Bajan Birds Pull Strings: Two Wild Antillean Species Enter the Select Club of String-Pullers

<div><p>String-pulling is one of the most popular tests in animal cognition because of its apparent complexity, and of its potential to be applied to very different taxa. In birds, the basic procedure involves a food reward, suspended from a perch by a string, which can be reached by a series of coordinated pulling actions with the beak and holding actions of the pulled lengths of string with the foot. The taxonomic distribution of species that pass the test includes several corvids, parrots and parids, but in other families, data are much spottier and the number of individuals per species that succeed is often low. To date, the association between string-pulling ability and other cognitive traits was never tested. It is generally assumed that string-pulling is a complex form of problem-solving, suggesting that performance on string-pulling and other problem-solving tasks should be correlated. Here, we show that individuals of two innovative species from Barbados, the bullfinch <i>Loxigilla barbadensis</i> and the Carib grackle <i>Quiscalus lugubris fortirostris</i>, pass the string-pulling test. Eighteen of the 42 bullfinches tested succeeded, allowing us to correlate performance on this test to that on several other behavioral measurements. Surprisingly, string-pulling in bullfinches was unrelated to shyness, neophobia, problem-solving, discrimination and reversal learning performance. Only two of 31 grackles tested succeeded, precluding correlational analyses with other measures but still, the two successful birds largely differed in their other behavioral traits.</p></div

Ablation of proliferating cells in CNS decreases lifespan of SOD1^G93A mice.

<p>Kaplan-Meier survival curve shows that transgenic mice Sod1^G93A (n = 7) treated with Ara-C between 75 and 115 days had a mean survival of 134 days while untreated SOD1^G93A (n = 9) had a mean survival of 141 days. Log-rank test shows that this difference is significant (<i>p</i> = 0.0081).</p

Modulation of the inflammatory response in Ara-C treated SOD1^G93A mice.

<p>Quantitative RT-PCR results (values are normalized to GADPH and relative to wild-type control treated with vehicle; no significant difference was found between wild-type controls treated with vehicle or M-CSF for any marker). Significant differences were found between Ara-C and vehicle treated SOD1^G93A in levels of mRNA for TGF-b1 (*<i>p</i> = 0.0148), IL-1b (**<i>p</i> = 0.0072), IL-6 (**<i>p</i> = 0.0014) and IGF-1 (*<i>p</i> = 0.0108). Note that all mRNA levels were significantly higher in vehicle treated transgenic mice compared to WT, treated or not (<i>p</i><0.0025), except for IL-4 (<i>p</i> = 0.7582). All values are mean ± SEM; <i>n</i>(WT) = 9, <i>n</i>(Tg-Vehicle) = 6, <i>n</i>(Tg-Ara-C) = 15.</p

Ara-C treatment caused a decrease in microglia, NG2+ progenitors, oligodendrocytes, astrocytes and T cells in the spinal cord of SOD1^G93A mice.

<p>Immunofluorescence for cell markers Iba1 (A), CD68 (B), NG2 (C), GFAP (D), CD3 (E) and Olig2 (F) in the lumbar spinal cord of mutant SOD1 transgenic mice treated with vehicle or Ara-C. (G) Quantification of Iba positive cells showed a 1.5 folds reduction of cells in Ara-C treated mice compared to controls (**<i>p</i> = 0.0086). (H) Quantification of CD68 marker showed a 1.5 folds reduction of cells in Ara-C treated mice compared to controls (**<i>p</i> = 0.0099). (I) Quantification of NG2+ marker showed a 1.7 folds reduction of cells in Ara-C treated mice compared to controls (<i>p</i> = 0.0713) (J) Quantification of GFAP marked cells showed a slightly reduced number of astrocytes (1.2 folds) in Ara-C treated mice compared to controls, although this result was not significant (<i>p</i> = 0.3430). (K) Quantification of Olig2 positive cells showed a 2.0 folds reduction of cells in Ara-C treated mice compared to controls (*<i>p</i> = 0.0236) (L) Quantification of CD3+ cells showed 3.8 folds reduction of cells in Ara-C treated mice compared to controls (*<i>p</i> = 0.0122). All mice were analyzed at 115 days. All values are means ± SEM. Scale bars: 100 µm.</p