Research Methods in Psychology Spring 2012, PSYC.314.007

I. A brief description of the Morris water maze task used to measure spatial navigation in rodents and

humans

II. BrainStorming 2.0

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water maze AND learning - 2,866 total hitsPubMed Search 2/25/05

The Morris water maze

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The Morris water mazePubMed Search 2/25/05

PubMed Search 2/25/05The Morris water maze

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The Morris water maze

The Morris water maze

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Dependent MeasuresPlace learning (acquisition)

Escape latency – time (sec) to reach the platformDistance – length (cm) of swim pathHeading angle – deviation (deg) from a direct pathCumulative distance – cumulative average deviation (proximity to the

goal in cm) from a direct pathProbe test – spatial memory (retention)

Quadrant time – % time (sec) in each quadrant

Annulus crossings – number of passes through target and non-targetannuli (= or 2x surface area of platform)

Proximity – average distance (cm) from target and non-targetannuli

Distance – path length (cm) in each quadrant

Thigmotaxis – swimming near wall – % time (sec) in outer zoneGeneral performance measures

Swim speed – cm/sec

Place Task

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4 trials/day - 30 secPlace Learning

http://pages.towson.edu/bdevan/videos.htm

Trial 40 of place navigation for a control rat

Controls (8 trials/day, 60 sec TTI)

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blindsFigure 1. Schematic showing the pool and configuration of cues present for the probe test in room 500 B. The platform was formerly positioned at location 1 (blue circle). Location 2 represents the goal position relative to the door/entrance in the previous room (500 A). Also note that location 4 is close to the door while location 3 is closest to the experimenter. These locations are also near the west start point.

The experimenter – really looks like Morris!

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Figure 2. Results for initial place acquisition in room 500 A. There were no significant differences in escape latency, cumulative distance, swim speed or absolute heading error.

Probe Test

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Figure 3. Compared to males, females demonstrated a more accurate absolute heading to the goal location on the probe test following latent learning in the second room (500 B).

Heading Error

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Figure 6. Time bin analysis of preference scores for quadrant 1 (top) and quadrant 4 (bottom). Females show less persistence in preference for quadrant 1, where the goal was formerly located, across time bins. Females also show a stable greater preference for quadrant 4, near the door/entrance relative to males.

Saline

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Swim paths of aged rats on retention probe test

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Vardenafil in pre-trained aged rats

Sex difference• has been attributed to a difference in strategy use

• Females use local cues and geometry (e.g. pool wall)

• Males use distal cues• This results in a male advantage in new learning

(sometimes)• However a female advantage occurs after pretraining• Females also tend to do better on a DMP task (multi-

tasking?)

Hypothesis - females may use distal cues (when they’re not so distal at the edge of the pool) to identify start points and plan subsequent egocentric responses leading directly to the goal.

New hypothesis (i.e., wild speculation)

Start point views of the virtual water maze

Panoramic view of cues from center of the virtual WM

‘Sex difference virtual water maze’ search on PubMed

Sex & Drugs: So let’s rock ‘n roll with a novel study

Two video clips to get you thinking…

Strategies: different ways to solve the same problem – distal vs local cuesMultitasking: keeping track of different start pointsPersistence: males are persistent in searching a no-longer valid goalHormone activation: estrogen vs testosterone (interactions with stress hormones)Hormone organization: fetal exposure to sex hormones in Utero may influence sexual differentiation of the brain. 4th to 2nd finger length ratio is related to the early exposure to testosterone.