Summary
Irradiation of the neonatal rat hippocampus reduces the proliferation of granule cells in the dentate gyrus and results in locomotor hyperactivity, behavioral perseveration and deficits on some learned tasks. In order to address the role of changes in stimulus salience and behavioral inhibition in animals with this type of brain damage, irradiated and normal rats were compared in their startle reactions to an acoustic stimulus. A portion of the brain of 10 rats was exposed to a fractionated total dose of 13 Gy during the first 16 days post partum. This procedure produced selective hypoplasia (91% reduction) of the granule cells in the hippocampal dentate gyrus. Other rats (N = 10) were sham irradiated. Sudden tones were presented to each adult rat at a rate of 1 every 30 s (spaced trials) during an initial 10-min session and 1 every 15 s (massed trials) during a subsequent session. Irradiated rats startled with a consistently higher amplitude than controls and were more likely to exhibit startle responses. These animals with hippocampal damage also failed to habituate to the startle stimulus and, under certain circumstances, showed potentiated startle responses after many tone presentations.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Altman J (1986) An animal model of minimal brain dysfunction. In: Lewis M (ed) Learning disabilities and prenatal risk. University of Illinois Press, Urbana Chicago, pp 241–304
Altman J, Anderson WJ, Wright KA (1968) Gross morphological consequences of irradiation of the cerebellum in infant rats with repeated doses of low-level x-ray. Exp Neurol 21: 69–91
Altman J, Brunner RL, Bayer SA (1973) The hippocampus and behavioral maturation. Behav Biol 8: 557–596
Bayer SA, Altman J (1975) Radiation-induced interference with postnatal hippocampal cytogenesis in rats and its long-term effects on the acquisition of neurons and glia. J Comp Neurol 163: 1–20
Bayer SA, Peters PJ (1977) A method for x-irradiating selected brain regions in infant rats. Brain Res Bull 2: 153–156
Bayer SA, Brunner RL, Hine R, Altman J (1973) Behavioural effects of interference with the postnatal acquisition of hippocampal granule cells. Nature New Biol 242: 222–224
Blanchard RJ, Fial RA (1968) Effects of limbic lesions on passive avoidance and reactivity to shock. J Comp Physiol Psychol 66: 606–612
Brunner RL, Altman J (1974) The effects of interference with the maturation of the cerebellum and hippocampus on the development of adult behavior. In: Stein DG, Rosen JJ, Butters N (eds) Plasticity and recovery of function in the central nervous system. Academic Press, New York, pp 129–148
Casarett GW (1980) Radiation histopathology, Vol II, CRC Press, Boca Raton
Coover GD, Levine S (1972) Auditory startle response of hippocampectomized rats. Physiol Behav 9: 75–77
Davis M (1984) The mammalian startle response. In: Eaton RC (ed) Neural mechanisms of startle behavior. Plenum Press, New York London, pp 287–351
Douglas RJ (1967) The hippocampus and behavior. Psychol Bull 67: 416–442
Eaton RC (ed) (1984) Neural mechanisms of startle behavior. Plenum Press, New York London
Groves PM, Wilson CJ, Boyle RD (1974) Brain stem pathways, cortical modulation, and habituation of the acoustic startle response. Behav Biol 10: 391–418
Handelmann GE, Olton DS (1981) Spatial memory following damage to hippocampal CA3 pyramidal cells with kainic acid: impairment and recovery with preoperative training. Brain Res 217: 41–58
Hicks SP (1958) Radiation as an experimental tool in mammalian developmental neurology. Physiol Rev 38: 337–356
Hicks SP, D'Amato CJ (1966) Effects of ionizing radiations on mammalian development. In: Woollam DHM (ed) Advances in teratology. Logos Press, London, pp 195–250
Isaacson RL (1974) The limbic system. Plenum Press, New York
Isaacson RL, Wickelgren WO (1962) Hippocampal ablation and passive avoidance. Science 138: 1104–1106
Isaacson RL, Douglas RJ, Moore RY (1961) The effect of radical hippocampal ablation on acquisition of avoidance responses. J Comp Physiol Psychol 54: 625–628
Kimble DP (1968) Hippocampus and internal inhibition. Psychol Bull 70: 285–295
LaBoissière E (1976) Histological processing for the neural sciences. Thomas, Springfield, Ill.
Landis C, Hunt WA (1939) The startle pattern. Farrar and Rinehart, New York
Leaton RN (1981) Habituation of startle response, lick suppression, and exploratory behavior in rats with hippocampal lesions. J Comp Physiol Psychol 95: 813–826
Means LW, Leander JD, Isaacson RL (1971) The effects of hippocampectomy on alternation behavior and response to novelty. Physiol Behav 6: 17–22
Mickley GA, Ferguson JL, Nemeth TJ, Mulvihill MA, Alderks CE (1989) Spontaneous perseverative turning and other behavioral changes in rats with radiation-induced hippocampal damage. Behav Neurosci (in press)
Mosier HD, Jansons RA (1970) Effect of x-irradiation of selected areas of the head of the newborn rat on growth. Radiat Res 43: 92–104
O'Keefe J, Nadel L (1978) The hippocampus as a cognitive map. Oxford University Press, Oxford
Paxinos G, Watson C (1982) The rat brain in stereotaxic coordinates. Academic Press, Sidney
Teitelbaum H, Milner P (1963) Activity changes following partial hippocampal lesions in rats. J Comp Physiol Psychol 56: 284–289
Tilson HA, Rogers BC, Grimes L, Harry GJ, Peterson NJ, Hong JS, Dyer RS (1987) Time-dependent neurobiological effects of colchicine administered directly into the hippocampus of rats. Brain Res 408: 163–172
Wallace RB, Altman J (1970a) Behavioral effects of neonatal irradiation of the cerebellum. I. Qualitative observations in infant and adolescent rats. Dev Psychobiol 2: 257–265
Wallace RB, Altman J (1970b) Behavioral effects of neonatal irradiation of the cerebellum. II. Quantitative studies in young-adult and adult rats. Dev Psychobiol 2: 266–272
Walsh TJ, Schulz DW, Tilson HA, Schmechel DE (1986) Colchicine-induced granule cell loss in rat hippocampus: selective behavioral and histological alterations. Brain Res 398: 23–36
Weisbroth SH (1979) Bacterial and mycotic diseases. In: Baker HJ, Lindsey JR, Weisbroth SH (eds) The laboratory rat: biology and diseases, Vol I. Academic Press, New York, pp 206–208
Wilkins DE, Hallett M, Wess MM (1986) Audiogenic startle reflex of man and its relationship to startle syndromes. Brain 109: 561–573
Zimmer J, Sunde N, Sorensen T (1985) Reorganization and restoration of central nervous connections after injury: a lesion and transplant study of the rat hippocampus. In: Will BE, Schmitt P, Dairymple-Alford JC (eds) Brain plasticity, learning and memory. Plenum Publishing, London, pp 505–518
Zimmer J, Laurberg S, Sunde N (1986) Non-cholinergic afferents determine the distribution of the cholinergic septohippocampal projection: a study of the AChE staining pattern in the rat fascia dentata and hippocampus after lesions, X-irradiation, and intracerebral grafting. Exp Brain Res 64: 158–168
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mickley, G.A., Ferguson, J.L. Enhanced acoustic startle responding in rats with radiation-induced hippocampal granule cell hypoplasia. Exp Brain Res 75, 28–34 (1989). https://doi.org/10.1007/BF00248526
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00248526