Transcript Chapter 2 - Biological Basis of Behavior

Psychology
Biological Basis of Behavior
Biological Basis of Behavior
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“DNA, by itself, does nothing at all”
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Denis Noble, Genes and Causation
The expression of genotype is completely
dependent on molecular, physiological,
behavioral, and environmental conditions.
The gene is not an infallible unit of heredity,
but rather part of an extremely complex,
reciprocally-determined developmental system
Biological Basis of Behavior
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Heredity and Behavior
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Darwin’s Theory of natural selection has been applied to the
development of species-typical behaviors
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Certain behaviors, that would serve to the survival and
reproduction of the organism would become geneticallydetermined over many generations
This theory, while appealing, is generally frowned upon by
developmental scientists
 The development of species-typical behavior is
determined by the organism’s ontogenetic niche: a
complex system of hierarchically-organized environmental
and biological constraints that an organism would
typically “inherit”
 The ontogenetic niche includes genes, epigenetics,
physical forces (gravity, temperature) and social
experience.
Biological Basis of Behavior
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Genotype: the genetic structure an organism inherits; DNA
Phenotype: The individual organism’s characteristics, resulting
from the interaction between genetics and environment
Epigenenome: a series of molecular mechanisms (methyl
groups and histones) that alter the expression of the genome as
a result of environmental stimuli
 MZ or identical twins, who share 100% DNA, can have vastly
different epigenomes, based on experience, and therefore can
have vastly different developmental outcomes
 Epigenetic tags can be inherited
 Your behavior can effect your epigenome and the
epigenome of your children/grandchildren.
Neurology
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Central Nervous System (CNS): Brain and spinal cord
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Communication
Reflexes
Peripheral Nervous System (PNS): the nerve fibers that
connect the CNS to the rest of the body. The peripheral
nervous system is composed of two subsystems:
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Autonomic Nervous System: regulates basic life processes
and survival; unconscious; responds to threats (fight or
flight)
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Sympathetic division: EMERGENCY!!
Parasympathetic: routine, homeostasis
Somatic Nervous System: regulates conscious actions of
skeletal muscle
Neurology
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Sensory Neuron: carry messages from sense receptor cells toward the
CNS
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There are different kinds of sensory neurons specializing in different senses
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Photoreceptors
Chemoreceptors
Nociceptors
Ect…
Motor Neuron: carry messages from the CNS to muscles and glands
Interneuron: part of the intermediate network between sensory,
motor, and other interneurons.
Mirror Neurons*: a neuron that responds when an individual observes
another performing a motor action or experiencing a sensation, has
implications for social imitation and empathy; only observed in nonhuman primates.
Glia cell: “support cells” or scaffolding for neurons
Neurology
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Plasticity: The malleability of neural
structures in response to experience.
Neurology
http://www.youtube.com/watch?v=TKG0MtH5crc
Neurology
Neurology
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Neurotransmitters: chemical messengers from one neuron
to the next
 Influenced by stimuli, behavior, and drugs
 Problems occur when there is too much or too little
Neurology
Common Neurotransmitters
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Acetylcholine: skeletal muscles, attention, memory
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Dopamine: voluntary movement, “reward system”
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Norepinephrine: mood and arousal
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Serotonin: sleep & wake cycle, aggression
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GABA:regulation of anxiety
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Glutamate: learning and memory
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Endorphins*: pain relief and stress response
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Oxytocin*: social bonding
Brain Imaging
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PET (positron emission tomography)
CAT or CT (computerized axial tomography)
EEG (electroencephalogram)
MRI (magnetic resonance imaging)
fMRI (functional magnetic resonance imaging)
Brain Imaging: Your Professor’s Brain!
Neuroanatomy: Brain Stem
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Medulla: regulates
breathing, blood
pressure, and
heartbeat
Pons: “bridge”
between spinal cord
and brain; regulates
sleep
Thalamus: relays
sensory information
Neuroanatomy: Limbic System
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Hippocampus: explicit
memory
Amygdala: emotion,
aggression, fear, and
related memories
Hypothalamus: motivated
behavior and homeostasis
Olfactory Bulb: smells
Neuroanatomy: The BRAINS (Cortex)!!
Neuroanatomy: BRAINS!!
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Cerebrum: the region of the brain that
controls higher cognitive and emotional
processes (the brain-looking part). Divided
into left and right hemispheres:
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Left and right hemispheres are connected by the
corpus collosum, anterior and posterior
commissures.
Cerebral cortex: the outer surface of the brain
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Sulci: the trenches in the cortex
Gyri: the folds of the cortex
Cerebellum: attached to the brainstem and
controls motor coordination, posture, and
balance
More BRAINS!!
http://www.youtube.com/watch?v=jHxyP-nUhUY
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The sensory and motor cortex strips are bilateral,
with the left hemisphere controlling the right side
of the body, and the right hemisphere controlling
the left side of the body
The sensory and motor cortex strips allocate
space based on complexity and sensitivity
“Split Brain” Patients
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http://www.youtube.com/watch?v=ZMLzP1VCANo
Endocrine System & Behavior
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The endocrine system uses hormones to
supplement the work of the nervous system
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The endocrine system regulates metabolism, and
influences body growth, mood, and sexual
characteristics
Pituitary: the “Master Gland” in the brain that
regulates the endocrine system
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Endocrine glands include:
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Thyroid
Adrenals
Pancreas
Ovaries
Testes
Take Away
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The brain is super complicated!
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No one spot is “in charge” of any
process; it’s all about the connections
and interactions between areas
Experience effects neurology and
neurology effects experience
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Either chemical (drugs) or environmental
(behavior) can break and change the
entire cycle