Chapter 1. Brain Development: Middle Adulthood

Synopsis

Human Development Video Activity
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You must read each slide, and complete any questions on the slide, in sequence.
axon
Long, slender nerve fiber that extends from the neuron's cell body. Axons create the transmission lines of the nervous system as they rapidly conduct electrical impulses from one neuron cell body to the dendrites of adjacent neurons.
axons
Long, slender nerve fiber that extends from the neuron's cell body. Axons create the transmission lines of the nervous system as they rapidly conduct electrical impulses from one neuron cell body to the dendrites of adjacent neurons.
cerebral cortex
The folded outer layers of the brain covering the cerebrum that are critically involved in many complex functions, such as memory, attention, perceptual awareness, thought, language, and consciousness.
neuron
A nerve cell that receives and communicates information throughout the body as part of the central nervous system.
neurons
A nerve cell that receives and communicates information throughout the body as part of the central nervous system.
senescence
The state of being old or growing old. Biological aging.
synapse
The microscopic gap across which the axon of a neuron can transfer an electrical impulse to the dendrites of an adjacent neuron.
synapses
The microscopic gap across which the axon of a neuron can transfer an electrical impulse to the dendrites of an adjacent neuron.
Man in middle adulthood is a teacher who is helping a student.

Brain Development: Middle Adulthood

Author

Man in middle adulthood is a teacher who is helping a student.

S. Stavros Valenti, Hofstra University

Synopsis

In this activity, you will observe changes that take place in the brain during adulthood and throughout the middle adult years. Animations will provide excellent visual aids to demonstrate the loss of brain volume and the thinning of gray matter and white matter that occur throughout middle adulthood. The activity also discusses how people experience improvements in aspects of their lives during the middle adult years.

REFERENCES

Kolb, B., & Whishaw, I. Q. (2001). An introduction to brain and behavior. New York: Worth Publishers.

Spear, L. (2000). The adolescent brain and age-related behavioral manifestations. Neuroscience and Biobehavioral Reviews, 24, 412-463.

The Brain in Middle Adulthood

Man in middle adulthood is working in a laboratory setting.

Many people describe a more positive outlook on their lives between the ages of 30 and 65 — greater knowledge, improved relationships, more satisfying careers, or newfound leisure activities. Ironically, this increasing sense of fulfillment in middle adulthood appears in spite of senescence, the gradual decline in the optimum functioning of all bodily systems. The brain changes associated with senescence begin in emerging adulthood and continue throughout middle age and beyond.

Changes in Gyri and Sulci of the Cerebral Cortex

As the amount of brain tissue gradually diminishes during normal aging, there is a compensatory increase in the volume of cerebrospinal fluid that causes enlargement of the ventricles.

Starting in the early 20s and continuing through the life span, there is a gradual loss of brain volume as the gyri (“hills”) of the cerebral cortex become narrower and the sulci (“valleys”) become wider. This loss of brain volume is offset by an increase in the size of the ventricles, which are the inner chambers of the brain filled with cerebrospinal fluid.

Play the animation to view the loss of brain volume in the adult years.

Thinning of Gray and White Matter

As a general rule, normal aging is associated with loss of gray matter, but the rate of loss varies considerably between different areas of the brain.

One of the first signs of the aging brain is the thinning of the gray matter layer, where neurons are concentrated. This thinning is usually detectable in a person’s early 20s, but the process may start even earlier. In contrast, the white matter in the brain increases until about age 40 when it begins to decrease.

Play the animation to view brain changes of gray and white matter during the adult years.

Brain Changes and Behavior

Although there are clear signs of aging in the brain during middle adulthood, these changes do not seem to be associated with a drop in the quality of life at home or on the job. Some of the brain changes, such as the reduction in the number of synapses (gray matter), are part of an overall process of “fine-tuning” of the neural circuits. This fine-tuning leads to more efficient information processing.

There are many factors affecting a person’s thoughts, feelings, and behaviors. These factors include general health, knowledge and expertise, and motivation to perform. Researchers have much to learn about how health, experiential, and motivational factors interact with age-related brain changes in middle adulthood.

Play the animation to watch again some of the brain changes that occur during the middle adult years.

Microscopic Brain Changes

When observed under the microscope, the thinning of the gray matter is due mainly to a loss of neurons and a reduction in the number of synapses. The thinning of the white matter is due to a loss of axons and their myelin sheaths and a loss of glial (support) cells.

Play the animation to observe the thinning of gray matter and white matter during the adult years.

Question 1.1

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Consider the fact that most middle-aged adults experience improvement in many areas of their lives, including self-confidence, relationships, career satisfaction, and leisure activities. The brain changes that occur during the middle years might have an influence on this improvement. Elaborate on what you think is the connection between the brain changes and life improvement

Assessment: Check Your Understanding

Man in middle adulthood is a teacher who is helping a student.

Question 1.2

FDbgZgBxMyrN3bCUVtTiBHX0S5Adx5ZT91LYrkY2Lz2KpxCqWQnMDWb3h2adi9EO71244lDRYgNx1zDAawrOR7ufipqatQ9uEW4rs1xN6yHiwSKc9QZ+IX7l6KnD4eD/ysEtgXIXK76PwbvRidVf2GIFu1J7faqb9l7HyR+evpAayHBn5sAyxJiFhK04ZlBhQJzbTQJpNb8Dry8tJDQMMoQISBOWjcyB5fsm/hZMi+bpjBMnaBOkaw==
Correct! Many people describe a more positive outlook on their lives between the ages of 30 and 65 — greater knowledge, improved relationships, more satisfying careers, or newfound leisure activities.
Sorry. Many people describe a more positive outlook on their lives between the ages of 30 and 65 — greater knowledge, improved relationships, more satisfying careers, or newfound leisure activities.

Assessment: Check Your Understanding

Man in middle adulthood is working in a laboratory setting.

Question 1.3

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Correct! With senescence, there is a gradual loss of brain volume as the gyri (“hills”) of the cerebral cortex become narrower and the sulci (“valleys”) of the cerebral cortex become wider.
Sorry. With senescence, there is a gradual loss of brain volume as the gyri (“hills”) of the cerebral cortex become narrower and the sulci (“valleys”) of the cerebral cortex become wider.

Assessment: Check Your Understanding

Man in middle adulthood is a teacher who is helping a student.

Question 1.4

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Correct! Gray matter thinning is the first sign of senescence in the brain. White matter increases up until about age 40 when it begins to decrease.
Sorry. Gray matter thinning is the first sign of senescence in the brain. White matter increases up until about age 40 when it begins to decrease.

Assessment: Check Your Understanding

Man in middle adulthood is working in a laboratory setting.

Question 1.5

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Correct! Thinning of the gray matter is due mainly to a loss of neurons and a reduction in the number of synapses. The thinning of the white matter is due to a loss of axons and their myelin sheaths and a loss of glial (support) cells.
Sorry. Thinning of the gray matter is due mainly to a loss of neurons and a reduction in the number of synapses. The thinning of the white matter is due to a loss of axons and their myelin sheaths and a loss of glial (support) cells.

Assessment: Check Your Understanding

Man in middle adulthood is a teacher who is helping a student.

Question 1.6

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Middle adulthood is a time when people describe improvement in many areas of life — greater knowledge, better relationships, more satisfying careers, or newfound leisure activities. During this age, there are signs of senescence in the brain, including the thinning of gray and white matter. However, the reduction in the number of synapses (in gray matter) acts to fine-tuning the neural circuits. This fine tuning may lead to a greater efficiency in information processing, and this may explain some of the improvements described by those between ages 30 and 65.

Congratulations! You have completed this activity.Total Score: x out of x points (x%) You have received a provisional score for your essay answers, which have been submitted to your instructor.