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Updated: Jul 3, 2026
Investigating Long-term Synaptic Plasticity in Interlamellar Hippocampus CA1 by Electrophysiological Field Recording
Published on: August 11, 2019
Hippocampal plasticity predicts behavioral lateralization and stress resilience in laying hen chicks
Catharina M H Broekmeulen1, Jamie R Tulip2, Timothy Boswell3
1Centre for Proper Housing: Poultry and Rabbits (ZTHZ), Division of Animal Welfare, Vetsuisse Faculty, University of Bern, Burgerweg 22, Zollikofen CH-3052, Switzerland; Animal Health and Welfare Department, Wageningen Livestock Research, Wageningen University and Research, P.O. Box 338, Wageningen 6700 AH, the Netherlands.
Insights
Perinatal conditions like light incubation and immediate feed access did not alter chick hippocampal plasticity. However, intrinsic neural organization may drive brain asymmetry and influence cognitive behaviors like threat detection and stress resilience.
Area of Science:
- Neuroscience
- Developmental Biology
- Animal Behavior
Background:
- Perinatal environmental factors influence neural and cognitive development in poultry.
- The combined impact of lighted incubation and immediate post-hatch resource access on chick development is not well understood.
Purpose of the Study:
- To investigate the effects of lighted incubation and immediate feed/water access on hippocampal plasticity and lateralization in layer chicks.
- To explore the relationship between hippocampal plasticity, brain lateralization, and visuomotor responses.
Main Methods:
- Layer chick embryos were exposed to continuous light (days 18-21) and given immediate post-hatch feed/water access.
- Hippocampal expression of plasticity markers (BDNF, DCX, PCNA) was measured at 8 weeks.
- Lateralized visuomotor responses were assessed using behavioral tests.
Main Results:
- Neither lighted incubation nor immediate resource access affected overall hippocampal plasticity or lateralization.
- A significant left-right asymmetry was observed in the caudal hippocampus.
- Hemispheric plasticity showed correlations with predator detection latency, stress resilience, and detouring behavior.
Conclusions:
- Hippocampal plasticity and lateralization appear to be primarily influenced by intrinsic developmental organization rather than the tested early-life environmental conditions.
- Early environmental factors may have modest effects on these traits.
- Findings suggest intrinsic neural organization is crucial for cognitive and behavioral traits, alongside environmental influences.
Abstract:
Perinatal environmental conditions can shape neural and cognitive development in poultry, yet the combined effects of lighted-incubation and immediate post-hatch feed and water access remain unknown. In this exploratory study, layer chick embryos were exposed to continuous light during embryonic days 18-21 and provided with immediate post-hatch access to feed and water, as exemplified in on-farm hatching systems. Hippocampal expression of neural plasticity markers (i.e., BDNF, DCX, PCNA) was measured in left and right hemispheres at eight weeks of age to assess structural plasticity and lateralization, and its relationship to lateralized visuomotor responses within the same individual chicks. The different plasticity markers correlated highly with each other and were combined in a hippocampal plasticity index. Neither lighted incubation nor immediate feed and water access altered hippocampal plasticity or lateralization, suggesting that these traits may reflect intrinsic hemispheric organization rather than early-life modulatory effect by environmental conditions. We did, however, find a pronounced left-right asymmetry, particularly in the caudal hippocampus (p = 0.04). Behavioral observations from a multitasking and step detour test revealed potential hemisphere-specific associations in these exploratory analyses. Right-hemispheric plasticity negatively correlated with latency to detect a predator, consistent with right-hemispheric dominance in threat detection. Higher overall hippocampal plasticity was associated with faster return to foraging after predator exposure (p = 0.01), hinting at a link between hippocampal plasticity and stress resilience, as has been found in mice. Detouring behavior also correlated with opposite patterns of hippocampal plasticity (p = 0.002), suggesting interactions between structural asymmetrical plasticity and lateralized cognitive processing. These findings suggest that hippocampal plasticity may primarily reflect intrinsic developmental trajectories, with early-life environmental factors exerting only modest effects, if any. These preliminary findings highlight the potential importance of considering intrinsic neural organization alongside perinatal environmental conditions in shaping cognitive and behavioral traits.
