Transcript A Guided Tour of the Brain

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Studying of the Brain
The Developing Brain
› Neurogenesis
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The Brainstem
› The Hindbrain
› The Midbrain
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The Forebrain
› Cerebral Cortex
 Lobes of the Brain
› The Limbic System
 Structures
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One early approach to mapping brain functions
involved examining the bumps on a person’s skull.
Case studies of individuals with brain damage have
provided valuable insights into behavior in such area as
memory, speech, emotion, movement, and personality.
Lesions- surgically altering, removing, or destroying
specific portions of the brain
› In humans, lesions are produced for medical reasons, such as
when part of the brain is surgically altered or removed to
relieve uncontrollable seizures
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Electroencephalograph- allowed scientists to record the
brain’s electrical activity through the use of large, diskshaped electrodes placed harmlessly on a person’s scalp
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By three weeks after conception, a sheet of
primal neural cells has formed. This sheet curls
to form the hollow neural tube.
The neural stem cells divide and multiply,
creating specific cells that eventually produce
neurons and glial cells.
As the neural tube expands, the cavities develop,
called the ventricles.
During peak periods in the brain development,
new neurons are being generated rapidly.
Triggered by chemical signals, the new neurons
travel to specific locations. 
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For many years, it was thought that the mature
brain could lose neurons, but not grow new ones.
But new studies showed that the hippocampus, a
brain structure that plays a vital role in forming
new memories, has the ability to generate new
neurons throughout the lifespan.
Studies since this discovery have shown that
stress, exercise, environmental complexity, and
social status have been shown to affect the rate of
neurogenesis in rats, birds, and monkeys.
But it is unknown if these findings can be applied
to the human brain. 
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Includes the hindbrain and midbrain
› Located at the base of the brain
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Hindbrain:
› A region at the base of the brain that contains
several structures that regulate basic life
functions
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Midbrain:
› The middle and smallest brain region, involved
in processing auditory and visual sensory
information 
Connected to the spinal cord with the rest of
the brain
 Made up of three structures
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› Medulla: Lies directly above the spinal cord;
contains centers active in control of breathing,
heart rate, and digestion; also controls swallowing,
coughing, vomiting, and sneezing
› Pons: swelling of tissue; relay information from
various other brain regions to the cerebellum
› Cerebellum: controls balance, muscle tone, and
coordinated muscle movements; affected by alcohol
consumption 
Relay station that contains centers
important to the processing of auditory
and visual sensory information
 Process auditory sensations from the left
and right ears
 Helps you visually locate objects and track
their movements
 Substantia nigra: in midbrain; contains a
large concentration of dopamine-producing
neurons 
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Cerebral Cortex: outer portion of forebrain
› Only a quarter an inch thick
› Mainly composed of glial cells and neuron cell bodies
and axons
 Gray matter (in reference to color)
 White matter consists of myelinated axons that
connect cerebral cortex to other brain regions
› Divided into two cerebral hemispheres connected by
corpus callosum
 Cerebral hemispheres are then divided into four
lobes
 Temporal, occipital, parietal and frontal lobes 
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Temporal Lobe
› Contains primary auditory cortex
Occipital Lobe
› Contains primary visual cortex
Parietal Lobe
› Involved in somatosensory information (somatosensory cortex)
Frontal lobe
› Largest lobe
› Primary motor cortex
› Involved in planning, initiating, and executing voluntary
movements
Association Areas
› Located on all lobes
› Combine sensory and motor information
› Coordinate interaction among different brain areas 
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Limbic System: structures that form a border around
brainstem and are involved in emotion, motivation,
learning, and memory.
› Plays a critical role in learning, memory, and emotional
control 
Hypothalamus
› Regulates behaviors related to survival
 Eating, drinking, and sexual activity
› Often referred to as “the brain within the brain”
› Controls secretion of endocrine hormones
 Influences anterior and posterior pituitary glands
 Amygdala
› Clump of neuron cell bodies at the base of temporal
lobe
› Involved in emotion and memory 
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