The provision of environmental enrichment (EE) for laboratory rats is recommended in
European guidelines governing laboratory animal welfare. It is believed the EE …

Although responses are sometimes easy to predict, at other times responding seems highly
variable, unpredictable, or even random. The inability to predict is generally attributed to …

Prepulse inhibition (PPI) is the attenuation of the startle reflex when the sudden intense
startling stimulus is shortly preceded by a weaker, non-startling sensory stimulus (prepulse) …

The Wistar-Kyoto (WKY) rat is an established depression model characterized by elevated
anxiety-and depression-like behavior across a variety of tests. Here we further characterized …

Attention-deficit hyperactivity disorder (ADHD) is a neuropsychiatric syndrome, affecting
human infants and adolescents. Two main behavioural features are reported:(1) impaired …

Unlike such psychiatric disorders as depression, schizo- symptoms such as aggression,
anxiety, and obsessivecompulsive behaviors but little or no inprovement in phrenia, and …

Although reinforcement often leads to repetitive, even stereotyped responding, that is not a
necessary outcome. When it depends on variations, reinforcement results in responding that …

An epidemiological study of Attention Deficit/Hyperactivity Disorder (ADHD) suggests that
the prevalence may be two to three times higher than the figure of 3–5% often cited. In …

Rationale. Hypertension is considered a risk factor for the development of cognitive
disorders, because of its negative effects on cerebral vasculature and blood flow …

Three experiments compared the amounts of behavioral variability generated with two
reinforcement rules. In Experiments 1 and 2 pigeons received food whenever they …