Evoked response

Bansal G, DiVietro JA, Kuehn HS, Rao S, Nocka KH, Gilfillan AM, Druey KM RGS13 controls G protein-coupled receptor-evoked responses of 56 human mast cells. J Immunol 2008 181 7882-7890. 

In addition to changes within the nerve, sympathetic afferents become able to activate sensory afferents via as yet poorly characterised a-adrenoceptors. These interactions between adjacent sensory and autonomic nerve axons and between ganglion cells result in excitation spreading between different nerve fibres. These peripheral ectopic impulses can cause spontaneous pain and prime the spinal cord to exhibit enhanced evoked responses to stimuli, which themselves have greater effects due to increased sensitivity of the peripheral nerves. 

Delays in reflex development have been reported in rats during early postnatal life at PbB levels 59 pg/dL (Kishi et al. 1983), and alterations in visual evoked responses and decreased visual acuity in young rats occurred at mean PbB levels of 65 pg/dL (Cooper et al. 1980 Fox et al. 1977, 1982 ... 

Cooper GP, Fox DA, Howell WE, et al. 1980. Visual evoked responses in rats exposed to heavy metals. In MeriganWH, Weiss B, eds. Neurotoxicity of the visual system. New York, NY Raven Press, 203-218. 

Fox DA, Lewkowski JP, Copper GP. 1977. Acute and chronic effects of neonatal lead exposure on development of the visual evoked response in rats. Toxicol Appl Pharmacol 49 449-461. 

Rothenberg SJ, Poblano A, Garza-Morales S. 1994. Prenatal and perinatal low level lead exposure alters brainstem auditory evoked responses in infants. Neurotoxicology 15 695-700. 

Quantal analysis defines the mechanism of release as exocytosis. Stimulation of the motor neuron causes a large depolarization of the motor end plate. In 1952, Fatt and Katz [11] observed that spontaneous potentials of approximately 1 mV occur at the motor endplate. Each individual potential change has a time course similar to the much larger evoked response of the muscle membrane that results from electrical stimulation of the motor nerve. These small spontaneous potentials were therefore called... 

Pao2 = 20 mmHg generally results in coma. In graded hypoxia in experimental animals, brain ATP levels remain normal at Pao2 = 20-25 mmHg despite EEG slowing and attenuated sensory evoked responses. 

Measuring muscle-evoked responses to repetitive motor nerve electrical stimulation permits detection of presyn-aptic neuromuscular junction dysfunction. In botulism and the Lambert-Eaton syndrome, repetitive stimulation elicits a smaller than normal skeletal muscle response at the beginning of the stimulus train, due to impaired initial release of acetylcholine-containing vesicles from presyn-aptic terminals of motor neurons followed by a normal or accentuated incremental muscle response during repeated stimulation. This incremental response to repetitive stimulation in presynaptic neuromuscular disorders can be distinguished from the decremental response that characterizes autoimmune myasthenia gravis, which affects the postsynaptic component of neuromuscular junctions. 

As to the primary developmental actions of testosterone, growth and differentiation appear to be involved. Testosterone or estradiol stimulates outgrowth of neurites from developing hypothalamic neurons that contain estrogen receptors [14, 15]. This is believed to be one of the principal aspects of testosterone action that increases the number and the size of neurons within specific hypothalamic nuclei in males, compared to females [1, 14, 15]. 5a-DHT may have a similar effect on androgen-sensitive neurons. Differentiation of target neurons also occurs in adult brain tissue, hormones like estradiol can evoke responses that differ between adult male and female rats [1,14,15],... 

The development of mild forms of anxiety and neuroveg-etative and/or cognitive responses to stress may represent an adaptive evolutionary step against environmentally (external) or self-triggered (internal) threats, but maladaptive reactions have also emerged in human evolution. Thus, anxiety disorders are maladaptive conditions in which disproportionate responses to stress, or even self-evoked responses, are displayed. Anxiety disorders are one of the most frequent psychiatric illnesses, and have a lifetime prevalence of 15- 20% [1, 89]. The most common presentations are generalized anxiety disorder, with a lifetime prevalence rate of close to 5% [1, 89] social anxiety disorder, with very variable lifetime prevalence rates ranging from 2 to 14% [90] panic disorder, with rates from 2 to 4% [1,89] and post-traumatic stress disorder (PTSD), with a prevalence rate close to 8%. Specific phobias, acute stress and obsessive-compulsive behavior are other clinical presentations of anxiety disorders. 

M. Firbank, E. Okada, and D. T. Delpy. A theoretical study of the signal contribution of regions of the adult head to near-infrared spectroscopy studies of visual evoked responses. Neuroimage, 8 69-78, 1998. 

M. A. Franceschini, S. Fantini, J. H. Thompson, J. P. Culver, and D. A. Boas. Hemodynamic evoked response of the sensorimotor cortex measured noninva-sively with near-infrared optical imaging. Psychophysiology, 40 548-560, 2003. 

At 0.35 ppm, all three subjects exposed for 2 h developed mild headaches, and one of three subjects exposed for 8 h developed a mild headache. Two of three subjects exposed for 8 h developed severe headaches. One subject also developed slight eye irritation, which persisted throughout the 2 h exposure. Four of the nine subjects detected the odor of the compound, which they described as mild at this concentration however, the odor was not detectable after 5 min of exposure. The morphology of the visual evoked response, while variable, was altered, particularly in three subjects exposed for 8 h. The exposure produced an increase in the peak-to-peak amplitude of the 3-4—5 wave complex. The authors interpreted the VER changes as consistent with the VER changes produced by central nervous system depression. 

Uncertainty factors Interspecies 3—The monkey was more susceptible than the rat the lowest concentration in a range was chosen (70 ppm) humans and monkeys showed changes in the visual evoked response at similar concentrations the monkey is a good model for the human. The concentration inducing central nervous system depression does not vary greatly among mammalian species. Intraspecies 3—Individual variation in susceptibility to central nervous system depressants such as anesthetics varies no more than 2-fold. 

Change in visual evoked response 0.35 ppm for 8 h Threshold for impairment of balance 0.5 ppm for 6 h Threshold for abnormal cognitive test 1.5 ppm for 3.2 h End point/Concentration/Rationale A 6-h exposure at 0.5 ppm which resulted in severe headache and was the threshold for loss of equilibrium falls within the AEGL-2 definition of threshold for impaired ability to escape. 

Rebert C, Sorenson. 1983. Concentration-related effects of -hexane on evoked responses from brain and peripheral nerve of the rat. Neurobehav Toxicol Teratol 5 69-76. 

Startle reflex brainstem auditory evoked response... 

Auditory Amplitudes and durations of waveforms Brain auditory evoked response Dog Holliday et al.194... 

Holliday, T.A., Nelson, H.J., Williams, D.C., and Willits, N., Unilateral and bilateral brainstem auditory-evoked response abnormalities in 900 Dalmatian dogs, /. Vet. Intern. Med., 6,166-174, 1992. 

HPPD has been studied with quantitative EEC. Compared to controls, people with HPPD show a faster alpha frequency and shorter visual-evoked-response latency, consistent with LSD-induced cortical disinhibition (Abraham and Duffy 1996). Conversely, the auditory-evoked-response latency is increased. Analyses indicate that these differences are predominant in temporal and left parietal regions. 

Berti C, Nistri A. (1983). Influence of caffeine and midazoiam on gamma-aminobutyric acid-evoked responses in the frog spinai cord. Neuropharmacology. 22(12A) 1409-12. 

Minor chromosomal abnormalities Inhibition of intracellular hydrolytic enzymes of alveolar macrophages increased fraction of polymorphonuclear leukocytes Alterations in blood, including red-cell membrane and enzyme changes and increased serum vitamin E and lipid peroxides Decreased lung DNA synthesis Decreased electric response of specific areas of brain with evoked-response technique... 

Xintaras, C., B. L. Johnson, C. E. Ulrich. R. E. Terrill, and M. F. Sosecki Application of the evoked response techniques in air pollution toxicology. Toxicol Appl. Pharmacol. 8 77-87, 1966. 

A total of 21 compounds present in the surface and cephalic extracts of the queen bumblebee, Bomhus terrestris, evoked responses in male antennae. These included saturated and unsaturated fatty acids, ethyl and methyl esters of the fatty acids, heptacosene, 2-nonanone, and geranyl geraniol. A blend of synthetic versions of these compounds elicited typical male mating behavior. 

Exposure of nonsmokers to 50 ppm for 6-8 hours results in carboxyhemoglobin levels of 8-10%. Several investigators have suggested that the results of behavioral tests such as time discrimination, visual vigilance, choice response tests, visual evoked responses, and visual discrimination threshold may be altered at levels of carboxyhemoglobin below 5%. ... 

Figure 1. A. SimpMed diagram of the rodent hippocampal formation illustrating the major glutamatergic circuitry. The principal neuronal helds granule cells (GC) of the dentate gyrus and pyramidal cells of CAl and CA3 in Ammon s horn are shown. The main excitatory connections are also indicated the perforant path from entorhinal cortex to the granule cells, from there the mossy hbre (mf) axonal projections to CA3 and then the Schaffer collaterals (Sch) from CA3 to ipsilateral CAl and commissural (Comm) to contralateral CAl cells. Evoked responses in (B) were obtained by stimulating the afferent pathway from entorhinal cortex, the medial perforant path (Med), and recording the granule cell (GC) response in the hilus of the dentate gyrus.

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