Early emergence of motivational and hedonic feeding deficits in the TgF344-AD rat model of Alzheimer’s disease

Figures

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  FIGURE 1. (A) Mean free-feeding bodyweight (± SEM) for female (left) and male (right) TgF344-AD (Tg) and wildtype (WT) rats. Data are plotted across ages 3–4, 6–7, and 9–10 months as in subsequent panels. (B) Mean bodyweight-normalized sweet condensed milk (SCM) consumption (ml/kg; ± SEM) over successive 3 min bins during free-access tests conducted longitudinally across ages for male and female Tg and WT rats. Consumption rates have been collapsed across SCM concentration (four levels/age) to highlight the within-session pattern of intake over time. (C) Mean bodyweight-normalized SCM consumption (ml/kg; ± SEM) during the first 3 min of active SCM consumption across SCM concentration and across ages for male and female Tg and WT rats. (D) Mean bodyweight-normalized intake (ml/kg; ± SEM) of response-contingent SCM rewards during progressive ratio tests conducted across ages for male and female Tg and WT rats. Group sizes for all analyses were as follows: Female Tg (n = 11), Female WT (n = 11), Male Tg (n = 11), and Male WT (n = 7). ** p < 0.01, *** p < 0.001.

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  FIGURE 2. (A) Mean number of arm entries (± SEM; top) and (B) mean percentage of alternations (± SEM; bottom) in the Y-maze test for TgF344-AD [Tg: female (n = 11) and male (n = 9)] and Wildtype rats [WT: female (n = 11) and male (n = 4)]. (C) Mean (± SEM) distance traveled and (D) time in center during the first session of open field habituation for Tg [female (n = 11) and male (n = 11)] and WT rats [female (n = 11) and male (n = 5)]. (E) Schematic representation of design for object-in-place and object recognition testing (see text for procedural details). (F) Mean (± SEM) time spent exploring the two novel objects during the object-in-place training session and (G) the relative time spent exploring the object moved to a novel location at test [(discrimination index = (moved–unmoved)/(moved + unmoved)] (G) for Tg [female (n = 11) and male (n = 10)] and WT rats [female (n = 11) and male (n = 4)]. (H) Mean (± SEM) time spent exploring the two objects during object recognition training and (I) the percentage of total time spent exploring the novel object at test [(discrimination index = (novel–familiar)/(novel + familiar)] for Tg [female (n = 11) and male (n = 10)] and WT rats [female (n =…

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  FIGURE 3. (A) Summary of results from correlational analysis between progressive ratio (PR) performance at 3–4 months and cognitive test performance at 12–14 months. Significant relationships are in bold italic font. (B) Scatterplots and regression lines for each subgroup showing significant positive correlations between progressive ratio (PR) performance and object-in-place memory for female TgF344-AD and wildtype rats but not for males of either genotype.