Chemical and Electrical Stimulation of Hippocampus in Unrestrained Animals

MacLean, Paul D.

doi:10.1001/archneurpsyc.1957.02330380018002

Cited by 117 publications

(6 citation statements)

References 38 publications

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“…In line with earlier observations, recent investigations with chemical and electrical stimulation demonstrate the involvement of the hippo campus in pleasure and grooming reactions in the cat (222,223). Func tional relationships with the hypothalamus (130) are demonstrated by re cording hypothalamic seizure activity in response to stimulation of the lat eral amygdaloid nucleus, hippocampus, and septum (264) as well as by the study of behavioural changes attributable to destruction of rhinencephalic hypothalamic connections (31).…”

Section: Limbic Systemsupporting

confidence: 69%

Somatic Functions of the Nervous System

Cg¹

1959

Annu. Rev. Physiol.

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Vision.-Using the technique developed by Talbot & Kuffier (183, 297), Barlow et at. have demonstrated an increase in threshold in the light-adapted eye when the size of the light spot exceeds a certain magnitude (14). This change is interpreted as being caused by inhibition on the central parts of the receptive field exerted by surrounding areas. In the dark-adapted retina, there is no antagonistic interaction between peripheral and central parts of the receptive field. During dark adaptation, the lateral inhibition gradually ceases and summation occurs when the stimulus spot is increased. In this connection, the beautifully performed investigations by Hartline and co workers on the Limulus eye are of great interest (148, 149). Here mutual interaction occurs at the receptor level and is conveyed by the fibre plexus behind the ommatidia. Although this interaction is purely inhibitory and is mediated without participation of internuncial neurons, it produces complex effects, as illustrated by the fact that disinhibition may simulate facilitation. Brindley has provided evidence that the electroretinogram (ERG) is gen erated in the .receptors [see (41,42)]. Further, by using small test spots he has demonstrated that no interaction occurs between different parts of the retina producing the ERG (43), suggesting that no significant part of the ERG arises in the neural cell layers. This view is further strengthened by the finding that the complex intraretinal potentials described by Tomita and others may be absent although the ERG is normal. In other studies on potentials, a separate direct current component was obtained in isolation in the light-adapted eye of the cat (49).There seems still to be a great deal of confusion as to the origin of the sustained intraretinal potential designated as cone action potential (293). Similar potentials have been found in the eyes of different fishes (249) and in the cat's retina (142). According to Tomita (299), these potentials in the fish eye do not arise in the receptors. I t would be possible to settle the ques tion about the origin of these responses if the tip of the electrode could be accurately located within the retina. Recent attempts in this direction indi cate that these sustained potentials arise in structures proximal to the recep tors (224). The human flicker ERG has been studied (150), and it is sug gested that the splitting of the b-wave and the off-effect result frolll colour components with different latencies. Particular features of the ERG in colour-blind persons have also been demonstrated (151). Other reports deal with the effect on the ERG of dazzling the eye (174), retinal responses to 1 The survey of the literature pertaining to this review was concluded in April, 1958. 325 Annu. Rev. Physiol. 1959.21:325-352. Downloaded from www.annualreviews.org Access provided by University of Bath on 02/04/15. For personal use only. Quick links to online content Further ANNUAL REVIEWS

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Section: Limbic Systemsupporting

confidence: 69%

Somatic Functions of the Nervous System

Cg¹

1959

Annu. Rev. Physiol.

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“…Furthermore, not only electrochemical or electrical preoptic stimulation is effective in inducing ovulation in the rat (Everett, 1964), but also chemical stimulation by preoptic implants of crystalline carbachol (M. E. Velasco & S. Taleisnik, unpublished observations). Moreover, these facts suggest that preoptic neurones are responsible for the response since it has been recognized that cholinergic stimulation acts primarily at synaptic junctions, acti¬ vating cell bodies or dendrites without having a noticeable effect on adjacent fibres (Lorente de No, 1944;MacLean, 1957). Furthermore, Köves & Halász (1970) have recently shown that spontaneous ovulation occurs in rats after partial deafferenta¬ tions of the preoptic area.…”

Section: Discussionmentioning

confidence: 98%

Effects of the Interruption of Amygdaloid and Hippocampal Afferents to the Medial Hypothalamus on Gonadotrophin Release

Velasco¹,

Taleisnik²

1971

Journal of Endocrinology

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The effects of interruption of amygdaloid and hippocampal afferents to the hypothalamus on ovulation and on the release of luteinizing hormone (LH) were studied in rats. Animals acutely deprived on the morning of pro-oestrus of amygdaloid influences either by transection of the stria terminalis (ST) or lesions of the amygdala, failed to show the expected ovulation. Control lesions had no effect. In contrast, rats with long-term transection of either the ST, the cortico-hypothalamic tract (CHT), or both, had regular oestrus cycles and ovulated normally. Studies of ovulation which was induced after the administration of ovarian steroids revealed a differential response to oestrogen and progesterone. In animals with long-term transection of the ST the ovulatory response to oestrogen was similar to that induced in non-lesioned rats but fewer ovulations were induced by progesterone administration. The decreased ovulatory response after progesterone treatment was attributed to activation of inhibitory influences originating in the hippocampus, since administration of picrotoxin or section of the fornix re-established a normal response. Long-term interruption of the limbic efferents did not alter the increased levels of plasma LH found after ovariectomy. However, the release of LH induced by progesterone in ovariectomized rats primed with gonadal steroids was decreased after transection of the ST and increased after interruption of the CHT. These results are consistent with the concept that the amygdala and the hippocampus exert a modulating influence on gonadotrophin release; the influence of the amygdala being facilitatory and that of the hippocampus inhibitory.

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“…(41) obtained hypersexual behavior with lesions in the pyriform cortex or amygdala in the monkey and the cat. MacLean demonstrated that hippocampal stimulation elicited penile erection in the male monkey (42). Therefore, differential effects on thresholds of the electrical activity in various limbic areas during the estrous cycle may represent selective influences of hormones on specific CNS structures related to gonadotropic function and/or to sexual behavior.…”

Section: Discussionmentioning

confidence: 99%

Electrical Activity During the Estrous Cycle of the Rat: Cyclic Changes in Limbic Structures

1968

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Changes in electrical activity in the hippocampus and amygdala during the estrous cycle were investigated in the rat to examine the relationship between the limbic system and gonadal function. It has been shown that localized seizure threshold in the dorsal hippocampus was significantly decreased during the interval between the morning of proestrus and morning of estrus. The lateral part of the amygdala behaved in approximately the opposite direction, with an increased threshold during the same period. The thresholds for the medial part of the amygdala had decreased on the night of the second day of diestrus to the morning of proestrus, but had increased above the diestrous values by the night of proestrus.These observations were discussed with reference to plasma gonadal steroid levels and possible regulatory role of limbic areas on the release of gonadotropin. Whereas ovariectomy eliminated the cyclic aspects of activity in the limbic system, a dampened cyclicity was restored by a single injection of 10 ng of estradiol dipropionate in rats at 90-120 days of age. The same dose of estrogen was somewhat less effective in older animals, and it did not establish cyclicity in rats ovariectomized at birth. (Endocrinology 83: 207, 1968)

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Chemical and Electrical Stimulation of Hippocampus in Unrestrained Animals

Cited by 117 publications

References 38 publications

Somatic Functions of the Nervous System

Somatic Functions of the Nervous System

Effects of the Interruption of Amygdaloid and Hippocampal Afferents to the Medial Hypothalamus on Gonadotrophin Release

Electrical Activity During the Estrous Cycle of the Rat: Cyclic Changes in Limbic Structures

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