Transcript 1.3 Physiology large hemispheres cerebellum

Physiology of large hemispheres
of the brain and cerebellum
Author
ass.prof. N.M. Volkova
Neural Communication
Serotonin Pathways
Dopamine Pathways
Descending
Pathways
• The direct pathways
(corticobulbar and
corticospinal) are
indicated by the blue
arrow.
• The indirect
pathways and their
interconnections are
indicated by the red
arrows.
Posterior
Spinocerebellar Tract
• This tract transmits
proprioceptive
information from
the thorax, upper
limbs, and upper
lumbar region to
the cerebellum.
• Lines on the inset
indicate levels of
section.
Functional Regions of the Lateral
Side of the Left Cerebral Cortex
Demonstration of Cortical Activities During Speech
• The figures show the pathway for reading and naming
something that is seen, such as reading aloud.
• PET scans show the areas of the brain that are most
active during various phases of speech. Red indicates
the most active areas; blue indicates the least active
areas.
Topography of the
Somatic Sensory Cortex
• Cerebral cortex seen
in coronal section on
the left side of the
brain. The figure of
the body
(homunculus) depicts
the nerve
distributions; the size
of each body region
shown indicates
relative innervation.
• The cortex occurs on
both sides of the brain
but appears on only
one side in this
illustration. The inset
shows the somatic
sensory region of the
left hemisphere
(green).
Topography of the
Primary Motor Cortex
• Cerebral cortex
seen in coronal
section on the
left side of the
brain.
• The figure of the
body
(homunculus)
depicts the nerve
distributions; the
size of each
body region
shown indicates
relative
innervation.
Cerebral
Medullary
Tracts
The (a) alpha and (b) beta rhythms
of the EEG.
Effects of Aging on the Nervous System
• As a person ages, there’s a gradual decline in sensory
function because the number of sensory neurons declines,
the function of remaining neurons decreases, and CNS
processing decreases.
• In the skin, free nerve endings and hair follicle receptors
remain largely unchanged with age. Meissner’s corpuscles
and pacinian corpuscles, however, decrease in number.
The capsules of those that remain become thicker and
structurally distorted and, therefore, exhibit reduced
function. As a result of these changes in Meissner’s
corpuscles and pacinian corpuscles, elderly people are
less conscious of something touching or pressing on the
skin, have a decreased sense of two-point discrimination,
and have a more difficult time identifying objects by touch.
• These functional changes leave elderly people more prone
to skin injuries and with a greater sense of isolation.