Doublecortin-immunoreactive neurons in the piriform cortex are sensitive to the long lasting effects of early life stress.

The olfactory system is a niche of continuous structural plasticity, holding postnatal proliferative neurogenesis in the olfactory bulbs and a population of immature neurons in the piriform cortex. These neurons in the piriform cortex are generated during embryonic development, retain the expression of immaturity markers such as doublecortin, and slowly mature and integrate into the olfactory circuit as the animal ages. To study how early life experiences affect this population of cortical immature neurons, we submitted mice of the C57/Bl6J strain to a protocol of maternal separation for 3 h per day from postnatal day 3 to postnatal day 21.

Inhibition of the medial amygdala disrupts escalated aggression in lactating female mice after repeated exposure to male intruders.

Virgin female laboratory mice readily express pup care when co-housed with dams and pups. However, pup-sensitized virgins fail to express intruder-directed aggression on a single session of testing. To study whether repeated testing would affect the onset and dynamics of maternal or intruder-directed aggression, we tested dams and their accompanying virgins from postpartum day 4 to 6.

MeCP2 haplodeficiency and early-life stress interaction on anxiety-like behavior in adolescent female mice.

Background: Early-life stress can leave persistent epigenetic marks that may modulate vulnerability to psychiatric conditions later in life, including anxiety, depression and stress-related disorders. These are complex disorders with both environmental and genetic influences contributing to their etiology. Methyl-CpG Binding Protein 2 (MeCP2) has been attributed a key role in the control of neuronal activity-dependent gene expression and is a master regulator of experience-dependent epigenetic programming.

Motherhood-induced gene expression in the mouse medial amygdala: Changes induced by pregnancy and lactation but not by pup stimuli.

During lactation, adult female mice display aggressive responses toward male intruders, triggered by male-derived chemosensory signals. This aggressive behavior is not shown by pup-sensitized virgin females sharing pup care with dams. The genetic mechanisms underlying the switch from attraction to aggression are unknown.

Maternal Motivation: Exploring the Roles of Prolactin and Pup Stimuli.

Motherhood entails increased motivation for pups, which become strong reinforcers and guide maternal behaviours. This depends on steroids and lactogens acting on the brain of females during pregnancy and postpartum. Since virgin female mice exposed to pups are nearly spontaneously maternal, the specific roles of endocrine and pup-derived signals in the induction of maternal motivation remain unclear.

Afferent and efferent projections of the anterior cortical amygdaloid nucleus in the mouse.

The anterior cortical amygdaloid nucleus (ACo) is a chemosensory area of the cortical amygdala that receives afferent projections from both the main and accessory olfactory bulbs. The role of this structure is unknown, partially due to a lack of knowledge of its connectivity. In this work, we describe the pattern of afferent and efferent projections of the ACo by using fluorogold and biotinylated dextranamines as retrograde and anterograde tracers, respectively.

Afferent and Efferent Connections of the Cortex-Amygdala Transition Zone in Mice.

The transitional zone between the ventral part of the piriform cortex and the anterior cortical nucleus of the amygdala, named the cortex-amygdala transition zone (CxA), shows two differential features that allow its identification as a particular structure. First, it receives dense cholinergic and dopaminergic innervations as compared to the adjacent piriform cortex and amygdala, and second, it receives projections from the main and accessory olfactory bulbs. In this work we have studied the pattern of afferent and efferent projections of the CxA, which are mainly unknown, by using the retrograde tracer Fluorogold and the anterograde tracer biotinylated dextranamine.