Mammalian Brain Development

 

The embryonic fetal brains of all mammals develop in the same way. In humans and many other mammals, new neurons are created mainly before birth, and the infant brain contains more neurons than the adult brain. This is mentioned in the book as Neural Darwinism, the strongest neurons survive ans the weak deteriorate and die. There are, however, a few areas where new neurons continue to be generated throughout life. The two areas that are well established are the olfactory bulb, which is involved in the sense of smell, research shows that one of the first signs of mammalian brain evolution begun with the sense of smell, and the dentate gyrus of the hippocampus where there is evidence that the new neurons play a role in storing newly acquired memories. With these exceptions, however, the set of neurons that is present in early childhood is the set that is present for life. Glial cells are different: as with most types of cells in the body, they are generated throughout the lifespan. 

     All vertebrate brains share a common underlying form, which appears most clearly during early stages of embryonic development. In its earliest form, the brain appears as three swellings at the front end of the neural tube; these swellings eventually become the forebrain, midbrain, and hindbrain (the prosencephalon, mesencephalon, and rhombencephalon, respectively). At the earliest stages of brain development, the three areas are roughly equal in size. In many classes of vertebrates, such as fish and amphibians, the three parts remain similar in size in the adult, but in mammals the forebrain becomes much larger than the other parts, and the midbrain becomes very small.

    

     ^{Normally brain is compared in terms of its size. The larger the brain is compared to its body mass the higher the mental faculties of that animal is. However that is not the case in all species therefore it is not a very valid equation.}

     ^{Although the same basic components are present in all vertebrate brains, some branches of vertebrate evolution have led to substantial distortions of brain geometry, especially in the forebrain area. These distortions can make it difficult to match brain components from one species with those of another species.}

     ^{On a different note concerning brain size, research done on 500 different types of mammal species throughout their lifespan showed a correlation with brain size and their longevity. The article basically says that the larger the body brain size ration the longer the lifespan.}

      

Cocaine

   Commonly known as crack, cocaine is a highly addictive drug and exceedingly dangerous. What it does is block the re-uptake receptors for dopamine causing the euphoric feeling, noradrenoline which is responsible for the increased feelings of energy, and seratonin. By inhibiting the re-uptake the neurotransmitters cannot be recycled for later use and the CNS is left active until the neurotransmitters are degenerated causing the "crash" that comes after the "high"
    On average a high only last from 5-30 minutes, that is why the drug is so addictive. The user wants a prolonged effect so they will use dose after dose.What tends to happen is that the druggie develops an immunity to the effects of cocaine causing the struggle to obtain the same level of euphoria extremely life threatening. Some symptoms of an overdose include nausea, chills, paranoia, insomnia, and psychological breakdowns. Aside from these short term effects, long term effects are even more unpleasant.
   Psychosis, change in personality, paranoia, anxiety, various heart problems ranging from raised blood pressure to strokes and heart failure. If cocaine is "snorted" the nasal septum degenerates or disappears completely

  So yes, cocaine can really mess you up.

Blood-Brain Barrier, Breached...?

      As you all may know the blood-brain barrier works as high security gate against unknown intruders. One may think, great my brain has its own defense mechanism against potential threats, well that is true but it also has its drawbacks. There are cases in which the blood brain barrier may be penetrated which include high blood pressure, high concentrations of a certain substance in the blood stream, radiation and infection among others. Otherwise anything that wishes to proceed into the brain must be lipid soluble, not highly charged, and not too large.
     On the other assuming the brain is already damaged it is difficult to treat the problem directly if the blood brain barrier blocks all our efforts. For example, illnesses such as Alzheimer's, brain cancer and multiple sclerosis are all difficult to treat because the barrier blocks the medicine. However a breakthrough has been made.
     Although it is only the beginning of finding a way of better treating patients with these illnesses. There is still a lot of research to be done.

This picture show a capillary surrounded by an astrocytic glial membrane.

Intro to physiological psychology

Humans have been assumed to be the intelligent animals on the planet. However, scientist have failed to explain completely as to how intelligence is measured across species. Brain size is certainly not a good measure, IQ is rather relative, and neither is brain-to-body ratio. There are several animals that have a greater brain-to-body ratios than us and also as obesity increases among our kind brain-to-body ration is decreasing. What i find interesting is that to this day we haven't been able to find a correlation as to why us and not the dolphins or the whales as the dominant species. Apart from the obvious, what sets us apart intellectually from other animals?