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Module 1.4c

loss. Blindness or deafness makes unused brain areas available for other uses, such as sound
and smell ( Amedi et al., 2005 ; Bauer et al., 2017 ). If a blind person uses one finger to read
Braille, the brain area dedicated to that finger expands as the sense of touch invades the TEACH 1.4-8
visual cortex that normally helps people see ( Barinaga, 1992 ; Sadato et al., 1996 ). In sighted
people, Braille-reading training produces similar brain changes ( Debowska et al., 2016 ). Enrichment
Neuroplasticity also helps explain why some studies have found that deaf people Share with students that Christopher
who learned sign language before another language may have enhanced peripheral and
motion-detection vision ( Brooks et al., 2020 ). In deaf people whose native language is Reeve (an actor who formerly played
sign, the temporal lobe area dedicated to hearing waits in vain for stimulation. Finally, it Superman and broke his neck when
looks for other signals to process, such as those from the visual system used to see and he was thrown from a horse) devoted
interpret signs.
Similar reassignment may occur when disease or damage frees up other brain areas his later life to spinal cord research in
normally dedicated to specific functions. If a slow-growing left hemisphere tumor disrupts an effort to find effective treatments
language (which resides mostly in the left hemisphere), the right hemisphere may compen- for spinal cord injuries. Through inten-
sate ( Thiel et al., 2006 ). If a finger is amputated, the somatosensory cortex that received its
input will begin to receive input from the adjacent fingers, which then become more sensi- sive physical therapy, Reeve was able
tive ( Oelschläger et al., 2014 ). to regain some functioning in his lungs
Although the brain often attempts self-repair by reorganizing existing tissue, research- and his fingers. His work showed that
ers are debating whether it can also mend itself through neurogenesis — producing new
neurons ( Kempermann et al., 2018 ). Researchers have found baby neurons deep in the there is some hope for those with
Distributed by Bedford, Freeman & Worth Publishers. Not for redistribution.
brains of adult mice, birds, monkeys, and humans ( He & Jin, 2016 ; Jessberger et al., 2008 ). spinal cord damage to regain function-
These neurons may then form connections with neighboring neurons ( Gould, 2007 ; Luna ing, through either neuroplasticity or
et al., 2019 ).
Stem cells, which can develop into any type of brain cell, have also been discovered in neurogenesis.
the human embryo. If mass-produced in a lab and injected into a damaged brain, might
Copyright © Bedford, Freeman & Worth Publishers.
neural stem cells turn themselves into replacements for lost brain cells? Might surgeons TEACH 1.4-8
someday be able to rebuild damaged brains, much as we reseed the grass on damaged
sports fields? Stay tuned. In the meantime, we can all benefit from natural promoters of Enrichment
neurogenesis, such as exercise, sleep, and nonstressful but stimulating environments ( Liu &
Nusslock, 2018 ; Monteiro et al., 2014 ; Nollet et al., 2019 ). Explain to students that research
suggests that aerobic exercise such
The Divided Brain as jogging or swimming is positively
related to neuroplasticity and neuro-
1.4-9 What do split brains r eveal about the functions of our two brain hemi-
1.4-9 What do split brains reveal about the functions of our two brain hemi-

spheres?
spheres? genesis, especially in the hippocam-
pus, which is important in learning and
Our brain’s look-alike left and right hemispheres serve differing functions. This lateralization
becomes apparent after brain damage. Research spanning more than a century has shown memory. Additionally, evidence shows
that left-hemisphere accidents, strokes, and tumors can impair reading, writing, speaking, that aerobic activity can delay age-
arithmetic reasoning, and understanding. Similar right-hemisphere damage has less visi- related cognitive declines. Another
bly dramatic effects. Does this mean that the right hemisphere is just along for the ride?
Many believed this was the case until the 1960s, when a fascinating chapter in psychology’s reason to participate in physical
history began to unfold: Researchers found that the “minor” right hemisphere was not so activities!
limited after all.
neurogenesis the formation of
new neurons. Information from Vivar, C., Potter, M. C., & van
Splitting the Brain corpus callosum [KOR-pus Praag, H. (2013). All about running: Synaptic

In the early 1960s, two neurosurgeons speculated that major epileptic seizures were caused kah-LOW-sum] the large band plasticity, growth factors and adult hippocampal
of neural fibers connecting the
by an amplification of abnormal brain activity bouncing back and forth between the two two brain hemispheres and neurogenesis. Current Topics in Behavioral
cerebral hemispheres, which work together as an integrated system ( Bogen & Vogel, 1962 ). carrying messages between Neurosciences, 15, 189–210. http://doi.org/10
They wondered if they could end this biological tennis match by severing the corpus them. .1007/7854_2012_220

,
callosum the wide band of axon fibers connecting the two hemispheres and carrying
The Brain: Damage Response and Brain Hemispheres Module 1.4c 81 ENGAGE 1.4-8
(Out of class) Have students contact
a neuropsychologist to ask about
current research on neurogenesis.
03_myersAPpsychology4e_28116_ch01_002_163.indd 81 15/12/23 9:23 AM
Have them ask which promising
applications of this type of research
might occur, in their estimation.
Alternatively, you can contact a
neuropsychologist and ask them to
join your class virtually to address
these questions.

The Brain: Damage Response and Brain Hemispheres Module 1.4c 81

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