Research Methods in Psychology Spring 2012, PSYC I. A brief description of the Morris water maze task used to measure spatial navigation in rodents and humans II. BrainStorming 2.0

PubMed Search 2/25/05 The Morris water maze

PubMed Search 2/25/05

The Morris water maze Updated 2/29/09 Updated today: 5,175

The Morris water maze

Top View (camera) Side view Standard Water Maze Setup Submerged platform # Quadrant Start points Target Annulus L Zone Water level CBA Non-targetAnnuli

Dependent Measures Place learning (acquisition) Escapelatency Escape latency – time (sec) to reach the platform Distance Distance – length (cm) of swim path Heading angle Heading angle – deviation (deg) from a direct path Cumulative distance Cumulative distance – cumulative average deviation (proximity to the goal in cm) from a direct path Probe test – spatial memory (retention) Quadrant time Quadrant time – % time (sec) in each quadrant Annulus crossings Annulus crossings – number of passes through target and non-target annuli (= or 2x surface area of platform) Proximity Proximity – average distance (cm) from target and non-target annuli Distance Distance – path length (cm) in each quadrant Thigmotaxis Thigmotaxis – swimming near wall – % time (sec) in outer zone General performance measures Swim speed Swim speed – cm/sec

Place Learning

Trial 40 of place navigation for a control rat

Probe test without platform (60 sec)

Figure 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!

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.

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 90 o ~50 o

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 Vardenafil Swim paths of aged rats on retention probe test

Long-term retention probe Heading Error (deg +/- SEM) AGE (group) Vardenafil in pre-trained aged rats

Sex difference has been attributed to a difference in strategy usehas been attributed to a difference in strategy use Females use local cues and geometry (e.g. pool wall)Females use local cues and geometry (e.g. pool wall) Males use distal cuesMales use distal cues This results in a male advantage in new learning (sometimes)This results in a male advantage in new learning (sometimes) However a female advantage occurs after pretrainingHowever a female advantage occurs after pretraining Females also tend to do better on a DMP task (multi- tasking?)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 cues Multitasking: keeping track of different start points Persistence: males are persistent in searching a no- longer valid goal Hormone activation: estrogen vs testosterone (interactions with stress hormones) Hormone organization: fetal exposure to sex hormones in Utero may influence sexual differentiation of the brain. 4 th to 2 nd finger length ratio is related to the early exposure to testosterone.