Neuroanatomy can be fairly intimidating. Here at Brainstorm, we hope to break down complex brain structures into more easily understood anatomical segments. Today we'll discuss the limbic system!
The limbic system is one of the oldest portions of the brain. It is comprised of four key brain structures: the hypothalamus, amygdala, thalamus, and hippocampus. These structures are located deep within the brain and, collectively, they receive sensory information from the outside world and subsequently direct our behavior and emotions. The limbic system influences our perception of hunger and thirst as well as our response to pain.
We will discuss each part of the limbic system below, beginning with the hypothalamus!
Hypothalamus - The hypothalamus plays many distinct and important roles in our body via the production of specific hormones. It produces at least eight known hormones which each target different organs without our bodies. For example, the hypothalamus produces thyrotropin-releasing hormone which directs the anterior pituitary to release thyroid-stimulating hormone that subsequently stimulates thyroid hormone production downstream in the thyroid gland. Additionally, the hypothalamus produces corticotropin-releasing hormone which stimulates stimulates adrenocorticotropic hormone release from the anterior pituitary; this hormone then stimulates the adrenal cortex which produces its own hormones. Thus, the hypothalamus is involved in a multitude of bodily processes, including body temperature, blood pressure, and appetite regulation.
Amygdala - The amygdala plays a major role in emotional processing. Importantly, it helps to connect emotions and feelings to other aspects of brain function, such as memories and learning. One of the most important emotions regulated by the amygdala is fear. It can process sensory information around us to help determine what is dangerous, associating specific stimuli with fear. The amygdala also plays a role in addiction behavior and in interpreting social cues.
Thalamus - The thalamus is a major relay center in the brain for the processing of sensory information and for conduction of motor signals (fun fact: the only sense that is not relayed through the thalamus is the sense of smell!). The thalamus is divided into several nuclei which each affect a different output, such as pain regulation, motor function, and sensory domains. As a member of the limbic system, the thalamus also plays a role in learning, emotional processing, and memory.
Hippocampus - The hippocampus is best known for its function in memory formation. It also plays a role in memory processing, converting short-term memories into long-term memories. However, the hippocampus has several other functions including spatial navigation (detecting where our bodies are in space), emotional behaviors, learning, and decision-making.
The limbic system is made up of several key neuroanatomical structures. Which one is your favorite?!
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