Basiskennis;
Psychological Science, Gazzangia M.S. (6e Editie)
Chapter 3; Biology and behavior
3.1
Two basic units of the nervous system:
- Central nervous system (CNS); brain, spinal cord
- Peripheral nervous system (PNS); other nerve cells throughout the body
o Somatic component of the PNSà responsible for voluntary actions; picking up a pen
o Autonomic component of the PNS à responsible for involuntary actions; heartbeat
Neurons; basic units of the nervous system. They form connections with other neurons throughout the
body, forming circuits = Neural networks
Nerves are powered by electrical impulses and communicate with other nerve cells through chemical
signals from neighboring neurons.
Types of neurons:
- Sensory neurons: detect information from the physical world and pass that information along to
the brain.
The sensory neurons are connected to the somatosensory nerves in the skin and in the muscles
- Motor neurons: direct muscles to contract or relax thereby producing movement
- Interneurons: neurons between the sensory neurons and the motor neurons. They lie in the CNS
3.2
Neuronal structure
Messages are received by
the dendrites, processed
in the cell body,
transmitted along the
axon, and sent to other
neurons via chemical
substances released from
the terminal buttons
across the synapse.
The outer surface of a
neuron is the membrane
= semipermeable
The myelin sheath is a
fatty material, made up of
glia cells, that insulates
some axons to allow for
faster movement of
electrical impulses along
,the axon. The nodes of Ranvier (gaps between myelin sheath) is where the action potentials take place.
Without myelin, sodium channels along each part f the membrane must open.
Action potential/ neural firing = the electric signal that passes along the axon. It causes the terminal
buttons to release chemicals that transmit signals to other neurons.
Resting membrane potential = the electrical charge of a neuron when it is not active.
The difference in electrical charge between the inside and the outside of a neural membrane, when a
neuron is not active, is about -70mV
Possible chemical signals
from nearby neurons are
of two types:
- Excitatory;
increases
depolarization
- Inhibitory;
Decreases
depolarization
If the total amount of
excitatory input
surpasses the neuron’s
firing threshold (-55 mV),
and an action potential is
generated = an electrical
ripple that travels down
the axon like a wave.
When the action potential is generated, the sodium gates (Na+) open, sodium rushes into the neuron,
causing the inside of a neuron to become slightly more positively charged than the outside
(depolarization). The neuron responses by restoring the electrical charge by opening up the potassium
gates (K+) (repolarization). The sodium-potassium pump then gets the potassium back in and the sodium
back out of the neuron, returning the charge to it’s slightly negative resting state.
All or nothing principle = the principle that when a neuron fires, it fires with the same potency each
time; a neuron either fires or not- it cannot partially fire, although the frequency of the firing can vary,
which determines the strength of the stimulation.
3.3.
Receptors = in neurons, specialized protein molecules on the postsynaptic membrane; a
neurotransmitter bind to these molecules after passing across the synapse. Each receptor can be
influenced by only one type of neurotransmitter.
Three major events that terminate the neurotransmitter’s influence in the synapse are:
- Reuptake; a neurotransmitter is taken back into the presynaptic terminal buttons.
- Enzyme deactivation; occurs when an enzyme destroys the neurotransmitter in the synapse.
, - Autoreception; neurotranmitters bind with receptors on the presynaptic membrane.
Autosynaptors monitor how much neurotransmitter have been released into the synapse. When
an excess is detected, the autoreceptor signals the presynaptic neuron to stop releasing the
neurotransmitter
Agonist = Drugs and toxins that enhance the actions of neurotransmitters
Antagonist = Drugs and toxins that inhibit the actions of neurotransmitters
Important types of neurotransmitters:
Acetylcholine; motor control, muscles relax or contract. Learning, memory,
sleep, dreaming
Norepinephrine; arousal, attention, alertness
Monoamines Serotonin; emotional states, impulse control, dreaming
Dopamine; motivation, reward,
GABA (gamma-aminobutyric acid); inhibitory effect that keeps synaptic
excitation in control.
Glutamate; primary excitatory transmitter in the nervous system. Fast acting
neural transmissions, learning, memory
Endorphins (endogenous morphine); pain reduction and reward
3.4
Phrenology = the practice in which was believed that one could determine someone’s most active brain
regions and therefore their personality by feeling the bumps one their skull.
Broca’s area = a small portion of the left frontal region of the brain, crucial for the production of
language. (named after the discoverer of this brain area’s function)
, Psychologists collect data about the ways people physically respond to particular tasks or events.
Measurements used for collecting the data are so called psychophysiological assessments.
Examples of Psychophysiological assessments are:
- Polygraph test; lie detector. Measures one’s state of arousal
- Electroencephalograph (EEG). Measures someone’s brain activity by placing electrodes on the
scalp. EEG’s are not very specific and not able to isolate specific responses to particular stimuli.
To examine the brain’s response to a stimulus, scientist often use event related potential (ERP).
- Positron emission tomography (PET): a harmless radioactive substance in injected into the
bloodstream. The blood travels to the most active brain regions. A pet scan can therefore locate
de regions most involved in a specific stimulus.
- Magnetic Resonance imaging (MRI): a powerful electric field shortly disrupts the brain’s
magnetic forces. The energy (different for every type of brain tissue) released during this
process is measured and produces a high quality image of the brain.
- Functional magnetic resonance imaging (fMRI): maps mental activity by assessing changes in the
blood’s oxygen level in the brain.
- Transcranial magnetic stimulation (TMS): uses a very fast but powerful magnetic field to disrupt
brain activity momentarily in a specific brain region.
3.5
Main function spinal cord: carry sensory information up to the brain and carry motor signals from the
brain to the body.
Two distinct types of tissue:
- Gray matter; dominated by neuron’s cell bodies.
- White matter; dominated by axons and the myelin sheaths that surround them.
The spinal cord thickens and becomes more complex as it transforms into the brain stem.
Brain stem (reptile brain): responsible for the basic functions of survival & reflexes
- Medulla oblongata
- Pons
- Midbrain
The brain stem also contains a network of neurons which is collectively known as the reticular formation
Reticular formation: sleep and arousal.
Cerebellum: lays at the back of the brain stem and is
responsible for proper motor function (motor learning
and motor memory).
Psychological Science, Gazzangia M.S. (6e Editie)
Chapter 3; Biology and behavior
3.1
Two basic units of the nervous system:
- Central nervous system (CNS); brain, spinal cord
- Peripheral nervous system (PNS); other nerve cells throughout the body
o Somatic component of the PNSà responsible for voluntary actions; picking up a pen
o Autonomic component of the PNS à responsible for involuntary actions; heartbeat
Neurons; basic units of the nervous system. They form connections with other neurons throughout the
body, forming circuits = Neural networks
Nerves are powered by electrical impulses and communicate with other nerve cells through chemical
signals from neighboring neurons.
Types of neurons:
- Sensory neurons: detect information from the physical world and pass that information along to
the brain.
The sensory neurons are connected to the somatosensory nerves in the skin and in the muscles
- Motor neurons: direct muscles to contract or relax thereby producing movement
- Interneurons: neurons between the sensory neurons and the motor neurons. They lie in the CNS
3.2
Neuronal structure
Messages are received by
the dendrites, processed
in the cell body,
transmitted along the
axon, and sent to other
neurons via chemical
substances released from
the terminal buttons
across the synapse.
The outer surface of a
neuron is the membrane
= semipermeable
The myelin sheath is a
fatty material, made up of
glia cells, that insulates
some axons to allow for
faster movement of
electrical impulses along
,the axon. The nodes of Ranvier (gaps between myelin sheath) is where the action potentials take place.
Without myelin, sodium channels along each part f the membrane must open.
Action potential/ neural firing = the electric signal that passes along the axon. It causes the terminal
buttons to release chemicals that transmit signals to other neurons.
Resting membrane potential = the electrical charge of a neuron when it is not active.
The difference in electrical charge between the inside and the outside of a neural membrane, when a
neuron is not active, is about -70mV
Possible chemical signals
from nearby neurons are
of two types:
- Excitatory;
increases
depolarization
- Inhibitory;
Decreases
depolarization
If the total amount of
excitatory input
surpasses the neuron’s
firing threshold (-55 mV),
and an action potential is
generated = an electrical
ripple that travels down
the axon like a wave.
When the action potential is generated, the sodium gates (Na+) open, sodium rushes into the neuron,
causing the inside of a neuron to become slightly more positively charged than the outside
(depolarization). The neuron responses by restoring the electrical charge by opening up the potassium
gates (K+) (repolarization). The sodium-potassium pump then gets the potassium back in and the sodium
back out of the neuron, returning the charge to it’s slightly negative resting state.
All or nothing principle = the principle that when a neuron fires, it fires with the same potency each
time; a neuron either fires or not- it cannot partially fire, although the frequency of the firing can vary,
which determines the strength of the stimulation.
3.3.
Receptors = in neurons, specialized protein molecules on the postsynaptic membrane; a
neurotransmitter bind to these molecules after passing across the synapse. Each receptor can be
influenced by only one type of neurotransmitter.
Three major events that terminate the neurotransmitter’s influence in the synapse are:
- Reuptake; a neurotransmitter is taken back into the presynaptic terminal buttons.
- Enzyme deactivation; occurs when an enzyme destroys the neurotransmitter in the synapse.
, - Autoreception; neurotranmitters bind with receptors on the presynaptic membrane.
Autosynaptors monitor how much neurotransmitter have been released into the synapse. When
an excess is detected, the autoreceptor signals the presynaptic neuron to stop releasing the
neurotransmitter
Agonist = Drugs and toxins that enhance the actions of neurotransmitters
Antagonist = Drugs and toxins that inhibit the actions of neurotransmitters
Important types of neurotransmitters:
Acetylcholine; motor control, muscles relax or contract. Learning, memory,
sleep, dreaming
Norepinephrine; arousal, attention, alertness
Monoamines Serotonin; emotional states, impulse control, dreaming
Dopamine; motivation, reward,
GABA (gamma-aminobutyric acid); inhibitory effect that keeps synaptic
excitation in control.
Glutamate; primary excitatory transmitter in the nervous system. Fast acting
neural transmissions, learning, memory
Endorphins (endogenous morphine); pain reduction and reward
3.4
Phrenology = the practice in which was believed that one could determine someone’s most active brain
regions and therefore their personality by feeling the bumps one their skull.
Broca’s area = a small portion of the left frontal region of the brain, crucial for the production of
language. (named after the discoverer of this brain area’s function)
, Psychologists collect data about the ways people physically respond to particular tasks or events.
Measurements used for collecting the data are so called psychophysiological assessments.
Examples of Psychophysiological assessments are:
- Polygraph test; lie detector. Measures one’s state of arousal
- Electroencephalograph (EEG). Measures someone’s brain activity by placing electrodes on the
scalp. EEG’s are not very specific and not able to isolate specific responses to particular stimuli.
To examine the brain’s response to a stimulus, scientist often use event related potential (ERP).
- Positron emission tomography (PET): a harmless radioactive substance in injected into the
bloodstream. The blood travels to the most active brain regions. A pet scan can therefore locate
de regions most involved in a specific stimulus.
- Magnetic Resonance imaging (MRI): a powerful electric field shortly disrupts the brain’s
magnetic forces. The energy (different for every type of brain tissue) released during this
process is measured and produces a high quality image of the brain.
- Functional magnetic resonance imaging (fMRI): maps mental activity by assessing changes in the
blood’s oxygen level in the brain.
- Transcranial magnetic stimulation (TMS): uses a very fast but powerful magnetic field to disrupt
brain activity momentarily in a specific brain region.
3.5
Main function spinal cord: carry sensory information up to the brain and carry motor signals from the
brain to the body.
Two distinct types of tissue:
- Gray matter; dominated by neuron’s cell bodies.
- White matter; dominated by axons and the myelin sheaths that surround them.
The spinal cord thickens and becomes more complex as it transforms into the brain stem.
Brain stem (reptile brain): responsible for the basic functions of survival & reflexes
- Medulla oblongata
- Pons
- Midbrain
The brain stem also contains a network of neurons which is collectively known as the reticular formation
Reticular formation: sleep and arousal.
Cerebellum: lays at the back of the brain stem and is
responsible for proper motor function (motor learning
and motor memory).
