1. Chapter 49
Nervous Systems

2. Overview: Command and Control Center
The human brain contains about 100 billion neurons, organized into circuits more complex than the most powerful supercomputers
A recent advance in brain exploration involves a method for expressing combinations of colored proteins in brain cells, a technique called “brainbow”
This may allow researchers to develop detailed maps of information transfer between regions of the brain
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3. Figure 49.1
Figure 49.1 How do scientists identify individual neurons in the brain?

4. Concept 49.2: The vertebrate brain is regionally specialized
Specific brain structures are particularly specialized for diverse functions
These structures arise during embryonic development
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5. Figure 49.9a
Figure 49.9 Exploring: The Organization of the Human Brain

6. Embryonic brain regions Brain structures in child and adult
Figure 49.9b
Embryonic brain regions
Brain structures in child and adult
Cerebrum (includes cerebral cortex, white matter, basal nuclei)
Telencephalon
Forebrain
Diencephalon (thalamus, hypothalamus, epithalamus)
Diencephalon
Midbrain
Mesencephalon
Midbrain (part of brainstem)
Metencephalon
Pons (part of brainstem), cerebellum
Hindbrain
Myelencephalon
Medulla oblongata (part of brainstem)
Mesencephalon
Cerebrum
Diencephalon
Metencephalon
Midbrain
Midbrain
Diencephalon
Myelencephalon
Hindbrain
Figure 49.9 Exploring: The Organization of the Human Brain
Pons
Medulla oblongata
Spinal cord
Forebrain
Telencephalon
Cerebellum
Spinal cord
Embryo at 1 month
Embryo at 5 weeks
Child

7. Left cerebral hemisphere Right cerebral hemisphere
Figure 49.9c
Left cerebral hemisphere
Right cerebral hemisphere
Cerebral cortex
Corpus callosum
Cerebrum
Basal nuclei
Figure 49.9 Exploring: The Organization of the Human Brain
Cerebellum
Adult brain viewed from the rear

8. Diencephalon Thalamus Pineal gland Brainstem Hypothalamus Midbrain
Figure 49.9d
Diencephalon
Thalamus
Pineal gland
Brainstem
Hypothalamus
Midbrain
Pituitary gland
Pons
Figure 49.9 Exploring: The Organization of the Human Brain
Medulla oblongata
Spinal cord

9. Arousal and Sleep The brainstem and cerebrum control arousal and sleep
The core of the brainstem has a diffuse network of neurons called the reticular formation
This regulates the amount and type of information that reaches the cerebral cortex and affects alertness
The hormone melatonin is released by the pineal gland and plays a role in bird and mammal sleep cycles
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10. Input from nerves of ears
Figure 49.10
Eye
Input from nerves of ears
Figure The reticular formation.
Reticular formation
Input from touch, pain, and temperature receptors

11. Sleep is essential and may play a role in the consolidation of learning and memory
Dolphins sleep with one brain hemisphere at a time and are therefore able to swim while “asleep”
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12. Low-frequency waves characteristic of sleep
Figure 49.11
Key
Low-frequency waves characteristic of sleep
High-frequency waves characteristic of wakefulness
Location
Time: 0 hours
Time: 1 hour
Left hemisphere
Figure Dolphins can be asleep and awake at the same time.
Right hemisphere

13. Biological Clock Regulation
Cycles of sleep and wakefulness are examples of circadian rhythms, daily cycles of biological activity
Mammalian circadian rhythms rely on a biological clock, molecular mechanism that directs periodic gene expression
Biological clocks are typically synchronized to light and dark cycles
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14. The SCN acts as a pacemaker, synchronizing the biological clock
In mammals, circadian rhythms are coordinated by a group of neurons in the hypothalamus called the suprachiasmatic nucleus (SCN)
The SCN acts as a pacemaker, synchronizing the biological clock
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15. After surgery and transplant
Figure 49.12
RESULTS
Wild-type hamster
 hamster
Wild-type hamster with SCN from  hamster
 hamster with SCN from wild-type hamster 24 23 22
Circadian cycle period (hours) 21
Figure Inquiry: Which cells control the circadian rhythm in mammals? 20 19
Before procedures
After surgery and transplant

16. Emotions
Generation and experience of emotions involve many brain structures including the amygdala, hippocampus, and parts of the thalamus
These structures are grouped as the limbic system
The limbic system also functions in motivation, olfaction, behavior, and memory
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17. Thalamus Hypothalamus Olfactory bulb Amygdala Hippocampus Figure 49.13
Figure The limbic system.
Olfactory bulb
Amygdala
Hippocampus

18. Generation and experience of emotion also require interaction between the limbic system and sensory areas of the cerebrum
The structure most important to the storage of emotion in the memory is the amygdala, a mass of nuclei near the base of the cerebrum
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19. Nucleus accumbens Amygdala Happy music Sad music Figure 49.14
Figure Impact: Using Functional Brain Imaging to Map Activity in the Working Brain
Happy music
Sad music