Neuroscience: The Nervous System

he nervous system is the body’s speedy, electrochemical communication system. It consists of all the nerve cells of the peripheral and central nervous systems.

The central nervous system consists of the brain and spinal cord. The peripheral nervous system is the sensory and motor neurons that connect the central nervous system to the rest of the body. Nerves are the neural cables of the nervous system containing many axons. They are part of the peripheral nervous system. They are connected to the central nervous system by muscles, glands, and sense organs.

Sensory neurons carry incoming information from the sense receptors to the central nervous system. Interneurons are part of the central nervous system. They internally communicate and intervene between the sensory inputs and motor inputs. They are the most common type of neuron. Motor neurons carry outgoing information from the central nervous system to the muscles and glands.

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– The Peripheral Nervous System –

The peripheral nervous system is made up of the somatic nervous system and the autonomic nervous system. The somatic nervous system controls the body’s skeletal muscles. The autonomic nervous controls the glands and muscles of the internal organs. It is broken down into the sympathetic and the parasympathetic nervous system. The sympathetic nervous system arouse the body, mobilising its energy in stressful situations (fight or flight response). The parasympathetic nervous system calms the body, conserving its energy.

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– The Central Nervous System –

The spinal cord is the information highway connecting the peripheral nervous system to the brain. Ascending neural tracts send up sensory information. Descending neural tracts send down motor control information. Reflexes are the body’s autonomic response to stimuli controlled by the spinal cord. They are composed of 1 sensory neuron and 1 motor neuron that communicate through one interneuron. Because they only run through your spinal cord, they react automatically without your brain being involved in the process. The spine sends information back to the brain. Bodily pain or pleasure is controlled by the brain.

The brain receives information, interprets it and then decides on a response. It functions like a computer, receiving slightly differing images of an object from the eyes, it computes the differences and infers how far the object must be to project such a difference.

Neural networks are interconnected neural cells which, with experience, can learn, as feedback strengthens or inhibits connections that produce certain results. Stephen Kosslyn and Oliver Koening proposed to think of neural networks as networks of people. Neuron network with nearby neurons with which the can have short, fast connections. Each layer of a neural connects with various cells in the next layer. Learning occurs as feedback strengthens connections that produce certain results. New computer models simulate this process plus the excitatory and inhibitory conniptions to mimic the brain’s capacity for learning.