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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to pinpoint events precisely in time, and require that the brain be exposed to radiation; therefore, this technique has been replaced by the fMRI as an alternative diagnostic tool.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

How does cognition and memory links with perception?
Catalina Reply
let's talk Sigmund Freud psychosexual theory and psychoanalytic theory.
Catalina
sure but I dont kn now him actually so explain him
Ruth
can I ask u all a question?
Ruth Reply
no
Ximax
come on it's about profiling
Ruth
yeah
Sz
how do u know that someone is in trouble but pretend that they aren't
Ruth
you need to looks for clues. otherwise there is no ready-made answer to your question.
Paul
what if they were acting weird and want to talk but can't
Ruth
also clues like what
Ruth
how to ready human mind
Sujeet Reply
how to read human behaviour
Sujeet
Describe frontal lobe syndrome
Bridget Reply
Frontal lobe syndrome is an impairment of the frontal lobe that occurs due to disease or head trauma. 
Zafar
what does the bell curve represent in intelligence testing?
Sounny Reply
average
Angela
I'M A VERY CURIOUS PERSON WHO LOVES TO LEARN ABOUT DIFFERENT TYPES
Sheri Reply
I AM A PERSON WHO IS NOT CHOOSING TO LET MY MENTAL HEALTH AFFECT ME AND I AM AN
Sheri
different types means.?😂😂
rilek
Indeed....different types means what exactly and how does these different types transpire into our lives? there are many different ways of allowing ourselves to accommodate and continiously play out the fact we have mental illnesses!!!
Elizabeth
social learning theory
CONFERENCE Reply
how we know the people are telling lie
Vasu
human brain
SERAJ
if you want to learn how to detect the lie you have to observe their behaviour...
Aayan
that's common things..
MOHD
anything specially, tht we can say either person is telling yes or no..?
MOHD
Yes
rochell
I believe there are many factors that play into being a human lie detector.
Tasha
all of which is governed by the human brain.
Tasha
There's no accurate method of telling someone is lying unless we know the truth ourselves. Some people, especially people with manipulative tendencies, will make a lie as believable as possible. Behaviors could tell the person is hiding something or may be feeling uncomfortable while being observed.
agii
Ex. Talking too fast while explaining a story might indicate that the person is indeed hiding something. Other than that, people, usually with histrionic personality disorder, also tend to exaggerate stories.
agii
DORFRLYN It's not easier to feel lied at first moment of talking to someone you know or you don't know. The person will be guilty of what they tell in the first sentence.They first find a way to hide the the truth. By so doing, the movement, and the head knock, this symbloyz the shift of origin
dorfrlyn
for one to tell lies, should first read the mind of the listener.
dorfrlyn
I agree with you Agil.Usually a person talks too fast,is hiding something true. But also talking too slow will mean creation of new story rather than the truth.
dorfrlyn
some people have the habit of speaking too fast, so in that case how can we identify whether the person is lying or not?
Labdhee
pay attention on facial expressions
El
When people talk too fast to the point that it's incomprehensible, it could mean that that person is trying to have you move one from one topic to another to prevent you from asking questions.
agii
observe micro expressions
Zafar
thanks to all for giving ans😃
Vasu
I want to learn more about psychodynamic personality theory
MsPam
MsPam Ware send me you email ... I just did a paper on Psychodynamic ...I can email it to you .. you may find it useful
Shanelle
Just wrapped a blackboard discussion on that! Theory is a great class. :)
Rachael
what if somebody answers questions quickly because they have social anxiety
Ashley
detecting lies is easier than many think. the dynamics of listening, body language, facial expression, story line, deductive reasoning and most of all analytical skills all play a role in determining if someone is lying. micro expressions can be very hard to discern requiring close analysis!
Kyth
Any recommendations for apps related to positive psychology?
Andrew Reply
intresting I mean
Asfand
Sometimes if you type "positive psychology " in your play store, you'll get some good ones
Tahmetrea
I use Awakenings by Iyanla Vanzant... She have a positive outlook on life. She's awesome!
Tahmetrea
Thank you, I will check that out.
Andrew
CBT types?
Rachael
psychology FACTS
katy
ITS SUPER EASY TO USE ... and divides the kind of positive psychology your looking for into groups! check it out.
katy
mental association books?
Maya
CBT works, and I am also looking for a psych book to read... I like psychology facts
Andrew
anyone know about any bipolar advocate groups or support type groups where a person can talk n vent while remaining anonymous?
tonya
HI I'M SHERI AND IN ANSWER TO THE QUESTION ABOUT THE BIPOLAR SUPPORT GROUPS I LIVE IN SACRAMENTO CALIFORNIA AND I DO KNOW THAT THERE ARE MANY DIFFERENT GROUPS 1) WELLNESS RECOVERY PROGRAMS AND I KNOW OF 2 LOCATIONS ONE ON MARCONI IN NORTH SACRAMENTO AND ON BOWLING OFF FLORIN IN SOUTH SACRAMENTO
Sheri
what's the most common cause of suicide in adolescents
Aisha Reply
depression
Irfan
yes. it's depression.
Paul
Especially when adolescents go through identity issues. Not knowing if this boy wants to be a girl or vice or versa. Social awkwardness, depression and cruelty of other adolescents in my opinion, brings a lot of suicidal tendencies into the minds of them.
Tahmetrea
reasons that lead to depression caused by many reasons like rape, abusive parents or guardians, bullying and more causes for a person to suicide
Diana
not accepting the fact or situation or the reality. the adolescents can't face rejections, as soon as they are rejected , they commit suicide.
Labdhee
social pressures have a huge impact on this. I find that young people are more likely to take their own life because they feel they are not able to fit in to a particular group of society and feel they are criticised by others. environment and nature/nurture. identity is a huge factor.
Jody
I think a major problem is when someone feels they can't handle the situation or think it's out of the control even though there are a lot of ways to solve it, one of them being at least trying to tell someone, visit a psychologist. They might stop feeling alone/misunderstood by everyone else.
Thuy
well, I've a problem. I feel very conscious when I'm in a crowd. when I'm partying with friends, I feels like everyone is looking at me. when I look at them, each one of them have their eyes on me. I don't know how I should deal with this? can someone help me with that ?
puneet
Hey Puneet! I think it's the matter of time and getting comfortable in that kind of situation after you try to get out of your comfort zone and slowly get used to it. I used to have that problem too but then I acted to not give a 💩 and tried my best to pretend I didn't care at all. And it worked!
Thuy
*Fake it till you make it* in this case worked for me the best. Maybe you could try to start talking to one of the more open/friendly people in that group so you don't get that self-conscious. I'm sure they don't think they will judge you at all! Just do it!
Thuy
Bullying that leads to anxiety, shame and depression, sadly.
Rachael
Where do I go to find research or tips for integrating sex and mental heath?
Felicia Reply
integrating a sexual routine and a mental illness that has kept o e from intimacy for a prolonged time? can u be a Lil more specific
lindsay
I have experience with both
lindsay
y only these two.?
MOHD
yes
Abu
y only these two sex and mental
MOHD
knowledge some practice practical
Abu
so ur mentally in balanced with sex..cause you find a good satisfy partner.....
MOHD
u can explain
Abu
u can't find good sex partner....
MOHD
no
Abu
I m not understand your consepet
Abu
depends on your Lonely no family no friends
MOHD
ok
Abu
chill,u time to Understand these concepts..
MOHD
ok
Abu
u can explain in urdu
Abu
hi
Wendy
hi
Abu
please can you help me identify and explain atleast seven(7) reflexes of the new born.
Wendy
yes of course
Abu
kk, then i need your help please.
Wendy
what's going on?
Mohammad
@lindsay I want to show how sexuality and mental health correlate. How one affects the other.
Felicia
I can help on these subjects
Abiral
@Abiral what information do you have?
Felicia
Hello
Irfan
Spending quiet time alone, with nature can improve mental health. Offer your opinions?
tsav Reply
mmmm but me i cn not spend time alone
Gift
Different strokes for different folks 🤷🏽‍♂️
tsav
what do u mean
Gift
Some people prefer a quiet life to a busy, bright city life. Some lead very stressful lives. Those people often don't pay attention to how they feel apart from the obvious fact that they're tired and stressed
tsav
nature can be clarifying and soothing because it can be a mixture of just natural beauty and why else are nature sounds an option for white noise
Twisted
You're absolutely right
tsav
what is with human being brain that we don't know?
imran Reply
I guess there are lots of things we don't know, but perhaps your referring to that thing called Consciousness
GoldenWizard
Anything that happens, question it!
tsav
in addition we may ask the doctor's
Gift
the science of many feelings and emotions can be hard to describe. our brains light up at some things but we can't always understand why
Twisted
But yet we must persist
tsav
Using relevant examples discuss challenges encounter by the beginning teachers during the learning and teaching process
LEILA Reply
how do I know when someone is using psychology on me?
Danielle Reply
If yes, it would always bring a solution.
Professor
Psychology cannot be used *on* something. You can use your *knowledge* of psychology to help tackle a situation. But I think I know what you're asking: pay attention to someone when you're talking, if they are looking at you up and down, they're analysing you
tsav
reasons for studying psychology in schools
ibraa Reply
PERSONALLY I'M A PERSON WHO LOVES TO LEARN READ AND WRITE AND RESEARCH ON DIFFERENT TYPES OF THINGS THAT HAVE TO DO WITH MY OWN EXPERIENCES WITH ADDICTION BORN WITH ORGANIC BRAIN DISEASE AND DAMAGE ENDURED EVERY FORM OF ABUSE THERE IS DOMESTIC VIOLENCE PTSD EDD (EMOTIONALLY DEVELOPMENTALLY DELAYED)
Sheri
I'M MILDLY MENTALLY CHALLENGED CAME OUT OF SEVERELY DYSFUNCTIONAL HOME MARRIAGE AND RELATIONSHIPS
Sheri

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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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