Cortex Subject

Traumatic brain injury is the most common cause of death in subjects under the age of 40, and an important risk factor for AD. Loss of hippocampal cells and depletion of ACh and of muscarinic receptors can be attenuated in injured experimental animals, improve blood perfusion in ischemic areas and increase cholinergic transmission in cortex and hippocampus the same mechanism invoked for treatment of VD. 

The major androgen or androgen precursor produced by the adrenal cortex is dehydroepiandrosterone (DHEA). Most 17-hydroxypregnenolone follows the glucocorticoid pathway, but a small fraction is subjected to oxidative fission and removal of the two-carbon side chain through the action of 17,20-lyase. The lyase activity is actually part of the same enzyme (P450cl7) that catalyzes 17tt-hydroxylation. This is therefore a dual function protein. The lyase activity is important in both the adrenals and... 

Arora, R. C. Meltzer, H. Y. (1989). Serotonergic measures in the brains of suicide victims 5-HT(2) binding sites in the frontal cortex of suicide victims and control subjects. Am. J. Psychiatry, 146, 730-6. 

The average increase in rCMR after THC administration was less in marijuana users than in controls, and users had lower cerebellar metabolism than the controls at baseline [8]. Thus the cerebellum shows the greatest metabolic increase in response to acute THC and responds to chronic marijuana exposure with a decrease in baseline CMR. Habitual users but not controls responded to THC administration with increased rCMR in prefrontal cortex, orbitofrontal cortex, and basal ganglia. In contrast to the robust effects of THC on relative rCMR, changes in global CMR in response to THC were quite variable, with increases, decreases, and no changes seen in equal numbers of subjects. There was also variability in subjective effects, which were pleasurable for most subjects but either minimal or unpleasant (anxiety or paranoia) for others. 

In general, quality is assessed by quantifiable traits that are more or less related to specific attributes of the product and the production process. Moreover, the assessment depends on the information delivered by the sensory organs. Information is filtered and evaluated by the brain depending on the specific information provided but also on the concept of understanding that already exists in the cerebral cortex (Singer, 2000). A mental representation of a sensory event can shape neural processes that underlie the formulation of the actual sensory experience. Thus, the subjective sensory experience is shaped by interactions between expectations and incoming sensory information. 

The brain, like the seminal vesicles, is able to reduce testosterone to 5a-dihydrotestosterone (DHT) and, like the placenta, the brain aromatizes testosterone to estradiol (Fig. 52-4). Neither conversion occurs equally in all brain regions. The aromatization reaction is discussed below. Regional distribution of 5a-reductase activity toward testosterone in rat brain reveals that the highest activity is found in the midbrain and brainstem, intermediate activity is found in the hypothalamus and thalamus, and the lowest activity is found in the cerebral cortex [1]. The pituitary has higher 5a-reductase activity than any region of the brain, and its activity is subject to changes as... 

Early postmortem neurochemical studies suggested reductions in presynaptic markers for the GABAergic neurons, such as glutamatic acid decarboxalase (GAD) activity, in prefrontal cortex in schizophrenic subjects... 

Stark, A. K., Uylings, H. B., Sanz-Arigita, E. and Pakkenberg, B. Glial cell loss in the anterior cingulated cortex, a subregion of the prefrontal cortex, in subjects with schizophrenia. Am. J. Psychiatry 161 882-888, 2004. 

None of the exposures produced changes in clinical chemistry values (blood count, blood nitrate, blood urea nitrogen, serum enzymes, and serum electrolytes or urinalysis and nitrate and nitrite urinary excretion), spontaneous electrical activity of the cortex of the brain (detected by EEG), pulse rate and sinus rhythm, or pulmonary function. Visual and auditory acuity, exercise EKG, and time estimation tests did not differ from control values for any of the exposures. Only one of several cognitive tests was affected by exposure and the change occurred only in the four subjects exposed at 1.5 ppm. The test was taken during the time the subjects were experiencing severe headaches. 

Scopolamine increases cerebral blood flow to lateral occipital cortex bilaterally and to the left orbitofrontal region (Grasby et al. 1995). Decreases are seen in the right thalamus, precuneus, and lateral premotor areas bilaterally. When normal subjects are chronically administered scopolamine, there is a 12% increase in cerebral blood flow on single photon emission computed tomography (SPECT), but a decrease in cerebral muscarinic binding (Sunderland et al. 1995). On the other hand, acute administration dose-dependently reduces cortical blood flow, which is maximal in frontal cortex (Gitelman and Prohovnik 1992 Prohovnik et al. 1997). 

Enzyme activity in sheep, marmoset, and human brain extracts. CYP7B mRNA in human hippocampus, cerebellum, cortex less in dentate neurons from Alzheimer s diseased subjects by in situ hybridization (Yau et al., 2003). 

Smoking-related stimuh produced greater activation in nicotine-dependent subjects than in nonsmokers in prefrontal cortex, hippocampus, amygdala, ventral tegmental area, and thalamus. 

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