Transcript Slide 1

Biological Psychology
Reductionism: the attempt to explain complex phenomena
by reducing them to combinations of simpler components.
I. Nervous System Cells
A. Neurons: the cells in your nervous system that process
information.
1) Sensory Neurons: carry messages from sense receptor cells toward
the central nervous system.
2) Motor Neurons: carry messages away from the central nervous
system.
3) Interneurons: relay messages from sensory neurons to other
interneurons or to motor neurons. They account for most of the
neurons in the brain.
B. Glia: other cells in the brain that insulate neurons and
help to remove neuronal waste products. There are five
times more glial cells in the brain than there are neurons.
Neuron
C. Cell Body (soma): contains the nucleus of the cell.
D. Dendrites: widely branching structures that receive
transmissions from other neurons.
E. Axon: a single, long, thin, fiber with branches near its tip.
F. Myelin Sheath: aids in the transmission of impulses along
the axon.
II. How does an axon send communication?
A. Action Potential: an excitation that travels along an axon
at a constant strength, no matter how far it must travel.
This happens through a series of electrical and chemical
processes.
B. All-or-None Law: if an action potential occurs at all, it will
always be of the same magnitude.
C. Refractory Period: the period of rest during which a new
nerve impulse cannot be activated in a segment of an axon.
D. Resting Potential: an electrical polarization across the
membrane of an axon, with a negative charge inside the axon.
III. Where does neuronal communication
occur?
A. Synapse: the specialized junction between one neuron and
another. A neuron releases a chemical that either excites or
inhibits the next neuron.
B. Presynaptic Ending: one of the endings of the several
branches at the end of an axon.
C. Neurotransmitter: a chemical that has been stored in the
neuron and that can activate receptors of other neurons.
D. Postsynaptic Neuron: the neuron on the receiving end of
the synapse.
E. What happens to neurotransmitters after release?
1) Reuptake: the neurotransmitter gets reabsorbed by the neuron that
transmitted it.
2) The neurotransmitter could get metabolized and go back into the
blood stream or exit the body through urine.
3) The neurotransmitter could return to the postsynaptic neuron and
re-excite it.
IV. Neurotransmitters and Behavior
A. Endorphins: reduce the sensation of pain and affect
emotions.
B. Acetylcholine: is important for memory. A deterioration
of neurons that transmit this neurotransmitter may contribute
to Alzheimer's Disease.
C. Glutamate: is important for memory, emotional
regulation, and learning. Low levels of this neurotransmitter
can impair both the speed and overall ability to learn.
D. GABA: too little of this neurotransmitter can raise levels
of anxiety.
E. Norepinephrine and Serotonin: a decrease in these
neurotransmitters is associated with depression.
F. Dopamine: a gradual decay of the neurons that release
this neurotransmitter causes…
1) Parkinson’s Disease: causes difficulty initiating voluntary
movement, tremors, rigidity, and depressed mood.
V. The Nervous System and Behavior
A. Central Nervous System: consists of the brain and the
spinal cord.
B. Peripheral Nervous System: composed of bundles of
axons between the spinal cord and the rest of the body.
C. Breakdown of the Peripheral Nervous System:
1) Somatic Nervous System: is made up of the peripheral nerves that
communicate with the skin and muscles (voluntary movements).
2) Autonomic Nervous System: controls the involuntary actions of the
heart, stomach and other organs (involuntary movements).
D. Breakdown of the Autonomic Nervous System:
1) Sympathetic Nervous System: is the crisis management center.
2) Parasympathetic Nervous System: is in charge of long-term
survival related functions, nutrition and energy conservation.
E. Embryological Development
(1) The Forebrain becomes the cerebrum, cerebral cortex, and other higher
structures. (2) The Midbrain and (3) The Hindbrain become the brainstem.
F. Cerebrum: consists of two separate hemispheres, left and
right, and constitutes the bulk of the forebrain.
G. Corpus Callosum: a thick bundle of axons crossing between
the two hemispheres of the brain enabling them to communicate
with each other.
H. Cerebral Cortex: the outer covering of the forebrain.
The cerebral cortex is comprised of…
I. Gray Matter: the cell bodies of neurons.
(Note: Gray matter is also found within deeper parts of the forebrain.)
J. White Matter: the axons of neurons and constitutes the bulk
of the deeper parts of the forebrain.
K. The Occipital Lobe: is at the rear of the head and contains
many specialized areas for interpreting visual information.
L. The Parietal Lobe: contains…
1) Primary Somatosensory Cortex: the area of the brain that is
specialized for body senses and awareness of the location of body parts.
M. The Temporal Lobes: are located on the sides of the head,
near the ears and are the main processing areas for hearing and
complex aspects of vision.
1) Visual Agnosia: difficulty remembering faces often because they
can’t see the whole face.
N. The Frontal Lobe: contains...
1) Primary Motor Cortex: the area that is important for control of fine
movements.
2) Prefrontal Cortex: is responsible for organization, planning of action,
and aspects of memory.
O. Midbrain: controls many important functions such as the
visual and auditory systems as well as eye movement and
certain aspects of body movement.
P. Hindbrain:
1) The Cerebellum: important for coordination, balance, and timing.
2) Pons: involved in respiration, attention, sleep, and dreaming.
3) Medulla: involved in the regulation of heartbeat and respiration.
4) Pons and Medulla: control the muscles of the head (chewing,
swallowing, etc.).
Q. Reticular Formation: regulates arousal in the brain.
R. Spinal Cord: controls the muscles from the neck down,
including both voluntary responses and reflexes.
1) Reflex: a rapid, automatic response to a stimulus.
VI. Other Structures and Systems
A. Thalamus: sends incoming sensory information to the
appropriate area of the cerebral cortex.
B. The Limbic System: involved in motivated behaviors,
emotional states, memory, body temperature, & blood pressure.
1) Hypothalamus: helps to regulate emotional and motivated behavior
and maintain homeostasis (the body’s internal equilibrium).
2) Amygdala: regulates emotional control and the formation of emotional
memories.
3) Hippocampus: a vital structure for memory acquisition and processing.
C. The Endocrine System: a system of glands that release
hormones into the bloodstream.
1) Hormones: chemicals that affect mood, behavior, and anatomy
(e.g. testosterone “male sex hormone”, estrogen and progesterone
“female sex hormones”).
2) The Pituitary Gland: governed by the hypothalamus, its most primary
function is the secretion of growth hormones responsible for the growth
of muscles, bones, and other glands.
3) The Pineal Gland: secretes the hormone melatonin, which helps
regulate the sleep-wake cycle.
4) The Thyroid Gland: secretes the hormone thyroxin, which affects
the body’s metabolism.
5) The Adrenal Glands: secretes hormones called cortical steroids,
which aid in coping with stress.
VII. Measuring Brain Activity
A. EEGs and MEGs: record electrical and magnetic activity
in the brain.
B. PET: provides a high-resolution picture of brain activity using
radioactivity from chemicals injected into the bloodstream.
C. fMRI: uses magnetic detectors outside the head to measure
the amounts of hemoglobin and oxygen in different areas of the
brain.
VIII. Experience and the Brain
A. Nerve cell generation
B. Learning changes the brain
C. The “binding” problem
D. The split-brain phenomenon