Navigational Experience Affects Hippocampus Size in Homing Pigeons

Abstract

Homing (racing) pigeons (Columba livia f.d.) are well-known for their homing abilities, which are thought to be based on a genetic predisposition, multimodal learning and spatial cognition. On average, the hippocampus, a forebrain structure that processes spatial information, is larger in homing pigeons compared to other non-homing pigeon breeds or their wild ancestor, the rock dove. Here we show that this characteristic hippocampus volume is dependent on flying and navigational experience. Twenty homing pigeons originating from the same breeding stock were raised in the same loft under identical constraints. After fledging, 10 of them were allowed to fly around the loft, gain navigational experience and participate successfully in races. The other 10 stayed permanently in the loft and thus did not share the navigational skill experienced by the first group. After reaching sexual maturity, individuals of both groups were sacrificed and morphometric analyses were carried out to measure the volumes of total brain, telencephalon, hippocampus and 12 other brain structures. Individuals with experience in flying and navigation had an 11.2% larger hippocampus relative to the telencephalon compared to non-experienced individuals (p = 0.028). This effect is not seen in any of the other measured brain subdivisions. Given that plasticity in hippocampal volume has a genetic component, our results confirm that there is also an experience component, and that has certain implications for navigational ability. Evidently, experience is a precondition to full hippocampal development.

Brain and Cognition in Teleost Fish

“…Recent studies have also found increases in the relative size of the lateral pallium associated with elaborated spatial behaviour in several species of teleost fishes (Shumway 2008;Costa et al 2011). These results showing that training in spatial tasks and differential experience in natural environments produce morphological and neurochemical learning-dependent plastic changes in the lateral pallium are similar to those found in the hippocampus of amniotes (Jacobs & Spencer 1994;Hampton et al 1995;Basil et al 1996;Healy et al 1996;Ramirez-Amaya et al 1999, 2001Holahan et al 2006;Roth et al 2006;Cnotka et al 2008).…”

Asymmetry of different brain structures in homing pigeons with and without navigational experience

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Cnotka et al, 2008; Mehlhorn and Rehkämper, 2009). Several orientation cues and mechanisms -olfactory cues, visual landmarks, sun compass, magnetic compass -are known to be involved in homing behaviour, and parameters such as motivation and experience are also known to be important for fast and successful homing (Papi et al, 1974;Visalberghi and Alleva, 1975; SchmidtKönig, 1990;Bingman, 1993; Lipp, 1996;Walcott, 2005).

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A vision-based terrain morphology estimation model inspired by the avian hippocampus

“…There is evidence to suggest that the more exploration of an environment an organism does, the greater the volume of its hippocampus [7,11,12]. In [7] for example, black cab taxi drivers were observed to have larger hippocampus than the average human.…”