Itt írjon a(z) SubcorticalAsymmetries-ról/ről

= Title 1 =;Asymmetries in the subcortical region of the Brain

== Title 2 ==Introduction

Asymmetries in the subcortical region of the brain is primarily concerned with ratio of white matter to grey matter in anatomical structures involving the Basal Ganglia, Planum Temporale, Thalamus and Limbic System. The grey matter is the cell bodies of the neurons, while the white matter is the tendrils, called dendrites and axons that spread out from the cell bodies to connect to other neurons. Signals pass between them by the release and capture of neurotransmitter and neuromodulator chemicals, such as glutamate, dopamine, acetylcholine, noradrenalin, serotonin and endorphins.

The functions mainly concerned with the subcortical region of the brain are psychological processes including learning, memory, language, and cognitive functions. The subcortical structures receive a wide array of different inputs from the cerebrum and peripheral sense organs and stretch receptors. Through the use of recurrent feedback loops this information is integrated and a response is constructed to provide output which contributes to sequencing, timing and preciseness of movement, as well as learning and automation of motor and non-motor behaviours. brain image.png

Extra Asymmetries or disturbed asymmetries of the subcortical region can cause impairments regarding the above functions and schizophrenia. Schizophrenia is a condition which will be discussed in detail below, but for now we need to understand the basics behind it. Schizophrenia is strongly associated with volumetric alterations within the cortical region. As a result features such as smaller bilateral hippocampus, amygdale, thalamus and accumbens can be observed. Similarly the opposite occurs regarding the bilateral caudate and putamen, which are seen to increase.

=== Title 3 ===;Asymmetry of the Subcortical System

Firstly we need to understand what exactly lateralization is, by scientific terms lateralization refers to ’how neural functions or cognitive function tend to be dominant in one hemisphere of the brain’. There is evidence to show that lateralization occurs in the hypothalamic, limbic, and other brain structures. These structures were also identified as physiological structures which are all directly or indirectly involved in the control of the endocrine glands. Data suggest predominance of the right half of brain structures in controlling gonadal function. (Gerendai, Halász.,2001.)

• Hypothalamus The hypothalamus is a section responsible for the production of many of the body’s essential hormones (thyrotropin-releasing, gonadotropin-releasing, growth hormone-releasing, corticotrophin-releasing, somatostatin, and dopamine) that help control different cells and organs.

  Experimental observations supporting the view regarding the hypothalamus asymmetries were conducted and a special experiment was designed: brain lesion on either the right or left side of the brain, was performed in animals subjected to removal of the right or the left endocrine gland, following this changes in biochemical parameters were measured in the right and left halves of the hypothalamus following right- or left-sided complete removal of the ovary. The results of the experiment, were the gonadotropic hormone-releasing hormone (GnRH) content of the hypothalamus halves, studied in hemi-ovariectomized rats, indicated that in intact control animals the GnRH content is significantly higher in the right half of the hypothalamus than in the left half (Gerendai et al.,1978.)

  Further studies, similar to the previously mentioned, indicated that in the male rat the right side of the hypothalamus also contains significantly more GnRH than the left (Bakalkin GY et al.,1984.) This simple experiment proved the presence of asymmetries in the Hypothamlic system, it also displayed how asymmetries on either the left or right has an effect on the gonads on the opposite side of the body.

  Hypophysis/ Pituitary gland