Morris maze

Wahlsten, D., Cooper, S. F. and Crabbe, J. C. (2005) Different rankings of inbred mouse strains on the Morris maze and a refined 4-arm water escape task. Behav Brain Res 165, 36-51. 

The rat Morris maze we use consists of a circular water tank (150cm in diameter) tilled with water and maintained at 27 °C with an escape platform (15 cm in diameter) 18 cm from the perimeter always in the same position 2 cm beneath the surface of the water. The water is made opaque by addition of milk powder rendering the platform invisible. 

In contrast to the one-trial passive avoidance procedure, the Morris maze permits the progress of learning to be evaluated within the test. Furthermore, subsequent learning can be compared with initial swimming performance. Both factors allow a clearer interpretation of drug effects. The Morris maze depends on the animal s use of extra-maze visual cues. The behavior can therefore be more readily interpreted in terms of the animal s capacity to learn to orient itself in space (spatial learning) and the effects thereon of the test substance. 

The capacity to conduct multiple variants of the procedure (see further details below) endows the Morris maze with a wide range of possibilities for interpreting drug-induced change in cognitive function. This together, with its functional simplicity, no doubt explains the popularity of the procedure. 

Fig. 8. Effects of 3 neuroleptics (tiapride, haloperidol and risperidone) on escape latencies during the first session of the Morris maze task in the rat. Note the clear decrease in escape latencies in the vehicle control group (short-term memory) and the absence of effect of the 3 substances on performance at the first trial (absence of intrinsic effects on swimming performance). Tiapride has modest but dose-dependent effects on the decrease in escape latency from trial to trial, whereas haloperidol and risperidone clearly attenuate this decrease (perturbing effect on short-term memory).

Further modifications are the size of the swimming tank and the position of the escape platform. Both parameters differ widely between different laboratories. In general, larger tanks increase the difficulty for the animal to find the escape platform with a consequently flatter learning curve. Indeed age- or drug-related changes in Morris maze performance depend critically on such factors (van der Staay 2000). 

Another aspect of radial maze performance is the use of positive motivation (food reward), in contrast to the aversive motivations maintaining the passive avoidance and Morris maze procedures. Data suggesting drug-induced cognitive impairment are more convincing if the impairments span the different motivational systems maintaining the behaviors. 

Gouqi (Lycium barb arum). Zhang et al. [243] examined the effects of Gouqi (Lycium barb arum) on the learning and memory abilities of an APP/PS1 double transgenic mouse model of AD. Oral administration of Gouqi extracts at 10 mg/kg improved the performance of the APP/PS1 mice in the learning and the memory retrieval phases of the Morris maze and the levels of A()i 2 in hippocampal tissue were reduced. 

The Morris (1984) water maze is a large circular glass tank (1.5m diameter) filled with opaque (e.g. dye-treated) water to a depth of some 50 cm. A small platform, large enough to take the rat, is placed in the water with its top about 1.5 cm below the surface, so it cannot be seen. When placed in the water the rat finds and escapes to the platform, the position of which is apparently learnt by reference to peripheral visual markers. Memory is demonstrated by the rat s ability to swim to the platform when put back into the water at various points and measured by the time or the length of path taken to do so (Fig. 18.3). 

Morris, RGM (1984) Development of a water-maze procedure for studying spatial learning in the rat. J. Neurosci. Meth. 11 47-60. 

Jett DA, Kuhlmann AC, Farmer SJ, et al. 1997. Age-dependent effects of developmental lead exposure on performance in the Morris water maze. Pharmacol Biochem Behav 57(l-2) 271-279. 

Passive avoidance task Morris water maze radial maze operant behavior tasks... 

Kanit L, Taskiran D, Furedy JJ, Kulali B, McDonald R, Pogun S. (1998). Nicotine interacts with sex in affecting rat choice between "look-out" and "navigational" cognitive styles in the Morris water maze place learning task. Brain Res Bull. 46(5) 441-45. 

Socci DJ, Sanberg PR, Arendash GW. (1995). Nicotine enhances Morris water maze performance of young and aged rats. Neurobiol Aging. 16(5) 857-60. 

In the fimbria/fornix or cingulate bundle, selectively reduced the concentration of serotonin in the rat hippocampus but had no effect on spatial memory in the Morris water maze or radial arm maze. However, the lesion... 

Quartermain et al. 1993, 1994 Rowan et al. 1990 Winter and Petti 1987). Also, low doses of gepirone and atropine, which individually fail to modify rat performance in a spatial task, when administered together impair performance [Barrett and Rowan 1990]. Similarly, the selection of a single dose of MDL 73,005EF that did not impair the acquisition or recall of a task in the Morris water maze enhanced the deficits caused by gepirone or atropine [Barrett and Rowan 1992]. 

In a passive avoidance procedure in the rat, low doses of ondansetron reversed the scopolamine-induced memory deficit, whereas tropisetron was ineffective. However, in the Morris water-maze test, tropisetron but not ondansetron counteracted the learning and memory impairment caused by scopolamine [Pitsikas and Borsini 1997]. 

Fontaine R, Ontiveros A, Ehe R, et al A double-blind comparison of nefazadone, imipramine and placebo in major depression. J Clin Psychiatry 55 234-241, 1994 Fontana DJ, Daniels SE, Flenderson C, et al Ondansetron improves cognitive performance in the Morris water maze spatial navigation task. Psychopharmacology 120 409-417, 1995... 

---