Mapping of brain networks involved in consolidation of lamb recognition memory.
In sheep, ewes at parturition are responsive to any newborn lamb, but within less than 1 h, mothers learn to recognize the odor of their lamb and restrict maternal care to their own offspring (maternal selectivity). In a first experiment, we investigated the long-term retention of maternal selectivity after various mother-young contact and separation durations. After 4 h of contact, 36 h of separation leads to a total loss of selectivity. Increasing contact duration to 7 days prior to this separation maintains selectivity. These data suggest that lamb memory after going through an initial labile state after parturition, is consolidated over time into a more stable long-term memory. Fos immunohistochemistry reveals that reintroduction of the lamb after 4 h of mother-young contact and 3 h of separation activates different maternal brain regions than reintroduction of the lamb after 7 days of mother-young contact and 3 h of separation. While the piriform cortex shows an enhanced activation at both times, a selective enhancement of activation is observed in the frontal medial and orbitofrontal cortices only after 7 days of mother-young contact. These data suggest that as consolidation occurs, the neurobiological networks sustaining lamb memory involve different structures.
Keller
M
M
Equipe Comportement, Laboratoire de Physiologie de la Reproduction et des Comportements, UMR 6175 INRA/CNRS/Université de Tours/Haras Nationaux, 37380 Nouzilly, France.
Meurisse
M
M
Lévy
F
F
D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D002452:Cell Count / Q000379:methods; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D005938:Glucocorticoids / Q000494:pharmacology; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008425:Maternal Behavior / Q000187:drug effects / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D009769:Object Attachment; D016761:Oncogene Proteins v-fos / Q000378:metabolism; D049590:Postpartum Period / Q000187:drug effects; D011247:Pregnancy; D021641:Recognition, Psychology / Q000502:physiology*; D012756:Sheep; D018709:Statistics, Nonparametric; D013391:Sucking Behavior / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
D005938:Glucocorticoids; D016761:Oncogene Proteins v-fos; D003907:Dexamethasone