The mind at work : a handbook of applied psychology / edited by Geoffrey Rhodes.

Date:
1914
Catalogue details

Licence: In copyright

Credit: The mind at work : a handbook of applied psychology / edited by Geoffrey Rhodes. Source: Wellcome Collection.

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    first, that for the reflex action to produce sensa- tion certain nerves which run in the spinal cord up towards the brain must be intact ; and, secondly, that in normal conditions of health certain impulses must be passing down the spinal cord from the higher nervous centres which con- trol, or, as it is called “ inhibit,” excessive reflex action. If either the nerve from the tendon to the spinal cord or the nerve from the spinal cord to the muscle is divided, or if the injury to the spinal cord is at the spot where the interchange of afferent to efferent impulse occurs, no reflex action can be produced. There are many other instances of reflex action in the body. Thus, tickling the sole of the foot will lead to the leg being suddenly drawn away; a feigned blow at the eyes or a sudden flash of light will lead to involuntary closing of the eye- lid ; a loud, unexpected noise will cause a start. Many of these reflex actions are protective in character : for example, the eyelid closes to pro- tect the eye from the injurious effect of excessive light. The mechanism of all these reflex actions appears to be that a stimulus applied to nerve endings in the eye, the ear, the tendon, or the skin, is conveyed through the axis-cylinder pro- cesses of afferent nerves to certain cells in or near the central nervous system. Through the