Localization of function of the human brain
I. Areas below the neocortex are called subcortical
areas.
A. The medulla oblongata lies immediately
anterior to the spinal cord.
1. site of nuclei of cranial nerves
2. regulates heart rate and force of
contraction
3. regulates distribution of blood flow
4. sets the pace of respiratory movements
5. controls vomiting
B. The pons lies immediately anterior to the
medulla.
1. “bridge” to cerebral hemispheres from
medulla
2. “bridge” between cerebral cortex and
cerebellum
C. The cerebellum is dorsal to the medulla and the
pons.
1. represents 1/8 the mass of the brain
2. coordinates motor function based upon the
integration of motion and positional
information from the inner ear and
individual muscles
3. does not initiate movement
4. helps maintain balance and posture
D. The midbrain lies anterior to the pons
1. involved in control of eye movement
2. reflexive responses during vision
3. involuntary control of muscle tone
4. portion of reticular formation important in
sleep-wake cycle
E. The thalamus lies anterior to the midbrain
1. relay for sensory pathways carrying visual,
auditory, and somatorsensory information
to appropriate regions of the cerebral
cortex (neocortex)
2. contains pineal gland that secretes
melatonin
3. some nuclei are involved in emotion
F. The hypothalamus lies underneath the
thalamus.
1. controls autonomic functions such as body
temperature and heart rate via control of
sympathetic and parasympathetic centers
in the medulla.
2. sets appetitive drives (such as thirst,
hunger, sexual desire) and behaviors
3. sets emotional states with the limbic system
G. The limbic system consists of a number of
structures which include the septum,
amygdala, and hippocampus
1. system is focused on emotional states and
related behavioral drives and provides a link
between the intellectual functions of the
cerebral cortex and the autonomic functions
of the brain stem.
2. The septum may be associated with rageful
behavior and hypersensitivity
3. The amygdala may be associated with
feeding, fighting and other behaviors
involved in self-preservation as well as
facilitating formation of emotion-laden
memories
4. The hippocampus is important in storage of
long-term memories and involved in
aspects of learning.
II. Convoluted neocortex is about 80% of the volume
of our brain and is responsible for higher functions
such as thought and planning.
A. Convolutions increase the of the brain and
provide a means of
1. gyri (rolls) form the folding out portion of
the neocortex
2. sulci are valleys in the convolutions
3. fissures are deeper than sulci, extending to
ventricles in the brain.
B. Lobes are four regions of the cerebral cortex of
each of the two hemispheres
1. Left and right frontal lobes are anterior to
the central sulcus and superior to the
lateral fissure
2. Left and right temporal lobes are inferior to
the central sulcus
3. Left and right parietal lobes are posterior to
the central sulcus, anterior to the
parietal-occipital fissure and superior to the
lateral fissure
4. Left and right occipital lobes are posterior to
the parietal-occipital fissure
C. Regions in each of the lobes receive info related
to sensations and process the info.
1. Occipital lobe= visual information
2. Somatorsensory region: anterior strip of
both parietal lobes which receives
information regarding stimulation of
various body parts.
3. Motor cortex is located in the posterior area
of the frontal lobe just anterior to the
somatosensory cortex. The motor cortex is
concerned with integration of activities
performed by skeletal muscles and initiates
movement.
4. Auditory cortex is located in the temporal
lobes. Sensations of smell and taste are
processed anteriorly in the temporal lobes.
5. Speech is one skill that demonstrates
multiple representations of information.
a. visual speech = occipital cortex
b. auditory speech = temporal cortex
c. motor speech = frontal cortex
6. Association areas are not specifically
localized involving integration of
information from other areas with respect to
thinking, memory, learning, etc.