Hamsters’ (Mesocricetus auratus) Memory in a Radial Maze Analog: The Role of Spatial Versus Olfactory Cues Franc ¸ois Tonneau CIPSI—Universidade do Minho Felipe Cabrera CUCI—Universidad de Guadalajara Alejandro Corujo CETP—Universidad del Trabajo del Uruguay The golden hamster’s (Mesocricetus auratus) performance on radial maze tasks has not been studied a lot. Here we report the results of a spatial memory task that involved eight food stations equidistant from the center of a circular platform. Each of six male hamsters depleted the food stations along successive choices. After each choice and a 5-s retention delay, the hamster was brought back to the center of the platform for the next choice opportunity. When only one baited station was left, the platform was rotated to evaluate whether olfactory traces guided hamsters’ choices. Results showed that despite the retention delay hamsters performed above chance in searching for food. The choice distributions observed during the rotation probes were consistent with spatial memory and could be explained without assuming guidance by olfactory cues. The radial maze analog we devised could be useful in furthering the study of spatial memory in hamsters. Keywords: hamsters, radial platform, spatial memory, spatial cues, olfactory cues The radial arm maze (Olton & Samuelson, 1976) and its variants constitute a paradigm of choice to study spatial memory in rodents (Carrillo-Mora, Giordano, & Santamarı ´a, 2009). An important issue when dealing with radial maze performance is the nature of the cues that guide animal navigation (Zoladek & Roberts, 1978). Available cues potentially range from distant allocentric signals (optical, auditory, or magnetic) to movement-generated cues (dead reckoning) and olfactory marks left during previous visits (Maas- winkel & Whishaw, 1999). Evaluating the role of olfactory marks in rodent navigation is especially important from a methodological standpoint because contrary to the other types of cues, olfactory traces allow the animal to negotiate a maze without relying on spatial memory at all (Wallace, Gorny, & Whishaw, 1992). Studies of spatial memory in rodents have shown that they rely preferen- tially on visual landmarks and movement-generated cues instead of olfaction (e.g., Zoladek & Roberts, 1978). This hierarchy in cue utilization, however, is flexible and depends on the salience and validity of each type of signal (Maaswinkel & Whishaw, 1999) as well as on details of the experimental procedure. Rats, for exam- ple, rely on olfactory traces in obscurity (Lavenex & Schenk, 1998) and in water mazes in which the location of the escape platform is constant across animals (Means, Alexander, & O’Neal, 1992). In comparison with other rodents, the spatial memory of golden hamsters in radial mazes remains poorly understood. Most of the information on hamsters’ navigation comes from homing studies in which the hamsters return to their nest after a single outward trip (e.g., Etienne, Joris Lambert, Reverdin, & Teroni, 1993; Etienne, Teroni, Maurer, Portenier, & Saucy, 1985), and only two reports of hamsters’ performance in radial mazes have been published. Jones, McGhee, and Wilkie (1990) showed that hamsters performed above chance on a seven-arm radial maze with only four arms baited. The hamsters depleted the baited arms one by one, gener- ally by exploring them clockwise or counterclockwise. Etienne, Sitbon, Dahn-Hurni, and Maurer (1994) trained two groups of hamsters on an eight-arm maze either in the light or in the dark. The group trained in the dark mastered the task (presumably through dead reckoning), but performance was better in the group trained in the light (implicating visual cues). Recently, Cabrera (2009) studied hamsters’ spatial memory in an open field analog of the radial maze. The apparatus consisted of a platform with eight food stations arranged in a circle around a starting box. The hamster was allowed to visit each station in order to retrieve food from it. After each choice, the hamster was brought back manually to a box at the center of the platform, which served as a starting point for the hamster’s next outward trip. Hamsters performed above chance in this situation. Computed along successive choices, the average probability of going to a baited station instead of an empty one decreased from 1, for choice number one, to about .50 at the level of choice number eight. Cabrera’s (2009) setup has one main advantage over a radial maze with closed arms. Choices in the latter case are strongly constrained by the relative breadth of the arms and of the central Franc ¸ois Tonneau, Department of ●●●, CIPSI—Universidade do Minho, Braga, Portugal; Felipe Cabrera, Department of ●●●, CUCI— Universidad de Guadalajara, ●●●, Me ´xico; Alejandro Corujo, Department of ●●●, CETP—Universidad del Trabajo del Uruguay, ●●●, Uruguay. Franc ¸ois Tonneau was supported by the Portuguese FCT during the writing of this article. Correspondence concerning this article should be addressed to Franc ¸ois Tonneau, Department of ●●●, CIPSI—Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal. E-mail: ftonneau@psi.uminho.pt Journal of Comparative Psychology © 2011 American Psychological Association 2011, Vol. ●●, No. ●, 000–000 0735-7036/11/$12.00 DOI: 10.1037/a0025019 1 AQ: 4 AQ: 5 AQ: 6 AQ: 7-8 AQ: 9 tapraid5/zct-com/zct-com/zct00311/zct2272d11z xppws S=1 7/20/11 1:05 Art: 2010-0666