Download Chapter 2—Biological Bases of Behavior I. Neuroanatomy-

Chapter 2—Biological Bases of Behavior
I. Neuroanatomy-A. Neurons—individual nerve cells; the building blocks of the nervous system
1. parts of a neuron
 Dendrites—
 Soma—
 Axon—
 Myelin Sheath—
 Terminal Buttons—
 Synapse—
2. how a neuron fires (neuron has slightly negative charge in its resting state)
 Neurotransmitters from Neuron A fit like
 If enough are received (“threshold”), the cell membrane of Neuron B
 This change in charge spreads down the length of Neuron B like
 Neurons fire completely or not at all…called
 After neuron fires there is a brief refractory period, during which
 Neural firing is an “electrochemical” process, electricity travels within
the cell (dendrites to terminal buttons) and chemicals
(neurotransmitters) travel between cells in synapse. Electricity does
NOT
B. Neurotransmitters—chemicals in terminal buttons that travel in the synaptic gap
between neurons
1. Some are ____________________________________they excite the next cell into firing
2. Some are ____________________________________they inhibit the next cell from firing
3. Important Neurotransmitters:
A. ACH—Acetylcholine—
 When ACH is released to muscle,
 If ACH transmission is blocked,
 Curare—poison used by S. American Indians—blocks ACH
receptor sites—
 Botulin—causes paralysis
 Black widow spider venom—causes flood of ACH—
***loss of ACH linked to
B. GABA—Gamma-amino butyric acid—inhibitory—prevents neurons
from overly exciting their neighbors
 Low levels of GABA—
C. Serotonin- Also plays role in
 Antidepressants—
D. Norepinephrine—involved in controlling alertness and wakefulness; in
some forms of depression (too little) and mania (too much)
E. Dopamine—
 Too much—
 Too little
F. Endorphins—important role in control of emotional behavior (anxiety,
fear, tension, pleasure)
 Called
4. Amount and type of neurotransmitters received on receptor sites of
neuron determine
C. Types of Neurons—neurons fire in one direction—we need two types: one to take
info. to our brain, the other from brain to muscles
1. Sensory Neurons (Afferent)—
2. Interneurons—
3. Motor Neurons (Efferent)
II. The Nervous System—composed of the Central Nervous System and Peripheral Nervous
System
A. Central Nervous System (CNS)
1.
B. Peripheral Nervous System (PNS)
1.
2. divided into two categories: somatic and autonomic nervous system
a. somatic—
b. autonomic—
 Sympathetic—“fight or flight”
 Parasympathetic—“resting and digesting”
C. Normal Nervous System Transmission—you stub your toe…….
 Sensory (afferent) neurons in toe send message to spinal cord;
 Motor cortex in brain sends impulses down spinal cord to muscles
controlling
D. Reflexes—an exception
Some reactions occur when sensory neurons reach the spinal cord
 Just below kneecap—
 Intense heat or cold—
III. The Endocrine System—our body’s chemical messenger system that interacts with the
nervous system to regulate behavior and bodily functions
 Consists of glands that secrete
 Hormones travel to target organs where
 Some glands located in the brain (hypothalamus, pituitary, pineal), some in
the neck (thyroid, parathyroid’s), the adrenals on top of kidneys, and gonads
in the lower torso
A. The Endocrine Glands
1. Hypothalamus—
2. Pituitary Gland—
3. Pineal Gland-4. Thyroid—
5. Parathyroids—
6. Adrenals—adrenal cortex—outer layer—
Adrenal medulla—the core—
7. Pancreas—
8. Gonads—sex glands
 Testes—
 Ovaries—
IV. The Brain—three interconnected areas
A. The Brain Stem—found deep in brain; autonomic processes like heartbeat,
breathing, swallowing, digestion
1. Medulla—
2. Pons—
3. Reticular Formation (Reticular Activating System)—serves as the brain’s
sentinel. Arouses cerebral cortex to
4. Thalamus—
5. Cerebellum—attached to brain stem at base of skull;
B. The Limbic System—involved with motivation, emotion and memory
1. Hippocampus—largest limbic structure
 Role in
 Damage does not impair
2. Amygdala—role in emotional control and formation of emotional memories
3. Hypothalamus—smallest structure in brain, yet plays vital role
 Regulates
 Also regulates
C. Cerebrum—2/3 of total mass of brain
 Regulates higher cognitive and emotional functions
 Divided into
 Central sulcus—
 Lateral fissure—
 These two divisions help define 4 areas or lobes of brain:
Frontal lobe—
Parietal lobe—
Occipital lobe—
Temporal lobe—
D. Cerebral Cortex Areas
1. Motor—
2. Sensory—
3. Auditory—
4.Visual—
5. Association Cortex—interprets, integrates, information processes such as
planning and decision-making
a. higher mental functions
b. language depends on several different brain regions; depending on
 Damage to angular gyrus—
 Damage to Broca’s area—
 Damage to Wernicke’s area—
V. Studying the Brain and Nervous System
***5 techniques used
A. Accidents/Brain Damage—Phineas Gage
B. Lesioning—
 Brain tumors—
 Frontal lobotomies—
C. Electrical Stimulation—Wilder Penfield did pioneering work in the 1940’s
 Major tool—
 Penfield observed result—
D. EEG--Electorencephalogram
 Detects
 Widely used in
E. Brain Scans—CAT, MRI, PET, fMRI
1. CAT—Computerized Axial Tomography
 Gives 3D image of brain
 Can only
 Example—
2. MRI—Magnetic Resonance Imaging
 Uses magnetic fields and radio waves to
 No radiation (unlike CAT scan)
 Also only gives info
3. PET—Positron Emission Tomography
 Lets researchers see
 How much of certain chemicals
4. fMRI—Functional MRI
 New technology
 Combines
 Can show details of brain stucture with info about
VI. Hemispheric Specialization
A Two Hemispheres of Cerebral Cortex
 Contralateral Control—right hemisphere controls motor functions,
gets sensory info. from left side of body; left hemisphere controls
motor functions, gets sensory info. from right side of body
B. Specialization—each hemisphere has different functions
 We have dominant, nondominant hemispheres; dominant usually
opposite of the hand we write wit
 Right handed usually means
C. Left Hemisphere
 Analytic in function;
 Language,
D. Right Hemisphere
 Less prominent role
 Sensitive to
 Intuitive
 Artistic,
E. Split-Brain Research—how we know about hemispheric specialization
 Roger
 Patients whose