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Monday, December 12, 2011 I wish love was like a poem; you write it, you read it and re-read it again and again till your lips hurt...but in real life love is not written, nor can you read it and re-read it with the same tenable passion; it is many times unaccomplished, many times unrequited, many times forbidden, many times incomplete and unimportant. And yet we venture every day with the will to write it, read it and re-read it till our lips hurt. But love isn't like a poem. It's more like a text message lost in the gutter of cyberspace :/

posted by Jonathan @ 5:45 PM 0 Comments: Post a Comment << Home

Neurobiology is a branch in science concerned with the functions and the structure of cells in the nervous system. It is centered about the brain. Today's technologies have allowed scientists and neurobiologists to look into the brain and the human body through different methods.

Creator's Purpose

The creator of this web-site, Juan D. Romero, will provide the student with a summary of the set of methods by which neurobiologists study the brain and its affected areas; Neuron/Nervous System and the Brain Structure.

NEUROIMAGING

-Neuroimaging includes the use of an assortment of techniques to either directly or indirectly image the structure, function/pharmacology of the brain. It is a comparatively new discipline within medicine and neuroscience/psychology.

Neuroimaging falls into two broad categories:

-Structural imaging, which deals with the structure of the brain and the diagnosis of gross (large scale) intracranial disease (such as tumor), and injury, and -Functional imaging, which is used to diagnose metabolic diseases and lesions on a finer scale (such as Alzheimer's disease) and also for neurological and cognitive psychology research and building brain –computer interfaces.

MRI, CAT, PET, EGG, fMRI

Magnetic Resonance Imaging (MRI): (it images structure) Used to view the structure of the brain. Magnetic resonance imaging (MRI) is a non-invasive way to take pictures of the body. Unlike x-rays and computed tomography (CT) scans, which use radiation, MRI uses powerful magnets and radio waves. The MRI scanner contains the magnet. The magnetic field produced by an MRI is about 10 thousand times greater than the earth's. The magnetic field forces hydrogen atoms in the body to line up in a certain way (similar to how the needle on a compass moves when you hold it near a magnet). When radio waves are sent toward the lined-up hydrogen atoms, they bounce back, and a computer records the signal. Different types of tissues send back different signals. For example, healthy tissue sends back a slightly different signal than cancerous tissue.

Position Emission Tomography (PET): PET ­produces images of the body by detecting the radiation emitted from radioactive substances. These substances are injected into the body, and are usually tagged with a radioactive atom, such as Carbon-11, Fluorine-18, Oxygen-15, or Nitrogen-13, that has a short decay time . These radioactive atoms are formed by bombarding normal chemicals with neutrons to create short-lived radioactive isotopes.

Computed Axial Tomography (CAT): it traces amounts of glucose in the brain. The more active parts of the brain metabolize more glucose. This is used to see which parts of the brain are more active; for example, when we listen to music, do math problems etc. This occurs because the glucose is injected into the bloodstream and it goes to the brain, but a harmless radioactive compound is also injected in the bloodstream along with glucose.

Electroencephalogram (EEG): it has to do with electrical stimulation of the brain. EEG records natural electrical activity of the brain. EEG detects brain waves (minute amounts of electrical activity) that pass between the electrodes [a conductor through which electric currents are passed] attached to the scalp. We must note that certain waves in the brain are associated with different functions and feelings and different stimuli ;sounds, lights. EEG is also used to locate tumors.

Functional Magnetic Resonance Imaging (f-MRI): (It images function) It relies on subtle shifts of blood flow (more blood flows to the more active parts of the brain). Person lies on powerful magnetic field and is exposed to radio waves that cause certain parts of the brain to emit signals, which are measured form multiple angles.

Brain Structure

The Structure of the Brain

Biologically, the function of the brain is to generate behaviors that promote the survival of the being. It works by the manner in which the brain allows the body to interact with the environment.In some cases the actions may be immediate as sensory and reflex allows us to react and recognize danger. Many of such responses may need to be stored in the brain in order for one to recognize danger in the future or one to be able to perform certain actions without having to think about them. This is how the brain develops.

The Medial Geniculate Nucleus controls blood pressure, breathing, and heart rate.

The Pons is located on the brain stem above the medulla and toward the front. It's responsible for facial expression. Some expressions that are universal. All culture have smiles and fears. Some are innate and some are culturally based.

The Cerebellum is next to the medulla. Means "little brain"; controls movement. Is what allows us both of our eyes to go on one direction to track something. Controls habitual muscle movements and things you don't think about like walking; like learning a dance, you didn't know first, but if you practice you won't think how to do it.

The three structures are called hind brain or primitive brain. This is what we have in common with all animals. It's the oldest part of the brain. From hind brain you come up into the mid-brain. Sensory motor region; motor controls movement and sensory recevies sensation. The mid-brain coordinates behavior like when we hear something and focus our eyes somewhere and we coordinate. There is a net-like or network (Reticular formation or Sensory and motor strip) of neurons that connect sensory and motor functions. -if someone comes into the room and speaks to you and you don't know where they are but you don't know--something has happened at cerebellum.

Brain Plasticity is the ability of the brain to adjust to new experiences and new types of learning. As we acquire new types of knowledge the brain must learn how to connect new certain types of pathways. This ability of the brain is known as neuroplasticity

Neurons/Nervous System

With the help of the nervous system, a group of cells that work to help the organism respond to its environment and itself, our body is able to transmit information through chemical electrical signals in the neurons. Different types of neurons work in different manners. A neuron is composed of a dendrite, which receives all information that is going to go to the brain and come back to a certain area. We have the Myelin sheet which propagates the impulses and the rate at which they are transmitted into the brain. The Axon conducts electrical impulses away from the cell. The nucleus' function is usually much like the function of the nucleus in various other cells. The Axon terminal passes the information received through a dendrite to another dendrite of another neuron; it is through the axon, as it goes through the synapse that certain chemicals trapped in vesicles are expounded into the dendrites of another neuron. Different neurons have different chemicals in these vesicles depending on the function they want to achieve, the rate at which they want it achieved, or the amplification at which they want it achieved.

There are as well several types of neurons. Sensory or receptive (afferent) neurons respond to touch, sound, light and other stimuli that may be affecting sensory organ cells, organs that then send signals to the spinal cord and brain. Motor neurons (efferent) receive signals from the brain and spinal cord and cause muscle contractions and affect glands. Inter-neurons connect neurons to other neurons within the brain and spinal cord.

The nervous system is a very important part of the body which controls various functions that allows us humans to perform everyday tasks like opening and closing our eyes, moving our pupils, moving ourselves about or even thinking. That is why the nervous system and the neurons are so important in carrying out such tasks which one may find negligible.

Basic Genetics

When we refer to genetics, we have various species which may have an allele which could be analogically explained as an ice cream with different types of flavors; we may have for example a flower with different colors. The flower itself may be homozygous which refers to a daughter cell that has the same trait from each parent such as (TT) for the for a plant whose parents were both tall. A heterozygous on the other hand is when the daughter cell has a different trait from each parent, and the process here may be more difficult for we may have a parent whose seeds are round, and the other parents' seeds are uniform. Then the possibility of a daughter cell with round seeds or uniform seeds depends upon the punnet square, where one parent has round seeds (S) and the other has uniform seeds (s) so it would be (Ss).

In basic genetics, we may also have different manners in which the egg is fertilized and the results are consequently different. There is a dizygote which are fraternal twins and it is when two sperms get fertilized at the same time. They may look similar, or they may be of different sexes or the same sex. Just siblings that happen to have the same age. We may also have a monozygotic which is one egg that gets fertilized by one sperm and then it splits in two and these are identical twins. That is when the physical appearance is not exactly the same, but they have nearly identical DNA. They are always the same sex and are genetically identical. If the egg splits within two days it is dichorionic diamniotic (different placenta and sacs). if it splits after two days it is monochonoti cdiamniotic (one placenta and different sacs). if the zygote splits extremely late it may result in conjoined twins.