Your Beautiful Brain

Your brain weighs approximately 2.5 pounds and consumes approximately 40% to 60% of blood glucose . . . . It produces electricity including synchronized and collective actions of small and large groups of neurons linked by axonal and dendritic connections. Each neuron is like a dynamically oscillating battery that is continually being recharged. Locally connected neurons recruit neighboring neurons with a sequential build up of electrical potential referred to as the recruiting response and the augmenting response also called EEG “burst activity” and “spindles”. . . . EEG burst activity is recognized by spindle shaped waves that wax and wane (i.e., augmenting by sequential build up then asymptote and then decline to repeat as a waxing and waning pattern) are universal and are present in delta (1 – 4 Hz) theta (4-7.5Hz), alpha (8 to 12 Hz), beta (12.5 Hz to 30 Hz) and gamma (30 Hz – 100 Hz) frequency bands during waking in normal functioning people.

 

                -Robert Thatcher, PhD, 2004

 

The Basics: A Neuroanatomy Glossary

 

          

 

Neurons: Neurons are pretty much the most basic unit of the brain. When measuring EEG—we are measuring “action potentials” along the axon. An action potential is a firing—bam!—that is the swapping of potassium and sodium along the border of the axon.

 

Amygdala: The amygdala is located within the temporal lobes. It is essential to the experience of fear responses and its primary function is arousal. This complex structure controls the Autonomic Responses Associated with Fear; emotional responses (i.e. rage and anger) and Hormonal Secretions. The amygdala is an almond shaped mass of nuclei located deep within the temporal lobes, medial to the hypothalamus and adjacent to the hippocampus.

 

Whalen, P.J. (1998). Fear, vigilance, and ambiguity: Initial neuroimaging studies of the human amygdala.
Current Directions in Psychological Science, Vol 7(6). 177-188. doi:10.1111/1467-8721.ep10836912

 

Basal Ganglia: The Basal Ganglia are collections of nerve cells deep within the brain. Most of the basal ganglia are concerned with movement, though parts are devoted to language, thought, motivation and emotion.

 

Brain Stem: The brainstem is responsible for carrying all information from the body to the cerebrum and cerebellum (hindbrain) and from the brain to the body. The pathways ascending from the body to the brain are the sensory pathways and communicate to your brain that which is going on with the body (pain, hunger, desires, temperature, sensations, etc). The descending pathways move from the brain to the body. The last job of the brain stem is its regulation of various systems, such as you cardiovascular system, respiratory system, pain sensitivity controls, as well as alertness, and consciousness.

 

The brainstem plays a primary role in conduit functions. That is, all information related from the body to the cerebrum and cerebellum and vice versa, must traverse the brain stem. The ascending pathways coming from the body to the brain are the sensory pathways. Descending tracts are upper motor neurons destined to synapses on lower motor neurons. The brain stem also has integrative functions. It is involved in cardiovascular system control, respiratory control, pain sensitivity control, alertness, and consciousness.

 

Cerebral Cortex: This is a crinkled sheet of nerve cells that is better known as grey matter. I like to think of it as the bark of the brain. It is 1/5” thick. This is the house of the highest level of neural processing (e.g. language, memory, cognitive functioning). The cerebral cortex can be divided into areas concerned with particular functions. What lies underneath the cortex is considered white matter.

 

Cerebellum: The cerebellum is the hindbrain structure that is connected to the brainstem by fibers that carry information into and out of its interior. The main function of the cerebellum is coordinating movement and planning motor activity (balance, muscle tension, joint position, and coordinated movements). It is folded, like the cortex, which gives it high information processing power.

  

Dendrites: Dendrites are the branched projections of a neuron that act to conduct the electrical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project.

 

Hippocampus: The hippocampus is a part of the forebrain, located in the medial temporal lobe. It belongs to the limbic system and plays major roles in short term memory and spatial navigation.

 

Hypothalamus: The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). The hypothalamus controls body temperature, hunger, thirst, fatigue, anger, and circadian cycles. The hypothalamus is located below the thalamus, just above the brain stem. The hypothalamus is responsible for certain metabolic processes and other activities of the Autonomic Nervous System. It synthesizes and secretes neurohormones, often called hypothalamic-releasing hormones, and these in turn stimulate or inhibit the secretion of pituitary hormones.

 

Pituitary: The pituitary is a small pea-size master gland of the endocrine system that sits in a bony depression beneath the hypothalamus. Its job deals with directing chemical changes to regulate the entire organic system.

 

Reticular formation: The reticular formation is at the core of the brainstem and plays a vital role in sleep, emotion, breathing, blood pressure, and heart rate.

 

Thalamus: The thalamus is an egg-shaped structure deep within the brain that acts as a relay station, receiving information from all senses (except olfactory) processing the data and passing it up into the cerebral cortex.