Download Neurotransmitters: Acetylcholine (Ach) transmitter plays a role in

Unit 3 – Biological Basis of Behavior
Localization of functions – the idea that various brain
regions have particular functions.
Biological Psychology – the scientific study of the links
between biological (genetic, neural, hormonal) and
psychological processes.
Ions – electrically charged atoms are exchanged.
 The fluid outside an axon’s membrane has
mostly (+) positively charged ions.
 A resting axon’s fluid interior mostly has (-)
negatively charged ions.
This positive outside / negative inside state is called the
resting potential.
An axon’s surface is selectively permeable  Sodium ions cause a chain (domino) reaction that
depolarizes sections. (positively charged sodium
ions flood the cell membrane).
Neurons: are our body’s building blocks.
Dendrite fibers – receive information from other cells and
conduct it towards the cell body.
Axon – the neuron extension that passes messages through
its branches to other neuron, muscles, or glands.
* Dendrites Listen, Axons Speak *
Myelin Sheath – a layer of fatty tissue that covers the axon of
some neurons and helps speed neural impulses.
Terminal branches of axon – form junctions with other cells.
Cell body – the cell’s life-support center.
Synapse – the space between the terminal branches of one
neuron and the dendrites of the next neuron.
Neurotransmitters –the release of chemical messengers.
Reuptake- when the sending neurons reabsorb the excess
neurotransmitters.
Refractory period – a period of inactivity after a neuron
has fired.
 Excitatory – excite the next cell into firing.
 Inhibitory – inhibit the next cell from firing.
If excitatory signals exceed inhibitory signals the combined
signals trigger an action potential.
Threshold – the level of stimulation required to trigger a
neural impulse.
*Increasing the level of stimulation above the threshold will
NOT increase the neural impulse’s intensity. *
How a Neuron Fires…
Action Potential – a neural impulse; a brief electrical
charge that travels down an axon.
 Neurons fire these impulses in responses to
senses or other neurons.
A neurons reaction is an all-or-none response (neurons
either fire or they don’t)
*A strong stimulus can trigger more neurons to fire, and to
fire more often…But it does not affect the action potentials
strength or speed*
Neurotransmitters:
 Acetylcholine (Ach) transmitter plays a role in learning
and memory.
 Endorphins – natural opiate, like neurotransmitters
linked to pain control and pleasure.
Drugs and other chemicals affect brain chemistry at synapses,
by either exciting or inhibiting neurons to fire.
 Agonist – a molecule that, by binding to a receptor
site, stimulates a response (mimics effect).
 Antagonists – binds to a receptor but its effect instead
blocks a neurotransmitter function.
Nervous System: the body’s speedy, electrochemical
communication network, consisting of all the nerve cells of
the peripheral and central nervous system.
Central Nervous System (CNS) – consists of the brain and
the spinal cord. The body’s decision maker.
Peripheral Nervous System (PNS) – is responsible for
gathering information and for transmitting CNS decisions to
other body parts.
Information travels to the nervous system through three
different
types of neurons….
 Afferent Neurons (Sensory Neurons) – carry
messages from the body’s tissues and sensory
receptors inward to the brain and spinal cord for
processing.
 Motor Neurons – carry instructions from the central
nervous system out to the body’s muscles and glands.
 Interneurons – between the sensory input and motor
output, information is processed in the brains internal
communications system.
Endocrine System: the body’s “slow” chemical
communication system
 a set of glands that secretes hormones into the
bloodstream. (Influences our interest in sex, food, and
aggression).
 Adrenaline Glands: fight-or-flight
 Pituitary Gland: releases a growth hormone that
stimulates physical development
*The nervous system is faster than the endocrine system*
*Endocrine messages tend to outlast the effects of neural
messages*
Lesion – destroy tiny clusters of brain cells,
leaving the surrounding tissue unharmed.
 Electroencephalogram (EEG) – amplified
recording of the waves of electrical activity
sweeping across brains surface.
 CT Scan (Computer Tomography) –
examines the brain by taking x-ray
photographs that can reveal brain damage.
 PET (position emission tomography scan) –
depicts brain activity by showing each
brain’s areas consumption of its chemical
fuel.
 MRI (Magnetic resonance imaging) – show
brain anatomy.
 fMRI (functional MRI) – can reveal the
brains functioning as well as its structure.
Reticular Formation – enables arousal.
Hypothalamus: Reward center
Lateral Hypothalamus = Launch “hunger messages”
Ventromedial Hypothalamus= vomit “you’ve had
enough”
The Limbic System: lies between the oldest and newest brain areas.
Structure of the Cortex:
Cerebral Hemisphere – the two halfs of the brain.
Cerebral Cortex – interconnected neural cells covering
the cerebral hemispheres. (Higher level functioning).
Glial Cells (glue cells) – support, nourish, and protect
neurons, along with playing a role in learning and
thinking.
*Each hemisphere cortex is subdivided into four lobes*
Frontal Lobes – involved in speaking and muscle
movements, and making plans and judgments.
Parietal Lobes – portion of brain that receives sensory
input for touch and body position.
Occipital Lobes – includes areas that receive
information from the visual fields.
Temporal Lobes – each receiving information primarily
from the opposite ear.
Broca’s area = speaking
Wernicke’s area = understanding
Motor Cortex – an area at the rear of the frontal loves that
controls voluntary movements.
Somatosensory Cortex – an area at the front of the parietal loves
that registers and processes body touch and movement
sensations.
Prefrontal Cortex – in the forward part of the frontal loves
enables judgment, planning, and processing of new memories.
Association Areas – are involved in higher mental functions
such as learning, remembering, thinking, and speaking.
Plasticity – the brain’s ability to modify itself after damage.
1. Severed neurons usually don’t regenerate.
2. Some brain functions seem pre-assigned to specific
areas.
3. Some of the brain’s tissue can reorganize.
Neurogenesis – formation of new neurons.
Consciousness – our awareness of ourselves and our environment.
Cognitive Neuroscience – the interdisciplinary study of the brain activity linked with our mental processes.
 Stronger Stimulus involved with language, attention, and memory.
 Weaker Stimulus may trigger localized visual cortex activity that quickly dies out.
Dual Processing – the principle that information is often simultaneously processed on separate conscious and
unconscious tracks.
*Our unconscious parallel processing is faster than sequential conscious processing *
Corpus Callosum – the large band of neural fibers connecting the two brain hemispheres
and carrying messages between them.
Split brain – a condition resulting from surgery that isolates the brain’s two hemispheres by
cutting the fibers connecting them.
*Information from the left half of your field of vision goes to your right hemisphere and
information from your right half goes to your left hemisphere *
Increased activity in Right Hemisphere = blood flow, brain waves, glucose consumption.
 Excels in making inferences
 Helps us modulate our speech
 Helps orchestrate our sense of self
Increased activity in Left Hemisphere = when speaking or calculating.
 Makes quick, literal interpretations of language.
Genes: our codes for life.
Behavior geneticists – the study of the
relative powers and limits of genetic and
environmental influences on behavior.
Environment – every external influence.
Chromosomes – threadlike structures
made of DNA molecules that contain the
genes.
Genes can be with active (expressed /
can physically see the trait) or inactive.
Genome – genetic makeup, the complete
instructions for making an organism.
Phenotype – biochemical characteristics
determined by both genetic makeup and
environmental influences.
*Our genetic predisposition- our
genetically influenced traits- help to
explain both our shared human nature
and our human diversity *
Identical Twins (monozygotic) –
develop from a single fertile egg that
splits into two genetically identical.
Fraternal Twins (dizygotic) – develop
from separate fertilized eggs  they
are genetically no closer than brother
and sister that share a fetal
environment.
Thomas Bouchard – was in charge of
the separated twin studies.
Biological vs. Adoptive Parents
Molecular Genetics – studies the
molecular structure and function of
genes and how they influence behavior.
Heritability – the extent to which
variation among individuals can be
attributed to their differing genes.
*Genes are self-regulating *
Interaction – the interplay that occurs
when the effect of one factor
(environment) depends on another
factor (heredity).
 Gender Differences in Sexuality
 Mating Preferences
 Nature vs. Nurture
*Genes are all pervasive but not all
powerful* *
*Although genes have the
potential to influence
development, environment
triggers can switch them on or off
*
Evolutionary psychologists –
focus on what makes us so much
alike.
\
Natural Selection and Adaptation
*Our behavioral and biological
similarities arise from our shared
human genome *
*Differences initiated by our
nature may be amplified by our
nature *
*We are predisposed to behave
in ways that promoted our
ancestor’s surviving and
reproducing *