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| Unit 4. | Neurons, Hormones, and the Brain (cont'd) | ||||||||
Localization of Function and Brain Lateralization:
The brain exhibits "localization of function." This means that different parts of the brain carry out different fucntions (e.g., vision, control of voluntary movement, understanding speech, etc.) and, conversely, that not all parts of the brain do the same thing. This may seem obvious, but other organs, such as the liver, do not exhibit localization of function; one part of the liver does the same thing as another part six inches away.
We will not study ALL of the functions
of the brain. However, the localized functions that you should know
are listed in the table below:
| Function | Description | Location |
|---|---|---|
| Motor | Control of voluntary movement | The back edge of the frontal lobes |
| Somatosensory | Bodily sensations, including heat, cold, pain, pressure, and body position | The front edge of the parietal lobes |
| Vision | Ability to see | Occipital lobe |
| Auditory | Ability to hear | Top part of the temporal lobe |
| Speech production ("motor" speech) | Ability to produce speech sounds | "Broca's" area in the frontal lobe in the left hemisphere |
| Speech planning and comprehension ("sensory" speech) | Ability to plan and understand speech | "Wernicke's" area at the junction of the partiety, temporal, and occipital lobes in the left hemisphere |
| Biologically-based motives | Control of drives to satisfy basic biological needs, such as hunger and thirst | Hypothalamus, loacted at the bottom of the brainstem, near where the brainstem meets the cerebrum |
| Limbic functions | Regulation of emotions | "Limbic system" consisting of a group of brain areas located near the corpus callosum and extending into the temporal lobes |
The diagram below summarizes the localization
of these functions in the brain. Note that you are looking at the
left hemisphere. All of the listed functions except for speech functions
are symmetrical and are localized in comparable areas in the right and
left hemispheres.
|
Check out the following links that will show you where various functions are localized (located) in the brain:
Thalamus - http://www.waiting.com/brainfunctwo.html (Find out where the hypothalamus is!)
Cerebellum and Brain Stem - http://www.waiting.com/brainfuncthree.html
The Brain: Right Down the Middle
- useful drawing and succinct information about the location and functions
of brain structures that can be seen on the midsagittal plane, presented
by Eric Chudler http://faculty.washington.edu/chudler/sagittal.html
Functional Divisions of the Cerebral Cortex - Succinct information about the location and functions of the major functional subdivisions of the cerebral cortex, presented by Eric Chudler http://faculty.washington.edu/chudler/functional.html Link to self-test available at the end (not interactive; print it out) http://faculty.washington.edu/chudler/pdf/revcort.pdf(must have Adobe Acrobat to view and print the quiz)
Lobes of the Brain - Succinct information about the location and functions of the four lobes of the cerebrum, presented by Eric Chudler http://faculty.washington.edu/chudler/lobe.html Includes link to "Lobes of the Brain Review," a very brief quiz on functions associated with major lobes of the brain. Answers provided online. http://faculty.washington.edu/chudler/revlobe.html
Specialized Functions of the Cerebral Cortex - nice overview of functional localization in the brain http://www.epub.org.br/cm/n01/arquitet/cortex_i.htm
Theories on the Role of Brain Structures
in the Formation of Emotions - article by Júlio Rocha de Amaral,
MD & Jorge Martins de Oliveira, MD, PhD, published in the online journal,
Brain
and Mind http://www.epub.org.br/cm/n05/mente/teorias_i.htm
| Left Hemisphere | Right Hemisphere |
|---|---|
| Speech | Music and art appreciation, drawing ability |
| Movement of the right side of the body | Movement of the left side of the body |
| Sensation on the right side of the body | Sensation on the left side of the body |
| Vision in the right half of the "visual field" | Vision in the left half of the "visual field" |
Check out the following links related to hemispheric specialization and the function of the corpus callosum:
One Brain... or Two - information on lateralization of function (hemispheric specialization) and how the functions of the hemispheres may be studied, presented by Eric Chudler http://faculty.washington.edu/chudler/split.html
The Split-Brain Student - activity developed by Edward J. Morris, at Owensboro Community College, that allows you to simulate being a "split brain" patient, without having to have the surgery http://www.apa.org/ed/split.html
What Does Handedness Have to Do with Brain Lateralization (and Who Cares?) - very nice page on hemispheric specialization (brain lateralization) http://www.indiana.edu/~primate/brain.html