Results
Environmental enrichment
enhances visual discrimination and reversal learning
EE housing elicited subtle improvements on visual discrimination (Figure 1). EE housing did not influence the odds that an animal would choose the correct stimulus for VD (p=0.397, OR = 0.917, 95% CI = [0.751, 1.120]), but did decrease the XXX for correction trials (p<0.001, Coef = -0.184, 95% CI = [-0.275,-0.094]). Housing had no significant effect on trials to criterion (p>0.999) nor on total number of correction trials (p=0.213).
EE housing had more robust improvement effects on reversal learning (Figure 2). EE housing increased the odds that an animal would choose correctly in RL (p<0.001, OR = 1.316, 95% CI = [1.158, 1.494]) and decreased the XXX for correction trials (p=0.024, Coef = -0.0894, 95% CI = [-0.167,-0.0117]). Housing had no significant effect on trials to criterion (p=0.386) but did decrease total number of correction trials (p=0.0252).
Environmental enrichment does
not enhance pattern separation or working memory at baseline
Our results show a clear effect of both pattern separation level (p<0.001, OR = 1.682, 95% CI = [1.504,1.881]) and working memory delay (p<0.001, OR = 0.856, 95% CI = [0.838, 0.873]) in decreasing task performance (Figure 3), in keeping with
Kim 2015. No effect of housing on task performance was observed for either the pattern separation (p=0.788, OR = 1.019, 95% CI = [0.890,1.166]) or working memory (p=0.789, OR = 1.023, 95% CI = [0.862,1.215]) probes.
mGlu5 is not necessary for
spatial working memory, but EE improves task performance after chronic injections
After performing the baseline probes to test for the effects of EE on working memory, we wished to observe whether MTEP would disrupt working memory as previously reported (Figure 4). 20mg/kg MTEP had no effect upon working memory performance (p=0.570, OR = 0.974, 95% CI = [0.890, 1.066]). However, during the MTEP probe an effect of housing was observed (p=0.001, OR = 1.180, 95% CI = [1.070,1.301]). This occurred without a housing x MTEP interaction (p=0.744, OR = 1.031, 95% CI = [0.859,1.238]), suggesting that the effect of housing was independent of the effects of MTEP.
Environmental enrichment
affects locomotor activity in touchscreen chambers
We noticed that over time EE animals appeared to have decreased locomotor activity relative to SH animals (Table 1). Median regressions on back infrared beam-breaks demonstrated that EE animals had significantly relatively decreased locomotor activity per trial during the TUNL task.