The Amazing Human Brain and Human Development

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Action potential: This is an electrical charge that travels down the axon of a neuron to the synaptic terminal. Once there, it can increase or decrease the probability that hundreds of intracellular vesicles filled with neurotransmitter will fuse with the pre-synaptic membrane of that neuron, and release the neurotransmitter into the synaptic cleft. The action potential occurs when the neuron has been activated and temporarily reverses the electric polarity of the interior membrane from negative to positive.

Amygdala: This is a structure in the forebrain. It is part of the limbic system and plays a major role in emotional memory and the response to threat.

Axon: This is the tiny fibrous extension of a neuron, which travels away from the cell body to other target cells (neurons, muscles, glands).

Autonomic Nervous System: The ANS is that part of the nervous system responsible for regulating the activity of the body's other organs (e.g., skin, muscle, circulatory, digestive, endocrine).

Central Nervous System: This is the portion of the nervous system comprising the spinal cord and brain.

Cerebellum: This is a large structure resembling a cauliflower on the top of the brainstem. This structure is very important in motor movement and motor-vestibular memory and learning.

Cerebral Cortex: This is the outermost layer of the cerebral hemispheres of the brain. The cortex mediates all conscious activity including planning, problem solving, language, and speech. It is also involved in perception and voluntary motor activity.

Cognition: This refers to the mental process by which we become aware of our environment, and use that awareness to problem solve and make sense out of the world. It is somewhat oversimplified, but cognition refers to thinking and all of the mental processes related to thinking.

Glia: These are specialized cells that nourish, support, and complement the activity of neurons in the brain. Actrocytes are the most common and appear to play a key role in regulating the amount of neurotransmitter in the synapse by taking up excess neurotransmitter. Oligodendrocytes are those glia that specialize to form the myelin sheath around many axonal projections.

Hippocampus: This is a thin structure in the subcortex shaped like a seahorse. It is an important part of the limbic system and plays a major role in learning, memory, and emotional regulation.

Homeostasis: This is the tendency of a physiological system (i.e., a neuron, neural system, or the body as a whole) to maintain its internal environment in a stable equilibrium

Hypothalamus: This is a group of important nuclei that mediates many important functions. It is located at the base of the brain, and is connected to the pituitary by a network of specialized blood vessels. The hypothalamic nuclei are involved in regulating many of the body's internal organs via hormonal communication. The hypothalamus is a key part of the hypothalamic-pituitary-adrenal (HPA) axis that is so important in the stress response.

Limbic System: This is a group of functionally and developmentally linked structures in the brain (including the amygdala, cingulate cortex, hippocampus, septum, and basal ganglia). The limbic system is involved in the regulation of emotion, memory, and in processing complex socio-emotional communication.

Neuron: A cell specialized for receiving and transmitting information. While neurons have tremendous heterogeniety in structure, they all have some form of both dendritic projections (that receive incoming information) and axonal projections (that communicate to other cells).

Neurotransmitter: A chemical that is released from a neuron, and that relays information to another cell by binding to a receptor on the membrane of the target cell.

Plasticity: This refers to the remarkable capacity of the brain to change its molecular, microarchitectural, and functional organization in response to injury or experience.

Synapse: This is the specialized space between two neurons that is involved in information transfer. Neurotransmitter is released from one neuron, enters the synaptic cleft (space), and sends a signal to the post-synaptic neuron by occupying that receptor's receptors.

Thalamus: This is a paired structure of two tiny egg-shaped structures in the diencephalon. The thalamus is a crucial area for integrating and organizing sensory information that comes into the brain. In the thalamus, information is processed and forwarded to the key cortical areas, where more processing and integrating take place.

Use-dependent: This refers to the specific changes in neurons and neural systems following activation. Repetitive, patterned stimulation alters the organization and functioning of neurons and neural systems and, thereby, the brain.


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