​Tourette syndrome:
Symptoms of Tourette syndrome are uncontrollable movement (aka. Tics), blinking repeatedly, shrugging solders, or saying offensive language.  The symptoms appear around 4 years of age.  The symptoms of Tourette syndrome can either lessen in older age or it can persist across the person’s lifetime.  Problems associated are learning difficulties, obsessive thought such as that in OCD and compulsive disorders such as OCD.  Causes of Tourette syndrome have been linked to the cortex, basal ganglia, thalamus, and cerebellum.  Environmental factors such as anxiety and stress have been proven to be linked to Tourette syndrome.  Also, gene defects in the SLITRK1 gene (a gene linked to neuronal development) have been linked to Tourette syndrome.  There are many treatments to Tourette syndrome.  Some medications can be used such as Antipsychotics and SSRI (these drugs are also used to control nausea, high blood pressure, seizures or anxiety, OCD and depression). Methylphenidate and Dextroamphetamine (these drugs are used to cure ADHD and overall attention loss) are also used to cure Tourette syndrome. However, these drugs have side effects such as weight gain, muscular rigidity fatigue, motor, restlessness so some people chose to use behavioral therapy to cure the syndrome.
 
Major Depression:
Symptoms of Major Depression are feeling hopeless and a loss of interest in life, as well as reduced emotion, well being. Other symptoms of major depression are a disturbance in sleep, low energy as well as an elevated risk of suicide. Genes, as well as environmental factors, can create a depressive episode.  There are 2 ways parts of the brain are affected in depression it can either be hypoactive or hyperactive.  Hypoactive means that there is low neuronal activity while hyperactive means high neuronal activity.  The anterior cingulate cortex is a hyperactive part of the brain. While the prefrontal cortex, amygdala, thalamus, hypothalamus among other areas are hypoactive.  There are 5 types of ways to cure major depression.   Deep Brain stimulation is one way. In deep brain stimulation electrodes send stimulation to specific parts of the brain.  Antidepressants are used to increases serotonin in the brain also an increase of norepinephrine is also used.  Another drug named ketamine is used this drug blocks NMDA receptors.  Psychotherapy is also used. And in severe cases, Electoconclusive therapy is used. 

Psychiatric Disorders affect 18% of all people in the USA.  23% of everyone diagnosed with anxiety disorders are categorized as a severe case.  There are 4 types of anxiety disorders these types are OCD (Obsessive Compulsive Disorder), panic, phobias, and PTSD (Post Traumatic Stress Disorder).
 
OCD:
People with OCD get trapped in their own repetitive thoughts and behavior. OCD occurs in cycles.  The cycle of OCD starts with obsession. Obsessions create unwanted thoughts, urges, and mental images. An example of this is a person with OCD might check if the doors are locked repeatedly. This leads to a situation of anxiety.  It makes the person feel like there is an imposing threat.  The 3rd step in the cycle is compulsions. This causes the person to repeatedly check to see if the doors are locked. They might check the door once and immediately feel like the door needs to be checked again. The last step in the cycle of OCD is a relief. This sense of relief is short-lived. The relief often goes away quickly causing new obsessions and compulsion starting the cycle all over again. PET scans on people with OCD found that they have found abnormalities in their brain in the deep layer of the cortex.
 
Panic Disorders:
Patients with panic disorder feature severe levels of panic.  When they panic the patient experiences sweatiness, dizziness, weakness, and shortness of breath. Panic disorder can be cured by with Selective Serotonin uptake Inhibitors (SSRIs), Sertraline and Paroxetine.
 
Phobias:
Phobias are referred to as an intense or irrational fear of a particular situation do object. Some examples of phobias are being scared of blood, snakes, spiders or heights. Cognitive behavior therapy is an effective way to treat phobias as well as exposure therapy.  Symptoms of phobias are dizziness, fear of fainting, and a fear of going insane, cold or hot flushes, shortness of breath.
 
PTSD:
 
PTSD is a stress disorder.  PTSD starts with an extreme stressor. Such as war, assault or witnessing a crime. Symptoms of PTSD are depression, excess stress hormones, and disordered sleep. A trigger in the environment causes symptoms to increase.  There are 4 types to treat PTSD.  The first one is psychotherapy (also known as cognitive behavior therapy CBT). The second type is a reduction in norepinephrine (a stress hormone). The 3rd type is an increase in GABA neurotransmitters and the 4th and the last type is Antidepressants (also known as Antipsychotic medication).

Down syndrome:
1 in 691 babies in the USA is born with Down syndrome. There are around 6,000 cases of Down syndrome each year in the USA.  Down syndrome is also referred to as trisomy-21. During the time of conception, an extra copy of chromosome 21 is created. Neuroscientists have not found out the reason for this but there seems to be a linkage with the age of the mother.  Symptoms of Down syndrome are usually physical. Some symptoms of Down syndrome are a space between the 1st and 2nd toe, an abnormally shaped ear, a small mouth and a large tongue, an upward slant to the eyes and joint laxity.  There is no current cure for Down syndrome. However, Neuroscientist is working to find the role of chromosome 21 in human development.



​Dyslexia:                             
80% of all learning disabilities are cases of Dyslexia.  People with Dyslexia have normal IQ and regular levels of motivation.  Dyslexia is caused by a defect in the language system called phonology. Some symptoms are a lack in taking fluently, a hard time retrieving words; they hesitate before responding (this is because they cannot think of the right words to say) and they often mis-pronounce words. A typical brain uses 3 parts of the brain to read. These parts are the Broca’s Area, Parieto Temporal and the Occipital Temporal. The Broca’s Area works with saying the words on the page as well as word analysis. The Parieto Temporal works with word analysis as well and the Occipital Temporal helps with word form. However, a Dyslexic brain only uses the Broca’s Area. This lead to a loss of word form as well as a limitation of word analysis as well as other issues. The treatment for Dyslexia often composes of practice reading stories as well as teaching the child to read using phonics.

 
ASD (Autism Spectrum Disorder):
1 in 110 babies born in the USA has ASD.  There are 40,000 cases of ASD each year in the USA.  ASD is highly genetic.  However, no specific gene has been associated with ASD. There are about 100 possible genes that could link directly with ASD.  There is 2 type of symptoms associated with ASD. The first kid is referred to as core features.   The core features of ASD are repetitive behaviors and problems with social communications.  The second type is called associated conditions. Some examples of associated conditions are anxiety, hyperactivity, mood swings, self-harm, tantrums, etc.  Currently, there is no medical or blood test that can detect ASD.  ASD is currently diagnosed with behavioral symptoms.  Patients with ASD have a larger brain than a normal person.  There is no cure for ASD.  However, behavior therapy, Learning programs, medications, and other treatments have shown to lessen the symptoms of ASD.
 
ADHD (Attention Deficit Hyperactive Disorder)
ADHD affects about 5% of all school-aged children. People with ADHD might have trouble in school, keeping a job or having good relationships.  Symptoms of ADHD more ape by middle childhood. There are 3 core symptoms of ADHD. The first core symptom is inattention. This is when people with ADHD do not focus.  This is mostly because they are too focused on something else to listen to what you are saying.  Most of the time a person with ADHD does not purposefully ignore you.  ADHD can co-exist with other disorders such as depression or ASD.  Like ASD ADHD does not have a specific diagnostics. ADHD is diagnosed by family history, DSM-IV criteria, childhood symptoms as well as physiological assessment.  ADHD could occur because of altered brain citrus in the cortex, cerebellum as well as other areas of the brain

​The Human body can undergo 2 types of stress acute stress and chronic stress.  Acute stress is temporary.  Examples of Acute stress are a new challenge, a competition, and trouble at work, getting stuck in traffic or lifting heavyweights. These are all temporary and the stress will be relieved after the event.  Chronic stress is a stress that is prolonged. Examples of chronic stress are poor sleep habits, difficult friends or a bad schedule.  

There are many disorders that take place when we sleep.  One such example is called REM sleep disorder. This disorder takes place in the REM stage of sleep. This happens when your muscles do not lock fully and you are not completely paralyzed as you sleep. If you have REM sleep disorder than you act out your dreams. For example, if in your dream you are walking you will start to walk in real life.
Another sleep disorder is called Narcolepsy.  Narcolepsy is when you cannot control when you sleep. A person with Narcolepsy cannot perform everyday jobs such as driving.  A person with Narcolepsy will fall asleep at any time they can fall asleep anytime. Because of this, they cannot do many things.
 
Another sleep disorder that affects people is called Sleep Apnea. Sleep Apnea is when your airflow gets blocked while you sleep. You cannot breathe when you sleep so you wake up. When you wake up it is only momentarily so you do not realize you woke up during the night. However, this cycle of waking and sleeping can cycle about 100 times a night. This leads to less time spent in deeper sleep such as stage 3 sleep. People with sleep apnea can fell tired even after they slept a full night sleep.
 
The last sleep disorder we will talk about is restless leg syndrome. This is when your leg starts felling various types of pain such as crawling, itching, throbbing and pulling.  There is also nighttime leg twitching. This usually starts after being at rest.  Movement can provide relief to restless leg syndrome.  Symptoms of this syndrome typically worsen in the evening and towards bedtime. 


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Our body has a Circadian Rhythm. Our circadian rhythm acts as a 24-hour internal clock. Our Circadian Rhythm is regulated by the Suprachiasmatic Nucleus.  A Suprachiasmatic Nucleus is a group of nuclei located in the hypothalamus.  The Suprachiasmatic Nucleus expresses clock proteins.  The function of these clock proteins set the pace for the day of activity it controls sleep and hormone releases. 
                                       
The Homeostatic system responds to longer wake periods by adding an urge to sleep.  Neuroscientist discovered that people who are awake have an increased level of adenosine.  The level of adenosine increases during sleep.  Adenosine also decreases during cellular activity.

There are 5 stages of sleep.  The first stage is referred to as light sleep. During the first stage of sleep, muscle activity is lowered and people can be easily awakened from stage 1 sleep. The next stage is stage 2 sleep. In stage 2 sleep the breathing pattern and heart rate slow down. We spend most of our time sleeping in stage 2 sleep.  During stage 3 the brain produces delta waves. Breathing and heart rate go to their lowest level.  During stage 4 there is rhythmic breathing and very limited muscle activity. Stage 5 of sleep is known as REM (Rapid Eye Movement) sleep.  You lose consciousness during REM sleep.  You dream during this period of REM sleep. Also, your body becomes paralyzed all of your limbs lock in place. Your breathing rate and blood pressure rise as well.  During REM sleep your eyes move very rapidly back and forth under your eyelids. This is how the name REM was derived.

​Language is one of the most prominent human abilities.  A neuroscientist has learned a lot about language from stroke patients.  A problem in a language is referred to as aphasia. There are 3 types of language problems Broca’s Aphasia, Wernicke’s Aphasia and word deafness. Broca's Aphasia takes place in the left frontal lobe.  Speech is impaired and it is often slow and it requires the patient a lot of effort. Although speech is impaired people with Broca's Aphasia can still comprehend language. Wernicke’s Aphasia takes place in the left temporal lobe. People with Wernicke’s Aphasia talk at a fluent rate however they cannot make proper sentences.   word deafness takes place in both sides of the temporal lobe.  They cannot who is talking or comprehend speech. Another prominent human ability is the ability to recognize objects.  A loss of this function is called agnosia.  Agnosia is defined as the loss of ability to recognize an object. A case study for this is a patient referred to as D.B.O. D.B.O suffered from many strokes. These strokes led to damage to his temporal lobe.  This damage resulted in the visual entry to the anterior temporal lobe.  D.B.O could not name objects he saw but only objects he touched this is Agnosia. Some other parts of the brain that helps us recognize objects they are fusion face area ( FFA), Parahippocampal Place Area ( PPA)  and Visual word form area ( VWFA).  The FFA is critical for recognizing faces. Damage to the FFA will cause face blindness also known as prosopagnosia. The PPA responds to specific locations such as specific buildings or cities. VWFA recognizes written letters and words.  connections between the VWFA and the rest of the brain work to establish written language.

Patient with  Wernicke's Aphasia video : https://www.youtube.com/watch?v=3oef68YabD0
Patient with Broca’s Aphasia video : https://www.youtube.com/watch?v=JWC-cVQmEmY&t=89s

​Learning and memory is a complex process and a lot of research is currently happing about it.  One famous case study that helps us learn about memory is H.M.  H.M had severe epilepsy as a child. He had severe epilepsy as a child.  He had surgery performed on him to help him alleviate his epilepsy. During this surgery, he lost his hippocampus and his temporal lobe. He lived but he lost his ability to make long term memories. There are 2 types of memory declarative and nondeclarative.  Declarative memory is short term memory and everyday facts. Nondecaltive memory is long term memory and skilled behavior and learned habits.  The prefrontal cortex is very helpful in memory. It helps with your working memory and especially retrieving that memory.  You have semantic memory and nonsemantic memory. semantic memory helps you with object knowledge and nonsemantic memory remembers memories of specific events you witnessed. Memories are stored by changes in synaptic connections