Differences in Activation and Deactivation in Children with Sickle Cell Disease Compared with Demographically Matched Controls.

BACKGROUND AND PURPOSE: Declines in both functional activation and functional connectivity have been reported in patients with sickle cell disease. In this study, we derived the functional and default mode responses to a word stem paradigm in age-, ethnicity-, and background-matched subjects with sickle cell disease and control groups, with the aim of testing whether both networks were similarly attenuated and whether the changes were related to physiologic parameters that characterize sickle cell disease. MATERIALS AND METHODS: Both the functional and default mode responses were obtained from age- and background-matched controls and the sickle cell population by using a visually presented word stem paradigm on a 3T scanner. RESULTS: We observed an attenuated response to both activation and deactivation in the sickle cell disease group. There were no significant differences in the activation response between the 2 groups for the contrast control > sickle cell disease; however, significant differences were observed in the medial parietal cortex, the auditory cortex, and the angular gyrus for the default mode. For the sickle cell group, a significant correlation between the activation z scores and the physiologic parameters was observed; for the deactivation, the results were not significant but the trend was similar. CONCLUSIONS: The results indicate that the physiologic parameters modulate the activation in the expected fashion, but that the effect was weaker for deactivation. Given that significant differences between the 2 groups were only seen for deactivation, additional factors must modulate the deactivation in sickle cell disease.

The Pavlovian power of palatable food: lessons for weight-loss adherence from a new rodent model of cue-induced overeating.

OBJECTIVE: Relapsing to overeating is a stubborn problem in obesity treatment. We tested the hypothesis that context cues surrounding palatable food (PF) intake have the power to disrupt caloric regulation even of less PF. Context cues are non-food cues that are in the environment where PF is habitually eaten. DESIGN: Rats were conditioned to associate intake of Oreo cookies as the PF to cages with distinct context cues that differed from cues in cages where they were only given chow. PF naturally stimulated greater caloric intake. The rats were then tested in the PF cage with only chow available to determine whether the PF-paired cues, alone, could elicit overeating of plain chow. SUBJECTS: Non-food-deprived female Sprague-Dawley rats. MEASUREMENTS: Intake of plain chow under PF-paired cues vs chow-paired cues was compared. This was also measured in tests that included a morsel of PF as a priming stimulus. We also controlled for any effect of binge-prone vs binge-resistant status to predict cued-overeating. RESULTS: Rats consumed significantly more chow when exposed to context cues paired earlier with PF than with chow (P<0.01). This effect occurred using various cues (for example, different types of bedding or wallpaper). The effect was strengthened by priming with a morsel of PF (P<0.001) and was unaffected by baseline differences in propensity to binge on PF. CONCLUSION: Context-cues associated with PF intake can drive overeating even of a less PF and abolish the ability of rats to compensate for the calories of a PF primer. Just as drug-associated context cues can reinstate drug-addiction relapse, PF-paired cues may trigger overeating relapses linked to weight regain and obesity. This model should help identify the reflex-like biology that sabotages attempts to adhere to healthy reduced calorie regimens and call greater attention to the cue-factor in the treatment of binge eating and obesity.