Time decay of object, place and temporal order memory in a paradigm assessing simultaneously episodic-like memory components in mice.
A common trait of numerous memory disorders is the impairment of episodic memory. Episodic memory is a delay-dependant memory, especially associating three components, the "what", "where" and "when" of a unique event. To investigate underlying mechanisms of such memory, several tests, mainly based on object exploration behaviour, have been set up in rodents. Recently, a three-trial object recognition task has been proposed to evaluate simultaneously the different components of episodic-like memory in rodents. However, to date, the time course of each memory component in this paradigm is not known. We characterised here the time course of memory decay in adult mice during the three-trial object recognition task, with inter-trial interval (ITI) ranging from 1h to 4h. We found that, with 1h and 2h, but not 4h ITI, mice spent more time to explore the displaced "old object" relative to the displaced "recent object", reflecting memory for "what and when". Concomitantly, animals exhibited more exploration time for the displaced "old object" relative to the stationary "old object", reflecting memory for "what and where". These results provide strong evidence that mice establish an integrated memory for unique experience consisting of the "what", "where" and "when" that can persist until 2h ITI.
Normandie Universités, Université de Caen Basse-Normandie, Groupe Mémoire et Plasticité comportementale (GMPc), EA 4259, F-14032 Caen, France; Université des Sciences et de la Technologie Houari Boumediene, Laboratoire de Neurosciences Comportementales et Cognitives, 16111 Alger, Algeria.
Hassina
H
Belblidia
Université des Sciences et de la Technologie Houari Boumediene, Laboratoire de Neurosciences Comportementales et Cognitives, 16111 Alger, Algeria.
Abdelmalek
A
Abdelouadoud
Normandie Universités, Université de Caen Basse-Normandie, Groupe Mémoire et Plasticité comportementale (GMPc), EA 4259, F-14032 Caen, France.
Christelle
C
Jozet-Alves
Normandie Universités, Université de Caen Basse-Normandie, Groupe Mémoire et Plasticité comportementale (GMPc), EA 4259, F-14032 Caen, France.
Hélène
H
Dumas
Normandie Universités, Université de Caen Basse-Normandie, Groupe Mémoire et Plasticité comportementale (GMPc), EA 4259, F-14032 Caen, France.
Thomas
T
Freret
Normandie Universités, Université de Caen Basse-Normandie, Groupe Mémoire et Plasticité comportementale (GMPc), EA 4259, F-14032 Caen, France.
Marianne
M
Leger
Normandie Universités, Université de Caen Basse-Normandie, Groupe Mémoire et Plasticité comportementale (GMPc), EA 4259, F-14032 Caen, France. Electronic address: pascale.schumann-bard@unicaen.fr.
Pascale
P
Schumann-Bard
D000704:Analysis of Variance; D000818:Animals; D005106:Exploratory Behavior; D008297:Male; D061212:Memory, Episodic; D051379:Mice / Q000523:psychology*; D009483:Neuropsychological Tests; D011581:Psychological Tests; D021641:Recognition, Psychology; D065852:Spatial Memory; D013997:Time Factors; D013998:Time Perception
Episodic-like memory; NMRI mice; Object recognition