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Figure 15-1 An Overview of Neural Integration
CHAPTER 15 CHAPTER 16
OVERVIEW OF NEURAL INTEGRATION
Sensoryprocessingcenters in
brain
Sensorypathways
Generalsensory
receptors
Conscious andsubconsciousmotor centers
in brain
Motorpathways
SomaticNervous
System (SNS)
Skeletalmuscles
Memory, learning, andintelligence may
influence interpretationof sensory information
and nature of motoractivities
Higher-Order Functions
AutonomicNervous
System (ANS)
Visceral effectors(examples: smoothmuscles, glands,cardiac muscle,
adipocytes)
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15-1 Sensory Information
• Sensory Receptors
• Specialized cells that monitor specific conditions
• In the body or external environment
• When stimulated, a receptor passes information to
the CNS
• In the form of action potentials along the axon of a
sensory neuron
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15-1 Sensory Information
• Sensory Pathways
• Deliver somatic and visceral sensory information to
their final destinations inside the CNS using:
• Nerves
• Nuclei
• Tracts
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15-1 Sensory Information
• Somatic Motor Portion of the Efferent Division
• Controls peripheral effectors
• Somatic Motor Commands
• Travel from motor centers in the brain along somatic
motor pathways of:
• Motor nuclei
• Tracts
• Nerves
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15-1 Sensory Information
• Somatic Nervous System (SNS)
• Motor neurons and pathways that control skeletal
muscles
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15-2 Sensory Receptors
• General Senses
• Describe our sensitivity to:
• Temperature
• Pain
• Touch
• Pressure
• Vibration
• Proprioception
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15-2 Sensory Receptors
• Sensation
• The arriving information from these senses
• Perception
• Conscious awareness of a sensation
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15-2 Sensory Receptors
• Special Senses
• Olfaction (smell)
• Vision (sight)
• Gustation (taste)
• Equilibrium (balance)
• Hearing
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15-2 Sensory Receptors
• The Special Senses
• Are provided by special sensory receptors
• Special Sensory Receptors
• Are located in sense organs such as the eye or ear
• Are protected by surrounding tissues
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15-2 Sensory Receptors
• The Interpretation of Sensory Information
• Arriving stimulus reaches cortical neurons via labeled
line
• Takes many forms (modalities)
• Physical force (such as pressure)
• Dissolved chemical
• Sound
• Light
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15-2 Sensory Receptors
• The Interpretation of Sensory Information
• Sensations
• Taste, hearing, equilibrium, and vision provided by
specialized receptor cells
• Communicate with sensory neurons across chemical
synapses
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15-2 Sensory Receptors
• Adaptation
• Reduction in sensitivity of a constant stimulus
• Your nervous system quickly adapts to stimuli that
are painless and constant
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15-3 Classifying Sensory Receptors
• Classifying Sensory Receptors
• Exteroceptors provide information about the external
environment
• Proprioceptors report the positions of skeletal
muscles and joints
• Interoceptors monitor visceral organs and functions
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15-3 Classifying Sensory Receptors
• Proprioceptors
• Provide a purely somatic sensation
• No proprioceptors in the visceral organs of the
thoracic and abdominopelvic cavities
• You cannot tell where your spleen, appendix, or
pancreas is at the moment
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15-3 Classifying Sensory Receptors
• General Sensory Receptors
• Are divided into four types by the nature of the
stimulus that excites them
1. Nociceptors (pain)
2. Thermoreceptors (temperature)
3. Mechanoreceptors (physical distortion)
4. Chemoreceptors (chemical concentration)
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15-3 Classifying Sensory Receptors
• Nociceptors (Pain Receptors)
• Are common
• In the superficial portions of the skin, in joint capsules
• Within the periostea of bones,around the walls of blood
vessels
• Carry sensations of fast pain, or prickling pain, such as
that caused by an injection or a deep cut
• Carry sensations of slow pain, or burning and aching
pain
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15-3 Classifying Sensory Receptors
• Nociceptors
• May be sensitive to:
1. Temperature extremes
2. Mechanical damage
3. Dissolved chemicals, such as chemicals released by
injured cells
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15-3 Classifying Sensory Receptors
• Thermoreceptors
• Also called temperature receptors
• Conducted along the same pathways that carry pain
sensations
• Are free nerve endings located in:
• The dermis
• Skeletal muscles
• The liver
• The hypothalamus
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15-3 Classifying Sensory Receptors
• Mechanoreceptors
• Sensitive to stimuli that distort their plasma
membranes (Tactile, Baroreceptors,
Proprioceptors)
• Contain mechanically gated ion channels whose
gates open or close in response to:
• Stretching
• Compression
• Twisting
• Other distortions of the membrane
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15-3 Classifying Sensory Receptors
• Chemoreceptors
• Respond only to water-soluble and lipid-soluble
substances dissolved in surrounding fluid
• Receptors exhibit peripheral adaptation over period of
seconds
• Central adaptation may also occur
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15-4 Sensory Pathways
• Somatic Sensory Pathways
• Carry sensory information from the skin and
musculature of the body wall, head, neck, and limbs
• Three major somatic sensory pathways
1. The spinothalamic pathway
2. The posterior column pathway
3. The spinocerebellar pathway
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Figure 15-5 Somatic Sensory Pathways
SPINOTHALAMIC PATHWAY
KEYAxon of first-order neuron
Second-orderneuron
Third-orderneuron
Crude touch and pressure sensationsfrom right side of body
Anteriorspinothalamictract
Midbrain
Medullaoblongata
The anterior spinothalamictracts of the
spinothalamicpathway carry
crude touch and pressure sensa-
tions.
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Figure 15-5 Somatic Sensory Pathways
SPINOTHALAMIC PATHWAYKEY
Axon of first-order neuron
Second-orderneuron
Third-orderneuron
Pain and temperature sensationsfrom right side of body
Midbrain
Medullaoblongata
Spinalcord
Lateralspinothalamictract
The lateral spinothalamictracts of the
spinothalamicpathway carry pain
and temperaturesensations.
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Figure 15-5 Somatic Sensory Pathways
POSTERIOR COLUMN PATHWAY
Dorsal rootganglion
Medullaoblongata
Mediallemniscus
Midbrain
Nucleusgracilis and
nucleuscuneatus
Fasciculusgracilis and
fasciculuscuneatus
Fine-touch, vibration, pressure, andproprioception sensations from rightside of body
Ventral nucleiin thalamus
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Figure 15-5 Somatic Sensory Pathways
SPINOCEREBELLAR PATHWAY
PONS
Cerebellum
Spinocerebellarpathway
Posteriorspinocerebellartract
Anteriorspinocerebellartract
Medullaoblongata
Spinalcord
Proprioceptive input from Golgitendon organs, muscle spindles,and joint capsules
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15-4 Sensory Pathways
• Sensory Information
• Most somatic sensory information
• Is relayed to the thalamus for processing
• A small fraction of the arriving information
• Is projected to the cerebral cortex and reaches our
awareness
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15-4 Sensory Pathways
• Visceral Sensory Pathways
• Collected by interoceptors monitoring visceral tissues
and organs, primarily within the thoracic and
abdominopelvic cavities
• These interoceptors are not as numerous as in
somatic tissues
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15-4 Sensory Pathways
• Visceral Sensory Pathways
• Interoceptors include:
• Nociceptors
• Thermoreceptors
• Tactile receptors
• Baroreceptors
• Chemoreceptors
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15-4 Sensory Pathways
• Visceral Sensory Pathways
• Cranial Nerves V, VII, IX, and X
• Carry visceral sensory information from mouth, palate,
pharynx, larynx, trachea, esophagus, and associated
vessels and glands
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15-5 Somatic Motor Pathways
• The Somatic Nervous System (SNS)
• Also called the somatic motor system
• Controls contractions of skeletal muscles (discussed
next)
• The Autonomic Nervous System (ANS)
• Also called the visceral motor system
• Controls visceral effectors, such as smooth muscle,
cardiac muscle, and glands (Ch. 16)
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15-5 Somatic Motor Pathways
• Somatic Motor Pathways
• Always involve at least two motor neurons
1. Upper motor neuron
2. Lower motor neuron
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15-5 Somatic Motor Pathways
• Upper Motor Neuron
• Cell body lies in a CNS processing center
• Synapses on the lower motor neuron
• Innervates a single motor unit in a skeletal muscle
• Activity in upper motor neuron may facilitate or inhibit
lower motor neuron
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15-5 Somatic Motor Pathways
• Lower Motor Neuron
• Cell body lies in a nucleus of the brain stem or spinal
cord
• Triggers a contraction in innervated muscle
• Only axon of lower motor neuron extends outside CNS
• Destruction of or damage to lower motor neuron eliminates
voluntary and reflex control over innervated motor unit
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15-5 Somatic Motor Pathways
• Levels of Processing and Motor Control
• Integrative centers in the brain
• Perform more elaborate processing
• As we move from medulla oblongata to cerebral cortex,
motor patterns become increasingly complex and
variable
• Primary motor cortex
• Most complex and variable motor activities are directed
by primary motor cortex of cerebral hemispheres
© 2012 Pearson Education, Inc.
An Introduction to the ANS and Higher-Order Functions
• Somatic Nervous System (SNS)
• Operates under conscious control
• Seldom affects long-term survival
• SNS controls skeletal muscles
• Autonomic Nervous System (ANS)
• Operates without conscious instruction
• ANS controls visceral effectors
• Coordinates system functions
• Cardiovascular, respiratory, digestive, urinary, reproductive
© 2012 Pearson Education, Inc.
Figure 16-1 An Overview of Neural Integration
CHAPTER 16CHAPTER 15
Higher-Order FunctionsConscious andsubconsciousmotor centers
in brain
Motorpathways
Memory, learning, andintelligence may
influence interpretationof sensory information
and nature of motoractivities
AutonomicNervous
System (ANS)
Visceral effectors(examples: smooth
muscle, glands,cardiac muscle,
adipocytes)
Sensoryprocessingcenters in
brain
Sensorypathways
Generalsensory
receptors
SomaticNervous
System (SNS)
Skeletalmuscles
OVERVIEW OF NEURAL INTEGRATION
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16-1 Autonomic Nervous System
• Organization of the ANS
• Visceral motor neurons
• In brain stem and spinal cord, are known as
preganglionic neurons
• Preganglionic fibers
• Axons of preganglionic neurons
• Leave CNS and synapse on ganglionic neurons
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16-1 Autonomic Nervous System
• Visceral Motor Neurons
• Autonomic ganglia
• Contain many ganglionic neurons
• Ganglionic neurons innervate visceral effectors
• Such as cardiac muscle, smooth muscle, glands,
and adipose tissue
• Postganglionic fibers
• Axons of ganglionic neurons
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Figure 16-2a The Organization of the Somatic and Autonomic Nervous Systems
Somatic nervous system
Somaticmotor nucleiof spinal cord
SPINALCORD
Lowermotor
neurons
Skeletalmuscle
Skeletalmuscle
Somatic motornuclei of brain
stem
BRAIN
Upper motorneurons in
primary motorcortex
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Figure 16-2b The Organization of the Somatic and Autonomic Nervous Systems
Autonomic nervous system
Smoothmuscle
Cardiacmuscle
Adipocytes
Glands
Visceral Effectors
Preganglionicneuron
BRAIN
Autonomicganglia
Ganglionicneurons
Preganglionicneurons
Autonomicnuclei inbrain stem
SPINALCORD
Autonomicnuclei inspinal cord
Visceral motornuclei in
hypothalamus
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16-1 Divisions of the ANS
• The Autonomic Nervous System
• Operates largely outside our awareness
• Has two divisions
1. Sympathetic division
• Increases alertness, metabolic rate, and muscular
abilities
2. Parasympathetic division
• Reduces metabolic rate and promotes digestion
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16-1 Divisions of the ANS
• Sympathetic Division
• “Kicks in” only during exertion, stress, or
emergency
• “Fight or flight”
• Parasympathetic Division
• Controls during resting conditions
• “Rest and digest”
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16-1 Divisions of the ANS
• Sympathetic and Parasympathetic Division
1. Most often, these two divisions have opposing effects
• If the sympathetic division causes excitation, the
parasympathetic causes inhibition
2. The two divisions may also work independently
• Only one division innervates some structures
3. The two divisions may work together, with each
controlling one stage of a complex process
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16-1 Divisions of the ANS
• Sympathetic Division
• Preganglionic fibers (thoracic and superior lumbar;
thoracolumbar) synapse in ganglia near spinal cord
• Preganglionic fibers are short
• Postganglionic fibers are long
• Prepares body for crisis, producing a “fight or flight”
response
• Stimulates tissue metabolism
• Increases alertness
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16-1 Divisions of the ANS
• Seven Responses to Increased Sympathetic Activity
1. Heightened mental alertness
2. Increased metabolic rate
3. Reduced digestive and urinary functions
4. Energy reserves activated
5. Increased respiratory rate and respiratory passageways dilate
6. Increased heart rate and blood pressure
7. Sweat glands activated
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16-1 Divisions of the ANS
• Parasympathetic Division
• Preganglionic fibers originate in brain stem and sacral
segments of spinal cord; craniosacral
• Synapse in ganglia close to (or within) target organs
• Preganglionic fibers are long
• Postganglionic fibers are short
• Parasympathetic division stimulates visceral activity
• Conserves energy and promotes sedentary activities
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16-1 Divisions of the ANS
• Five Responses to Increased Parasympathetic
Activity
1. Decreased metabolic rate
2. Decreased heart rate and blood pressure
3. Increased secretion by salivary and digestive glands
4. Increased motility and blood flow in digestive tract
5. Urination and defecation stimulation
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Figure 16-5 The Distribution of Sympathetic Innervation
Preganglionic neuronsGanglionic neurons
KEY
T1 T1
Gray rami tospinal nerves
Cervicalsympathetic
ganglia
Superior
Middle
Inferior
PONS
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Figure 16-5 The Distribution of Sympathetic Innervation
Preganglionic neuronsGanglionic neurons
KEY
T1
PONS
Sympathetic nerves
Cardiac andpulmonary plexuses(see Figure 16-10)
Eye
Salivaryglands
Heart
Lung
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Figure 16-5 The Distribution of Sympathetic Innervation
Preganglionic neuronsGanglionic neurons
KEY
Coccygealganglia (Co1)
fused together
L2
Superiormesenteric
ganglion
Splanchnicnerves
Uterus Ovary
Greatersplanchnicnerve
T1
Celiac ganglion
Inferiormesentericganglion
Penis Scrotum Urinary bladder
Liver and gallbladder
Stomach
SpleenPancreas
Largeintestine
Smallintestine
AdrenalmedullaKidney
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Figure 16-5 The Distribution of Sympathetic Innervation
Preganglionic neuronsGanglionic neurons
KEY
Spinal cord
Sympatheticchain ganglia
L2
Postganglionic fibersto spinal nerves
(innervating skin,blood vessels,sweat glands,
arrector pili muscles,adipose tissue)
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16-2 The Sympathetic Division
• Sympathetic Activation
• Change activities of tissues and organs by:
• Releasing NE at peripheral synapses
• Target specific effectors, smooth muscle fibers in
blood vessels of skin
• Are activated in reflexes
• Do not involve other visceral effectors
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16-2 The Sympathetic Division
• Sympathetic Activation
• Changes activities of tissues and organs by:
• Distributing E and NE throughout body in bloodstream
• Entire division responds (sympathetic activation)
• Are controlled by sympathetic centers in
hypothalamus
• Effects are not limited to peripheral tissues
• Alters CNS activity
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16-2 The Sympathetic Division
• Changes Caused by Sympathetic Activation
• Increased alertness
• Feelings of energy and euphoria
• Change in breathing
• Elevation in muscle tone
• Mobilization of energy reserves
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Figure 16-8 The Distribution of Parasympathetic Innervation
Preganglionic neuronsGanglionic neurons
KEY
N X (Vagus)
N IX
N VII
N III
PONS
Otic ganglion
Ciliary ganglion
Pterygopalatine ganglion
Submandibular ganglion
Lacrimal gland
Eye
Salivary glands
Heart
Lungs
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Figure 16-8 The Distribution of Parasympathetic Innervation
Preganglionic neuronsGanglionic neurons
KEY
Liver andgallbladder
Stomach
Spleen
Pancreas
LargeintestineSmallintestineRectum
Kidney
Uterus Ovary Penis Scrotum
Lungs
Urinary bladder
S2
S3
S4
Spinalcord
Pelvicnerves
Autonomic plexuses(see Figure 16-10)
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16-4 The Parasympathetic Division
• Parasympathetic Activation
• Centers on relaxation, food processing, and
energy absorption
• Localized effects, last a few seconds at most
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16-4 The Parasympathetic Division
• Major Effects of Parasympathetic Division
• Constriction of the pupils
• (To restrict the amount of light that enters the eyes)
• And focusing of the lenses of the eyes on nearby objects
• Secretion by digestive glands
• Including salivary glands, gastric glands, duodenal
glands, intestinal glands, the pancreas (exocrine and
endocrine), and the liver
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16-4 The Parasympathetic Division
• Major Effects of Parasympathetic Division
• Secretion of hormones
• That promote the absorption and utilization of nutrients
by peripheral cells
• Changes in blood flow and glandular activity
• Associated with sexual arousal
• Increase in smooth muscle activity
• Along the digestive tract
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16-4 The Parasympathetic Division
• Major Effects of Parasympathetic Division
• Stimulation and coordination of defecation
• Contraction of the urinary bladder during urination
• Constriction of the respiratory passageways
• Reduction in heart rate and in the force of contraction
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16-6 Dual Innervation
• Sympathetic Division
• Widespread impact
• Reaches organs and tissues throughout body
• Parasympathetic Division
• Innervates only specific visceral structures
• Sympathetic and Parasympathetic Division
• Most vital organs receive instructions from both
sympathetic and parasympathetic divisions
• Two divisions commonly have opposing effects
© 2012 Pearson Education, Inc.
Figure 16-9 Summary: The Anatomical Differences between the Sympathetic and Parasympathetic Divisions
KEYNeurotransmitters
Epinephrine
Norepinephrine
Acetylcholine
Parasympatheticganglion
TARGET
Circulatorysystem
Sympatheticganglion
or
Postganglionicfiber
Ganglionicneurons
Preganglionicneuron
Preganglionicfiber
CNS
PNS
Sympathetic Parasympathetic
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16-7 Visceral Reflexes Regulate the ANS
• Higher Levels of Autonomic Control
• Simple reflexes from spinal cord provide rapid and automatic responses
• Complex reflexes coordinated in medulla oblongata
• Contains centers and nuclei involved in:
• Salivation
• Swallowing
• Digestive secretions
• Peristalsis
• Urinary function
• Regulated by hypothalamus
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Figure 16-12 A Comparison of Somatic and Autonomic Function
CentralNervousSystem
PeripheralNervousSystem SNS ANS
Cerebral cortex
Thalamus
Somatic sensory
Hypothalamus
Limbicsystem
Visceralsensory
Relay and processing centers in brain stem
Somaticreflexes
Longreflexes
Lower motorneuron
PreganglionicneuronSensory
pathways
Shortreflexes
Ganglionicneuron
Skeletalmuscles
Sensoryreceptors
Visceraleffectors
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Figure 16-13 Memory Storage
Sensoryinput
Repetitionpromotesretention
Consolidation
Permanent loss dueto neural fatigue,shock, interferenceby other stimuli
Temporary loss
Permanent loss
• Cerebral cortex (fact memory)• Cerebral cortex and cerebellar cortex (skill memory)
Short-termMemory
Long-term Memory
SecondaryMemory
TertiaryMemory