Transcript Biological Bases of Behavior

Laurel McKay
Period 1
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EEG- measures changes in brain electrical activity, can
allow for localization of functions in the brain
CAT Scans-make cross-sectional images of the brain
MRI- similar to a CAT scan but generates more detailed
pictures of the brain
Functional MRI’s and PET Scans allow scientists to
view the brain as it is working, uses a diffusion of
radioactive glucose in the brain to highlight the point of
interest
PET Scan
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Central Nervous System: brain & spinal cord
Peripheral Nervous System: all other nerves
Brain= central processing center for thoughts, motivations &
emotions (made up of neurons)
In the spinal cord neurons are bundled together into nerves
Afferents=nerves sending info to the brain
Efferents=nerves conveying info from the brain
Most movements are controlled by the brain but some are
controlled by transmission from afferent to efferent cells
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The Peripheral Nervous System can be divided into:
- Somatic Nervous System
-Autonomic Nervous System
Somatic: responsible for voluntary movement of large
skeletal muscles
Autonomic: controls the nonskeletal or smooth muscles
(ex: in the heart and digestive tract)
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Autonomic Nervous
System divides into:
◦ Sympathetic Nervous System
◦ Parasympathetic Nervous System
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Sympathetic: associated
with processes that burn
energy, fight or flight
reaction
Parasympathetic:
associated with
conserving energy
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Brain’s 3 regions: Forebrain, Midbrain, Hindbrain
Forebrain= limbic system, hypothalamus, thalamus &
cerebral cortex
Limbic System: area of the brain involved in learning,
emotion, and memory, includes the hippocampus
(learning and memory formation), the amygdala (used
when angry) , and the septum (used when fearful)
Hypothalamus: controls the temperature and water
balance of the body & the ANS & the endocrine system
Thalamus: gateway for sensory input to the brain
Cerebral Cortex: outer layer of the brain, used in higher
cognitive functions (thinking, language use, etc.)
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Midbrain=reticular
activating system
(consciousness, attention,
wakefulness), processes
sensory input
The midbrain, hindbrain,
thalamus & hypothalamus
form the brain stem
(junction between the brain
& spinal cord)
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Hindbrain=cerebellum, medulla oblongata & pons
Cerebellum: controls muscle tone and balance
Medulla Oblongata: controls heart rate, swallowing,
breathing, and digestion
Pons: passes info from one brain to another
Cerebral Cortex: covers the outer surface of the brain
Corpus Callosum: a band of nerves that joins together
the two halves of the brain
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Frontal Lobe: higher level thought and reasoning,
contains the primary motor cortex
Parietal Lobe: somatosensory info, contains the
primary somatosensory cortex (temp., pressure, texture
and pain)
Temporal Lobe: auditory input
Occipital Lobe: visual input
Apraxia: inability to organize movement
Agnosia: inability to process sensory input
Alexia: the inability to read
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Nerves=bundles of neurons
Soma= cell body
Dendrites=branch out from the
soma
Axon=a long, tube-like
structure that responds to input
from dendrites and soma
Myelin Sheath=fatty coating
around the axon
Terminal buttons=knobs on the
branched end of the axon
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Resting potential: the electrical charge of a neuron at rest
Once the electrical charge reaches minus 50 millivolts the
neuron will be ready to fire which leads to…
Action Potential: the nerve impulse/ sending the message
During action potential the axon membrane is pierced by ion
channels, then sodium ions rush into the axon
After the impulse there is a negative after-potential (a drop in
electrical charge below the resting potential)
Neurotransmitters: chemical messengers that cross the synapse
(ex: acetylcholine, serotonin, dopamine)
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Relays info from one part of the body to another using
glands that release hormones
Pituitary Gland: master gland, releases hormones to
other glands, controlled by the hypothalamus
Adrenal gland secretes epinephrine (adrenaline) and
norepinephrine (noradrenaline)
Thyroid Gland: at the front of the neck, regulates
metabolism
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The application of principles of evolutionary theory to
the study of behavior
Traits: distinctive characteristics or behavior patterns
that are determined by genetics
A dominant trait is more likely to be expressed in
offspring than a recessive trait
The environment influences us too
Nature vs. Nurture debate
Genetic Abnormalities cause disorders such as Down’s
Syndrome (a break in the 21st chromosome)