Summary
In the base of each temporal lobe in 4 monkeys (Macaca fascicularis) we sectioned the pia mater in an antero-posterior line along the most medial part of the inferior temporal visual association cortex (area TE), lateral to the parahippocampal cortex. This pial section interrupts the blood flow in branches of the posterior cerebral artery which cross the parahippocampal gyrus en route to area TE. Histologically, the brains of 2 of these animals did not show any abnormalities in cresyl violet stained material, apart from the small cortical damage along the line of the pial section itself. Of the remaining two animals, one had a small unilateral infarct in TE and one had bilateral infarcts in TE. All of these animals were impaired in visual discrimination learning, and the severity of impairment was correlated only imperfectly with the severity of infarction. These results show that pial section along the medial boundary of area TE can affect visual discrimination learning without producing large infarcts. Further, since aspiration lesions of the hippocampal formation require the pia mater to be sectioned in a similar way to that reported here, the effects of such aspiration lesions on visual learning and memory may be mediated in part by effects on TE.
Similar content being viewed by others
References
Amaral DG, Insausti R, Cowan WM (1987) The entorhinal cortex of the monkey; 1. Cytoarchitectonic organization. J Comp Neurol 264:326–355
Bachevalier J, Mishkin M (1989) Mnemonic and neuropathological effects of occluding the posterior cerebral artery in Macaca mulatta. Neuropsychologia 27:83–105
Cummings JL, Tomiyasu U, Read S, Benson DF (1984) Amnesia with hippocampal lesions after cardiopulmonary arrest. Neurology 34:679–681
Gaffan D, Harrison S (1989a) A comparison of the effects of fornix transection and sulcus principalis ablation upon spatial learning by monkeys. Behav Brain Res 31:207–220
Gaffan D, Harrison S (1989b) Place memory and scene memory: effects of fornix transection in the monkey. Exp Brain Res 74:202–212
Gaffan D, Saunders RC (1985) Running recognition of configural stimuli by fornix-transected monkeys. Q J Exp Psychol 37B:61–71
Gaffan EA, Gaffan D, Hodges JR (1991) Amnesia following damage to the left fornix and to other sites: a comparative study. Brain 114:1297–1313
Jaspers RMA, Block F, Heim C, Sontag K-H (1990) Spatial learning is affected by transient occlusion of common carotid arteries (2VO): comparison of behavioural and histopathological changes after “2VO” and “four-vessel occlusion” in rats. Neurosci Lett 117:149–153
Mahut H, Zola-Morgan S, Moss M (1982) Hippocampal resections impair associative learning and recognition memory in the monkey. J Neurosci 2:1214–1229
Moss M, Mahut H, Zola-Morgan S (1981) Concurrent discrimination learning of monkeys after hippocampal, entorhinal or fornix lesions. J Neurosci 1:227–240
Parkinson JK, Murray EA, Mishkin M (1988) A selective mnemonic role for the hippocampus in monkeys: memory for the location of objects. J Neurosci 8:4159–4167
Zola-Morgan S, Squire LR, Amaral DG (1986) Human amnesia and the medial temporal region: enduring memory impairment following a bilateral lesion limited to field CA1 of the hippocampus. J Neurosci 6:2950–2967
Zola-Morgan S, Squire LR, Amaral DG (1989a) Lesions of the hippocampal formation but not lesions of the fornix or the mammillary nuclei produce long-lasting memory impairment in monkeys. J Neurosci 9:898–913
Zola-Morgan S, Squire LR, Amaral DG, Suzuki WA (1989b) Lesions of perirhinal and parahippocampal cortex that spare the amygdala and hippocampal formation produce severe memory impairment. J Neurosci 9:4355–4370
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gaffan, D., Lim, C. Hippocampus and the blood supply to TE: parahippocampal pial section impairs visual discrimination learning in monkeys. Exp Brain Res 87, 227–231 (1991). https://doi.org/10.1007/BF00228525
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00228525