Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion and socio-sexual behaviours. Oestrogen (neuroestrogen) synthesized in the brain from androgen by aromatase regulates male socio-sexual behaviours. Here we show that GnIH directly activates aromatase and increases neuroestrogen synthesis in the preoptic area (POA) and inhibits socio-sexual ...

Social competence - the ability of animals to dynamically adjust their social behavior dependent on the current social context - is fundamental to the successful establishment and maintenance of social relationships in group-living species. The social opportunity paradigm, where animals rapidly ascend a social hierarchy following the removal of more dominant individuals, is a well-established a...

Animal studies have identified the preoptic area as the key thermoregulatory region of the brain but no comparable information exists in humans. We used fMRI to study the preoptic area of human volunteers. Subjects lay in a 3T MRI scanner and were subjected to whole body heating by a water-perfused suit, to a level that resulted in a low rate of discrete sweating events (measured by finger skin...

GABA-containing (GABAergic) interneurons play an important role in the function of the cerebral cortex. Through mostly inhibitory mechanisms, interneurons control hyperexcitability and synchronize and shape the spatiotemporal dynamics of cortical activity underlying various brain functions. Studies over the past 10 years have demonstrated that, in most mammals, interneurons originate during dev...

Systemic salt loading has been reported to facilitate operant heat-escape/cold-seeking behavior. In the present study, we hypothesized that the median preoptic nucleus (MnPO) would be involved in this mechanism. Rats were divided into two groups (n = 6 each): one group had the MnPO lesion with ibotenic acid (4.0 mug) and the other was the vehicle control. After subcutaneous injection (10 ml/kg)...

Our long-term goal is to understand the relationship between complex behaviors and complex brains. Here, we explore the effects of social organization, specifically monogamy versus polygamy, on the brains and behavior of African cichlid fishes. Since cichlids process social information visually, we began by behaviorally comparing the visual acuity of monogamous and polygamous fish. We then expl...

The mechanisms responsible for generating the pulsatile release of gonadotropins from the pituitary gland are unknown. We develop here a methodology in mice for controlling the activity of the gonadotropin-releasing hormone (GnRH) neurons in vivo to establish the minimal parameters of activation required to evoke a pulse of luteinizing hormone (LH) secretion. Injections of Cre-dependent channel...

BOULANT, J. A., AND K. E. BIGNALL. Hypothalamic neuronal responses to peripheral and deep-body temperatures. Am. J. Physiol. 225(6) : 1371-1374. 1973.-Single-unit activity was recorded in the anterior hypothalamic-preoptic area of anesthetized rats and ground squirrels. The local thermosensitivity (i.e., impulses/set . “C) of 28 units was determined by their change in firing rate to changes in ...

The aim of this immunohistochemical study was to evaluate the distribution of kisspeptin neurons in the preoptic area (POA) of gonadally intact adult male and female rhesus monkeys, and to determine whether imposition of an estradiol (E2)-positive feedback signal in the castrate male increased kisspeptin in the POA. Additionally, kisspeptin in the POA of the intact female was examined during an...

Using the immunoperoxidase method, neurons containing luteinizing hormone-releasing hormone (LHRH) and somatostatin (SRIF) were identified in the hypothalamus of growing ewe lambs between 3 days and 16 weeks of age. Both peptidergic neuronal systems were well developed in the early postnatal period. The centres producing LHRH were found to be situated in the anterior region of the hypothalamus ...