Acquisition and persistence of intermittent access-induced escalated sucrose intake in male rats.

Ad lib fed male rats with 23 h every third day access (E3DA) to 4% sucrose come to double the sucrose intake of rats with everyday access (EDA). These differences are maintained if all rats are then put on an alternate day schedule. In two experiments, we explored how initial patterns of sucrose availability influenced consumption when access conditions changed.

Digital dementia in the internet generation: excessive screen time during brain development will increase the risk of Alzheimer's disease and related dementias in adulthood.

Converging evidence from biopsychosocial research in humans and animals demonstrates that chronic sensory stimulation (via excessive screen exposure) affects brain development increasing the risk of cognitive, emotional, and behavioural disorders in adolescents and young adults. Emerging evidence suggests that some of these effects are similar to those seen in adults with symptoms of mild cognitive impairment (MCI) in the early stages of dementia, including impaired concentration, orientation, acquisition of recent memories (anterograde amnesia), recall of past memories (retrograde amnesia), social functioning, and self-care. Excessive screen time is known to alter gray matter and white volumes in the brain, increase the risk of mental disorders, and impair acquisition of memories and learning which are known risk factors for dementia.

Sucrose solution concentration and the intermittent access induced consumption increase.

Animals fed ad libitum consume less of a preferred additional food with daily access than with access only once every few days. With 4% sucrose solution, rats can drink over twice as much in a day if they receive it every fourth day compared to daily access. These differences are maintained when all rats are put on the same schedule.

Reduced caloric intake allows access-induced consumption differences to emerge with concentrated sucrose solutions.

Rats given intermittent access to 4% (w/v) sucrose solution elevate their consumption of solution relative to rats with continuous access, a difference that does not appear at higher concentrations. Here, we examined the hypothesis that a limit on the intake of sucrose calories prevents rats from demonstrating access-induced differences in consumption of a more concentrated sucrose solution. Energy-replete rats were given every day (ED) or every third day (E3D) access to sucrose solutions adulterated with bitter quinine which reduced solution palatability and consumption levels while intake was measured.

Intermittent access to a sucrose solution for rats causes long-term increases in consumption.

Intermittent access to palatable food can elevate consumption beyond an animal's immediate needs. If adult male rats (with ad lib access to food and water) are provided with a 4% sucrose solution, daily sucrose consumption is determined by the sucrose access schedule: access that is intermittent leads to high levels of consumption. In Experiment 1, sucrose solutions were first provided continuously or every second, third, or fourth day for 23.

Can overeating induce conditioned taste avoidance in previously food restricted rats?

While feeding is rewarding, the feeling of satiation has been theorized to have a mixed affect. Using a food restriction model of overeating we examined whether bingeing was capable of supporting conditioned taste avoidance (CTA). Adult male Sprague-Dawley rats were maintained on either an ad lib (n=8) or restricted (50% of regular consumption; n=24) food access for 20 days.

Chlorpromazine specifically prevents the wheel-induced feeding suppression in rats.

In rats, limited daytime wheel access suppresses feeding over the subsequent night [Lattanzio SB, Eikelboom R. Wheel access duration in rats: I. effects on feeding and running.

The effects of prior weight reduction on the running wheel-induced feeding suppression in rats.

Adult male rats given ad lib access to food and a running wheel show an initial feeding and weight suppression. Over 6-10 days feeding recovers, but body weight remains low. It is not clear which effect is primary, the wheel-induced feeding or weight change.

Dissociation of conditioned and unconditioned factors in the running-induced feeding suppression.

In adult rats, running wheel introduction induces a 7 to 10 day feeding suppression, either due to a learned conditioned taste avoidance or to the direct unconditioned effects of wheel running. The three experiments investigated the effects of wheel introduction on familiar (rat chow) and novel (24% sucrose solution) food consumption (Experiment 1), and then explored how alternate-day wheel access affected sucrose consumption when it was novel (Experiment 2) or familiar (Experiment 3). When paired with wheel introduction the consumption of a novel sucrose solution was completely suppressed for an extended period, whether the rats had continuous or alternate-day wheel access.

Modulation of the pair housing induced feeding suppression.

The present experiments explored how manipulating the period of individual housing, partner novelty, or short periods of conspecific interaction affected the feeding suppression evident when young adult male rats were moved from individual to pair housing. In the first experiment, after a period of pair housing, rats were individually housed for 0, 3, 10, or 14 days before being rehoused with either the same or a novel partner. There was an increase in the feeding suppression as the duration of individual housing grew, and at 3 days, the novel partner produced a stronger suppression than did the familiar partner.

Relationship between wheel running, feeding, drinking, and body weight in male rats.

The amount of wheel running varies widely between rats. Wheel introduction and running also have profound effects on the animal's energy balance. We explored the effects of ad lib wheel access and running levels on feeding, drinking, and body weight in 30 young adult male rats with wheel access and in 30 rats without wheel access.

Wheel access duration in rats: II. Day-night and within-session changes.

Time of day and duration of wheel access were manipulated to see how running changed over days. Young male rats were given 2 hr of wheel access, during either the light or dark phase. Over 24 days, running increased 4-fold in the dark group but remained low and stable in the light group.

Wheel access duration in rats: I. Effects on feeding and running.

The effects of 0-, 2-, and 24-hr wheel access on the pattern of running, feeding, and weight were explored over 24 days in 3 groups of 8 male rats. Both 2 and 24 hr of wheel access suppressed feeding by about 15% for about 8 days before feeding gradually returned to normal. Weight in these 2 groups was similar and was suppressed for the 24 days.