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Brain imaging

You have learned how brain injury can provide information about the functions of different parts of the brain. Increasingly, however, we are able to obtain that information using brain imaging techniques on individuals who have not suffered brain injury. In this section, we take a more in-depth look at some of the techniques that are available for imaging the brain, including techniques that rely on radiation, magnetic fields, or electrical activity within the brain.

Techniques involving radiation

A computerized tomography (CT) scan    involves taking a number of x-rays of a particular section of a person’s body or brain ( [link] ). The x-rays pass through tissues of different densities at different rates, allowing a computer to construct an overall image of the area of the body being scanned. A CT scan is often used to determine whether someone has a tumor, or significant brain atrophy.

Image (a) shows a brain scan where the brain matter’s appearance is fairly uniform. Image (b) shows a section of the brain that looks different from the surrounding tissue and is labeled “tumor.”
A CT scan can be used to show brain tumors. (a) The image on the left shows a healthy brain, whereas (b) the image on the right indicates a brain tumor in the left frontal lobe. (credit a: modification of work by "Aceofhearts1968"/Wikimedia Commons; credit b: modification of work by Roland Schmitt et al)

Positron emission tomography (PET) scans create pictures of the living, active brain ( [link] ). An individual receiving a PET scan drinks or is injected with a mildly radioactive substance, called a tracer. Once in the bloodstream, the amount of tracer in any given region of the brain can be monitored. As brain areas become more active, more blood flows to that area. A computer monitors the movement of the tracer and creates a rough map of active and inactive areas of the brain during a given behavior. PET scans show little detail, are unable to pinpoint events precisely in time, and require that the brain be exposed to radiation; therefore, this technique has been replaced by the fMRI as an alternative diagnostic tool. However, combined with CT, PET technology is still being used in certain contexts. For example, CT/PET scans allow better imaging of the activity of neurotransmitter receptors and open new avenues in schizophrenia research. In this hybrid CT/PET technology, CT contributes clear images of brain structures, while PET shows the brain’s activity.

A brain scan shows different parts of the brain in different colors.
A PET scan is helpful for showing activity in different parts of the brain. (credit: Health and Human Services Department, National Institutes of Health)

Techniques involving magnetic fields

In magnetic resonance imaging (MRI)    , a person is placed inside a machine that generates a strong magnetic field. The magnetic field causes the hydrogen atoms in the body’s cells to move. When the magnetic field is turned off, the hydrogen atoms emit electromagnetic signals as they return to their original positions. Tissues of different densities give off different signals, which a computer interprets and displays on a monitor. Functional magnetic resonance imaging (fMRI) operates on the same principles, but it shows changes in brain activity over time by tracking blood flow and oxygen levels. The fMRI provides more detailed images of the brain’s structure, as well as better accuracy in time, than is possible in PET scans ( [link] ). With their high level of detail, MRI and fMRI are often used to compare the brains of healthy individuals to the brains of individuals diagnosed with psychological disorders. This comparison helps determine what structural and functional differences exist between these populations.

A brain scan shows brain tissue in gray with some small areas highlighted red.
An fMRI shows activity in the brain over time. This image represents a single frame from an fMRI. (credit: modification of work by Kim J, Matthews NL, Park S.)

Techniques involving electrical activity

In some situations, it is helpful to gain an understanding of the overall activity of a person’s brain, without needing information on the actual location of the activity. Electroencephalography (EEG) serves this purpose by providing a measure of a brain’s electrical activity. An array of electrodes is placed around a person’s head ( [link] ). The signals received by the electrodes result in a printout of the electrical activity of his or her brain, or brainwaves, showing both the frequency (number of waves per second) and amplitude (height) of the recorded brainwaves, with an accuracy within milliseconds. Such information is especially helpful to researchers studying sleep patterns among individuals with sleep disorders.

A photograph depicts a person looking at a computer screen and using the keyboard and mouse. The person wears a white cap covered in electrodes and wires.
Using caps with electrodes, modern EEG research can study the precise timing of overall brain activities. (credit: SMI Eye Tracking)

Summary

The brain consists of two hemispheres, each controlling the opposite side of the body. Each hemisphere can be subdivided into different lobes: frontal, parietal, temporal, and occipital. In addition to the lobes of the cerebral cortex, the forebrain includes the thalamus (sensory relay) and limbic system (emotion and memory circuit). The midbrain contains the reticular formation, which is important for sleep and arousal, as well as the substantia nigra and ventral tegmental area. These structures are important for movement, reward, and addictive processes. The hindbrain contains the structures of the brainstem (medulla, pons, and midbrain), which control automatic functions like breathing and blood pressure. The hindbrain also contains the cerebellum, which helps coordinate movement and certain types of memories.

Individuals with brain damage have been studied extensively to provide information about the role of different areas of the brain, and recent advances in technology allow us to glean similar information by imaging brain structure and function. These techniques include CT, PET, MRI, fMRI, and EEG.

Personal application questions

You read about H. M.’s memory deficits following the bilateral removal of his hippocampus and amygdala. Have you encountered a character in a book, television program, or movie that suffered memory deficits? How was that character similar to and different from H. M.?

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Questions & Answers

I was recently diagnosed schizophrenic. after a lifetime of major depression. time I did hear voices not for long. how does one know if they really schizophrenic?
Cathy Reply
because psychology is the dissection and study of the mind, some find it hard to believe a diagnosis under mental health concerns. if you feel you have been misdiagnosed, go to another doctor. be 100% honest in all questions asked. to lie to your doctor is much like lying to yourself/hurting self
on the contrary, a diagnosed schizophrenic doesn't always have episodes. it may start off very mild and progress over time. it may also be triggered by events/situations/certain states of mind the patient may experience
diagnosed schizophrenics are normally prescribed a medication that can help. if you feel your medication is not working, or that it may make matters worse, discuss this with your doctor so he/she can make adjustments. what works for one person may not work for them all, and so doctors need to know
i want to study about psychology b'coz my father has a mental illness. iwant to help my father to healed from her sicknessed.
Layca
please whats the answer
Fortune Reply
answer to what?
Gaunt
what is mean by what?
Mohammad
to the questions ooo i can't find the answers
Fortune
Can you repeat the question or comment the page you saw it?
Haim
why they named it psychology
zayn Reply
telll me
ABDUL
the word "psychology" comes from the Greek words "psyche" meaning life and "logos" meaning "explanation".
Soma
Psyche, in Greek mythology was a goddess who comes to represent the human soul's triumph over the misfortunes of life. The term psychology was coined. Psyche, meaning soul or mind and the root "ology" meaning the study of. I hope this helped.
JC
well done
ABDUL
what is chunking
Ritika Reply
Chunking is a process by which individual pieces of an information set are broken down and then grouped together in a meaningful whole.
Azquan
chunking is to information as syllabus is to word
ABDUL
what dose it means, operant and classic conditioning in short words?
Mikiyas Reply
scientific method, critical thinking.
jeddy Reply
the dealings with the thought process and human behavior.
jeddy
for acquiring knowledge by experimentation.
jeddy
study scientific study of mind and behavior.
jeddy
scientific study of the human mind and behavior.
jeddy
hey jeddy I have question s for you
Yussuf
hi what is behavioralism ?
jusem
what is psychology..?
Ania
the science of mental life.
Mikiyas
it focuses on understanding and modifying human behaviour
ABDUL
because emotion can't be measured.
marikrizz Reply
only by the person having the emotion.
Jason
it is subjective feeling
suman
only placed within levels of itself
Teena
and accepted as extended or beginning versions of emotions that are completely free of restrictions
Teena
anyone know, (2+2)/2
start
Emotions can't be measured, but they can be recognized. To be able to recognize certain characteristics that'll give me an idea about an individual's state of mind.
jeddy
any one knows (2+2)/2
start
it is 6
suman
anyone (2+2)/2
start
2
fadil
😂
suman
then more then just recognize but to comprehend the emotions being observed separating your own emotions from the situation currently in.. and rationally gaging the environment.. while then pulling each possible emotional vibe or energy exerted from the human being observed
Teena
How does learning influence behaviour
Tumpa Reply
our choice of study molds us and encourages us to practice what we learn. social structure also changes behavior based on the environment and peers. how we learn can be experimental as not everyone lesrns the same. some are more of a hands-on absorber, whereas others may learn better from listening
A confidence from personal knowledge. Not from having been taugbt. knowledge that you learned what was taught.
jeddy
life is choice, be ready for the best and be prepare for what yet to come in your way(Destiny)
Wayne
what is development
Momna Reply
In what Context are you referring to
Hassan
the progression/degression/growth of something. it is interpreted most commonly in psychology as how something is created or formed. ex: When did you develop an interest in psychology?
when refering to physical, cognitive, and social development, these types of development are determined by many circumstances. such as demographics, biology, and personality/character
it is the apprehensions fluency based by the process of configurations to a design based on product/witness series noticeboards to note the stats on order to retail agreements on stated series order.
Kay
Evolving
jeddy
I'm on my first year of a psychology course, is there anything I should know? anything you wished you knew when you just started psychology ? because I feel like I'm walking into all of this blindly
Lia Reply
hello
GOPAL
I feel exactly the same. Just about to start Psychology and Criminology. feeling slightly nervous 🙈
Sarah
and everything is online
Lia
only for a few weeks I believe. Unless I have read it wrong. I believe that they will try and filter everyone in.
Sarah
it's different for every country
Lia
hi
GOPAL
I start 9/14. Online as well.
LaQuisha
I know very little about Psychology
GOPAL
which area are you specialising in
Elle
yeah, everthing your just know, that psychology is everthing come out with, mind, behavior and emotion. and believe, once you study it, you will understand, wjy people act like that.
EDWARD
Don't be in the class with pre notions.. yh
ABDUL
after a successful job interview,Mr.Abhishek felt relaxed and calm,he stopped sweating and felt hungry,which part of his nervous system was activated
Babaljeet Reply
Hypothalamus
Words
what is the Borysenko model and why is it important?
Sarah
It explains the link between stress and diseases ie.. How long term stress on the mind or body can lead to chronic migraines, ulcers, depression...
Jennifer
I understand there is a link between stress and illness and disease. that when you are in high-stress situations for prolonged periods of time that the brain releases an abundance of stress hormones such as epinephrine, norepinephrine, cortisol, and aldosterone. idk anymore than that.
Sarah
what is the strees anger
Divya
what is difference between illness and disease
Umair
anyone knows (2+2)/2
start
Hy everybody any one who can help me to understand the concept of Structuralism in easy words?
sabiha Reply
If you really considered looking into yourself find the reason of the possibilities or the environment and atmosphere in which you're placed with or without choice in voluntary or involuntary from birth to now, and also consider all existential extensions of yourself including spiritual recognition.
Darling
? and compare them to social,judicial, learned events,experiences, influences and dive into there branches? somehow reflects our mechanic motivations and has an effect on who we are and what we represent. ?😲
Darling
critical evaluation on attitude change and formation those that even exist
COMORDOR
who is considered of a father of psychology
Satyendra Reply
Freud
Lithemba
Immanuel Kant: Critique of Pure Reason.
David
wundt
Namrata
Wundt
Disha
wundt
NishaOfficial
wundt
Naheed
wundt
Jasmine
id say freud but wundt continued his work. let's face it without freud there wouldn't be a psychology practices
Michelle
Freud is considered as the father of Psychoanalysis not psychology
Indefatigable
technically Freud would be the father of psychology because he discovered the id ego and super ego
Bryce
Its kind of a loaded question. There are many early greats in psychology each having their own theories and views. I think it is more of a collective of ideals that make up our current view and understanding of psychology.
Jason
I agree with you Jason. there are Amazing psychologist back then that made the foundation for the field of psychology
Bryce
Wilhelm Winston ryt
Faazi
Wundt
Waris
i agree to you Jason
Welli
is there any name for the fear of dying painfully? is it the same as thanatophobia?
Matthew Reply
hello matthew i am new
Barbara
who is reinhart
Hannah Reply
hello, why are you asking me this?
She
hello, how are you?
Corey
hey Corey, all fine, how are you doing?
She
Hello everyone
Indefatigable
hello
Hannah
Which specialization in psychology interest you? why?
Ailyn
hello, hannah, I'm fine thanks and how are you?
Corey
or she
Corey
hello hannah and corey
Barbara

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Source:  OpenStax, Psychology. OpenStax CNX. Feb 03, 2015 Download for free at https://legacy.cnx.org/content/col11629/1.5
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