Hippocampal lesion effects on learning strategies in homing pigeons

1996 ◽  
Vol 263 (1370) ◽  
pp. 529-534 ◽  
Keyword(s):  
Learning Strategies ◽  
Hippocampal Lesion ◽  
Food Reward ◽  
The Sun ◽  
Sun Compass ◽  
Homing Pigeons ◽  
Directional Information ◽  
Intact Control ◽  
Hippocampal Lesions ◽  
Clock Shift

Several studies have shown that birds have a directional view of space and tend to use the sun compass over landmark beacons when both are available. Intact homing pigeons can use either the sun compass or colour beacons to locate a food reward, whereas pigeons with hippocampal lesions are unable to use the sun compass, but quickly learn to use colour beacons. We trained hippocampal ablated and intact pigeons to find a reward in an outdoor octagonal arena when both sun compass information (directional cues) and intramaze landmark beacons (colour cues) were available. The intact control pigeons learned the task by preferentially relying on directional cues while effectively ignoring the colour beacons. The behaviour of the hippocampal ablated birds, based on a clock-shift manipulation and after the rotation of the colour beacons, showed that they learned to locate the food reward in the arena only on the basis of the landmark beacons, ignoring the sun compass directional information.

An analysis of clock-shift experiments: is scatter increased and deflection reduced in clock-shifted homing pigeons?

1997 ◽  
Vol 200 (16) ◽  
pp. 2269-2277 ◽  
Author(s):  
J Chappell
Keyword(s):  
Internal Clock ◽  
Magnetic Compass ◽  
Control Group ◽  
The Sun ◽  
Visual Landmarks ◽  
Sun Compass ◽  
Homing Pigeons ◽  
Vector Length ◽  
The Mean ◽  
Clock Shift

Clock-shifting (altering the phase of the internal clock) in homing pigeons leads to a deflection in the vanishing bearing of the clock-shifted group relative to controls. However, two unexplained phenomena are common in clock-shift experiments: the vanishing bearings of the clock-shifted group are often more scattered (with a shorter vector length) than those of the control group, and the deflection of the mean bearing of the clock-shifted group from that of the controls is often smaller than expected theoretically. Here, an analysis of 55 clock-shift experiments performed in four countries over 21 years is reported. The bearings of the clock-shifted groups were significantly more scattered than those of controls and less deflected than expected, but these effects were not significantly different at familiar and unfamiliar sites. The possible causes of the effects are discussed and evaluated with reference to this analysis and other experiments. The most likely causes appear to be conflict between the directions indicated by the sun compass and either unshifted familiar visual landmarks (at familiar sites only) or the unshifted magnetic compass (possible at both familiar and unfamiliar sites).

The Initial Orientation of Homing Pigeons at the Magnetic Equator: Compass Mechanisms and the Effect of Applied Magnets

1991 ◽  
Vol 161 (1) ◽  
pp. 299-314
Author(s):  
RONALD RANVAUD ◽  
KLAUS SCHMIDT-KOENIG ◽  
JÖRG U. GANZHORN ◽  
JAKOB KIEPENHEUER ◽  
ODIVAL C. GASPAROTTO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Migratory Birds ◽  
Sensory System ◽  
Magnetic Equator ◽  
The Sun ◽  
Sun Compass ◽  
Homing Pigeons ◽  
Directional Preference ◽  
Compass Mechanisms ◽  
Inclination Compass

Homing pigeons are thought to use the earth's magnetic field for direction finding. Though the sensory system and the characteristics of the magnetic field used are unknown, it can be hypothesized that pigeons have an inclination compass, as do some migratory birds. When released at the magnetic equator, this inclination compass ought to be suspended. In addition, releasing pigeons when the sun is at or very close to the zenith renders the sun compass inoperational. However, released under these conditions, homing pigeons are not disorientated. Though they vanish on average in a different direction from pigeons released when the sun compass is available, they still show a directional preference close to magnetic north. This directional preference could be disrupted in some years by the application of magnets to the pigeons' back. In other years this treatment as well as another magnetic treatment did not produce any difference between experimental pigeons and controls. These results confirm once more that, if magnetic effects exist, they are of a rather discrete nature.

scholarly journals Is There Visual Lateralisation of the Sun Compass in Homing Pigeons?

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 740 ◽  
Author(s):  
Charlotte Griffiths ◽  
Richard Holland ◽  
Anna Gagliardo
Keyword(s):  
Visual System ◽  
Right Hemisphere ◽  
Natural Setting ◽  
The Sun ◽  
Sun Compass ◽  
Homing Pigeons ◽  
Significant Difference ◽  
Conflict Condition ◽  
The Right ◽  
Cue Conflict

Functional lateralisation in the avian visual system can be easily studied by testing monocularly occluded birds. The sun compass is a critical source of navigational information in birds, but studies of visual asymmetry have focussed on cues in a laboratory rather than a natural setting. We investigate functional lateralisation of sun compass use in the visual system of homing pigeons trained to locate food in an outdoor octagonal arena, with a coloured beacon in each sector and a view of the sun. The arena was rotated to introduce a cue conflict, and the experimental groups, a binocular treatment and two monocular treatments, were tested for their directional choice. We found no significant difference in test orientation between the treatments, with all groups showing evidence of both sun compass and beacon use, suggesting no complete functional lateralisation of sun compass use within the visual system. However, reduced directional consistency of binocular vs. monocular birds may reveal a conflict between the two hemispheres in a cue conflict condition. Birds using the right hemisphere were more likely to choose the intermediate sector between the training sector and the shifted training beacon, suggesting a possible asymmetry in favour of the left eye/right hemisphere (LE/RH) when integrating different cues.

Changes in the short-term deflector loft effect are linked to the sun compass of homing pigeons

1988 ◽  
Vol 36 (1) ◽  
pp. 150-158 ◽  
Author(s):  
Jerry A. Waldvogel ◽  
John B. Phillips ◽  
A. Irene Brown
Keyword(s):  
The Sun ◽  
Short Term ◽  
Sun Compass ◽  
Homing Pigeons

scholarly journals In Situ Clock Shift Reveals that the Sun Compass Contributes to Orientation in a Pelagic Seabird

2018 ◽  
Vol 28 (2) ◽  
pp. 275-279.e2 ◽  
Author(s):  
Oliver Padget ◽  
Sarah L. Bond ◽  
Marwa M. Kavelaars ◽  
Emiel van Loon ◽  
Mark Bolton ◽  
...  
Keyword(s):  
The Sun ◽  
Sun Compass ◽  
Pelagic Seabird ◽  
Clock Shift

Partial experience with the arc of the sun is sufficient for all-day sun compass orientation in homing pigeons, Columba livia

2000 ◽  
Vol 203 (15) ◽  
pp. 2341-2348 ◽  
Author(s):  
C.A. Budzynski ◽  
F.C. Dyer ◽  
V.P. Bingman
Keyword(s):  
Cloud Cover ◽  
Sun Exposure ◽  
Columba Livia ◽  
Time Of Day ◽  
Control Group ◽  
The Sun ◽  
Compass Orientation ◽  
Sun Compass ◽  
Homing Pigeons ◽  
Experimental Group

The ability of animals to learn to use the sun for orientation has been explored in numerous species. In birds, there is conflicting evidence about the experience needed for sun compass orientation to develop. The prevailing hypothesis is that birds need entire daytime exposure to the arc of the sun to use the sun as an orientation cue. However, there is also some evidence indicating that, even with limited exposure to the arc of the sun, birds, like insects, can use the sun to orient at any time of day. We re-examine this issue in a study of compass orientation in a cue-controlled arena. Two groups of young homing pigeons received different exposure to the sun. The control group experienced the sun throughout the day; the experimental group experienced only the apparent descent of the sun. After 8 weeks of sun exposure, we trained both groups in the afternoon to find food in a specific compass direction in an outdoor arena that provided a view of the sun but not landmarks. We then tested the pigeons in the morning for their ability to use the morning sun as an orientation cue. The control group and the experimental group, which was exposed to the morning sun for the first time, succeeded in orienting in the training direction during test 1. The orientation of the experimental group was no different from that of the control group, although the experimental first trial directional response latencies were greater than the control latencies. Subsequently, we continued training both groups in the afternoon and then tested the pigeons during the morning under complete cloud cover. Both groups displayed random directional responses under cloud cover, indicating that the observed orientation was based on the visibility of the sun. The data indicate that pigeons with limited exposure to the arc of the sun can, like insects, use the sun for orientation at any time of day.

Hippocampal participation in the sun compass orientation of phase-shifted homing pigeons

1996 ◽  
Vol 179 (5) ◽  
pp. 695-702 ◽  
Author(s):  
V.P. Bingman ◽  
A. Gagliardo ◽  
P. Ioal�
Keyword(s):  
The Sun ◽  
Compass Orientation ◽  
Sun Compass ◽  
Homing Pigeons

Hippocampal Lesion Syndrome: Switching to and from a Place Hypothesis

1983 ◽  
Vol 35 (4b) ◽  
pp. 299-314 ◽  
Author(s):  
Jerome H. Blue
Keyword(s):  
Learning Strategies ◽  
Discrimination Learning ◽  
Adult Male ◽  
Hippocampal Lesion ◽  
Spatial Discrimination ◽  
Male Rats ◽  
Learning Experiment ◽  
Hippocampal Lesions ◽  
Shift Experiment ◽  
Learning Test

Spatial discrimination learning (Experiment I) and strategy shifts (Experiment II) were examined in experimentally lesioned rats. Sixty adult male rats were in one of five lesion groups ( N = 12/group): operated controls, fornical, entorhinal, fornicoentorhinal and dorsal-ventral hippocampal. All animals reached criterion on the discrimination learning test. In the strategy shift experiment, however, animals with hippocampal lesions had more difficulty than animals without hippocampal lesions. The findings suggest that the hippocampus may not be involved in learning strategies, but in switching a strategy.

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