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The Brain Module 4. The Biology of Mind. Older Brain Structures The Brain Stem CLOSE UP: The Tools of Discovery – Having Our Head Examined The Thalamus The Reticular Formation The Cerebellum The Limbic System. The Cerebral Cortex Structure of the Cortex Functions of the Cortex - PowerPoint PPT Presentation
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The Brain
Module 4
The Biology of Mind
Older Brain Structures The Brain Stem CLOSE UP: The Tools of Discovery –
Having Our Head Examined The Thalamus The Reticular Formation The Cerebellum The Limbic System
The Cerebral Cortex Structure of the Cortex Functions of the Cortex The Brain’s Plasticity
Our Divided Brain Splitting the Brain Right-Left Differences in the Intact Brain
CLOSE UP: The Tools of Discovery – Having Our Head Examined
Lesion [LEE-zhuhn]: tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue.
Electroencephalogram (EEG): an amplified recording of the waves of electrical activity that sweep across the brain’s surface, measured by electrodes on the scalp.
PET Scan
PET (positron emission tomography)
Scan is a visual display of brain
activity that detects a radioactive form of glucose while the
brain performs a given task.
Courtesy of N
ational Brookhaven N
ational Laboratories
MRI ScanMRI (magnetic resonance imaging) uses magnetic fields and radio waves to produce computer -generated images of soft tissue, showing brain anatomy.fMRI (functional MRI): technique for revealing bloodflow and, therefore, brain activity by comparing successive MRIscans, showing brain function.
Both photos from Daniel Weinberger, M.D., CBDB, NIMH
MRI scan of a healthy individual (left) and a person with schizophrenia (right)
The Brainstem and the Thalamus
The brainstem, including the pons and medulla, is an extension of the spinal cord.
The thalamus is attached to the top of the brainstem. The reticular formation passes through both structures.
Brainstem
Brainstem
The Medulla [muh-DUL-uh] is the base
of the brainstem that controls heartbeat
and breathing.
10
11
Brainstem
Reticular Formation is a nerve network in the brainstem that plays an important role in controlling
arousal.
Brainstem
The Thalamus [THAL-uh-muss] is the brain’s sensory switchboard, located on top of the brainstem. It directs
messages to the sensory areas in the cortex and transmits
replies to the cerebellum and
medulla.
12
The Brain
Cerebellum [sehr-uh-BELL-um] the “little brain”
attached to the rear of the brainstem
it helps coordinate voluntary movement and balance
The Brain by the Brain
The Brain
The Limbic System is a neural system
(includingthe hippocampus,
amygdala, and hypothalamus)
located below the cerebral
hemispheres;associated with
emotions and drives.
The Limbic System
Amygdala
The Amygdala [ah-MIG-dah-la] consists of two lima bean-sized neural clusters linked to the
emotions of fear and anger.
Hypothalamus
The Hypothalamus lies below (hypo) the thalamus. It directs several maintenance activities like eating,
drinking, body temperature, and
control of emotions. It helps govern the
endocrine system via the pituitary gland.
Rats cross an electrified grid,
accepting painful shocks, for self-
stimulation when electrodes are placed
in the reward (hypothalamus) center.
Hypothalamus
Reward Center
The Cerebral Cortex
Cerebral Cortex the intricate fabric of interconnected
neural cells that covers the cerebral hemispheres
the body’s ultimate control and information processing center
The Cerebral CortexThe cerebral [seh - REE-bruhl] cortex is the intricate fabric of interconnected neural cells that covers the
cerebral hemispheres. The body’s ultimate control and information processing center.
The Cerebral Cortex
Frontal Lobes involved in speaking and muscle movements and in making
plans and judgments Parietal Lobes
include the sensory cortex Occipital Lobes
include the visual areas, which receive visual information from the opposite visual field
Temporal Lobes include the auditory areas
The Cerebral Cortex
Functions of the Cortex
The Motor Cortex is the area at the rear of the frontal lobes that control voluntary
movements. The Sensory Cortex (parietal cortex) receives information from skin
surface and sense organs.
Visual Function
The functional MRI scan shows the visual cortex is
active as the subject looks at a photo. C
ourtesy of V.P. C
lark, K. K
eill, J. Ma.
Maisog, S. C
ourtney, L.G
. U
ngerleider, and J.V. H
axby, N
ational Institute of Mental H
ealth
More intelligent animals have increased “uncommitted” or association areas of the cortex.
Neurons in these areas integrate information.
Association Areas
Language: Specialization and Integration
Brain areas involved in language processing
•
Language: Specialization and Integration
Aphasia: impairment of language, usually caused by left-hemisphere damage either to Broca’s area or Wernicke’s area.
Broca’s area: controls language expression; an area of the frontal lobe, usually in the left hemisphere, directs muscle movements involved in speech.
Wernicke’s area: controls language reception; usually in the left temporal lobe, involved in language comprehension and expression.
Specialization & Integration
Brain activity when hearing, seeing, and speaking words
Brain Rulesfrom John Medina 2008
1. Exercise boosts brain power2. The human brain evolved, too.3. Every brain is wired differently.4. We don’t pay attention to boring things.5. Repeat to remember.6. Remember to repeat.7. Sleep well, think well.8. Stressed brains don’t learn the same way.9. Stimulate more of the senses.10. Vision trumps all other senses.11. Male and female brains are different.12. We are powerful and natural explorers.
Phineas Gage
Gage Page
Brain Reorganization
Plasticity the brain’s capacity for modification, as
evident in brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development
Video
Seven tenets of plasticity Change can occur only when the brain is in the mood. Change strengthens connections between neurons engaged
at the same time. Neurons that fire together wire together. Initial changes are just temporary. Brain plasticity is a two-way street and we can either drive
brain change positively or negatively. memory is crucial to learning. motivation is a key factor in brain plasticity.
New skill acquisition is key to plasticity.
Our Divided Brain
Our brain is divided into two hemispheres.
The left hemisphere processes reading, writing, speaking, mathematics, and
comprehension skills. In the 1960s, it was termed as the dominant brain.
Splitting the BrainA procedure in which the two hemispheres of the brain are isolated by cutting the connecting fibers
(mainly those of the corpus callosum) between them.
Split Brain Patients
With the corpus callosum severed, objects (apple) presented in the right visual field can be named. Objects (pencil) in the left
visual field cannot.
Testing the Divided Brain
Try This!
Try drawing one shape with your left hand and one with your right hand,
simultaneously.B
BC
Right-Left Differences in the Intact Brain
People with intact brains also show left-right hemispheric differences in mental
abilities.
A number of brain scan studies show normal individuals engage their right
brain when completing a perceptual task and their left brain when carrying out a
linguistic task.
Example of Brain Processing
Read the following slide silently to yourself
as I read it out loud
Eaxmlpe of PcrocessnigThe paomnnehil pweor of the hmuan mnid. Aoccdrnig to a rscheearch sutdy at Cmabrigde Uinervtisy, it
deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is that the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
amzanig huh?