Regions of interest.

<p>The prefrontal cortex (blue), caudate putamen (red), amygdala (purple) and the somatosensory cortex (yellow) of the left (L) and the right (R) hemisphere were delineated on the B₀ images and the estimated diffusion parametric maps, referencing to a rat brain atlas <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095077#pone.0095077-Paxinos1" target="_blank">[25]</a>.</p

Sucrose consumption test.

<p>The rats were presented with a sucrose solution (1.5%) for one hour after 14 hours of food and water deprivation in order to evaluate their hedonic state during the CMS procedure (8 weeks). The studied animals showed a significant decrease of sucrose consumption in the anhedonic-like group, whereas the resilient animals showed no change compared with the control animals. The analysis was performed with two-way ANOVA for repeated measures. The data are presented as mean±SD. *p<.001. The figure was adapted from Delgado y Palacios <i>et al.</i> <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095077#pone.0095077-DelgadoyPalacios1" target="_blank">[18]</a>.</p

Results of the diffusion analysis of the amygdala.

<p>Groups mean (± SD) diffusion kurtosis (top) and diffusivity (bottom) parameters of the amygdala. One-way analysis of variance followed by post hoc least significant difference tests showed a significant increase of RD in both the anhedonic-like and resilient animals as compared with the unchallenged group. *p<.05 AD, Axial diffusion; AK, axial kurtosis; MD, mean diffusion; MK, mean kurtosis; RD, radial diffusion; RK, radial kurtosis.</p

Results of the diffusion analysis of the caudate putamen.

<p>Mean (±SD) diffusion kurtosis (top) and diffusivity (bottom) parameters of the caudate putamen. One-way analysis of variance followed by post hoc least significant difference tests showed a significant increase of AD in both the anhedonic-like and resilient animals as compared with the unchallenged group. In addition, MK is significantly decreased in anhedonic-like animals as compared with resilient animals. *p<.05 AD, Axial diffusion; AK, axial kurtosis; MD, mean diffusion; MK, mean kurtosis; RD, radial diffusion; RK, radial kurtosis.</p

MicroRNA Profiling in the Medial and Lateral Habenula of Rats Exposed to the Learned Helplessness Paradigm: Candidate Biomarkers for Susceptibility and Resilience to Inescapable Shock

<div><p>Depression is a highly heterogeneous disorder presumably caused by a combination of several factors ultimately causing the pathological condition. The genetic liability model of depression is likely to be of polygenic heterogeneity. miRNAs can regulate multiple genes simultaneously and therefore are candidates that align with this model. The habenula has been linked to depression in both clinical and animal studies, shifting interest towards this region as a neural substrate in depression. The goal of the present study was to search for alterations in miRNA expression levels in the medial and lateral habenula of rats exposed to the learned helplessness (LH) rat model of depression. Ten miRNAs showed significant alterations associating with their response to the LH paradigm. Of these, six and four miRNAs were significantly regulated in the MHb and LHb, respectively. In the MHb we identified miR-490, miR-291a-3p, MiR-467a, miR-216a, miR-18b, and miR-302a. In the LHb miR-543, miR-367, miR-467c, and miR-760-5p were significantly regulated. A target gene analysis showed that several of the target genes are involved in MAPK signaling, neutrophin signaling, and ErbB signaling, indicating that neurotransmission is affected in the habenula as a consequence of exposure to the LH paradigm.</p></div

Additional file 1 of Novelty-induced memory consolidation is accompanied by increased Agap3 transcription: a cross-species study

Supplementary Material

Pathway analysis.

<p>Displaying the most significant KEGG pathways predicted to be targeted by the indicated miRNAs for A) miR-18b-5p, B) miR-291-3p, C) miR-760-5p and D) miR-367-3p. miR-18b-5p and miR-291-3p were identified in the medial habenula. miR-760-5p and miR-367-3p were identified in the lateral habenula. Only non-cancer pathways with FDR < 0.05 are shown. Lists are limited to maximum 10 pathways. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160318#sec002" target="_blank">Materials and Methods</a> section for further detail.</p

Learned helplessness.

<p>A) Deficit pattern, number of failures to terminate shock within the first 20 s of a trial (mean ±SEM). B) Failure pattern, failure to terminate shock results in a failed trial (mean ±SEM). C) Latency, the accumulated latency to press the lever (mean ±SEM).</p

Differential miRNA expression.

<p>A+C) miRNAs exhibiting significant expression changes in MHb are depicted in a heatmap (A) and relative quantity (RQ) compared to control, ANOVA p-value and FDR are shown in a table (C). B+D) miRNAs exhibiting significant expression changes in LHb are depicted in a heatmap (B) and relative quantity (RQ) compared to control, ANOVA p-value and FDR are shown in a table (D). (See supporting <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160318#pone.0160318.s003" target="_blank">S1 Table</a> for all expressed miRNAs). Significance, indicated by * was found by Benjamini-Hochberg corrected ANOVA (FDR < 0.05) with Tukey post hoc test. Colors represent mean centered, negative Ct values. LH: Rats becoming helpless under the learned helplessness paradigm. NLH: Rats resistant to the learned helplessness paradigm.</p

Cluster analysis.

<p>Fig 3 shows a cluster analysis based on the miRNA expression levels. The results show a clear segregation into medial (MHb) and lateral (LHb) habenular subgroups. The analysis further shows a clear segregation into the learned helpless (LH), non-learned helpless (nLH), and non-shocked controls (NS).</p