Processing of spatial and non-spatial information reveals functional homogeneity along the dorso-ventral axis of CA3, but not CA1

• Published in: Neurobiology of learning and memory 2014-05, Vol.111, p.56-64
• Main Authors: Beer, Zachery, Chwiesko, Caroline, Sauvage, Magdalena M.
• Format: Article
• Language: English
• Subjects: Animals; Arc (Arg3.1); Behavioral psychophysiology; Biological and medical sciences; Brain; CA1; CA1 Region, Hippocampal - metabolism; CA3; CA3 Region, Hippocampal - metabolism; Cognition & reasoning; Cytoskeletal Proteins - metabolism; Dorsal; Emotions; Fundamental and applied biological sciences. Psychology; Hippocampus; Immediate-early gene (IEG); Information processing; Male; Mice, Inbred C57BL; Nerve Tissue Proteins - metabolism; Neurobiology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Recognition (Psychology) - physiology; Recognition memory; Spatial Memory - physiology; Ventral
• ISSN: 1074-7427; 1095-9564
• DOI: 10.1016/j.nlm.2014.03.001

•Ventral CA1 and CA3 are involved in spatial and non-spatial memory recognition memory.•Ventral CA1 and CA3 are more activated during spatial and non-spatial memory.•Dorsal and ventral CA1 and CA3 all make comparable contributions to spatial memory.•Dorsal CA1 is more activated than the other hippocampal areas during non-spatial memory. The ventral hippocampus is thought to principally contribute to emotional memory, while its dorsal part would be more involved in spatial processes. However, few studies have investigated ventral hippocampal function in spatial or non-spatial memories devoid of strong emotional components, and conflicting results have emerged regarding the role of the dorsal hippocampus in non-spatial (object) recognition memory. Moreover, even fewer reports have dissociated the contribution of the hippocampal subfields CA1 and CA3 to those processes, despite growing evidence of a functional segregation between these subfields. In a recent study, we detected the immediate-early gene Arc, used as a marker of neuronal activity, during spontaneous spatial and non-spatial recognition memory tasks, and showed that dorsal CA3 was spatially tuned while dorsal CA1 processed spatial and non-spatial information to the same extent (Beer, Chwiesko, Kitsukawa, & Sauvage, 2013). Here, we analyze the pattern of Arc expression detected in ventral CA1 and CA3 to determine their role in spatial or non-spatial recognition memory, and investigate whether ventral CA1 and CA3 activation differs from that of their dorsal counterparts. We report that ventral CA1 and CA3 are recruited for both spatial and non-spatial memories, but more strongly for spatial memory (e.g. were spatially tuned), and that CA3 is functionally homogeneous along the dorso-ventral axis, but not CA1.