Biology and Technology

CT
A CT scanner produces images known as tomography  which offer a much more detailed image than X-rays and permit doctors to see images of the interior organs and structures of the body. IT is a ring-shaped and has a motorized bed that moves through it slowly. The generated images will ultimately be sent to a computer for analysis. The X-ray revolves around the patient, scanning and creating images of different areas of the body. This forms a complete picture of the body, which shows a cross-section of the inside of the body that many people refer to as 'slices.' The cross-sectional images enable doctors to diagnose a number of different conditions and diseases. They can also show inflammation, bleeding, damage to internal organs and abnormal structures, such as tumors. The images are generated by X-ray scanners, which capture images as the motorized bed moves through the scanner. A radiographer operates the scanner and they will ensure that the bed is in the correct position. Different parts of the body can be scanned, and the bed moves slowly to allow many diverse images to be taken. The radiographer may ask the patient to breathe in or hold their breath at certain points during the scan.

CT scans provide very detailed images of the internal structures in the body. This allows doctors to spot things that would be missed with other types of scans, and quicker than MRI scans and be used on different parts of the body, and also for diagnostic processes. CT scans are a very effective means of checking for damage following an accident or severe injury, as the images enable doctors to detect damage, bleeding or inflammation. They can then decide on a course of treatment very quickly. Scans can also be used to test for damage following a stroke or hearth attack.

The amount of radiation a person receives during a CT scan is minimal. In men and non-pregnant women it has not been shown to produce any adverse effects. However, doing a CAT test hides some risks. If the subject or the patient is pregnant it maybe recommended to do another type of exam to reduce the possible risk of exposing her fetus to radiation. Also in cases of asthma or allergies it is also recommended to avoid this type of scanning. Since the CT scan requires a contrasts medium, there's a slight risk of an allergic reaction to the contrast medium. Having certain medical conditions; Diabetes, asthma, heart disease, kidney problems or thyroid conditions also increases the risk of a reaction to contrast medium.

PET

A PET scan uses radiation, or nuclear medicine imaging, to produce 3-dimensional, color images of the functional processes within the human body. PET stands for positron emission tomography. The machine detects pairs of gamma rays which are emitted indirectly by a tracer (positron-emitting radionuclide) which is placed in the body on a biologically active molecule. The images are reconstructed by computer analysis. Modern machines often use a CT X-ray scan which is performed on the patient at the same time in the same machine. 

PET scans can be used to diagnose a health condition, as well as for finding out how an existing condition is developing. PET scans are often used to see how effective an ongoing treatment is.

Radiotracer - Before carrying out a PET scan, a radioactive medicine is produced in a cyclotron (a type of machine). The radioactive medicine is then tagged to a natural chemical. This natural chemical could be glucose, water, or ammonia. The tagged natural chemical is known as a radiotracer. The radiotracer is then inserted into the human body. 

When it is inside the radiotracer will go to areas inside the body that use the natural chemical. For example, FDG (fluorodeoxyglucose - a radioactive drug) is tagged to glucose to make a radiotracer. The glucose goes into those parts of the body that use glucose for energy.Cancers, for example, use glucose differently from normal tissue - so, FDG can show up cancers. 

Detecting positrons - A PET scan detects the energy emitted by positively-charge particles (positrons). As the radiotracer is broken down inside the patient's body positrons are made. This energy appears as a 3-dimensional image on a computer monitor. 
The image - The image reveals how parts of the patients body function by the way they break down the radiotracer. A PET image will display different levels of positrons according to brightness and color. 

When the image is complete it will be examined by a radiologist who reports his/her findings to a doctor. A radiologist is a doctor who specializes in interpreting these types of images, as well as MRI scan, CT scan, Ultrasound and X-ray images.

• Epilepsy - it can reveal which part of the patient's brain is being affected by epilepsy. This helps doctors decide on the most suitable treatments.MRI and/or CT scans are recommended for people after a first seizure, this study explains.


• Alzheimer's disease - it is very useful in helping the doctor diagnose Alzheimer's disease. A PET scan that measures uptake of sugar in the brain significantly improves the accuracy of diagnosing a type of dementia often mistaken for Alzheimer's disease, a study revealed.


• Cancer - PET scans can show up a cancer, reveal the stage of the cancer, show whether the cancer has spread, help doctors decide on the most appropriate cancer treatment, and give doctors an indication on the effectiveness of ongoing chemotherapy. A PET scan several weeks after starting radiation treatment for lung cancer can indicate whether the tumor will respond to the treatment, a study showed. This article looks at whether PET scans are beneficial during cancer diagnosis, staging and monitoring.


• Heart disease - a PET scan helps detect which specific parts of the heart have been damaged or scarred. Any faults in the working of the heart are more likely to be revealed with the help of a PET scan. A study revealed how comprehensive diagnosis of heart disease based on a single CT scan is possible.


• Medical research - researchers, especially those involved in how the brain functions get a great deal of vital data from PET scans.

fMRI

Functional magnetic resonance imaging, or FMRI, works by detecting the changes in blood oxygenation and flow that occur in response to neural activity – when a brain area is more active it consumes more oxygen and to meet this increased demand blood flow increases to the active area. FMRI can be used to produce activation maps showing which parts of the brain are involved in a particular mental process.

fMRI helps to explain what the brain does and which brain regions are involved in what types of processes. While fMRI and other imaging methods cannot tell us whether a region is definitely involved in a specific process (patients with lesions and the use of transmagnetic stimulation are the only techniques so far which can suggest causation), it can still help us understand what functions are carried out by which regions. Knowing which regions engage in which processes aids in understanding variations between individuals as well as complementing data from patient studies.

Sample IB Psychology Question

Explain using examples the functions of two hormones on human behavior.

Cortisol and Memory

A hormone produced by adrenal glands in response to stress and to restore homeostasis. The glands are part of a system called the endocrine system. Hormones are chemical messengers carried by glands. Chronic stress may result in prolonged cortisol secretion, which can damage the immune system and impair memory.

Newcalmer et al. (1999) - experiment on cortisol and memory
To investigate how levels of cortisol levels interfere with verbal declarative memory.
Procedure: A self-selected sample (through and advertisement) of 51 normal and healthy people ages 18~30 was used. Randomized, controlled and double-blinded. 3 conditions.

Condition 1: A high level of cortisol (160 mg tablet), was given. Same as cortisol released in a stressful event.
Artificial cortisol is to know the result and procedure.
Condition 2: Low level of cortisol (40 mg tablet) same as minor stressful event.
Condition 3: A placebo

Results: The high leveled group performed worse on verbal memory test than the low level group and placebo group. The low level group showed no memory decrease.
Evaluation: It was controlled and randomized so it was possible to establish a cause and effect relationship. They received informed consent. Negative effect of cortisol levels was reversible so no harm was done.

Oxytocin
Oxytocin is secreted by the hypothalamus into the brain and into the bloodstream via the pituatory gland. Linked to increase in trust. Evolutionary psychologists say trust was critical in forming relationships or staying away from bad ones. Learning to trust in vital for survival. One way it could work is by reducing four reactions via the amygdala as a consequence of betrayal.

Baumgartner et al (2008)
The role of oxytocin in trust in economic behavior.

Aim: To investigate the role of oxytocin after breaches of trust in the trust game.

Procedure: The participants played a trust game used by scientists to study social interaction.

Findings: Oxytocin rise boosts trust/ increases trustworthiness. Flaws in brains ability to respond to oxytocin might contribute to social disorders.

Procedure: "Investor," player 1 gets a sum of money and must decide whether to keep it or share it with a "trustee." (player 2). What is shared is tripled. Player 2 must decide if the sum should be shared (trust) or kept ( violation of trust). fMRI scans were carried out on all participants. They received oxytocin or placebo via a nasal spray. Participants play against different trustees and were given feedback when the trust was broken by the experimenter.

Results:
Participants in the placebo group showed less trust after feedback of betrayal. They invested less. Participants in the oxytocin groups continued to invest at similar rates after receiving feedback of breech of trust. The fMRI scan showed decreases in responses in the amygdala and caudate nucleus. Amygdala is a part of our brain that is involved in basic emotions and has many receptors for oxytocin. The caudate nucleus is involved in learning and memory and plays a role in reward related responses and trust.

Evaluation
Oxytocin could explain why people are able to restore and trust and forgiveness in long-term relationships. fMRI gave us and idea about a possible correlation but gave us nothing definite about cause and effect. Giving the oxytocin artificially may not reflect a true physiological process. Oxytocin is very complex and it is too simplistic to call it the: "trust hormone."

Genetics and Twins

1.)    What is a “Twin Study”?

Twin studies measure the contribution of genetics to a given trait or condition of interest. This psychological study focuses specifically on twins. The usual study relies on studying twins raised in the same family environments. Twin study helps disentangle the relative importance of environmental and genetic effects on individual traits and behaviors. It is considered as a key tool in behavioral genetics and related fields.

2.)    Why do scientists and psychologists study twins?

Twin studies are normally conducted to further support or reject biological influences on a life forms development in many areas, such as mental illness, intelligence, and behavior. It states that that if the concordance rate is higher on twin study when compared to a non-twin study, the results can suggest that there is a biological link in the area they are researching, and this is mainly due to twins sharing the same genes.

 3.) What, in general, has been learned from past studies?

With their similar genetic makeup, twins represent an ideal opportunity to study health and behavior issues. From twin studies, it is possible to determine how genetic and environmental factors influence health. Studies can also provide scientific insights into twins and genetics, including conditions such as diabetes, heart disease, and obesity, as well as the effects of alcohol and tobacco use. By identifying the genetic components of these health problems and others through twins research, it is possible to develop early interventions and treatments.
For the National Institutes of Health and other clients, researchers at SRI's Center for Health Sciences conduct twins research studies on the pharmacokinetics of nicotine, the metabolism of commonly used medications, genetic susceptibility to cancer-causing chemicals, and sleep patterns in young twins.
The continually growing and diverse Twin Research Registry at SRI International  includes more than 3,000 members who volunteer to participate in SRI twin research studies.

Twin Facts and Figures

Fascination with twins is part of every culture -- and dates back centuries. Some interesting twin "facts and figures" include:

• In ancient times, doubleness in nature was often interpreted as a manifestation of the supernatural or intervention by the gods -- that is why many gods in different religions are twins or supertwins.
  
• In the Aztecs, Babylonian, Zuni and Ashanti cultural myths, twins took the form of warriors, builders, healers, symbols of light, water or thunder.
  
• Native American tribes in the Northwest believed that twins were actually salmon in human disguise.
  
• The frequency of twin births reported vary from country to country and range from 1 in 80 to 1 in 140.
  
• When it comes to phobias -- like fear of heights, of closed spaces, or of open spaces -- twins often respond similarly. Twins often share phobias, and more often than not if one twin harbors an irrational fear, the other does too.
  

4.) What are the differences between a Monozygotic and dizygotic twin?

Twin can either be monozygotic meaning that they develop from one zygote that splits and forms two embryos or dizygotic, which develop from two separate eggs that are fertilized by two separate sperms. This difference in fertilization in dizygotic shares an average of 50% of their genetic material and the monozygotic shares 100% of their genetic material. This difference in amount of shared genetic material sets the stage for a marvelous natural experiment and it is the basis of the twin method for research.

5.) What is and "adoption study"?

An "adoption study," is is one form of a clinical genetic study designed to evaluate genetic and environmental influences on phenotype  The study provides a unique opportunity to examine gene and gene by environment interactions for a variety of behavioral, psychiatric and medical disorders.
Adoption studies provide a unique research model where biological genetic effects can be estimated. Adoption studies can be helpful in uncovering gene–environment interactions in complex behavioral and psychiatric disorders. Adoption genetic studies utilize a variety of statistical techniques including calculation of odds ratios, logistic regression, log-linear statistical monitoring and path analysis.Recent advances in adoption study research have occurred by combining molecular genetic techniques to the genetic and environmental data of adoptees. Increased privacy concerns and privacy laws related to biological parent anonymity have made adoption studies more difficult to design and implement.

6.) How do adoption studies help researchers understand the question of how human traits are influenced by either genetic or environmental influences?

Adoption studies have shown the strong influence of genes (or nature). For instance, the Texas Adoption Project found "little similarity between adopted children and their siblings and greater similarity between adopted children and their biological parents."

7.) Describe the Minnesota Study of Twins Reared Apart (MISTRA)

The Minnesota Study of Twins Reared Apart (MISTRA) was one of the most important psychological studies of the last 50 years. It began in 1979, at a time when it was widely believed that intelligence and personality were almost infinitely malleable by the environment. By the time the study ended 20 years later, it had played a key role in overthrowing this dogma. It established beyond any doubt that genes are crucial to who we are.

 http://web.missouri.edu/~segerti/1000H/Bouchard.pdf
http://www.amren.com/features/2012/07/science-versus-ideology/

8.) Identify the findings from the MISTRA.

 MISTRA yielded what amount to two different kinds of findings: quantitative and impressionistic. The former come from personality, intelligence, medical, and other testing, whereas the latter include the almost eerie, unmeasurable ways in which MZA twins are alike.
The first twin pair MISTRA evaluated was particularly striking. The two men met when they were 39, and found that both had been in law enforcement but were now working as firemen. Both had loved math in school and hated spelling. Both did woodworking as a hobby, and their favorite vacation spot was Pas Grille Beach in Florida. One had named his son James Alan and the other had named his James Allan. They looked very much alike, had the same smoking habits, and always held a beer can with a pinky under the can. Both had put on 10 pounds at the same age for no apparent reason.
Not all twins were so alike, but this book is full of astonishing similarities. In one MZA pair, one twin was reared in Germany and the other in Trinidad, and they had never met before they came to Minnesota for testing. When they arrived at the airport each was wearing a light blue shirt with epaulettes, and wire-rimmed glasses. They both collected rubber bands, which they wore around their wrists, and washed their hands both before and after using the bathroom. Both liked to startle people by sneezing loudly in elevators.
One pair of MZA women both wet the bed until age 12 or 13. When they were teenagers they started having nightmares about the same things: fishhooks and doorknobs. Both had problems with nightmares for more than ten years.
One pair of MZA men had been overweight until middle school and then became quite thin. They had speech problems for which they received therapy in kindergarten or grade school. Both were diagnosed as hyperactive at about the same age, and both were actively and openly homosexual.
A pair of female MZA twins from Australia found each other because of a case of mistaken identity. They both worked as fashion buyers for competing department stores, and a customer accused one of moonlight for the competition. They were both very elegant, dressed with the same style and the same kind of jewelry, smoked the same cigarettes, and had the same hairstyle, posture, tastes, and speaking voice. One MZA pair of male twins were both fitness fanatics who ran their own body-building gyms. MZA twins generally have the same posture and arrange their hands and legs in the same way while DT twins do not.

9.) What are the limitations of twin and adoption studies?

In Twin studies, Monozygotic twins are rarely separated at birth and raised in a totally different environment, and are reared together sharing many of the same experiences. Dizygotic twins reared together may not share the same experiences due to levels of attractiveness or temperament.
On the other hand,selective placement is a problem tending babies to be placed with families similar in background to the natural parents, adopted children as well as twins are not representative of the children, and the act of being given up for adoption may affect the child's behavior.

10.) What are the ethical associated with twin and adoption studies?

• Unlike twin studies, in adoption studies individuals are exposed to a different environment to their biological or genetic relatives. This makes it easier to separate genetic and environmental factors.
• These studies are not easy to undertake as information on an adoptee and their biological families may not be available.
• There are ethical issues to be considered when approaching members of the biological family, about a child who was adopted many years ago.
• Adoption is not a random process, meaning that children are often placed in families resembling their biological family or in families that have been specially selected for other reasons.
• Adoption is also an unusual event in itself, leading to a small sample size.

Stroke: Killing Your Brain

 Questions on Stroke Effect

 1. Explain what happens to the brain when a stroke occurs.
1.) When the stroke occurs, the cerebrum of the brain is very damaged. The Wernicke's area, which is the central language area,  causes difficulty speaking understandably and comprehending speech, the confusion between left and right, difficulty reading, writing, naming objects, and calculating.  The Broca's area, which is involved in speech, causes difficulty speaking, and sometimes writing. The parietal lobe causes the loss of coordination of the right arm and leg, while the facial and limb areas of the motor cortex on the left side of the brain, effects the paralysis of the right arm and leg, plus the right side of the face. Finally, the facial and arm areas of the sensory cortex shows the absence of sensation in the right arm and the right side of the face Optic radiation loss of the right half of the visual field of both eyes.

2. Briefly explain the differences between the three different types of strokes.
2.) The three types of stroke, ischemic, hemorrhagic, and transient ischemic, all have different warning signs and symptoms, that a\occur in different areas of the brain, with various outcomes.
The Ischemic stroke, is usually caused by blood clot that lodges in an artery and blocks the flow of blood to a prat of the brain, which show high blood pressure. This is usually shown through loss of strength and sensation on one side of the body, problems with speech and language or changes in vision or balance. The Hemorrhagic Stroke, occurs when a blood vessel ruptures within the brain. There are two types of stroke due to ruptured blood vessel; sub-arachnoid hemorrhage due to ruptured aneurysms, and intra-cerebral hemorrhage due to ruptured blood vessels. As the symptoms occur suddenly, it tends to appear at younger ages. It shows very severe headache, nausea and vomiting, and partial or total loss of consciousness. Transient Ischemic stroke is a mini-stroke that occurs when a blood clot blocks an artery for a short time. This is a short-term stroke, but do not underestimate them.

3. Identify some of the most common risk factors - in other words, who is most likely to have a stroke?
3.)

Controllable	Uncontrollable
High blood pressure	Family History
Atrial Fibrillation (irregular heart beat)	African American, Hispanic, or Asian
High Cholesterol	Age
Diabetes	Gender
Tobacco Use/Smoking	History of Previous strokes or blocked arteries leading to the brain
Alcohol Use
Overweight

4. What disabilities can result from a stroke?

4.) Disabilities of stroke include, paralysis, cognitive deficits, speech problems, emotional difficulties, daily living problems, and pain.

5. What is brain plasticity and what does it mean in terms of recovering from a stroke?
5.) Brain plasticity, also referred to neuroplasticity,  are changes in neural pathways and synapses which are due to changes in behavior, environment and neural process, as well as changes changes resulting from bodily responses. Brain plasticity in terms of recovering from a stroke shows various ways. Plasticity allows the brain's ability to repair and reorganize cells. By sprouting new synaptic connections, it creates new pathways to in-effected parts of the brain Also exercising your brain. And brain plasticity shows why intensive therapy is such a critical element of stroke recovery.