Download Chapter 3

The Biology of
Behavior
Chapter 3- Part 1
Ettinger’s Psychology- The Science of
Behavior 4e
The Nervous System
• Nervous System -2 subdivisions
• CNS, Central Nervous System
• consists of the brain and spinal cord
• Peripheral Nervous System, PNS
• transmits messages to and from the brain
• Somatic NS
• Autonomic NS
FIGURE 3.1 Divisions of the Nervous System
Cent ral Ne rvous System
Brain
Spinal Cord
Periphe ral Ne rvous
System
Somatic System
Autonomic System
Sy mpathetic Sy stem
Parasy mpathetic Sy stem
Psychology: The Science of Behavior, 3/e, CHAPTER 3
© 2009 BVT Publishing
Neurons-basic units
• Neurons are the specialized cells of the
nervous system
• Billions in the brain alone
• 3 classes
• Sensory (afferent) neurons
• Motor (efferent) neurons
• Interneurons
• Communication between afferent and efferent
neurons as with ither interneurons
FIGURE 3.2 Neuron Structure
Telodend ria
Axon
Myelin Sheath
Node of Ra nv ier
Axon Hillo ck
Nucleus
Cell Body
Dend rites
Psychology: The Science of Behavior, 3/e, CHAPTER 3
Terminal Buttons
© 2009 BVT Publishing
Neural Transmission
• Chemical transmission of substances called
neurotransmitters
• Bundles of neuron fibers = nerves
• Bundles fibers allow continuous travel of
message from CNS
PNS
• http://bit.ly/q3PxTj
(neurotransmission animation)
FIGURE 3.3 Neuron Electrical Activity
Axon
Dendr ites
(A)
At rest
Axon
Hillo ck
(B)
Beginning
of action
potentials
Area of action potentia l
traveling along axon
Area of repolar izatio n
(C)
Propagatio n
of action
potentials
Psychology: The Science of Behavior, 3/e, CHAPTER 3
Area of action
potential tr aveling
along axon
© 2009 BVT Publishing
Neural Electric Activity
• Resting potential
• Net negative charge
• Graded potentials
• Voltage change in dendrites to prepare to
receive impulse
• Action potentials
• Electrical progression along axis to release
neurotransmitters
• All-or-none law: strength of action potential
doesn’t depend on strength of stimulation
• Animation to demonstrate electrical activity:
http://outreach.mcb.harvard.edu/animations/action
potential.swf
All or none…
• Glia cells inslulate, remove waste, provide
nutrients and increase conductivity
• Myelin sheath covers some axons, made of
glial cells
• Node of Ranvier- gap in myelin sheath
• Synapse- membranes on pre and post
membranes and gap (chasm) between
FIGURE 3.4 Synapse
Dend rites
Neuron Cell Body
Neurot ransmitter
Receptor
Axon of
Presy naptic
Neuron
Sy naptic Vesicle
Postsy naptic memb rane
How neurotransmitters get from one neuron to
another:
http://bit.ly/qxmpzn
Psychology: The Science of Behavior, 3/e, CHAPTER 3
© 2009 BVT Publishing
Neurotransmitters
Neurotransmitters and
Behavior
• Schizophrenia, a severe psychological
disorder, seems to be related to excessive
dopamine neutotransmitter and dopamine
neurons in several brain areas. Antipsychotic
drugs inhibit the effects of dopamine in the
brain, reducing the over- reaction to it.
• Depression, probably the most common
psychological disturbance, appears to be
related to 2 neurotransmitters:
norepinephrine and serotonin. Tricyclic drugs
are helpful in relieving depression and seem
to increase the availability in specific brain
area
FIGURE 3.5 Functions of the Sympathetic and Parasympathetic Nervous System
Parasy mpathetic
Nervous
Sy stem
Pupil Const ricts
Pupil Dilates
Sy mpathic
Nervous
Sy stem
Sti mulates Sali va
Speeds Breathing,
Rela xes Bronchi
Inhibits Sali va
Lung
Sl ows Breathing
Const ricts
Bronchi
Accele rates
Hea rt
Sl ows
Hea rt
Hea rt
Inhibits
Digestion
Releases Glucose
Sti mulates Gall Bladder
Sti mulates
Digestion
Cont racts Bladder
Rela xes Bladder
Inhibits
Sex Organs
Sti mulates
Sex Organs
Male
Psychology: The Science of Behavior, 3/e, CHAPTER 3
Female
© 2009 BVT Publishing
FIGURE 3.6 Bisected View of the Human Brain, Showing the Locations
of Major Structures and Areas
Fornix
Thala mus
Co r pus Callosum
Cereb ral Co r tex
Pineal Gland
Ol facto ry Bulb
Hypothala mus
Optic Chiasm
Pituita ry Gland
Pons
Cerebellum
Reticular
Formation
Medulla
Spinal Cord
Psychology: The Science of Behavior, 3/e, CHAPTER 3
© 2009 BVT Publishing
FIGURE 3.7 Neural Control of Simple Reflexes
Sy napse Bet ween
Senso ry Neuron
and Inte rneuron
Nerve Cell Body
3. Inte rneuron
Car ries
Message
to B rain
Dorsal Root
Inte rneuron
Arm Muscles
Vent ral Root
2. Senso ry Neuron Car ries
Impulse to Spinal Cord
Spinal Cord
1. Skin Receptors
Pick up Pain
Impulse
4. Motor Neuron Car ries
Impulse to A rm Muscle s,
Causing Hand to Withd raw
f rom Hot Bu rner
3. Inte rneuron
Si multaneously
Transmits Message
to Motor Neuron
Sy napse Bet ween Inte rneuron
and Motor Neuron
Hot St ove Bu rner
Psychology: The Science of Behavior, 3/e, CHAPTER 3
© 2009 BVT Publishing
FIGURE 3.8 The Limbic System
Thala mus
Fornix
Cingulate Gy rus
Septum
Septal Nuclei
Ol facto ry Bulb
Hippocampus
Hypothala mus
Pituita ry Gland
Mammila ry Body
Amygdala
Psychology: The Science of Behavior, 3/e, CHAPTER 3
© 2009 BVT Publishing
The Limbic System
• Structures in the central core of the brain.
• Emotional memory
• Memory, motivation, and learning
1.Amygdala
• Small structure near Hippocampus
• Important in aggression, anger, rage, fearmotivated behaviors
• (social cognition and decision-making)
Limbic System
2) Hippocampus
Important for learning and memory
• Damage may inhibit new learning
• May be impacted by early life stress
3) Septal Area
associated with experience of pleasure
• Pleasure and reward areas called mesolimbiccortical system
Limbic system
4) Hypothalamus
• Below the thalamus
• Contains control mechanisms for some body
systems to maintain homeostasis
• Hub of the neuroendochrine system influences
the pituitary gland
• Integrates emotional expressions through
interaction with endocrine system
Limbic System
5) Thalamus
• Pair of structures above the hypothalamus, in
each hemisphere
• Routes sensory info to cerebral cortex
• All sensory info except smell goes thru thalamus
before being sent to appropriate cortical area
• Works w/ reticular formation to regulate sleep
and alertness
• ADHD appears to be caused by interruptions in brain
circuits btw thalamus and frontal cortex
FIGURE 3.9 Localization of Cortical Functions in the Four Lobes of the Left Cerebral Cortex
Motor Co r tex
Somatosenso ry
Audito r y Co rtex
Cent ral Fissure Co r tex
(Hea ring)
Parietal
Lobe
Broca ’s Area
(Speech)
Frontal
Lobe
Occipital
Lobe
Visual
Co r tex
Wernicke’s Area
(Understanding
Speech)
Tempo ral Lobe
Termi nus of
Late ral Fissure
Psychology: The Science of Behavior, 3/e, CHAPTER 3
© 2009 BVT Publishing
The Basal Ganglia
• Made up of caudate nucleus, putamen and
substantia nigra
• Receive messages from cortex and thalamus
• Function: initiate and control motion
• Common disorder is Parkinson’s from
destruction of dopamine- containing neurons
Cerebral Cortex
• Thin outer covering of the brain, a.k.a. the
neo-cortex
• Contours are to make the most efficient use of
space
• Motor and Sensory Cortices
• Areas of the body that require the most motor
control and sensory information get the most
representation on the cortex.
• Attiribution of space on the cortices is upside
down
FIGURE 3.10 Primary Areas of the Motor Cortex and the Somatosensory Cortex
Trunk
Shoulder
Arm
Elb ow
Wrist
Trunk Hip
Head
Arm Neck
Elb ow
Forea rm
Hand
Fingers
Hip
Knee
Hand
Thumb
Thumb
Fingers
Eye
Leg
Toes
Genitals
Nose
Neck
Br ow
Eye
Face
Lips
Cent ral f issure
Face
Teeth
Gums
Motor
cortex
Lips
Jaw
Jaw
Somatosenso ry
cortex
Tongue
Pha ry nx
Tongue
Int ra-abdominal
Motor Co rtex (cross section just in f ront of central f issure)
Psychology: The Science of Behavior, 3/e, CHAPTER 3
Somatosenso ry Cortex (cross section just behind cent ral f issure)
© 2009 BVT Publishing
Cerebral cortex…
• Called gray matter because of lack of
myelination which appears white
• Memories are stored in the cortex
• Analyzes and translates incoming messages
into responses
• Motor and Sensory cortex =25% Association
cortex-the rest
Lobes and sulci
• Frontal lobe- largest and foremost
• Higher order functioning
• Motor cortex is just posterior
• Followed by Central Sulcus
• Function:
• Motor nerves from left motor cortex control right
side of the body
• Broca’s area very important in speech production
• Until 1960s, pre-frontal lobotomy was surgery that
intended to minimize dysfunction and calm moods
of mental patients
Lobes…
• Occipital
• Location of visual cortex
• Temporal Lobes
• Primary function: hearing
• Location of auditory cortex, and Wernicke’s
area- for understanding speech
• Damage or injury can cause agnosias
Lobes..
• Parietal- behind central fissure
• Front of the lobe made up of the
somatosensory cortex-receiver for all sensory
info
• Relates visual and spatial information
• Mental rotation
• Injury to parietal lobe can cause contralateral
neglect
FIGURE 3.11 Passage of Visual Information in Brains with an Intact and a
Severed Corpus Callosum
Lef t
Front
Right
Lef t
Optic
Chiasm
Speech
Left
Hemisphere
A.
Front
Right
Optic
Chiasm
Speech
Right
Hemisphere
Intact
Corpus Callosum
Psychology: The Science of Behavior, 3/e, CHAPTER 3
Left
Right
Hemisphere
Hemisphere
S evered
B.
Corpus Callosum
© 2009 BVT Publishing
FIGURE 3.12 The Major Glands of the Endocrine System
Pineal Gland
Pituita ry Gland
Parat hy roid Glands
Thy roid Gland
Adrenal Glands
Kidn ey s
Pancreas
Ovaries
Testes
Psychology: The Science of Behavior, 3/e, CHAPTER 3
© 2009 BVT Publishing