Striae Distensae, also known as stretch marks, are linear or curvilinear depressions in the skin that occur when the dermis is stretched beyond its limit of elasticity. They are often caused by rapid growth or weight gain, and can be seen in conditions such as pregnancy, obesity, adolescent growth spurts, and Cushing's syndrome.

Striae Distensae initially appear as reddish or purple lines that may have a glossy appearance. Over time, they fade to a lighter color and become less noticeable, but they do not typically disappear completely. They are most commonly found on the abdomen, breasts, hips, thighs, and buttocks.

Histologically, Striae Distensae are characterized by thinning of the dermis, fragmentation of collagen fibers, and increased deposition of ground substance. Treatment options for Striae Distensae include topical creams and ointments, laser therapy, and chemical peels, but results may vary depending on the severity and duration of the condition.

The septal nuclei are a collection of gray matter structures located in the basal forebrain, specifically in the septum pellucidum. They consist of several interconnected subnuclei that play important roles in various functions such as reward and reinforcement, emotional processing, learning, and memory.

The septal nuclei are primarily composed of GABAergic neurons (neurons that release the neurotransmitter gamma-aminobutyric acid or GABA) and receive inputs from several brain regions, including the hippocampus, amygdala, hypothalamus, and prefrontal cortex. They also send projections to various areas, including the thalamus, hypothalamus, and other limbic structures.

Stimulation of the septal nuclei has been associated with feelings of pleasure and reward, while damage or lesions can lead to changes in emotional behavior and cognitive functions. The septal nuclei are also involved in neuroendocrine regulation, particularly in relation to the hypothalamic-pituitary-adrenal (HPA) axis and the release of stress hormones.