Adapted Morris Water Maze protocol to prevent interference from confounding motor deficits on cognitive functioning.

Area of Science:

• Neuroscience
• Behavioral Neuroscience

Background:

• The Morris Water Maze (MWM) is a common tool for assessing spatial learning and memory.
• Motor deficits can significantly confound MWM results, making it difficult to isolate cognitive effects.
• Hemicerebellectomy (HCX) in mice provides a model with lateralized motor deficits.

Purpose of the Study:

• To investigate the impact of motor deficits on cognitive functioning in the MWM.
• To assess the confounding effect of motor deficits in hemicerebellectomized (HCX) mice using a lateralized study.
• To develop and validate an adapted MWM protocol that mitigates the influence of motor impairments.

Main Methods:

• Spatial learning was evaluated in adult mice after left or right hemicerebellectomy (HCX).
• Two MWM designs were employed: a traditional (Trad) MWM and an adapted (Adap) MWM with altered starting positions.
• Path length was used as the primary measure to assess spatial learning and the influence of motor deficits.

Main Results:

• In the Trad MWM, left HCX mice showed impaired spatial learning and memory compared to controls.
• These deficits observed in the Trad MWM disappeared in the Adap MWM when starting positions were mirrored.
• The findings imply that motor phenotype and increased task difficulty, not cognitive deficits alone, contributed to the results in the Trad MWM.

Conclusions:

• Motor impairments in HCX mice can confound MWM performance, leading to inaccurate assessments of cognitive function.
• The adapted MWM protocol effectively circumvents motor deficits as a confounding factor.
• This adapted MWM approach allows for a more accurate evaluation of cognitive MWM parameters, excluding motor influences.