The present study focused on the hypothesis that dietary supplementation with medium-chain TAG (MCT) will improve cognitive function in aged dogs by providing the brain with energy in the form of ketones. Aged Beagle dogs were subjected to a baseline battery of cognitive tests, which were used to establish cognitively equivalent control or treatment groups. The dogs in the treatment group were maintained on a diet supplemented with 5·5 % MCT. After an initial wash-in period, all the dogs were tested with a battery of cognitive test protocols, which assessed sequentially landmark discrimination learning ability, egocentric visuospatial function and attention. The groups were maintained on the diets for 8 months. The MCT-supplemented group showed significantly better performance in most of the test protocols than the control group. The group differences also varied as a function of task difficulty, with the more difficult task showing greater supplementation effects than the easier tasks. The group given the MCT supplement showed significantly elevated levels of b-hydroxybutyrate, a ketone body. These results indicate, first, that long-term supplementation with MCT can have cognition-improving effects, and second, that MCT supplementation increases circulating levels of ketones. The results support the hypothesis that brain function of aged dogs can be improved by MCT supplementation, which provides the brain with an alternative energy source.Brain ageing: Cognitive functions: Dogs: Medium-chain TAG: Ketone bodies Dog cognitive function, like that of other mammals, becomes impaired over the course of ageing, and it provides a model of human cognitive ageing (1,2) . Decline in energy metabolism is a common feature of ageing in animals, and it is one of the several processes that are closely associated with age-dependent cognitive decline. Rapoport et al. (3) found that brain glucose metabolism was reduced by up to 30 % between 3 and 12 months of age in rats. London et al. (4) reported that brain glucose metabolism was significantly reduced in Beagle dogs at 6 years of age than in 1-year-old dogs. Further changes occurred later in life, but in a manner that varied between brain structures. Brain metabolic decline has also been reported in aged monkeys (5) and human subjects (6) , and it appears to be particularly more pronounced in pathological ageing. Alexander et al.(7) reported that cerebral glucose metabolism was significantly lower in old patients with Alzheimer's disease than in healthy old control subjects. Drzezga et al.(8) traced the development of cognitive decline in patients with mild cognitive impairment, discovering that the clinical symptoms of Alzheimer's disease were associated with further declines in cerebral glucose metabolism. These data suggest that the age-associated reduction in cerebral glucose metabolism is a common feature in ageing, that the process involved may be progressive, starting around the middle age, and that metabolic decline contributes to cognitive decline associated with ...

An exploratory study examined adults' questions to small groups of children to determine how questions influenced their response rate and complexity of response. Thirteen educators of toddlers and 13 educators of preschoolers were videotaped during free-play. Both groups of educators used an equivalent frequency of open-ended and closed questions, but the preschool educators used more topic-continuing questions. Consistent with their developmental level, preschoolers responded more frequently than toddlers. Toddlers demonstrated few effects of question type. In contrast, preschoolers used more multiword utterances following open-ended questions and topic-continuing questions. Implications for in-service education for staff of early childhood settings include increasing the use of both open-ended and topic-continuing questions.

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Aging has been shown to disrupt performance on tasks that require intact visual search and discrimination abilities in human studies. The goal of the present study was to determine if canines show age-related decline in their ability to perform a novel simultaneous visual search task. Three groups of canines were included: a young group (N = 10; 3 to 4.5 years), an old group (N = 10; 8 to 9.5 years), and a senior group (N = 8; 11 to 15.3 years). Subjects were first tested for their ability to learn a simple two-choice discrimination task, followed by the visual search task. Attentional demands in the task were manipulated by varying the number of distracter items; dogs received an equal number of trials with either zero, one, two, or three distracters. Performance on the two-choice discrimination task varied with age, with senior canines making significantly more errors than the young. Performance accuracy on the visual search task also varied with age; senior animals were significantly impaired compared to both the young and old, and old canines were intermediate in performance between young and senior. Accuracy decreased significantly with added distracters in all age groups. These results suggest that aging impairs the ability of canines to discriminate between task-relevant and -irrelevant stimuli. This is likely to be derived from impairments in cognitive domains such as visual memory and learning and selective attention.

Exercise has been shown to reduce age-related losses in cognitive function including learning and memory, but the mechanisms underlying this effect remain poorly understood. Memory formation occurs in stages that include an initial acquisition phase, an intermediate labile phase, and then a process of consolidation which leads to long-term memory formation. An effective way to examine the mechanism by which exercise improves memory is to introduce the intervention (exercise), post-acquisition, making it possible to selectively examine memory storage and consolidation. Accordingly we evaluated the effects of post-trial exercise (10 min on a treadmill) on memory consolidation in aged canines both right after, an hour after, and 24 h after acute exercise training in concurrent discrimination, object location memory (OLM), and novel object recognition tasks. Our study shows that post-trial exercise facilitates memory function by improving memory consolidation in aged animals in a time-dependent manner. The improvements were significant at 24 h post-exercise and not right after or 1 h after exercise. Aged animals were also tested following chronic exercise (10 min/day for 14 consecutive days) on OLM or till criterion were reached (for reversal learning task). We found improvements from a chronic exercise design in both the object location and reversal learning tasks. Our studies suggest that mechanisms to improve overall consolidation and cognitive function remain accessible even with progressing age and can be re-engaged by both acute and chronic exercise.