Contrasting effects on path integration after hippocampal damage in humans and rats

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 110; no. 12; pp. 4732 - 4737
• Main Authors: Kim, Soyun, Sapiurka, Maya, Clark, Robert E., Squire, Larry R.
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences 19.03.2013; National Acad Sciences
• Subjects: Adult; Aged; Animal memory; Animals; Behavioral neuroscience; Biological and medical sciences; Biological Sciences; Brain damage; cognition; Cognitive ability; Experimentation; Female; Fundamental and applied biological sciences. Psychology; Hippocampus; Hippocampus - injuries; Hippocampus - physiopathology; Humans; Lesions; Male; Memory; Middle Aged; patients; Rats; Rats, Long-Evans; Rodents; Temporal lobe; Temporal Lobe - injuries; Temporal Lobe - physiopathology; Tiles; Vertebrates: nervous system and sense organs; vision; Working memory; Human; Vertebrata; amnesia; navigation; Mammalia; Rat; Animal; Rodentia; Central nervous system; Hippocampus; Encephalon
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1300869110

The hippocampus and other medial temporal lobe structures have been linked to both memory and spatial cognition, but it has been unclear how these ideas are connected. We carried out parallel studies of path integration in patients with medial temporal lobe lesions and rats with hippocampal lesions. Subjects entered a circular arena without vision, searched for a target, and then attempted to return to the start location. Patients performed accurately, and as well as controls, so long as the outward path was relatively direct and the target was found within 20 s. In sharp contrast, rats with hippocampal lesions were impaired, even when the outward path was shorter than 1 m, involved no turns, and the target was found within 3 s. We suggest that patients succeeded because performance could be supported by working memory and that patients and rats differ after hippocampal lesions in their ability to construct a coherent working memory of spatial environments.