Anatomy of the Brain Stem

The brain stem , which is only two and a half inches long, is seen here cut from top to bottom and laid open, in a similar way to which a book is opened. The central dark area is the reticular formation. The left side shows the motor nuclei of the cranial nerves and the right side illustrates their sensory nuclei. The anatomy of the brain includes: the motor nuclei of cranial nerves, this one represents the oculomotor nucleus; the choroid plexus, which secretes a clear, watery fluid--the cerebrospinal fluid; a sensory nucleus of the fifth cranial nerve; the thalamus, which receives both motor and sensory nerve fibers as they pass into and out of the brain; the trigeminal nerve, which is comprised of single fibers which unite to form a nerve bundle; the pituitary stalk, which is part of the forebrain and lies above the pons; the optic nerve, which splits to enter the chiasma and lies in front of the brain stem; the pons, which is made up of transverse nerve fibers interwoven with longitudinal nerve fibers; the medulla oblongata, which is the lower part of the brain stem; the spinal cord, a cord of central gray matter surrounded by white matter; motor nerve bundles, which emerge from the right side of the brain and cross to supply the body's left side; the sensory nerve bundles, which arise from the left side of the body and pass to the right side of the brain after crossing in the medulla; and the motor and sensory nerve fibers, which pass through the brain stem on their way into and out of the spinal cord, and cross in the medulla to serve and supply areas on the opposite sides of the body.

Cerebellum

The cerebellum (Latin for little brain) is a region of the brain that plays an important role in the integration of sensory perception, coordination and motor control. In order to coordinate motor control, there are many neural pathways linking the cerebellum with the cerebral motor cortex (which sends information to the muscles causing them to move) and the spinocerebellar tract (which provides proprioceptive feedback on the position of the body in space). The cerebellum integrates these pathways, like a train conductor, using the constant feedback on body owning to fine-tune motor movements.

Because of this 'updating' function of the cerebellum, lesions within it are not so debilitating as to cause paralysis, but rather present as feedback deficits resulting in disorders in fine movement, equilibrium, posture, and motor learning. Initial observations by physiologists during the 18th century indicated that patients with cerebellar damage show problems with motor coordination and movement. Research into cerebellar function during the early to mid 19th century was done via lesion and ablation studies in animals. Research physiologists noted that such lesions led to animals with strange movements, awkward gait, and muscular weakness. These observations and studies led to the conclusion that the cerebellum was a motor control structure. However, modern research shows that the cerebellum has a broader role in a number of key cognitive functions, including attention and the processing of language, music, and other sensory temporal stimuli.

Development of Nervous system

Definition

The nervous system is a network of specialized cells that communicate information about an animals surroundings and its self, it processes this information and causes reactions in other parts of the body. It is composed of neurons and other specialized cells called glia, that aid in the function of the neurons. The nervous system is divided broadly into two categories; the peripheral nervous system and the central nervous system. Neurons generate and conduct impulses between and within the two systems. The peripheral nervous system is composed of sensory neurons and the neurons that connect them to the nerve cord, spinal cord and brain, which make up the central nervous system. In response to stimuli, sensory neurons generate and propagate signals to the central nervous system which then process and conduct back signals to the muscles and glands. The neurons of the nervous systems of animals are interconnected in complex arrangements and use electrochemical signals and neurotransmitters to transmit impulses from one neuron to the next. The interaction of the different neurons form neural circuits that regulate an organisms perception of the world and what is going on with its body, thus regulating its behavior. Nervous systems are found in many multicellular animals but differ greatly in complexity between species.[1]

About the Speaker

This Lecture is conducted by Professor Marian Diamond who is first women science faculty Berkely,her current research is on environmental effects on the structure and function of the brain

Professor Diamond's discovery that the brain continues to develop at any age with proper stimulation has revolutionized thinking about aging. An equally significant finding of Daimond's is that female and male brains are structured differently. Her studies conclusively show that positive, nurturing environments that encourage interaction and response are the prime conditions for developing the more complex neural networks that appear to be the "hardware" of intelligence. Her work also indicates the ongoing influence of environment, experience, learning, and emotions on neural equipment throughout life- for better or for worse.