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Science Brain and Behavior contiuned 15

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eyes closed, the rhythmical brain waves shown in Figure 4-25B often emerge. These
alpha rhythms are extremely regular, with a frequency of approximately 11 cycles per
second and amplitudes that wax and wane as the pattern is recorded. In humans,
alpha rhythms are generated in the region of the visual cortex at the back of the brain.
If a relaxed person is disturbed or opens his or her eyes, the alpha rhythms abruptly
stop.
Not everyone displays alpha rhythms, and some people display them much better
than others. You can buy a little voltmeter for monitoring your own alpha rhythms. A
lead from one pole of the voltmeter is attached to the skull with a paste that conducts
an electrical current, and the reference wire is pasted to the ear lobe.You can then relax
with eyes closed, trying to make the voltmeter “beep.” Each wave of the alpha rhythm,
if sufficiently large, produces a beep.Many people can quickly learn to turn alpha waves
on and off by using this procedure. A generation ago, beeping EEG voltmeters were
promoted as a way of quickly learning how to reach a meditative state.
The EEG is a sensitive indicator of behaviors beyond simple arousal and relaxation.
Figure 4-25C through E illustrates EEG changes as a person goes from drowsiness to
sleep and finally into deep sleep. EEG rhythms become progressively less frequent and
larger in amplitude. Still slower waves appear during anesthesia, after brain trauma, or
when a person is in a coma (illustrated in Figure 4-25F). In brain death, the EEG becomes
a flat line.
These distinctive brain-wave patterns make the EEG a reliable tool for monitoring
sleep stages, estimating the depth of anesthesia, evaluating the severity of head injury,
and searching for other brain abnormalities. The brief periods of unconsciousness and
involuntary movements that characterize epileptic seizures, described at the beginning
of this chapter, are associated with very abnormal spike-and-wave patterns in the EEG.
The important point here is that EEG recording provides a useful tool both for research
and for diagnosing brain abnormalities.
An EEG measures the summed graded potentials from many thousands of neurons.
Neurons of the neocortex provide an especially good source of EEG waves
because these cells are lined up in layers and have a propensity to produce graded potentials
in a rhythmical fashion. EEG waves are usually recorded with a special kind of
oscilloscope called a polygraph (meaning “many graphs”), illustrated in Figure 4-26.
Each channel on a polygraph is equivalent to one oscilloscope. Instead of measuring
electrical activity with a beam of electrons, the polygraph electrodes are connected
to magnets, which are in turn connected to pens. A motor pulls a long sheet of paper
at a constant rate beneath the pens, allowing the patterns of electrical activity to
be written on the paper. Because the graded potentials being measured have quite low
HOW DO NEURONS TRANSMIT INFORMATION? ! 141
Time (s)
(A) Awake or excited
(B) Relaxed, eyes closed, alpha rhythms generated
Time (s)
(C) Drowsy—slowed frequency, increased-amplitude waves (D) Asleep—slower, higher-amplitude waves
1 2 3 4 5 6 7
(F) (E) Deep sleep—even slower and higher-amplitude waves Coma—further slowing
1 2 3 4 5 6 7
Figure 4-25
Characteristic EEG Recordings
Wave patterns reflect different states
of consciousness in humans. Adapted from
Epilepsy and the Functional Anatomy of the
Human Brain (p. 12), by W. Penfield and H. H.
Jasper, 1954, Boston: Little, Brown.
Alpha rhythm. Rhythmical EEG wave
with a frequency of 11 cycles per second.
On the Foundations CD, find the EEG
section in the module on research
methods. Here you can review the model
of an electroencephalograph described
on page 115 (margin note).
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142 ! CHAPTER 4
Event-related potential (ERP). Brief
change in slow-wave brain activity in
response to a sensory stimulus.
frequencies, the pens can keep up with them. To read this record, the experimenter simply
observes its changing patterns.
Recently, computers have been programmed to read EEG waves.Many channels of
EEG activity are fed into the computer, which then matches active areas with specific
regions of the brain. The computer screen can display a representation of the brain,
with changes in color representing brain activity.
Because the EEG is recorded as a subject is engaged in some behavior or problemsolving
activity, the computer display can show an on-line display of brain activity in
real time. The computer-assisted analysis is useful for finding how the brain processes
sensory information, solves problems, and makes decisions. It is also useful in clinical
diagnosis—for example, for charting the progress of abnormal electrical activity associated
with epilepsy.
Miniaturized computer-based polygraphs about the size of an audiocassette recorder
can be worn on a belt. They store the EEG record of a freely moving person for
later replay on a chart polygraph or computer. One possible future use of miniaturized
EEG recording devices is to enable brain-wave patterns to control the cursor on a computer.
This technology would be very helpful to people who are paralyzed. If they could
learn to control their EEGs sufficiently to command a cursor, they would be able to use
the computer to communicate with others.
Event-Related Potentials
Brief changes in an EEG signal in response to a discrete sensory stimulus are called
event-related potentials (ERPs), which are largely the graded potentials on dendrites
that a sensory stimulus triggers.You might think that they should be easy to detect, but
they are not. The problem is that ERPs are mixed in with so many other electrical signals
in the brain that they are difficult to spot just by visually inspecting an EEG record.
One way to detect ERPs is to produce the stimulus repeatedly and average the recorded
responses. Averaging tends to cancel out any irregular and unrelated electrical activity,
leaving in the EEG record only the potentials that the stimulus generated.
To clarify this procedure, imagine throwing a small stone into a lake of choppy
water.Although the stone produces a splash, that splash is hard to see among all the ripples
and waves. This splash made by a stone is analogous to an event-related potential
caused by a sensory stimulus. Like the splash surrounded by choppy water, the ERP is
hard to detect because of all the other electrical activity around it.A solution is to throw
Polygraph pen recorder
Pen
Electrodes
Electrodes are attached to
the skull, corresponding to
specific areas of the brain.
1
Polygraph electrodes are
connected to magnets, which
are connected to pens...
2
...that produce a paper
record of electrical activity
in the brain. This record
indicates a relaxed person.
3
Figure 4-26
Polygraph Recording EEG
A simple method for recording
electrical activity of the human
brain.
Michael Rosenfeld/Stone Images
SIU/Photo Researchers
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HOW DO NEURONS TRANSMIT INFORMATION? ! 143
a number of stones exactly the same size, always
hitting the same spot in the water and producing
the same splash over and over. If a computer is
then used to calculate an average of the water’s activity,
random wave movements will tend to average
one another out, and you will see the splashes
produced by the stones as clearly as if a single
stone had been thrown into a pool of calm water.
Figure 4-27 shows an ERP record (top) that
results when a person hears a tone.Notice that the
EEG record is very irregular when the tone is first
presented. But, after averaging over 100 stimulus
presentations, a distinctive wave pattern appears,
as shown in the bottom panel of Figure 4-27. This
ERP pattern consists of a number of negative (N)
and positive (P) waves that occur over a period of
a few hundred milliseconds after the stimulus.
The waves are numbered in relation to the
time at which they occur. For instance, in Figure
4-27, N1 is a negative wave occurring about 100
ms after the stimulus, whereas P2 is a positive
wave occurring about 200 ms after the stimulus.
Not all these waves are unique to this particular
stimulus. Some are common to any auditory
stimulus that might be presented. Other waves,
however, correspond to important differences in
this specific tone. ERPs to spoken words even contain distinctive peaks and patterns
that differentiate such similar words as “cat” and “rat.”
Among the many practical reasons for using ERPs to study the brain, one advantage
is that the technique is noninvasive. Electrodes are placed on the surface of the
skull, not into the brain. Therefore, ERPs can be used to study humans, including college
students—the most frequently used subjects.
Another advantage is cost. In comparison with other techniques, such as brain scans,
ERPs are inexpensive.Additionally,with modern technology, ERPs can be recorded from
many brain areas simultaneously, by pasting an array of electrodes (sometimes more
than 100) onto different parts of the skull. Because certain brain areas respond only
to certain kinds of sensory stimuli (e.g., auditory areas respond to sounds and visual
areas to sights), the relative responses at different locations can be used to map brain
function.
Figure 4-28 shows a multiple-recording method that uses 64 electrodes simultaneously
to detect ERPs at many cortical sites. Computerized averaging techniques reduce
the masses of information obtained to simpler comparisons between electrode
sites. For example, if the focus of interest is P2, the computer can display a graph of the
skull showing only the amplitude of P2. A computer can also convert the averages at
different sites into a color code, creating a graphic representation that shows the brain
regions that are most responsive.
ERPs can be used not only to detect which areas of the brain are processing particular
stimuli but also to study the order in which different regions play a role. This
second use of ERPs is important because, as information travels through the brain, we
want to know the route that it takes on its journey. In Figure 4-28, the subject is viewing
a picture of a rat that appears repeatedly in the same place on a computer screen.
Figure 4-27
Detecting ERPs In the averaging
process for an auditory ERP, a tone is
presented at time 0, and EEG activity in
response is recorded. After many
successive presentations of the tone, the
averaged EEG wave sequence develops a
distinctive shape that becomes extremely
clear after averaging 100 responses, as
shown in the bottom panel. Positive (P1
and P2) and negative (N1) waves that
appear at different times after the
stimulus presentation are used for
analysis.
0
100
50
10
1
100 200 300 400
Time (ms)
Tone
First response
Average of
10 responses
Number of tone presentations
Average of
50 responses
Average of
100 responses
P2
N1
P1
For more information on ERPs, visit
the Brain and Behavior Web site and go
to the Chapter 4 Web links.
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The P2 recorded on the posterior right side of the head is larger than P2 occurring anywhere
else, meaning that this region is a “hot spot” for processing the visual stimulus.
Presumably, for this particular subject, the right posterior part of the brain is central
in decoding the picture of the rat 200 ms after it is presented.
Many other interesting research areas can be investigated with the use of ERPs.
They can be used to study how children learn and process information differently as
they mature. They can also be used to examine how a person with a brain injury compensates
for the impairment by using other, undamaged regions of the brain. ERPs can
even help reveal which brain areas are most sensitive to the aging process and therefore
contribute most to declines in behavioral functions among the elderly. All these areas
can be addressed with this simple, inexpensive research tool.
SUMMARY
What two kinds of research provided early clues that electrical activity is somehow implicated
in the nervous system’s flow of information? The two kinds of research that provided
these early clues were electrical-stimulation studies and electrical-recording
studies. The results of early electrical-stimulation studies, which date as far back as the
eighteenth century, showed that stimulating a nerve with electrical current sometimes
In Review .
Neuroscientists use three major techniques to study the brain’s electrical activity. Singlecell
recording monitors a single neuron. Many hundreds of single-cell studies have been
conducted to determine what the firing patterns of particular neurons are and what stimuli
trigger them. The electrical activity of the brain can be recorded simply by placing electrodes
onto the skull and obtaining an electroencephalogram. EEGs show that the brain’s
electrical activity never ceases, even under anesthesia, that this activity can be rhythmical,
and that different patterns of brain waves are often associated with different behaviors.
Finally, researchers can study event-related potentials, the brief changes in an EEG in
response to a discrete sensory stimulus, such as a tone or a flash of light. ERPs allow scientists
to determine which areas of the brain are processing various kinds of stimuli and
in which order those areas come into play.
144 ! CHAPTER 4
Resting
Viewing
Electrodes in
geodesic sensor net
P2
Electrodes attached to the
scalp of research subject
are connected to…
…computer display of
electrical activity, showing a
large positive (P2) wave at
posterior right side of the
head.
This electrical activity can be
converted into a color
representation showing the hot
spot for the visual stimulus.
Figure 4-28
Multiple recording method As the
subject at the left—very likely a college
student volunteer—looks at a rat
displayed on a computer screen,
researchers view a two-dimensional
display of the electrode sites (center).
Brain images of the ERPs (right) in the
resting condition and 200 ms after
stimulation in the viewing condition.
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induces the contraction of a muscle. The results of early electrical-recording studies, in
which the brain’s electrical current was measured with a voltmeter, showed that electrical
activity is continually occurring within the nervous system.
What technical problems had to be overcome to measure the electrical activity of a single
neuron? To measure the electrical activity of a single neuron, researchers first had to
find neurons with axons large enough to study. They also had to develop both a recording
device sufficiently sensitive to detect very small electrical impulses and an electrode
tiny enough to be placed on or into a neuron. These problems were overcome by studying
the giant axons of squid, the invention of the oscilloscope, and the development of
microelectrodes.
How is the electrical activity of neurons generated? The electrical activity of neurons
is generated by the flow of electrically charged ions across the cell membrane. These
ions flow both down a concentration gradient (from an area of relatively high concentration
to an area of lower concentration) and down a voltage gradient (from an area
of relatively high voltage to an area of lower voltage). The distribution of ions is affected
as well by the opening and closing of ion channels in neural membranes.
What are graded potentials and how do they change the resting potential of a neuron’s
membrane? In an undisturbed neuron, the intracellular side of the membrane has an
electrical charge of about !70 mV relative to the extracellular side. This charge, called
the resting potential, is due to an unequal distribution of ions on the membrane’s two
sides. Large negatively charged protein anions are too big to leave the neuron, and the
cell membrane actively pumps out positively charged sodium ions. In addition, unequal
distributions of potassium cations and chloride anions contribute to the resting
potential. Then, when the neuron is stimulated, ion channels in the membrane are affected,
which in turn changes the distribution of ions, suddenly increasing or decreasing
the transmembrane voltage by a small amount. A slight increase in the voltage is
called hyperpolarization, whereas a slight decrease is called depolarization. Both conditions
are known as graded potentials.
What is an action potential and how is it related to a nerve impulse? An action potential
is a brief but large change in the polarity of an axon membrane triggered when the
transmembrane voltage drops to a threshold level of about !50 mV. The transmembrane
voltage suddenly reverses (with the intracellular side becoming positive relative
to the extracellular side) and then abruptly reverses again, after which the resting potential
is gradually restored. These reversals are due to the behavior of voltage-sensitive
channels—sodium and potassium channels that are sensitive to the membrane’s voltage.
When an action potential is triggered at the axon hillock, it can propagate along
the axon as a nerve impulse. Nerve impulses travel more rapidly on myelinated axons
because of saltatory conduction: the action potentials jump between the nodes separating
the glial cells that form the axon’s myelin sheath.
How do neurons integrate information? The summated inputs to neurons from other
cells can produce both excitatory postsynaptic potentials and inhibitory postsynaptic
potentials. EPSPs and IPSPs are summed both temporally and spatially, which integrates
the incoming information. If the resulting sum moves the voltage of the membrane
at the axon hillock to the threshold level, an action potential will be produced
on the axon.
How do nerve impulses travel into the nervous system and back out? Sensory-receptor
cells in the body contain mechanisms for transducing sensory energy into energy
changes in ion channels. These changes, in turn, alter the transmembrane voltage to
HOW DO NEURONS TRANSMIT INFORMATION? ! 145
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146 ! CHAPTER 4
the point at which voltage-sensitive channels open, triggering an action potential and
propagating a nerve impulse. After traveling through the nervous system and being
processed by the brain, nerve impulses may produce the muscular contractions that
enable behavioral responses. Ion channels again come into play at this end of the pathway
because the chemical transmitter acetylcholine, released at the axon terminal of a
motor neuron, activates channels on the end plate of a muscle-cell membrane. The
subsequent flow of ions depolarizes the muscle-cell membrane to the threshold for its
action potential. This depolarization, in turn, activates voltage-sensitive channels, producing
an action potential on the muscle fiber.
What techniques do researchers use to study the brain’s electrical activity? Single-cell
recordings trace action potentials from single neurons in the brain. Electroencephalograms
record graded potentials of brain cells, usually from electrodes on the surface of
the scalp. Recording event-related potentials, also from the scalp, show the brief changes
in an EEG signal in response to a particular sensory stimulus.
KEY TERMS
REVIEW QUESTIONS
1. Explain the contributions of the membrane, channels, and four types of ions to a
cell’s resting potential.
2. The transduction of sensory energy into neural activity at a sensory receptor, the
nerve impulse, and the activation of a muscle can all be explained by a common
principle. Explain that principle.
3. Name and describe how three techniques for monitoring brain activity measure
the electrical activity of the brain.
FOR FURTHER THOUGHT
The brain is in a constant state of electrical excitation, which requires a substantial
amount of energy to sustain. Why do you suppose this constant electrical activity is
needed?
absolutely refractory, p. 126
acetylcholine (ACh), p. 138
action potential, p. 124
alpha rhythm, p. 141
concentration gradient,
p. 119
current, p. 113
diffusion, p. 119
depolarization, p. 124
electrical potential, p. 113
electrical stimulation,
p. 114
electricity, p. 113
electrode, p. 113
electroencephalogram
(EEG), p. 115
end plate, p. 138
event-related potential
(ERP), p. 142
excitatory postsynaptic
potential (EPSP), p. 131
graded potential, p. 123
head-direction cell, p. 139
hyperpolarization, p. 124
inhibitory postsynaptic
potential (IPSP), p. 131
negative pole, p. 113
nerve impulse, p. 128
node of Ranvier, p. 128
positive pole, p. 113
relatively refractory, p. 126
oscilloscope, p. 117
resting potential, p. 122
saltatory conduction,
p. 130
spatial summation, p. 135
stretch-sensitive channel,
p. 136
temporal summation,
p. 133
threshold potential, p. 124
transmitter-sensitive
channel, p. 138
volt, p. 113
voltage gradient, p. 119
voltage-sensitive channel,
p. 124
voltmeter, p. 115
neuroscience interact ive
There are many resources available for
expanding your learning online:
www.worthpublishers.com/kolb
Try the Chapter 4 quizzes and flash
cards to test your mastery of the
chapter material. You’ll also be able to
link to other sites that will reinforce
what you’ve learned.
www.efa.org
Learn more about epilepsy at the Web
site for the Epilepsy Foundation of
America.
www.myasthenia.org
Investigate myasthenia gravis at the
Myasthenia Gravis Foundation of
America.
On your Foundations CD-ROM, you’ll
be able to learn more about how
information is conveyed between
neurons in the module on Neural
Communication. This module includes
animations of many processes,
including the membrane potential and
the action potential. In addition, the
Research Methods module has an
overview of many of the different
technological tools covered in this
chapter, including the EEG, electrical
stimulation, and microelectrodes.
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RECOMMENDED READING
Posner, M. I., & Raichle, M. E. (1994). Images of mind. New York:W. H. Freeman and
Company. This book will introduce you to the new field of imaging psychology. For the
past 300 years, scientists have studied people with brain injuries as a source of insight
into the relation between the brain and human behavior. This book describes how
computerized electroencephalographic recordings (EEGs), scans produced by
computerized axial tomography (CAT), scans produced by positron emission
tomography (PET), magnetic resonance imaging (MRI), and functional MRI allow
neuropsychologists to look at the structure and function of the living brain.
Valenstein, E. S. (1973). Brain control. New York:Wiley.When scientists discovered that they
could implant stimulating electrodes into the brains of animals to elicit behavior and to
generate what seemed to be pleasure or pain, it was not long before psychiatrists
experimented with the same techniques in humans in an attempt to control human
brain disease. A renowned scientist, Valenstein writes about the application of braincontrol
techniques to humans in an engaging and insightful manner, bringing his own
scientific knowledge to bear on the procedures and the ethics of this field.
HOW DO NEURONS TRANSMIT INFORMATION? ! 147
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Focus on Classic Research: The Basis of Neural
Communication in a Heartbeat
A Chemical Message
Structure of Synapses
Focus on Disorders: Parkinson’s Disease
Neurotransmission in Fours Steps
Varieties of Synapses
Excitatory and Inhibitory Messages
Evolution of Complex Neurotransmission Systems
Varieties of Neurotransmitters
Identifying Neurotransmitters
Classifying Neurotransmitters
Focus on Disorders: Awakening with L-Dopa
Receptors for Direct and Indirect Effects
Neurotransmitter Systems
and Behavior
Neurotransmission in the Somatic Nervous System
Neurotransmission in the Autonomic Nervous System
Neurotransmission in the Central Nervous System
Focus on Disorders: The Case of the Frozen Addict
Role of Synapses in Learning
and Memory
Habituation Response
Sensitization Response
Long-Term Potentiation and Associative Learning
Learning at the Synapse
Focus on New Research: Dendritic Spines, Small
but Mighty
148 !
C H A P T E R5
How Do Neurons Communicate
and Adapt?
Left: Dr. Dennis Kunkel/Phototake. Middle: Patrisha Thomson/Stone.
Right: ADEAR/RDF/Visuals Unlimited.
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The Basis of Neural Communication in a Heartbeat
Focus on Classic Research
D iscoveries about how neurons communicate actually
stem from experiments designed to study what
controls an animal’s heart rate. If you are excited or exercising,
your heartbeat quickens; if you are resting, it slows.
Heartbeat rate changes to match energy expenditure—
that is, to meet the body’s nutrient and oxygen needs.
Heartbeat undergoes a most dramatic change when you
dive beneath water: it almost completely stops. This drastic
slowing, called diving bradycardia, conserves the
body’s oxygen when you are not breathing. Bradycardia
(brady, meaning “slow,” and cardia, meaning “heart”) is a
useful survival strategy. This energy-conserving response
under water is common to many animals. But what controls
it?
To find out, in 1921 Otto Loewi conducted a now
classic experiment. As shown in the Procedure section
of Experiment 5-1, he first maintained a frog’s heart in
a salt bath and then electrically stimulated the vagus
nerve, the cranial nerve that leads from the brain to the
heart (see Figure 2-26). At the same time, Loewi channeled
some of the fluid bath from the container
with the stimulated heart through a
tube to another container where a second
heart was immersed but not electrically
stimulated.
Loewi recorded the beating rates of
both hearts. His findings are represented
in the Results section of Experiment 5-1.
The electrical stimulation decreased the
beating rate of the first heart, but, more
importantly, the second heartbeat also
slowed. This finding suggested that the
fluid transferred from the first to the second
container carried the message “slow
down.”
But where did the message come
from originally? Loewi reasoned that a
chemical released from the stimulated
vagus nerve must have diffused into the
fluid in sufficient quantity to influence
the second heart. The experiment therefore
demonstrated that the vagus nerve
contains a chemical that tells the heart to
slow its rate of beating.
A puffin (genus Fratercula, Latin for “little brother”), beak laden
with food, returns to her chick. Puffins fish by diving underwater,
propelling themselves by flapping their short stubby wings, as if
flying. During these dives, their hearts display the diving
bradycardia response, just as our hearts do.
Kevin Schafer
Procedure
Stimulating
device
Results
Recording
device
Frog heart 1 Frog heart 2
Fluid transfer
Vagus
nerve
Recording from frog heart
1 shows decreased rate of
beating after stimulation,…
3
The message is a
chemical released
by the nerve.
Conclusion
…as does the recording
from frog heart 2 after
the fluid transfer.
4
Stimulation
Rate of
heartbeats
1
Fluid is transferred
from first to
second container.
2
Question: How does a neuron pass on a message?
EXPERIMENT 5-1
Vagus nerve of
frog heart 1
is stimulated.
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dia. Apparently, the heart adjusts its rate of beating in response
to at least two different messages: an excitatory
message that says “speed up” and an inhibitory message
that says “slow down.”
Loewi subsequently identified the messenger chemical
as acetylcholine (ACh), the chemical transmitter described
in Chapter 4 that activates skeletal muscles. Yet here ACh
acts to inhibit, or slow heartbeat down. And, yes, Ach is the
chemical message that slows the heart in diving bradycar-
In this chapter we describe how neurons communicate through excitatory and inhibitory
signals: the chemicals that carry the neuron’s signal and the receptors on
which those chemicals act. In the final part of the chapter, we explore the neural
bases of learning—that is, the ability of neural synapses to adapt as a result of the organism’s
experience.
A CHEMICAL MESSAGE
Loewi’s successfully performed heartbeat experiment (see Experiment
5-1) marked the beginning of research into how chemicals
carry information from one neuron to another. In further experiments,
he stimulated another nerve to the heart, the accelerator
nerve, and obtained a speeded-up heart rate. As before, the fluid
that bathed the accelerated heart increased the rate of beating of a
second heart that was not electrically stimulated. Loewi identified
the chemical that carries the message to speed up heart rate in frogs
as epinephrine (EP), also known as adrenaline.
Adrenaline (Latin) and epinephrine (Greek) are the same substance, produced by
the adrenal glands located atop the kidneys.Adrenaline is the name more people know,
in part because a drug company used it as a trade name, but EP is common parlance
in the neuroscience community.
Further experimentation eventually demonstrated that the chemical that accelerates
heart rate in mammals is norepinephrine (NE, also noradrenaline), a chemical
closely related to EP. The results of Loewi’s complementary experiments showed that
ACh from the vagus nerve inhibits heartbeat, and NE from the accelerator nerve excites
it.
Messenger chemicals released by a neuron onto a target to cause an excitatory or
inhibitory effect are now referred to as neurotransmitters. Outside the central nervous
system, many of these same chemicals, EP among them, circulate in the bloodstream
as hormones. As detailed in Chapter 7, under control of the hypothalamus, the
pituitary gland directs hormones to excite or inhibit targets such as the organs and
glands in the autonomic nervous system. In part because hormones travel through the
bloodstream to distant targets, their action is slower than that of CNS neurotransmitters
prodded by the lightening-quick nerve impulse.
Later in the chapter, you will learn how groups of neurons project neurotransmitter
systems throughout the brain to modulate, or temper, aspects of behavior. In the next
section, we examine the synapse, the site where excitatory and inhibitory neurochemicals
take effect. The three Focus on Disorders boxes in this chapter tell the fascinating
Otto Loewi
(1873–1961)
Acetylcholine (ACh) Epinephrine (EP)
Epinephrine (EP, or adrenaline).
Chemical messenger that acts as a
hormone to mobilize the body for fight or
flight during times of stress and as a
neurotransmitter in the central nervous
system.
Norepinephrine (NE, or
noradrenaline). Neurotransmitter found
in the brain and in the parasympathetic
division of the autonomic nervous system.
Neurotransmitter. Chemical released
by a neuron onto a target with an
excitatory or inhibitory effect.
150 ! CHAPTER 5

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Kesehatan bagun Pagi dan Meditasi

Dimana saat bangun pagi hari dan melihat sekeliling hidup dimana setelah kedua bola mata ini mulai berkerja untuk melihat sesuatu apa saja,sehingga pikiran mulai bekerja dengan apa yang dilihat,Meditasi dapat dilakukan disaat aktifitas mata dan pikiran mulai bekerja untuk menetukan perbuatan apa yang mau dilakukan oleh pandangan dari kedua bola mata ini,jadi setiap gerakan dari lihatan mata pikiran bekerja untuk menetukan apa langka yang harus di laksanakan baik yah dan baik tidak,manusia itu sendiri yang menentukan apa yang perlu dikalukan,sampai dengan melihat dikala bangun dari tempat tidur dan berdiri untuk langka selajutnya apa,kemudian berjalan kemana yang di inginkan oleh penglihatan bola mata dan diperintakan oleh pikiran yah atau tidak,akan tetapi setiap kehidupan manusia baik wanita dan laki-laki itu sama cuman perbedaan jenis kelamin,coba pola melihat dan pikiran banyak yang menyerupai tidak bedannya dimana manusia itu hidup dalam lingkungan ,akan tetapi setiap mengerakan badan jasmani ini dapat dilihatberupa melihat dan bergerak keselulu penjuruh,Meditasi sangat mendukung dimana prilaku yang kurang sadar apabila manusia disaat mulai bergerak dari aktifitasnya,jadi disaat aktifitas dari setiap gerakan yang tidak sadar itu dapat menjadi sadar apabila di bantu dengan meditasi dan kosentrasi yang tidak sadar menjadi sadar yang muncul dari pikiran manusia itu,kadang-kadang dapat dilihat kesadaran seseorang dapat berkurang akibat banyaknya aktifitas,sibuk,strees,marah,benci,irihati,kawatir,banyak berpikir,menghayal,beragan-agan,ambisi,menagis,tertawa,derita,dan bahagia dan lain-lainnya,

Kehidupan yang sehat merupakan yang terbaik apabila pikiran yang sehat dan badan jasmani juga sehat,baik kesadaran yang baik dengan tidak terjadi kecelakaan baik yang kecil dan yang besar dan mencelakai diri sendiri itu merupakan kesehatan dari pikiran dan badan jasmani yang dalan keadaan sadar dan itu merupakan sehat dan kehidupan,Meditasi dapat menyehatkan tubuh jasmani manusia yang kurang sadar dalam kehidupannya,yang terpenting adalah konsentrasi apa saja yang dilakukan dalam kegiatan sehari-hari itu lebih baik. oleh : Tjung teck S.Ag
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kurang kesehatan dari jasmani dan rohani antara Meditasi

Banyak orang dari berbagai ragam manusia yang ada sangat saat ini kurang sehat dari semua apa yang diraih dari setiap kehidupan dimana berada,seperti dengan halnya ketidak stabilnya ekonomi masyarakat yang berkembang dengan masyarakat maju berkembang pesat,kadang-kadang dapat dilihat dari perselisihan yang terjadi akibat dari kurang sehatnya pikiran manusia yang ingin lebih baik dari sesamanya diaman berada.

Aternatip kesehatan dampak kesehatan biology dan Meditasi

kesehatan fisik (jasmani) dan rohani dari dampat yang ditimbulkan oleh system kerja dari badan fisik atau jasmani itu sanggak mendukung dimana proses demi proses setiap metabolisme dari tubuh fisik manusia itu berasal dari dirinya sendiri yang untuk menentukan dimana kemanpuan seseorang yang dinyatakan sehat, dimana harus mengetahui dari awal dan akhir terutama untuk melatih Meditasi,dimana orang yang mengalami sakit yang kornis sekalipun dapat melakuakan Meditasi itu,baik secara fisik dan rohania dapat melakukan meditasi secara konsentrasi dengan object masing-masing dari semua unsur kehidupan metabolosme dari setiap kehidupan dialam semesta ini.tentunya tidak luput dari pengaru lingkungan dimana manusia itu berada dengan sesamanya, baik kehidupan yang baik dan kehidupan yang buruk itu semua kembali dari awal dimana manusia itu tumbuh dan berkembang dimana berasal,tidak luput dari kesehatan dan terserang penyakit tidak memandang manusia apa saja itu bisa terjadi dimana saja dan kapan saja selagi manusia itu tumbuh dan berkembang biak dengan satu dengan yang lainnya.

Dampak keshatan biology dan Meditasi sangat berhubungan erat dimana dampak yang ditimbulkan berupa kesehatan dari fisik atau jasmani yang mengerakan semua kehidupan dari system tubuh monotorik dari kehidupan manusia itu,terutama kepada dirinya sendiri sebagai manusia dimana manusia itu mempunyai rohani yang disebut dengan batin dan pikiran yang timbul dan lenyap dari proses alamia dari otak besar dan otak kecil yang melalui memory-memory sensorik dari setaip saraf-saraf yang berkerja sama dengan otot-otot dan urat-urat baik besar,menegah dan kecil dari semua system anatomi tubuh metabolosme manusia itu,sehingga lebih banyak dilihat dari semua gerakan berasal dari hujut perintahan-peritahan dari pikiran itu,yang baik gerakan secara menual dan rifek dapat digerakan dengan menual dan otomatis dari setiap kehidupan tubuh manusia itu,kemudian tidak luput oleh setiap makan yang di konsumsi setiap hari oleh manusia yang dapat dilihat dari makan yang mengandung gizi atau tidak tergantung sisi kehidupan manusia itu berasal dari mana dan lingkungan dimana manusia itu hidup.

sprituality antara biology dan hubungan Meditasi kesadaran

sprituality antara biology dan hubungan Meditasi kesadaran
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kesehatan biology dan Meditasi

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Saya seorang Buddhist yang sedang menjalani kehidupan Spiritual sesuai dengan ajaran Buddha. Akan tetapi saya berusaha dengan tekun untuk manfaat bagi umat Buddha supaya terus melestarikan Buddha, Dharmma, dan Sangha dimana saja, perbuatan karma baik dapat berbuah dalam ketenangan dan kebahagiaan diri sendiri dan semua makhluk hidup di dunia ini. Agama Buddha adalah merupakan Ajaran yang mengajarkan kita untuk melaksanakan Danasikha, sila, samadhi dan Panna. Demikianlah suatu hujud prilaku dan moral etika dapat berjalan dengan baik, didalam kehidupan dimana berada untuk hidup tenang dan Bahagia sewaktu hidup, sebagai umat manusia dimana berada, jalankan kehidupan ini sebaik-baiknya supaya kehidupan dapat mengikuti aturan-aturan kehidupan yang berkeTuhanan Yang Maha Esa.
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