Search results for "MYG"
showing 10 items of 180 documents
Sexual dimorphism in the vomeronasal system of the rabbit.
2006
Abstract Studies have shown that the vomeronasal system (VNS), an olfactory neural network that participates in the control of reproductive physiology and behavior, is sexually dimorphic in the rat. These works have also shown two main characteristics of brain sexual dimorphism: (a) dimorphism appears in neural networks related to reproduction and (b) it can present two morphological patterns: one in which males present greater morphological measures than females (male > female) and another in which the opposite is true (female > male). The present work extends the hypothesis to the rabbit, as a representative species of Lagomorpha. In addition, the locus coeruleus (LC), which is known to s…
A basal ganglia-like cortical-amygdalar-hypothalamic network mediates feeding behavior.
2020
International audience; The network connecting the insular cortex, the central nucleus of the amygdala, and a caudal hypothalamic nuclear complex including the parasubthalamic nucleus (PSTN) is of interest due to its role in controlling feeding behavior. Here, we show that the organization of this network is similar to that of the basal ganglia network, implying that both fit within a simplified structural plan of the forebrain. Then, we demonstrate that the PSTN complex modulates behavior in response to hedonic factors normally inducing a “reward effect.” The PSTN complex is involved in a “non-feed” response equivalent of a “non-reward” evaluation: “I don’t want to consume this food, recog…
Attraction to male pheromones and sexual behaviour show different regulatory mechanisms in female mice.
2004
In rodents, female sexual behaviour is under hormonal control. The attraction females show for male-derived nonvolatile chemicals (pheromones) can be regarded as the first step of this behaviour, but it is unknown whether this attraction is also modulated by sexual steroids. To test this possibility, ovariectomized adult female mice with no experience of chemical signals from adult males were randomly assigned to four groups that received oil (control), progesterone, estradiol (E) or estradiol+progesterone (E+P) injections, respectively. Females were then tested for their attraction to male-soiled bedding and, subsequently, for their proceptive behaviour when confronted to adult males. Fema…
Acute stress does not impair long-term memory retrieval in older people.
2013
Previous studies have shown that stress-induced cortisol increases impair memory retrieval in young people. This effect has not been studied in older people; however, some findings suggest that age-related changes in the brain can affect the relationships between acute stress, cortisol and memory in older people. Our aim was to investigate the effects of acute stress on long-term memory retrieval in healthy older people. To this end, 76 participants from 56 to 76 years old (38 men and 38 women) were exposed to an acute psychosocial stressor or a control task. After the stress/control task, the recall of pictures, words and stories learned the previous day was assessed. There were no differe…
Role of the basolateral amygdala in retrieval of conditioned flavors in the awake rat.
2014
International audience; Learned association between odor, taste and further post-ingestive consequence is known as flavor nutrient conditioned preference. Amygdala is supposed to be one of the areas involved in these associations. In the present study, one flavor was associated with a 16% glucose (CS+) whereas another flavor was paired with less reinforcing 4% glucose (CS-). We showed that CS+ presentation after conditioning increased Fos expression in the basolateral nucleus of amygdala (BLA). Furthermore, we performed electrophysiological recordings in the BLA in free moving rats. After preference acquisition, rats were exposed to either the CS+ or the CS-. The proportion of neurons showi…
Mating Increases Neuronal Tyrosine Hydroxylase Expression and Selectively Gates Transmission of Male Chemosensory Information in Female Mice
2013
Exposure to chemosensory signals from unfamiliar males can terminate pregnancy in recently mated female mice. The number of tyrosine hydroxylase-positive neurons in the main olfactory bulb has been found to increase following mating and has been implicated in preventing male-induced pregnancy block during the post-implantation period. In contrast, pre-implantation pregnancy block is mediated by the vomeronasal system, and is thought to be prevented by selective inhibition of the mate's pregnancy blocking chemosignals, at the level of the accessory olfactory bulb. The objectives of this study were firstly to identify the level of the vomeronasal pathway at which selective inhibition of the m…
Estradiol masculinizes the posteromedial cortical nucleus of the amygdala in the rat
2000
It has been demonstrated that the posteromedial cortical amygdaloid nucleus (PMCo), is sexually dimorphic. It is shown (Experiment 1) that male orchidectomy on the day of birth (D1) decreases the volume and number of neurons of the PMCo, while a single injection of propionate testosterone to the female on D1 masculinizes the PMCo in this gender. Since male gonadectomy on D1 (Experiment 2) is counteracted by a single injection of estradiol benzoate in males it has been suggested that the masculinization of the PMCo is due to the aromatization of testosterone to estradiol in this structure. These findings support the hypothesis that the development of sex differences in structures that belong…
Effects of binge drinking and the anti-inflammatory drug indomethacin on spatial memory and cognitive flexibility in mice.
2021
Abstract In previous research, we found that chronic-intermittent ethanol administration (CIEA), a model of binge drinking, impaired emotional memory in mice, and this impairment was counteracted by the anti-inflammatory drug indomethacin. In the present study, we evaluated the effects of CIEA on spatial memory and cognitive flexibility in adolescent mice of both sexes. Animals were randomly assigned to one of four groups for each sex: SS (saline + saline), SA (saline + alcohol), SI (saline + indomethacin), and AI (alcohol + indomethacin). They were injected with saline, ethanol (3 g/kg) or indomethacin (10 mg/kg) for the first three days of each week, throughout three weeks. 96 h after tre…
Modifications of the spontaneous bioelectric activity and of the after discharge evoked in the amygdala after pallidal injection of kainic acid in th…
1982
Publisher Summary This chapter explains the modifications of the spontaneous bioelectric activity and of the after discharge (AD) evoked in the amygdala after pallidal injection of kainic acid (KA) in the cat. An experiment was conducted in which injection of KA, a neurotoxic drug analog of glutamate, was made into the entopeduncolar nucleus (EN), the equivalent of the medial globus pallidus of primates, to observe the modifications produced on the spontaneous amygdaloid bioelectric activity and on the evoked AD. An AD was evoked in the amygdala by stimulation of the ipsilateral pyriform cortex. The duration of the amygdaloid AD was related to the stimulus parameters. In the same animal, th…
A Critical Period for Prefrontal Network Configurations Underlying Psychiatric Disorders and Addiction
2020
The medial prefrontal cortex (mPFC) has been classically defined as the brain region responsible for higher cognitive functions, including the decision-making process. Ample information has been gathered during the last 40 years in an attempt to understand how it works. We now know extensively about the connectivity of this region and its relationship with neuromodulatory ascending projection areas, such as the dorsal raphe nucleus (DRN) or the ventral tegmental area (VTA). Both areas are well-known regulators of the reward-based decision-making process and hence likely to be involved in processes like evidence integration, impulsivity or addiction biology, but also in helping us to predict…