Page 74 - Zoo Animal Learning and Training

46 3 The Ultimate Benefits of Learning

VetBooks.ir tive) can have the largest impact on the onset depending on the type of brain injury and the
type of enrichment provided; activities
of Alzheimer’s disease, Cracchiolo et al.
(2007) carried out an experiment using
enrichment and/or training were better than
Alzheimer’s disease transgenic mice. At requiring learning whether environmental
six weeks of age, mice were transferred from physical activities at enhancing motor per-
standard social cages to one of the following formance after brain injury (Will et al. 2004).
conditions: (i) impoverished, animals were
housed individually in a standard Plexiglas© 3.4.3 Learning Opportunities
mouse cage; (ii) social housing, animals were Lead to Reduced Stress and/or
housed in standard cages with other mice of Stereotypy Reduction
the same gender; (iii) physical enrichment,
animals were socially housed, and had access One of the behavioural goals of providing
to running wheels; and (iv) complete environ- environmental enrichment can often be a
mental enrichment, animals were socially reduction in stress levels. Stereotypies and
housed, and had access to tubes, tunnels and self‐directed behaviours (SDBs) can develop
toys, etc. (within all housing conditions all when animals are housed in conditions which
items were changed weekly, and mice were do not meet their physical or psychological
placed in a novel complex environment three needs (e.g. Lutz et al. 2003). In many cases a
times a week). At 6 months of age all mice reduction in stereotypies and SDBs are used
were tested, over a period of 5 weeks, on a as indicators of reduced stress and thus the
range of behavioural tests: Y maze; Morris goal of many enrichment programmes may
water maze; circular platform task (1 escape be to reduce the occurrence of these behav-
box, 16 choices/holes); and platform recogni- iours (Swaisgood and Shepherdson 2005). For
tion, radial arm water maze. The authors example 14 captive sloth bears (Mehursus
found that during certain tasks mice raised ursinus) provided with ‘honey logs’ as a type
with complete environmental enrichment out- of feeding enrichment, showed a significant
performed mice raised in all other conditions. reduction in the percentage of time they
These data suggest that enhanced cognitive spent performing various stereotypic behav-
activity, beyond social and/or physical envi- iours (Anderson et al. 2010); the enrichment
ronmental enrichment, is required to protect consisted of logs with drilled holes in them,
against cognitive impairment as a result of which were filled with honey and then closed
Alzheimer’s disease. In their discussion of the with wooden plugs. The effect of the ‘honey
topic Cracchiolo et al. (2007) highlight that logs’ was seen regardless of whether the
whilst physical activity may protect against enrichment was provided on a continuous
‘normal’ cognitive decline associated with (every day for five days) or intermittent (every
ageing, or give enriched rodents an advantage other day) schedule (Anderson et al. 2010).
in cognitive tasks, these are not the same as Stereotypies may not be the most reliable
protecting against the effects of a neurodegen- indicator of stress levels. Once stereotypies
erative disease such as Alzheimer’s disease. have become established, they can become
A highly reported physiological benefit of emancipated from their original causal fac-
providing learning opportunities is enhanced tors and difficult to reduce and also be indic-
recovery after brain injury. In these studies, ative of previous rather than current stress
animals (traditionally rodent models) are levels (Mason 1991). In order to explore
subjected to some form of brain injury to whether providing learning opportunities
mimic naturally occurring incidents such as can reduce stress we can directly measure
brain lesions (e.g. Will et al. 2004). Animals the physiological indicators associated with
with brain injuries raised in enriched condi- stress such as cortisol and heart rate (HR)
tions generally had better recovery than (Fraser 2008). Langbein et al. (2004) tested
those housed in standard conditions. The visual discrimination in 12 young (15–
benefits of enrichment do seem to vary 22 weeks of age) Nigerian dwarf goats Capra