From June 7th to June 20th, I was at UC Berkeley for the Rosetta Institute of Biomedical Research Molecular Neuroscience summer camp. It was not only an exhilarating experience, but an extremely educational one. I was able to learn so much about one of the body’s most fascinating organs in such little time with the help of a great professor, Dr. Troy Rohn from Boise State University, and several team advisors. Because this course was my very first encounter with neuroscience, I learned all my basic knowledge about the brain from Dr. Rohn, which is the premise of this post. This post is the first of a two-part series covering the highlights of my experience.
Throughout this whole program, I was in complete awe of how complex and intricate each part of the brain was. Each part of the brain had an extremely important purpose and contributed immensely to the proper function of the human body. As a result of this program, I truly realized that the brain is the mastermind and control center for our body; without our brains, none of us would be who we are today, and that fact was extremely fascinating to me. Overall, the Molecular Neuroscience program kick started my passion for neuroscience and inspired me to pursue neuroscience further.
An Introduction to Brain
The brain is one of the largest and most complex organs in the human body that controls all bodily functions, interprets the millions of stimuli the body receives from the outside world each day, and embodies the essence of the mind. Intelligence, creativity, emotion, and memory are just a few of the many things governed by the brain.
Protected within the skull, the brain is made up of three main parts: the cerebrum, cerebellum, and brainstem. The cerebrum is the largest part of the brain and is composed of left and right hemispheres. It performs higher functions like interpreting touch, vision, and hearing as well as speech, critical reasoning, emotions, knowledge, and control of movement. The cerebellum is located under the cerebrum and its function is to coordinate muscle movements and maintain posture and balance. Finally, the brainstem acts as a telephone from the cerebrum and cerebellum to the spinal cord. It performs many autonomic, or involuntary, bodily functions, such as sweating, breathing, heart rate, body temperature, sleep cycles, sneezing, coughing, swallowing, etc.
Additionally, the surface of the cerebrum is called the cortex. It has a folded appearance with many hills and valleys that increase the surface area of the brain, allowing more neurons to fit in the same volume of the skull and enabling higher level functions. The cortex contains 16 billion neurons, which, combined with the 70 billion neurons in the cerebellum, make up the brain’s 86 billion neurons. The nerve cell bodies present in the cortex are grey-brown in color and make up the grey matter. Beneath the cortex, the long nerve fibers, or axons, of those cells that connect specific brain areas to each other are white in color, thus making up the white matter.
Right brain & Left brain
The cerebrum is divided into two halves: the left and right hemispheres. The halves are joined to each other by a broad band of nerve fibers called the corpus callosum that transmits information from one side to the other. Each hemisphere controls the opposite side of our body, meaning that the left hemisphere controls the right side of our body and the right hemisphere controls the left side of our body.
The hemispheres do not carry out identical functions. Each side of the brain specializes in certain functions, as detailed in the diagram above.
Lobes of the Brain
The cerebrum has distinct grooves, which divide the brain into four lobes, or regions, namely the frontal, parietal, occipital, and temporal lobes that serve a variety of different functions. Each lobe may be further divided, once again, into areas that serve very specific functions. The lobes do not function alone; complex relationships between different lobes of the brain and between the right and left hemispheres exist.
The frontal lobe (shown in blue on the diagram) is responsible for personality, behavior, and emotions. It regulates speech, specifically speaking and writing are controlled through Broca’s area, as well as body movement. It is involved in critical thinking behaviors, such as judgment, problem solving, and planning. Intelligence, concentration, and self awareness are all traits that stem from the frontal lobe. Teenage brains are prone to impulsivity and poor decision making because their frontal lobe has not completely developed and will not do so until adulthood.
The parietal lobe (shown in yellow on the diagram) interprets language and words. The body’s sense of touch, pain, and temperature are regulated by the sensory strip in the parietal lobe. The parietal lobe is responsible for processing visual, auditory, tactile, motor, sensory and memory cues, and it controls spatial and visual perception.
The occipital lobe (shown in red on the diagram) has the sole responsibility of interpreting the millions of stimuli the body receives from vision, including light, movement, and colors.
The temporal lobe (shown in green on the diagram) is responsible for understanding language, specifically through Wernicke’s area, recounting memories, processing auditory stimuli, and regulating sequencing and organization.
Cells in the Brain
There are two different types of cells in the brain: nerve cells and glial cells.
Nerve Cells (Neurons)
While there are many different shapes and sizes of neurons, each neuron consists of a cell body, many dendrites, and an axon. Neurons convey information from one neuron to another through action potentials, which are essentially signals or messages, as well as chemical neurotransmitters. A neuron that receives an action potential becomes excited and transmits its energy to other neurons in its close vicinity.
Neurons transmit their energy, or communicate, with each other across a microscopically small gap between neurons known as a synapse. Neurons also have many dendrites, which are essentially receptors that pick up information from other nerve cells. These messages are then sent to the cell body that determines whether the information is important enough to be passed along to more cells. Important messages are transported along the axon and Nodes of Ranvier using saltatory conduction, which is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials. Once the action potential reaches the end of the axon, it forces sacs that contain neurotransmitters to open. The neurotransmitters then cross the synaptic cleft, or the gap between the two adjacent neurons, fit into special receptors on the receiving neuron, and stimulate the receiving neuron to continue passing on the message.
Note: Feel free to reference the videos below for more information on how neurons communicate with each other:
Glial Cells
If neurons play the main roles in a movie, then glial cells play the supporting roles, meaning that although they are not the star of the show, they have a crucial role in the overall plot of the movie, nevertheless. Glia are the cells in the brain that provide neurons with structural support, nourishment, and protection. They are the most abundant cells in the nervous system, with there being about 10 to 50 times more glia than neurons. There are several different types of glial cells: oligodendrocytes, astrocytes, Schwann cells, microglia, ependymal cells, and satellite cells.
