nterweaving of axons and dendrites that
occurs in the cortex.]

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The Visual Centers

There is a visual-sensory area in the occipital lobe, at the back of
the brain, that is connected with the eye in the same way as the
auditory center is connected with the ear. Without it, the individual
still shows the pupillary reflex to light, but has no sensations of
sight. He is blind.

[Illustration: Fig. 18.--Vertical cross-section through the brain,
showing the cortex on the outside, the thalamus and other interior
masses of gray matter, some of the paths to and from the cortex, and
the callosum or bridge of axons connecting the two cerebral
hemispheres. The "Motor path" is the pyramidal tract, only the
beginning of which is shown here, its further course being indicated
in Fig. 14. (Figure text: tactile path, motor path, auditory path,
callosum, thalamus, olfactory area)]

This visual-sensory area occupies only a small portion of the
occipital lobe, and yet practically the whole lobe is concerned with
vision. Some portions of the lobe are concerned in perceiving words in
reading, and without them the individual is "word blind". Other
portions are concerned in perceiving (recognizing, understanding) seen
objects, and without them the individual is "object blind". Other {63}
portions are concerned in perceiving color relations, and still other
portions in perceiving spatial relations through the sense of sight
and so knowing where seen objects are and being able to guide one's
movements by sight.

Cortical Centers for the Other Senses

There is an olfactory area in a rather secluded part of the cortex,
and this is related to the sense of smell in the same general way.
Probably there is a similar taste center, but it has not been
definitely located. Then there is a large and important area called
the "somesthetic", connected with the body senses generally, i.e.,
chiefly with the skin and muscle senses. This area is located in a
narrow strip just back of the central fissure, extending parallel to
the motor area which lies just in front of the fissure, and
corresponding part for part with it, so that the sensory area for the
legs lies just behind the motor area for the legs, and so on.
Destruction of any part of this somesthetic area brings loss of the
sensations from the corresponding part of the body.

Just behind this direct sensory center for the body, in the parietal
lobe, are portions of the cortex conc