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LEGENDS TO SUPPLEMENTARY FIGURES

Figure 1: Two hours of environmental enrichment (see methods for enrichment arena) elicits widespread neuronal activation in the hippocampus as evidenced by enhanced c-fos staining. All cellular layers of the hippocampus showed increased number of c-fos+ cells. Representative animals are shown.

Figure 2: A, Two hours of enrichment elicits increased phosphorylation of the IGF-I receptor in the cerebellum. *p<0.05 vs controls (Wt mice under standard housing conditions (n= 10 per group). B, Enrichment did not enhance IGF-IR phosphorylation in serum IGF-Ideficient LID mice. A representative blot is shown. n= 85 in controls and n=13 in LIDs. ***p<0.001 vs controls and enriched LID mice.

Figure 3: Young (3 months-old) double mutant APP/PS1 mice already display abundant amyloid plaques in the forebrain whereas single mutant young (3 months-old) APP mice did not have any sign of amyloidosis. A representative animal of each group is shown.

Figure 4: A, Levels of hippocampal IGF-IR were similar in AD mice and controls (Wt mice of similar age; Wt n=10, APP/PS n=9 and APP n=8). B, Levels of phosphorylated IRS-1 at Ser616, an indicator of insulin/IGF-I resistance in AD brain (15), were significantly increased in the hippocampi of AD mice, both in APP/PS1 and in pre-symptomatic APP mice, confirming a resistant state in AD mice prior to overt pathology. (Wt n=14, APP/PS n=13 and APP n=7; 8*p<0.05 and **p<0.01 vs Wt controls). C, Levels of the multicargo transporter LRP1, known to be involved in transport of serum IGF-I into the brain (12), remained unaltered in young AD mice. (Wt n=15, APP/PS n=4 and APP n=6).

Figure 5: Intraperitoneal administration of IGF-I to anesthetized YG8R mice (a mouse model of Friedriech´s ataxia) induces changes in the ECG signature similar to those seen in wild type mice (see Figure 2 for comparison). Increased a, b, and θ frequencies are observed (n= 2).

Figure 6: The response of the ECG band b, measured as AUC, is directly proportional to the phosphorylation response of the hippocampal IGF-IR (determined as pIGF-IR/IGF-IR ratio) after 2 hours of enrichment as higher ECG responses in Wt mice after IGF-I stimulation correspond with higher responses to enrichment.

Supplementary Table 1. Levels of IGF-I in serum and CSF of AD patients

and age-matched controls

Group / Serum IGF-I (ng/ml) / CSF IGF-I (ng/ml) / n
Control / 40,38 ± 0.33 / 0.62 ± 0.03 / 10
AD / 77.79 ± 2.78** / 0.40 ± 0.02** / 35

**p<0.01 vs control

Supplementary Table 2. Levels of IGF-I in CSF of mouse

models of AD

Group / CSF IGF-I (pg/ml) / n
Control / 4.16 ± 0.28 / 10
APP/PS1 / 2.26 ± 0.41** / 17
APP / 1.45 ± 0.40** / 6

**p<0.01 vs control