BBB - The Forebrain Lesson

Forebrain

The forebrain contains the "newest" structures of the brain and those that are most important to know for this class. It is the part of the brain that makes us human and makes up 90% of the total brain volume. The forebrain is responsible for higher-order thinking, cognitive, sensory, and motor functions, as well as regulating temperature, reproduction, eating, sleeping, and emotions. It is made up of the limbic system and cerebral cortex.

Thalamus

The thalamus is a round mass of cell bodies located in each hemisphere. It acts as the operator or switchboard of our brain. All sensory information that comes through our bodies (except for smell) passes through the thalamus which then sends it on to the appropriate areas of the brain to be processed. The thalamus keeps all systems running smoothly and regulates levels of awareness, attention, motivation, and emotion.

Image showing the parts of the Limbic System: thalamus, hypothalamus, hippocampus, amygdala, parahippocampal gyrus, fornix, cingulate gyrus

The Limbic System

The limbic system borders the brain stem and is a complex system of neural circuits involved in learning, memory, and emotion. The structures of the limbic system that we need to know include the hypothalamus, the hippocampus, and the amygdala. 

  1. Hypothalamus - The hypothalamus is located beneath the thalamus and is the most important structure in our brain. It is about the size of a pea and contains more than forty neural pathways. It is charged with regulating the autonomic nervous system and a variety of behaviors related to survival. It also controls the suprachiasmatic nucleus (regulates sleep/wake cycles) and the pituitary gland.
  2. Hippocampus - The hippocampus is a large structure embedded in the temporal lobe. If sensory information is important, the hippocampus processes it in short-term, long-term, or out of memory. The hippocampus is the brain structure most open to change through learning and experiences.
  3. Amygdala - The amygdala is a clump of neurons at the base of the temporal lobes responsible for the memory of smell, sight, sound, emotions, and our emotional response patterns such as fear, anger, and disgust.

Watch the video on emotions and the limbic system below.

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