Lateral Asymmetry of Brain and Behaviour in the Zebra Finch, Taeniopygia guttata

Abstract

Lateralisation of eye use indicates differential specialisation of the brain hemispheres. We tested eye use by zebra finches to view a model predator, a monitor lizard, and compared this to eye use to view a non-threatening visual stimulus, a jar. We used a modified method of scoring eye preference of zebra finches, since they often alternate fixation of a stimulus with the lateral, monocular visual field of one eye and then the other, known as biocular alternating fixation. We found a significant and consistent preference to view the lizard using the left lateral visual field, and no significant eye preference to view the jar. This finding is consistent with specialisation of the left eye system, and right hemisphere, to attend and respond to predators, as found in two other avian species and also in non-avian vertebrates. Our results were considered together with hemispheric differences in the zebra finch for processing, producing, and learning song, and with evidence of right-eye preference in visual searching and courtship behaviour. We conclude that the zebra finch brain has the same general pattern of asymmetry for visual processing as found in other vertebrates and suggest that, contrary to earlier indications from research on lateralisation of song, this may also be the case for auditory processing.

Social odour activates the hippocampal formation in zebra finches (Taeniopygia guttata)

“…For instance, a rightward bias in the integration of visual and olfactory non-social cues has been found in chicks [84]. In zebra finches, several cases of a lateralization pattern have been demonstrated by both, behavioural and IEG-expression studies, which are compatible with that found in other species (reviewed in [85]). This includes a right hemisphere specialisation for monitoring threatening stimuli [85], a left hemisphere specialisation for controlling foraging behaviour [86] and complementary specialisation of the two hemispheres for different aspects of song processing [87][88][89].…”

Chiral Neuronal Motility: The Missing Link between Molecular Chirality and Brain Asymmetry

“…Intriguingly, lateralization has long since been controversial in the zebra finch, which produces songs with a rich spectro-temporal structure. A recent study reported that the left (right) hemisphere is superior in auditory processing of the temporal (spectral) feature of songs [36], which is consistent with the general directional asymmetry in visual processing [37]. The left hemisphere is dominant for the auditory perception of vocal communication in mice [38] and rats [39].…”

Does Functional Lateralization in Birds Have any Implications for Their Welfare?

“…The preference shown by zebra finches to use the right eye when courting a female would, at first sight, appear to contradict specialization of the left-eye-system for control of copulation, as found in the chick. However, as we have argued previously [40], courtship involves different control by the forebrain than does copulation. In fact, courtship behaviour requires inhibiting the actual copulation response.…”

“…Firstly, zebra finches display the same ability as chicks to discriminate grain from pebbles only when they use their right, and not their left, eye [39]. Secondly, zebra finches have been reported to show a preference to use the left eye when looking at a predator, as chicks also do [40]. Interestingly, Workman and Andrew [41] reported that, during courtship, males of this species prefer to approach females so that they view them with their right eye.…”

“…However, some species alternate viewing a stimulus first with one eye and then the other. In these species, the eye-system used first to fixate a stimulus (before alternating) indicates the predominant eye-system used (see method used in [40]).…”