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III. Biological Bases of Behavior (8–10%)
An effective introduction to the relationship between physiological processes and behavior—including the influence of
neural function, the nervous system and the brain, and genetic contributions to behavior—is an important element in
the AP course.
AP students in psychology should be able to do the following:
• Identify basic processes and systems in the biological bases of behavior, including parts of the neuron and the process
of transmission of a signal between neurons.
• Discuss the influence of drugs on neurotransmitters (e.g., reuptake mechanisms).
• Discuss the effect of the endocrine system on behavior.
• Describe the nervous system and its subdivisions and functions:
— central and peripheral nervous systems;
— major brain regions, lobes, and cortical areas;
— brain lateralization and hemispheric specialization.
• Recount historic and contemporary research strategies and technologies that support research (e.g., case studies, splitbrain research, imaging techniques).
• Discuss psychology’s abiding interest in how heredity, environment, and evolution work together to shape behavior.
• Predict how traits and behavior can be selected for their adaptive value.
• Identify key contributors (e.g., Paul Broca, Charles Darwin, Michael Gazzaniga, Roger Sperry, Carl Wernicke).
Lesson 1:
As technology has improved, scientists have used a wide range of techniques to
learn about brain and neural function
ANYTHING HIGHLIGHTED BLUE IS MY BLAH-BLAH-BLAH STUFF!
I. Greek philosophers and physicians linked the mind with the brain.
A. Hippocrates (460-377 B.C.) said that emotions, thought and mental health arise from the brain
(Plato agreed 427-347 B.C.).
B. Galen (circa 130-200 A.D.) thought that fluids of the brain in ventricles were
responsible for sensations, reasoning and judgment, memory and movement.
II. Although Franz Gall (1758-1828) and Johann Spurzheim (1776-1832) incorrectly related
bumps and depressions on the surface of the skull with personality traits and moral
character, phrenology encouraged others to seek empirical evidence for brain localization.
III. Studying patients with brain damage linked loss of structure with loss of function.
A. Phineas GageB. Paul Broca (1824-1880) performed an autopsy on the brain of a patient named
Leborgne (a.k.a. Tan)
C. Gunshot wounds, tumors, "strokes" (e.g. a blood clot obstructs an arteriole in the brain
blocking supply of oxygen and nutrients to region, causing that region to die), Alzheimer’s
disease, Korsakoff’s syndrome, etc. enabled further mapping of the brain.
IV. Producing lesions
V. Examination of neural tissue led to understanding of the neuron as the unit of structure and
function of the nervous system.Santiago Ramon y Cajal (1852-1934) perfected a selective
silver staining technique developed by Camillo Golgi (1843-1926) to examine single neurons.
Cajal described the structure of a neuron and noted a small space (synapse) between adjacent
neurons.
VI. Direct electrical stimulation.
A. Wilder Penfield (1952) used a fine wire electrode to localize the origin of seizures in a
patient.
B. Walter Hess (1955) inserted electrodes more deeply into the brain relating start/stop
functions with specific brain structures. An example is the "start eating and stop eating"
functions associated with areas of the hypothalamus.
VII. An EEG (electroencephalogram)
VIII. Imaging techniques in widespread use have enabled neuroscientists to observe the mind
as it functions.
A. CAT scans (also called CT)--computerized axial tomography
1. Creates a computerized image of x-rays
2. Procedure may involve injection
B. MRI--magnetic resonance imaging
1. Magnetic field causes usually random
2. Functional MRI or fMRI
C. PET scans--positron emission tomography
IX. Other advances in technology have enabled neuroscientists to learn more about the
relationship of neurological function to behavior. (Optional)
A. BEAM--brain electrical activity mapping
Feeds EEG information from numerous recording sites into a computer which constructs an image of the brain showing areas
with different gradations of voltage in different colors or shades to make more accurate diagnoses of brain tumors, epilepsy
and learning disorders
B. MEG--magnetoencephalography and SQUID--superconducting quantum interference device Based on the concept that
whenever an electrical current is present there is an accompanying magnetic field, MEG detects neural activity too brief to be
detected by PET or MRI. This technique has been used to locate seizure-producing regions in epileptic patients.
C. PRONG--parallel recording of neural groups
Electrodes that can measure many individual neurons in close proximity have uncovered information about communication
among neurons in a region.
D. SPECT--single-photon emission computerized tomography
Tracks cerebral blood flow as indicator of neural activity in specific brain regions during performance of various tasks.
Lesson 2:
The neuron is the unit of structure and function of the nervous system
I. The neuron or nerve cell
A. Three major regions of the neuron enable the cell to communicate with other cells.
1. The cell body (a.k.a. cyton or soma)
2. The dendrites are
3. The axon emerges from the
4. The axon may be covered by an insulating myelin sheath
B. Dozens of neurotransmitters have been identified that have a variety of chemical
structures and perform different functions.
1. Acetylcholine (ACh)
2. The amino acids glutamate and aspartate stimulate receptors associated with
learning and memory.
3. The amino acids glycine and gamma-aminobutyric acid (GABA)
4. Dopamine and norepinephrine are catecholamines.
5. Serotonin is associated
6. Opioid peptides such as enkephalin and endorphins
II. The nature of the neural impulse is electrical. A very thin wire with a recording electrode
inserted into a neuron would record a series of very short uniform bursts of activity on a
voltmeter because a neuron either "fires" or it doesn’t "fire." ("All-or-nothing principle")
B. An impulse along the axon is axonal transmission.
1. The neuron at rest
2. The resting potential
3. When sufficiently stimulated
4. The more intense a stimulus,
5. When the axon is myelinated
.
6. A brief period of time, called the refractory period
III. Neurons signal by transmitting chemical messages to adjacent neurons, gland
cells or muscle cells (synaptic transmission).
1. Tiny gaps between neurons are called synaptic clefts
2. When a neuron is sufficiently excited
3. A signal is transmitted from one neuron
4. If the binding of the neurotransmitter to the postsynaptic receptor site
5. Excitation by a neural impulse can
The simplest form of behavior, called a reflex, involves impulse conduction over a few
neurons. The path is called a reflex arc.
Sensory or afferent neurons
Interneurons,
Motor or efferent neurons transmit
Examples of reflexes include the pupillary reflex, knee jerk (patellar) reflex and blinking reflex.
Lesson 3:
The organization of the nervous system
I. Patterns of behavior are generally related to the functioning of structures of neural
tissue or regions within the brain rather than single or small groups of neurons.
Neural tissue can be categorized in a variety of ways.
A. Appearance by shade/color of neural tissue
1. Gray matter is composed of neural cell bodies which may be mixed with
capillaries. A large number of cell bodies grouped together constitute a nucleus
(within the central nervous system) or ganglion (in the peripheral nervous system).
2. White matter is composed of myelinated fibers. A large collection of
myelinated axons constitutes a fiber pathway, or tract (within the central nervous
system), or nerve (within the peripheral nervous system).
3. Reticular matter is composed of cell bodies and axons mixed together
giving a netlike appearance.
B. Description by location in the organism with respect to three axes.
1. From the back or dorsal portion to the belly or ventral portion. With
respect to the human brain, superior is synonymous with dorsal and inferior is
synonymous with ventral.
2. From the head or anterior portion to the tail or posterior portion.
3. From the midline or medial portion to the side or lateral portion.
II. General divisions of the nervous system are anatomical and physiological.
A. The peripheral nervous system
1. One subdivision is the somatic nervous system
2. The other subdivision is the autonomic nervous system
a. The autonomic nervous system is subdivided into the sympathetic and
parasympathetic nervous systems.
b.1. Sympathetic stimulation
b.2. Parasympathetic stimulation results
B. The central nervous system consists of the spinal cord and the brain. (No
correlation exists between brain size and intelligence.)
1. The spinal cord, protected by membranes called meninges
a. The cord itself is composed mainly of interneurons and glial cells
which are bathed by cerebrospinal fluid produced by the glial cells.
2. The brain that has the consistency of soft-serve yogurt or semi-soft
cheese, covered by protective membranes (dura, arachnoid and pia mater
collectively called the meninges) and housed in the skull, is studied from different
approaches.
a. The comparative approach describes the brain’s evolution from more
primitive organisms reasoning that new types of behavior developed as each new
layer evolved (correlating behavior and structure). According to one comparative
view (the Triune Brain model), the human brain has three major divisions that are
overlapping layers.
a.1. The R-complex or Reptilian Brain roughly corresponds to the central core
or brainstem (which usually is said to include the medulla, pons and cerebellum).
This "brain" is associated with maintaining homeostasis and instinctive behaviors.
a.2. The Old Mammalian Brain roughly corresponds to the limbic system
(which usually is said to include the septum, hippocampus, the amygdala and the
cingulate cortex), the hypothalamus and the thalamus, believed to b e important in
controlling affective/emotional behavior, some aspects of memory and vision.
a.3. The New Mammalian Brain or Neocortex, synonymous with the cerebral
cortex, is associated with higher functions of judgment, decision making, abstract
thought, foresight, hindsight and insight, language and computing.
b. The developmental approach describes changes in structure and relates that
to changes in function during the development of an individual, and looks at the
immature brain as a simplified model of the adult brain.
b.1. The embryonic spinal brain, across-brain, midbrain and between-brain
give rise to the medulla oblongata, pons, cerebellum, pineal body, hypothalamus and
thalamus. Behaviorists call this the brainstem.
b.2. The embryonic endbrain (also called forebrain) gives rise to the
neocortex, basal ganglia, limbic system, and olfactory bulb
Lesson 4:
Localization of function of the human brain
Multiple representations of information can be located within different areas of the human
brain, yet specific regions of the brain seem most critical in handling particular functions. This
localization of structure and function has been identified for numerous regions.
I. Areas below the neocortex are called subcortical areas.
A. The medulla oblongata lies immediately anterior to the spinal cord.
B. The pons lies immediately anterior to the medulla.
C. The cerebellum is dorsal to the medulla and the pons.
D. The midbrain lies anterior to the pons.
E. The thalamus lies anterior to the midbrain.
F. The hypothalamus lies underneath the thalamus.
G. The limbic system consists of a number of structures sheathing the periphery of the
brainstem. These include the septum, amygdala and hippocampus.
1. The septum may be associated with.
2. The amygdala may be associated
3. The hippocampus is important
II. The convoluted neocortex contains about 10 billion of our 100 billion nerve cells, accounts
for approximately 80% of the volume of our brain, and is responsible for "higher functions"
such as thought and planning.
A. Convolutions increase the surface area of the brain and provide a means of mapping
regions.
1. Gyri (rolls) form
2. Sulci are
3. Fissures are deeper than
B. Lobes are four large regions of the cerebral cortex of each of the two hemispheres.
C. Regions in each of the lobes receive information related to sensations and process the
information.
1. The occipital lobes process
2. The somatosensory region is the anterior strip
3. The motor cortex
4. The auditory cortex is partially buried
5. Multiple representations of information.
6. Association areas are not specifically localized involving integration of information from
other areas with respect to thinking, memory, learning, etc
Lesson 5:
Lateralization of function of the human brain (Split brain)
Although similarly located regions in both cerebral hemispheres generally have similar
functions, differences or lateralization of function has been shown to exist.
I. Different techniques have yielded information regarding brain lateralization.
A. Electrical stimulation of the brain can be accomplished with an alert patient so that
accurate reports can be made.
B. PET scans reveal information regarding brain activity during different tasks
C. Deficits resulting from cerebral vascular accidents ("strokes"), injury or lesioning
D. Brain wave patterns
E. Split brain (corpus callosum transection or commisurotomy) patients
F. Drugs that affect activity of half of the brain (sodium amytal in carotid artery)
G. Dichotic listening
II. Left hemisphere specialization
A. The left hemisphere is specialized for speech and language function
1. Receptive auditory language function is localized in a region of the left temporal lobe called
Wernicke’s area. Damage to this area results in Wernicke’s aphasia
2. Expressive language function is localized in a region of the left frontal lobe called Broca’s
area.
3. Almost all right handed people and about 2/3 left-handed people show this specialization of
function in their left hemispheres
B. Contralateral (opposite-side) representation
1. Left somatosensory cortex registers
2. Left motor cortex.
3. Left temporal cortex receives
4. Left occipital cortex processes
C. Some psychologists characterize the left hemisphere as predisposed to deal with auditory
materials, particularistic elements, focal representation.
III. Right hemisphere specialization
A. The right hemisphere is specialized for spatial functions.
1. Right hemisphere plays role
2. Right hemisphere plays dominant
3. Patients with right hemisphere
B. The right hemisphere is specialized for musical functions.
1. Variation in intonation2. Discrimination and memory
C. Contralateral representation
1.
2.
3.
4.
Right
Right
Right
Right
somatosensory cortex registers tactile (touch) sensations from the left side of the body
motor cortex initiates movements in the left side of the body
temporal cortex receives auditory information from the left ear
occipital cortex processes visual information from the left visual field from both retinas
Lesson 6:
The Endocrine System
Integration and control is achieved through interaction of the nervous system with the
endocrine system of glands that secrete chemical messengers called hormones which is its
primary function.
I. Comparison of endocrine and nervous system regulation
A. Endocrine gland cells
B. Endocrine transport may take minutes
C. Endocrine effects are typically
D. Both hormones and neurotransmitters
E. Overlap between systems is evidenced by neurotransmitters which are chemically identical
to hormones (such as noradrenaline), neurons which are neurosecretory cells that release
signal molecules intro the bloodstream and neurosecretory cells in endocrine glands (such as
the adrenal medulla) which transmit signals through the blood and to neurons.
II. Hormones are the signal molecules of the endocrine system.
A. Hormones are of three general chemical types: steroids, peptides or proteins, and amino
acid derivatives.
B. Hormones are active in very small amounts.
C. Hormones themselves are under tight negative feedback control.
D. Hormones are rapidly degraded in the body.
1. Steroids, peptides and proteins are broken down by the liver.
2. Amino acid derivatives are broken down by enzymes in the blood.
III. As in the brain, endocrine glands are specialized in function.
A. The pineal gland lies in the thalamic region of the brain.
B. The hypothalamus anterior to the pituitary gland has endocrine gland properties.
C. The pituitary gland is located at the base of the brain in the geometric center of the skull
inferior to the hypothalamus.
D. The thyroid gland is an H-shaped gland in the neck.
E. The parathyroid glands are pea-sized glands generally embedded in the thyroid.
F. The adrenal glands lie atop the kidneys.
G. The pancreas, dorsal to the stomach, regulates blood sugar
H. The ovaries and testes are the gonads in females and males respectively necessary for
reproduction and secondary sex characteristics.
I. Prostaglandins are fatty acids produced by cell membranes in organs of the body. They act
like hormones in very low concentrations stimulating contractions in smooth muscle (especially
uterus) and are associated with dysmenorrhea.