It would be ridiculous to have a blog dedicated to understanding the brain without first having a post on the basics of the brain. Think of this as an Introduction to Neuroscience course... just without papers, tests, multiple lessons, research articles, complex terminology, advanced cognition and.... You know what? No. Just think of it as the first lesson in an Introduction to Neuroscience course. I'm going to give you the basics - the absolute "need-to-know-so-you-can-read-this-blog" basics.
Here we go...
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First off, learn these words (I'll use them a lot): superior (or dorsal), inferior (or ventral), anterior and posterior. Superior (dorsal) is indicative of upward. Inferior (or ventral) is indicative of downward. As far as the brain is concerned, the word anterior indicates the frontal portion of your head closest to your face. Posterior is the opposite, indicating the back or behind.
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Neuroscientists classify the brain into three major sections: the hindbrain, midbrain and forebrain.
Hindbrain
The hindbrain is the section of the brain that extends dorsally (upward) from the spinal cord. It consists of three main structures, the medulla, pons and cerebellum.
The medulla and pons compromise part of the brainstem (along with the midbrain). They provide many of the sensory and motor cranial nerves (e.g., to face, mouth, throat). In their most basic sense, these two components can be remembered as involving vital functioning (breathing, heart rate), arousal (sleep-wake cycle) and the vestibular system (balance).
The cerebellum is connected to the rest of the brain via the pons. It is involved in performing complex movements and in maintaining posture.
Midbrain
The midbrain contains the inferior colliculus and superior colliculus. The inferior colliculus is a reflexive pathway for auditory processing. The superior colliculus is a reflexive pathway for integrating visual, auditory and somatosensory (touch) information.
Forebrain
The forebrain is the largest and most dorsal part of the brain. It consists of two systems: the diencephalon and telencephalon.
The telencephalon contains the thalamus and hypothalamus. The thalamus is a major relay center for all sensory information. The hypothalamus maintains homeostasis (normal body state) by triggering hormone release via the endocrine system.
The telencephalon is what people tend to imagine when they think of the word "brain." It is primarily involved in executive (or higher-level) functioning. The telencephalon is comprised of the cerebral cortex and subcortical structures.
The telencephalon comprises three major systems: The basil ganglia (subcortical), which plays numerous roles in motor control; the limbic system (cortical and subcortical), which is heavily involved in emotion and memory; and the cerebral cortex, which is a sheet of tissue that compromises the outer-most layer of the telencephalon. The cerebral cortex is, arguably, the most intricate part of the central nervous system, broken down into two hemispheres and four lobes.
Two Hemispheres:
The cerebral cortex is comprised of a left and right hemisphere. Each one is responsible for functioning on the opposite side of the body. So your right hemisphere controls your left eye, hand, foot etc.; whereas your left hemisphere controls your right eye, hand, foot, etc. Why? Because God is just that funny. The two hemispheres are bound by a structure called the corpus callosum, which is a bundle of neurons (estimated between 200-250 million) that facilitates understanding between the left and right hemisphere. You know that saying, "The left hand never knows what the right hand is doing?" Truth is, unless your corpus callosum is severed, the left hand should know exactly what your right hand is doing, because the two hemispheres are consistently transferring information to the other through the corpus callosum.
Four Lobes:
The frontal lobe is the most anterior (forward) part of your brain. There are two aspects to this hemisphere. The posterior (back) aspect is often referred to as the motor cortex, involved in processing information related to movement. The anterior aspect is often referred to as the prefrontal cortex and is involved in complex aspects of planning and executing behavior as well as in evaluating and manipulating information. You can essentially think of the prefrontal cortex as what makes us human - our character. And while this region of the brain can be damaged and result in little to no deficits in physical functioning, your personality will change drastically (look forward to the post on frontal lobe syndrome).
The parietal lobe, located posterior to the frontal lobe and dorsal to the occipital lobe, is often referred to as the somatosensory cortex. It is involved in processing information related to touch, pain, temperature sensation and limb position.
The occipital lobe is the most posterior aspect of the brain and is known as the visual cortex. This is responsible for processing visual features such as color, luminance, frequency, orientation and motion.
The temporal lobe, the most ventral (bottom) part of the brain, encompasses many functions. The dorsal portion of the temporal lobe is known as the auditory cortex. This is involved in processing sound information. The medial (middle) portion of the temporal lobe contains the hippocampus and amygdala, which are involved in learning, memory, emotion, and spatial processing.
And that's it (for now)! Does your brain hurt? Not possible - the brain itself does not feel pain, it just interprets pain receptors coming from other places in the body. That aside, I want to stress that this is the most basic way I could have written this. I'm sorry if it was painful, but with any luck you've learned something and will be better able to comprehend the unavoidable scientific rhetoric found throughout this blog.
