properties of adult-born neurons.

Figure 2—figure supplement 4.

Explicit learning did not modify (A) the resting membrane potential (Mann-Whitney: PC vs Cond p=0.12). (B) the membrane resistance (Mann-Whitney: PC vs Cond p=0.1) or (C) the membrane capacitance of adult-born neurons (Mann-Whitney: PC vs Cond p=0.16) (Pseudo-conditioned: PC; Conditioned: Cond). (D) The input-output curves of adult-born cells produced by 500 ms steps of injected currents at different intensities were not modified by explicit learning (PC n = 37 and Cond n = 49 cells). Only neurons that were not silent were considered (Mann Whitney, p>0.05). The data are expressed as mean values ± SEM.