Scoring Learning and Memory in Developing Rodents

Igor Branchi1, Laura Ricceri1

1 Istituto Superiore di Sanità, Rome
Publication Name:  Current Protocols in Toxicology
Unit Number:  Unit 13.11
DOI:  10.1002/0471140856.tx1311s27
Online Posting Date:  March, 2006
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Learning and memory abilities can be reliably measured in rodents starting from very early phases of postnatal development. In particular, in the study of learning and memory in periweanling or adolescent (from around postnatal day 20 to 50) mice or rats, two experimental protocols are appropriate for a reliable characterization of cognitive ability development: the water maze and the spatial open‐field with objects. These experimental protocols have been developed to study the behavior of adult rodents, but are easily adapted to the peculiar physiological and behavioral responses of immature animals by applying selected modifications to both test apparatuses as well as protocols. It is worth noting that these two experimental protocols have been proven to be complementary because they provide different information on possible cognitive deficits; thus, use of both is recommended for an exhaustive behavioral characterization.

Keywords: water maze; spatial open‐field with objects; adolescence; preweanling; postweanling

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Table of Contents

  • Basic Protocol 1: Water Maze Test of Learning and Memory in Developing Rodents
  • Support Protocol 1: Scoring Parameters for the Water Maze Test
  • Basic Protocol 2: Spatial Open‐Field with Objects Test of Learning and Memory in Developing Rodents
  • Support Protocol 2: Scoring Parameters for the Spatial Open‐Field with Objects Test
  • Commentary
  • Literature Cited
  • Figures
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Basic Protocol 1: Water Maze Test of Learning and Memory in Developing Rodents

  • Mice or rats (3‐, 4‐, or 7‐week‐old juveniles and 3‐month‐old adults; ∼12 animals per experimental group)
  • Balance accurate to 0.1 g
  • Videocamera
  • Computer with video‐tracking software (e.g., Ethovision,; Smart, http://www.panlab‐; VideoMot2, http://www.tse‐
  • Water maze apparatus: plastic circular pool with movable plastic platform (see Fig. and protocol 1 Introduction for size considerations)
  • Experimental room with visual cues (e.g., posters)
  • Holding cages (∼14 × 30 × 12–cm)
  • Opaque cup (approximate size: 15‐cm height, 15‐cm diameter)
  • Wire‐mesh grid (approximate size: 15 × 40–cm; 0.5‐cm mesh)
  • Infrared heat lamp, 150 watts

Support Protocol 1: Scoring Parameters for the Water Maze Test

  • Mice or rats (3‐, 4‐, 7‐weeks old juveniles and 3‐month‐old adults; ∼12 animals per experimental group)
  • 50% ethanol
  • Square open‐field arena: ∼45 × 45 × 35 (height)–cm or ∼80 × 80 × 60 (height)–cm for 3‐ or 4‐week‐old mice and rats, respectively, with a line grid (optional; see protocol 4), indirect, diffuse lighting, and a spatial visual cue (e.g., a striped pattern of at least 30 × 30 cm placed in a constant position just out of the arena)
  • Five plastic objects of different shapes similar in size to the experimental animals (height of 4 to 6 cm or 8 to 10 cm for 3‐ or 4‐week‐old mice and rats, respectively)
  • Videocamera and videorecorder
  • Computer with video‐tracking software (e.g., Ethovision,; Smart, http://www.panlab‐; VideoMot2, http://www.tse‐
NOTE: The procedures in this protocol consist of seven sessions in which two spatial modifications are presented: an object displacement (spatial rearrangement) and a novel object. Between sessions, return the animal to its home cage. Intersession intervals last 4 min, except for the interval between sessions 6 and 7, which can be longer (see below).
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Literature Cited

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Key References
   Bignami, G. 1996. Economical test methods for developmental neurobehavioral toxicity. Environ. Health Perspect. 104:285‐298.
  An overview of methodological issues concerning the study of behavior in young rodents from early postnatal development.
   Carman and Mactutus, 2001. See above.
  An elegant and exhaustive work on the role of response requirements in the Morris water maze for pre‐ and postweanling rats.
   Ricceri et al., 2000. See above.
  This longitudinal study investigates the emergence of spatial discrimination and reaction to novelty in CD‐1 mice in the spatial open‐field with objects test.
   Wolfer et al., 1998. See above.
  Spatial learning is confounded by species‐specific noncognitive strategies. This work shows how cognitive and noncognitive strategies affect the learning performance in the water maze task by factor analysis.
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