Blink Reflex: Comparison Of Latency Measurements In Different Human Races

The blink reflex latencies and cephalometric indexes were analysed in 30 male volunteers from three different races, 10 white, 10 black, and 10 Oriental. Ages ranged from 15 to 59 years, height from 1,60 to 1,80 m, and weight from 60 to 80 kg. Blink reflexes were obtained after unilateral electric stimulation of the supraorbital nerve for quantitative analysis of 3 responses, early ipsilateral (R1), late ipsilateral (R2i) and late contralateral (R2c), obtained from the orbicularis oculi muscle. Cephalometric indexes were calculated by multiplying the ratio between the longer transverse and the longer sagital head diameters by 100. The R1, R2i and R2c latencies were consistent with other published papers revealing no differences between the different racial groups. The mean of the cephalometric indexes of each group were consistent with respective racial characteristics. This study revealed that there are no differences between R1, R2i and R2c latencies in the 3 different studied races.603 A563565Kimura, J., Powers, J.M., Allen, M.W.V., Reflex responses of orbicularis oculi muscle to supraorbital nerve stimule (1969) Arch Neurol, 21, pp. 193-199Tokunaga, A., Oka, M., Murao, T., An experimental study on facial reflex by evoked electromyography (1958) Med J Osaka Univ, 9, pp. 397-411Terrell, G.S., Terzis, J.K., An experimental model to study the blink reflex (1958) J Reconstr Microsurg, 10, pp. 175-183Fine, E.J., Sentz, L., Soria, E., The history of the blink reflex (1992) Neurology, 42, pp. 450-454Dejong, R.N., Haerer, A.F., (1992) The Neurologic Examination. 5.Ed., pp. 184-188. , Philadelphia: LippincottOverend, W., Preliminary note on a new cranial reflex (1992) Lancet, 1, p. 619McCarthy, D.J., Der Supraorbitalreflex. ein neuer Reflex im gebeit des 5. und 7. Nervenpaares (1901) Neurol Zentralbl, 20, pp. 800-801Kugelberg, E., Facial reflexes (1952) Brain, 75, pp. 385-396Magladery, J.W., Teasdall, R.D., Corneal reflex an EMG study in man (1961) Arch Neurol, 5, pp. 51-56Rushworth, G., Observations on blink reflexes (1962) J Neurol Neurosurg Psychiatry, 25, pp. 93-108Bender, L.F., Maynard, F.M., Hastings, S.V., The blink reflex as a diagnostic procedure (1969) Arch Phys Med Rehabil, 50, pp. 27-31Thatcher, D.B., Allen, M.W.V., Corneal reflexes latency (1971) Neurology, 21, pp. 735-737Shahani, B.T., Young, R.R., Human orbicularis oculi reflex (1972) Neurology, 22, pp. 149-154Testut, L., Latarjet, A., (1988) Tratado de Anatomía Humana. 9.Ed., , Barcelona: SalvatClay, A.S., Ramseyer, J.C., The orbicularis oculi reflex in infancy and childhood (1976) Neurology, 26, pp. 521-524Kimura, J., Bodensteiner, J., Yamada, T., Electrically elicited blink reflex in normal neonates (1977) Arch Neurol, 34, pp. 246-249Blank, A., Ferber, I., Shapira, Y., Electrically elicited blink reflex in children (1983) Arch Phys Med Rehabil, 64, pp. 558-559Vecchierini-Blineau, M.F., Evolution du reflexe de clignement pendant les trois premieres années de la vie chez l'enfant (1983) Electroencephalogr Clin Neurophysiol, 13, pp. 137-144Vecchierini-Blineau, M.F., Guiheneuc, P., Maturation of the blink reflex in infants (1984) Eur Neurol, 23, pp. 449-458Khater-Boidin, J., Duron, B., The orbicularis oculi reflexes in healthy premature and full-term newborns (1987) Electroencephalogr Clin Neurophysiol, 67, pp. 479-484Shahani, B.T., Effects of sleep on human reflexes with a double component (1968) J Neurol Neurosurg Psychiatry, 34, pp. 574-579Ferrari, E., Messina, C., Blink reflex during sleep and wakefulness in man (1972) Electroencephalogr Clin Neurophysiol, 32, pp. 55-62Kimura, J., Harada, O., Excitability of the orbicularis oculi reflex in all nigth sleep: Its suppression in NREM and recovery in REM sleep (1972) Electroenceph Clin Neurophysiol, 33, pp. 369-377Silverstein, L.D., Grahan, F.K., Calloway, J.M., Preconditioning and excitability of the human orbicularis oculi reflex as a function of state (1980) Electroenceph Clin Neurophysiol, 48, pp. 406-417Boelhouwer, A.J.W., Brunia, C.H.M., Blink reflex and the state of arousal (1977) J Neurol Neurosurg Psychiatry, 40, pp. 58-63Sanes, J.N., Foss, J.A., Ison, J.R., Conditions that affect the thresholds of the components of the eyeblink reflex in humans (1982) J Neurol Neurosurg Psychiatry, 45, pp. 543-549Desmedt, J.E., Godaux, E., Habituation of exteroceptive suppression and of exteroceptive reflexes in man as influenced by voluntary contraction (1976) Brain Res, 106, pp. 21-29Lowitisch, K., Habituation of the Blink-reflex: Computer assisted quantitative analysis (1985) Electroenceph Clin Neurophysiol, 60, pp. 525-53

The diving behaviour of mammal-eating killer whales (Orcinus orca): variations with ecological not physiological factors

Mammal-eating killer whales (Orcinus orca (L., 1758)) are a rare example of social predators that hunt together in groups of sexually dimorphic adults and juveniles with diverse physiological diving capacities. Day–night ecological differences should also affect diving as their prey show diel variation in activity and mammal-eating killer whales do not rely on echolocation for prey detection. Our objective was to explore the extent to which physiological aerobic capacities versus ecological factors shape the diving behaviour of this breath-hold diver. We used suction-cup-attached depth recorders (Dtags) to record 7608 dives of 11 animals in southeast Alaska. Analysis of dive sequences revealed a strong bout structure in both dive depth and duration. Day–night comparisons revealed reduced rates of deep dives, longer shallow dives, and shallower long-duration dives at night. In contrast, dive variables did not differ by age–sex class. Estimates of the aerobic dive limit (cADL) suggest that juveniles exceeded their cADL during as much as 15% of long dives, whereas adult males and females never exceeded their cADL. Mammal-eating killer whales in this area appear to employ a strategy of physiological compromise, with smaller group members diving nearer their physiological limits and large-bodied males scaling down their physiological performance

Mitochondrial sequence divergence among Antarctic killer whale ecotypes is consistent with multiple species

Recently, three visually distinct forms of killer whales (Orcinus orca) were described from Antarctic waters and designated as types A, B and C. Based on consistent differences in prey selection and habitat preferences, morphological divergence and apparent lack of interbreeding among these broadly sympatric forms, it was suggested that they may represent separate species. To evaluate this hypothesis, we compared complete sequences of the mitochondrial control region from 81 Antarctic killer whale samples, including 9 type A, 18 type B, 47 type C and 7 type-undetermined individuals. We found three fixed differences that separated type A from B and C, and a single fixed difference that separated type C from A and B. These results are consistent with reproductive isolation among the different forms, although caution is needed in drawing further conclusions. Despite dramatic differences in morphology and ecology, the relatively low levels of sequence divergence in Antarctic killer whales indicate that these evolutionary changes occurred relatively rapidly and recently