Shumway Lab Research

Shumway Lab – Research Evolution of Brain and Behavior in African Cichlid Fishes
SPATIAL MEMORY
Do the Differences We See in the Brain Mean There are Differences in Behavior? In comparative studies, we previously found that our cichlids from more complex (rock) habitats have a larger telencephalon and better visual acuity compared to their sister species from less complex (sand) habitats (Pollen et al., 2006; Dobberfuhl et al., 2005). We also found that the hippocampal homologue, Dl, used in spatial memory, is larger in the rock-dwelling Asprotilapia leptura compared to their sand-dwelling sister species, Xenotilapia flavipinnis (Shumway et al., 2004). Do these morphological differences translate into cognitive differences? We tested fish in a spatial novelty assay and in a maze to find out.

How does Habitat Complexity Affect Spatial Memory? Part 1: Spatial Novelty We are using a spatial novelty assay to compare the spatial memory of sand dwelling fish and rock dwelling fish. This assay is a habituation/dishabituation paradigm used in a number of animals and even humans. Previous research has shown that the hippocampus is required for spatial novelty discrimination. The advantage is that the response to spatial novelty is unlearned and therefore does not require training. In this test, the animal roams in an arena containing several objects for 3 (habituation) trials. In the dishabituation trials, one object is displaced 90 degrees. Pilot experiments varying size, form, and color showed species-specific differences. The sand-dweller showed a significant change to the displaced object, as reflected in time spent in the displaced zone (Fig. 3, p < .05, n = 10/species ). Objects in a sand environment (such as sand craters) often shift in the wild. The pilot data suggest that the species also differ in global patterns of activity This work was completed by Kara Coffey for an Honors Thesis at Boston University Our collaborators at Boston University tested two closely related species of saltwater gobies: Amblygobius rainfordi that rests on reefs and Amblygobius phalaena that spends most of its time over sand. Similar to the cichlid results, the sand dwelling fish reacted significantly to the displaced object and spending more time in the zone the object was displaced to. This work was completed by Amber York for an Honors Thesis at Boston University This research was done in collaboration with Dr. Heike Neumeister of Albert Einstein College of Medicine and Dr. Les Kaufman of Boston University	Habituation Setup The pink lines represent the fish's path during the trial. Arrows point to the feature that is moved for the dishabituation trial. Dishabituation Trial Note how the sand crater has been displaced Results for X. flavipinnis: Blue bars represent the time spent in each zone during the final habituation period. Fuchsia bars represent the time spent in each zone during the dishabituation period. Results for A. leptura

Maze layout with intra maze and extra maze cues	How does Habitat Complexity Affect Spatial Memory? Part 2: Maze In preliminary experiments, we compared spatial ability of the two species in navigating through a sequential maze for a food reward. The maze included both intra maze and extra maze landmarks. We predicted that A. leptura would navigate the maze faster and more efficiently than X. flavipinnis. We found that A. leptura completed the maze trials in fewer trials and with fewer wrong turns than X. flavipinnis. A. leptura also completed the maze trials in half the time compared to X. flavipinnis. The initial rate of learning, based on the percentage of wrong turns out of the total number of turns, was similar between the two species. After completing the task, we tested the learning ability of A. leptura following changes to the cues. This species was successful in completing the maze upon a 90˚ shift of extra maze cues and with a complete removal of all landmark-based cues. A. leptura was also able to learn a new paradigm, following the landmarks when all doors and intra maze landmarks were reversed. The results suggest that the rock-dwelling species A. leptura possesses enhanced spatial abilities.

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Evolution of Brain and Behavior in African Cichlid Fishes

SPATIAL MEMORY

Do the Differences We See in the Brain Mean There are Differences in Behavior?

In comparative studies, we previously found that our cichlids from more complex (rock) habitats have a larger telencephalon and better visual acuity compared to their sister species from less complex (sand) habitats (Pollen et al., 2006; Dobberfuhl et al., 2005). We also found that the hippocampal homologue, Dl, used in spatial memory, is larger in the rock-dwelling Asprotilapia leptura compared to their sand-dwelling sister species, Xenotilapia flavipinnis (Shumway et al., 2004). Do these morphological differences translate into cognitive differences? We tested fish in a spatial novelty assay and in a maze to find out.

How does Habitat Complexity Affect Spatial Memory?
Part 1: Spatial Novelty

We are using a spatial novelty assay to compare the spatial memory of sand dwelling fish and rock dwelling fish. This assay is a habituation/dishabituation paradigm used in a number of animals and even humans. Previous research has shown that the hippocampus is required for spatial novelty discrimination. The advantage is that the response to spatial novelty is unlearned and therefore does not require training.

In this test, the animal roams in an arena containing several objects for 3 (habituation) trials. In the dishabituation trials, one object is displaced 90 degrees. Pilot experiments varying size, form, and color showed species-specific differences. The sand-dweller showed a significant change to the displaced object, as reflected in time spent in the displaced zone (Fig. 3, p < .05, n = 10/species ). Objects in a sand environment (such as sand craters) often shift in the wild. The pilot data suggest that the species also differ in global patterns of activity

This work was completed by Kara Coffey for an Honors Thesis at Boston University

Our collaborators at Boston University tested two closely related species of saltwater gobies: Amblygobius rainfordi that rests on reefs and Amblygobius phalaena that spends most of its time over sand. Similar to the cichlid results, the sand dwelling fish reacted significantly to the displaced object and spending more time in the zone the object was displaced to.

This work was completed by Amber York for an Honors Thesis at Boston University

This research was done in collaboration with Dr. Heike Neumeister of Albert Einstein College of Medicine and Dr. Les Kaufman of Boston University

Habituation Setup
The pink lines represent the fish's path during the trial. Arrows point to the feature that is moved for the dishabituation trial.

Dishabituation Trial
Note how the sand crater has been displaced

Results for X. flavipinnis: Blue bars represent the time spent in each zone during the final habituation period. Fuchsia bars represent the time spent in each zone during the dishabituation period.

Results for A. leptura

Maze layout with intra maze and extra maze cues

How does Habitat Complexity Affect Spatial Memory?
Part 2: Maze

In preliminary experiments, we compared spatial ability of the two species in navigating through a sequential maze for a food reward. The maze included both intra maze and extra maze landmarks. We predicted that A. leptura would navigate the maze faster and more efficiently than X. flavipinnis. We found that A. leptura completed the maze trials in fewer trials and with fewer wrong turns than X. flavipinnis. A. leptura also completed the maze trials in half the time compared to X. flavipinnis. The initial rate of learning, based on the percentage of wrong turns out of the total number of turns, was similar between the two species. After completing the task, we tested the learning ability of A. leptura following changes to the cues. This species was successful in completing the maze upon a 90˚ shift of extra maze cues and with a complete removal of all landmark-based cues. A. leptura was also able to learn a new paradigm, following the landmarks when all doors and intra maze landmarks were reversed. The results suggest that the rock-dwelling species A. leptura possesses enhanced spatial abilities.

More Research at New England Aquarium!

HOME CONSERVATION CONTACTS