Displaying publications 101 - 120 of 4446 in total

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  1. Cross-mating between Malaysian strains of Aedes aegypti and Aedes albopictus in the laboratory
    Nazni WA, Lee HL, Dayang HA, Azahari AH
    Southeast Asian J. Trop. Med. Public Health, 2009 Jan;40(1):40-6.
    PMID: 19323032
    Reciprocal and homologous mating experiments between Malaysian Aedes aegypti and Aedes albopictus mosquitoes were conducted in the laboratory. Two methods were employed, namely an artificial mating technique and a natural cage mating technique. The study demonstrated there exists a strong reproductive isolation between Ae. aegypti and Ae. albopictus. Insemination occurred in cross-mating experiments between Ae. aegypti females and Ae. albopictus males and also between Ae. albopictus females and Ae. aegypti males. Cross mating between Ae. aegypti females and Ae. albopictus males produced more eggs than that between Ae. albopictus females and Ae. aegypti males with both artificial mating and natural cage mating techniques. The matings did not result in the production of viable eggs by the females. No embryonation of these eggs was observed when the eggs were bleached. With homologous mating Aedes aegypti produced significantly greater numbers of eggs compared to Aedes albopictus mosquitoes, and all the eggs hatched successfully.
    Matched MeSH terms: Aedes/physiology*; Insemination/physiology*; Oviposition/physiology*; Sexual Behavior, Animal/physiology*
  2. What is the ultimate goal in acid-base regulation?
    Balakrishnan S, Gopalakrishnan M, Alagesan M, Prakash ES
    Adv Physiol Educ, 2007 Mar;31(1):51-4.
    PMID: 17327583
    It is common to see chapters on acid-base physiology state that the goal of acid-base regulatory mechanisms is to maintain the pH of arterial plasma and not arterial Pco(2) (Pa(CO(2))) or plasma HCO(3). A hypothetical situation in which the Pa(CO(2)) of arterial plasma is 80 mmHg and the plasma HCO(3) concentration is 48 mM is presented and analyzed to get over this misconception. As per the modified Henderson equation, the pH of arterial plasma would be 7.4; however, we explain that this may be associated with intracellular acidosis due to intracellular hypercapnia and that derangement of homeostasis is evident from the occurrence of respiratory depression and, eventually, coma in the patient described. This suggests that the ultimate goal of acid-base regulatory mechanisms is not just the maintenance of the pH of arterial plasma but the maintenance of the steady-state pH of intracellular fluid as well.
    Matched MeSH terms: Acid-Base Equilibrium/physiology*; Homeostasis/physiology; Physiology/education*
  3. Optimal hydration status for cryopreservation of intermediate oily seeds: Citrus as a case study
    Hor YL, Kim YJ, Ugap A, Chabrillange N, Sinniah UR, Engelmann F, et al.
    Ann Bot, 2005 Jun;95(7):1153-61.
    PMID: 15781438
    The purpose of this study was to investigate the basis of the optimal hydration status for cryopreservation of intermediate oily seeds using Citrus as a model.
    Matched MeSH terms: Citrus/physiology*; Lipids/physiology*; Seeds/physiology*; Water/physiology*
  4. Fulltext Eating with our eyes: From visual hunger to digital satiation
    Spence C, Okajima K, Cheok AD, Petit O, Michel C
    Brain Cogn, 2016 12;110:53-63.
    PMID: 26432045 DOI: 10.1016/j.bandc.2015.08.006
    One of the brain's key roles is to facilitate foraging and feeding. It is presumably no coincidence, then, that the mouth is situated close to the brain in most animal species. However, the environments in which our brains evolved were far less plentiful in terms of the availability of food resources (i.e., nutriments) than is the case for those of us living in the Western world today. The growing obesity crisis is but one of the signs that humankind is not doing such a great job in terms of optimizing the contemporary food landscape. While the blame here is often put at the doors of the global food companies - offering addictive foods, designed to hit 'the bliss point' in terms of the pleasurable ingredients (sugar, salt, fat, etc.), and the ease of access to calorie-rich foods - we wonder whether there aren't other implicit cues in our environments that might be triggering hunger more often than is perhaps good for us. Here, we take a closer look at the potential role of vision; Specifically, we question the impact that our increasing exposure to images of desirable foods (what is often labelled 'food porn', or 'gastroporn') via digital interfaces might be having, and ask whether it might not inadvertently be exacerbating our desire for food (what we call 'visual hunger'). We review the growing body of cognitive neuroscience research demonstrating the profound effect that viewing such images can have on neural activity, physiological and psychological responses, and visual attention, especially in the 'hungry' brain.
    Matched MeSH terms: Brain/physiology*; Hunger/physiology*; Satiation/physiology*; Visual Perception/physiology*
  5. Physical and physiological profiles of Malaysian dragon boat rowers
    Singh R, Singh HJ, Sirisinghe RG
    Br J Sports Med, 1995 Mar;29(1):13-5.
    PMID: 7788209
    Maximal oxygen consumption (VO2max) and maximal workload attained (WLmax) were determined in 28 Malaysian dragon boat rowers who were exercised to exhaustion on an arm ergometer. Mean VO2max was 2.75 l min-1 at a mean WLmax of 195.5 W. Anaerobic endurance power of the arms, determined by cranking at 100 RPM at a workload of 400 W and the time taken to maintain the cadence until it fell to 75 RPM, was 34.9(+/- 2.3) s. Leg performance, as determined by standing long jump and vertical jump, was 140.0(+/- 4.5) kg m and 100.3(+/- 3.1) kg m s-1 respectively. Right hand grip strength was significantly (p < 0.001) greater than the left hand. Percentage body fat of the rowers was 11.8(+/- 0.6)%. These values represent the first measurements of their kind performed on dragon boat rowers in Malaysia.
    Matched MeSH terms: Physical Endurance/physiology; Sports/physiology*; Exercise/physiology*; Muscle, Skeletal/physiology
  6. Fulltext Local context influences memory for emotional stimuli but not electrophysiological markers of emotion-dependent attention
    Barnacle GE, Tsivilis D, Schaefer A, Talmi D
    Psychophysiology, 2018 04;55(4).
    PMID: 29023754 DOI: 10.1111/psyp.13014
    Emotional enhancement of free recall can be context dependent. It is readily observed when emotional and neutral scenes are encoded and recalled together in a "mixed" list, but diminishes when these scenes are encoded separately in "pure" lists. We examined the hypothesis that this effect is due to differences in allocation of attention to neutral stimuli according to whether they are presented in mixed or pure lists, especially when encoding is intentional. Using picture stimuli that were controlled for semantic relatedness, our results contradicted this hypothesis. The amplitude of well-known electrophysiological markers of emotion-related attention-the early posterior negativity (EPN), the late positive potential (LPP), and the slow wave (SW)-was higher for emotional stimuli. Crucially, the emotional modulation of these ERPs was insensitive to list context, observed equally in pure and mixed lists. Although list context did not modulate neural markers of emotion-related attention, list context did modulate the effect of emotion on free recall. The apparent decoupling of the emotional effects on attention and memory, challenges existing hypotheses accounting for the emotional enhancement of memory. We close by discussing whether findings are more compatible with an alternative hypothesis, where the magnitude of emotional memory enhancement is, at least in part, a consequence of retrieval dynamics.
    Matched MeSH terms: Attention/physiology*; Brain/physiology*; Emotions/physiology*; Evoked Potentials/physiology*
  7. Fulltext Involvement of the uridine cytidine kinase 2 enzyme in cancer cell death: A molecular crosstalk between the enzyme and cellular apoptosis induction
    Malami I, Abdul AB
    Biomed Pharmacother, 2019 Jan;109:1506-1510.
    PMID: 30551402 DOI: 10.1016/j.biopha.2018.10.200
    Apoptosis is a series of molecular signalling regulating normal cellular growth and development. Cells resistance to apoptosis, however, leads to uncontrolled proliferation. Research involving cancer cell death is one of the most important targeted areas in the discovery of novel anticancer therapy. There are several biochemical pathways that are liked towards cancer cell death of which, uridine-cytidine kinase 2 (UCK2) was recently linked to cell apoptosis induction. UCK2 is responsible for the phosphorylation of uridine and cytidine to their corresponding monophosphate in a salvage pathway of pyrimidine nucleotides biosynthesis. Cytotoxic ribonucleoside analogues that target UCK2 enzyme activity are currently being investigated in clinical trials useful for cancer treatment. Whilst findings have clearly shown that these antimetabolites inhibit cancer development in clinical settings, they have yet to establish linking cytotoxic nucleoside analogues to cancer cell death. In this present review, we propose the probable molecular crosstalk involving UCK2 protein and cancer cell death through cell cycle arrest and triggering of apoptosis involving proteins, MDM2 and the subsequent activation of p53.
    Matched MeSH terms: Cell Death/physiology*; Apoptosis/physiology*; Cell Proliferation/physiology; Cell Cycle Checkpoints/physiology
  8. The effects of toe-out and toe-in postures on static & dynamic balance, risk of fall and TUG score in healthy adults
    Khan SJ, Khan SS, Usman J
    Foot (Edinb), 2019 Jun;39:122-128.
    PMID: 30580888 DOI: 10.1016/j.foot.2018.06.002
    BACKGROUND: Toe-in and toe-out foot positions have not yet been tested for dynamic balance and risk of fall. The aim of this study was to investigate the effects of these two modifications on static and dynamic postural stability and risk of fall through instrumental (Biodex Balance System®) and functional (timed up and go-TUG test) tools.

    METHODOLOGY: Twenty healthy adults (8 males, 12 females, age: 29±4.10years, BMI: 21.56±2.36kg/m2) participated in this study. Static and dynamic (levels 8 and 2) balance with single stance and double stance and dynamic (level 8 and levels 6-2) for risk of fall with double stance were tested with the Biodex Balance System with three self-selected feet positions: straight (13.8°), toe-out (35.6°) and toe-in (-11.9°) for each test condition. Additionally, TUG test was performed with toe-out and toe-in gait.

    RESULTS: The results of repeated measures ANOVA showed significant differences (p<0.05) between straight and modified toe angles in balance at dynamic level 2 with both double and single stance conditions. Significant differences (p<0.001) were also found in TUG scores for the test conditions.

    CONCLUSION: Toe-in and toe-out gait modifications have significant effects on balance at higher levels of platform tilt and functional balance. Further investigations with knee osteoarthritis patients and electromyography may provide insight in balancing strategies adopted by the body in toe-out and toe-in gait.

    Matched MeSH terms: Postural Balance/physiology*; Motor Activity/physiology; Posture/physiology*; Toes/physiology*
  9. The effects of moisture on ovipositional responses and larval eclosion of Aedes albopictus
    Saifur RG, Dieng H, Hassan AA, Satho T, Miake F, Boots M, et al.
    J Am Mosq Control Assoc, 2010 Dec;26(4):373-80.
    PMID: 21290932
    Moisture plays a major role in the dynamics of mosquito populations, especially those breeding in container habitats. Despite this importance, the role of moisture conditions as they affect oviposition and egg development in Aedes vectors remains largely unexplored. We investigated the effect of exposing gravid female Aedes albopictus mosquitoes and their eggs to different moisture levels (MLs) for various periods on oviposition and hatching. Overall, high-moisture substrates (HMSs; 66% and 72%) provided better environments for egg laying. The timing of initial egg laying was far longer at the lowest substrate moisture level (LSML, 25% and 41.2%) than at HMSs. The numbers of eggs laid were much lower in the drier environments. At LSMLs, gravid females retained increasing numbers of mature eggs until death, and egg retention decreased gradually with increasing ML. The HMSs also provided better environments for larval eclosion. The numbers of eggs hatched were lower at the LSML than the HSML environment. No egg hatching occurred after 1 h exposure to moisture. However, egg hatching occurred by installment, with spontaneous hatching (SH) increasing gradually with increasing ML. High-moisture conditions combined with long exposure (30 h and 48 h) favored SH. These results suggest that Ae. albopictus females can respond to better moisture conditions for increased success of embryonation and larval eclosion. This information may be useful in the colonization of floodwater Aedes species.
    Matched MeSH terms: Aedes/physiology*; Larva/physiology; Oviposition/physiology*; Ovum/physiology
  10. Introduction to the Cognitive Abilities Account for the Reminiscence Bump in the Temporal Distribution of Autobiographical Memory
    Janssen SMJ
    Psychol Rep, 2020 Feb;123(1):12-42.
    PMID: 31039675 DOI: 10.1177/0033294119843221
    Matched MeSH terms: Aging/physiology*; Aptitude/physiology*; Cognition/physiology*; Mental Recall/physiology*
  11. Fulltext Cryptic coloration of Macaranga bancana seedlings: A unique strategy for a pioneer species
    Fadzly N, Zuharah WF, Mansor A, Zakaria R
    Plant Signal Behav, 2016 07 02;11(7):e1197466.
    PMID: 27315145 DOI: 10.1080/15592324.2016.1197466
    Macaranga bancana is considered as a successful pioneer plant species. Usually found in disturbed and open areas, most of the current research focused on its relations with ants. One of the unique feature of the plants is that the seedling leaves are red, resembling and almost matching the background. Using a portable spectrometer, we measured the color reflectance of M. bancana seedlings (less than 20 cm in height). We also measured the leaf litter reflectance, adult M. bancana leaves and also seedlings of several other species found in the vicinity of M. bancana seedlings. The reflectances of M. bancana seedlings are very similar to that of the leaf litter background. We suggest that this cryptic coloration is crucial during the early stages of the plant when it still cannot rely on the protection of ants.
    Matched MeSH terms: Pigmentation/physiology; Plant Leaves/physiology; Euphorbiaceae/physiology; Seedlings/physiology
  12. Fulltext Pollination Services of Mango Flower Pollinators
    Huda AN, Salmah MR, Hassan AA, Hamdan A, Razak MN
    J Insect Sci, 2015;15.
    PMID: 26246439 DOI: 10.1093/jisesa/iev090
    Measuring wild pollinator services in agricultural production is very important in the context of sustainable management. In this study, we estimated the contribution of native pollinators to mango fruit set production of two mango cultivars Mangifera indica (L). cv. 'Sala' and 'Chok Anan'. Visitation rates of pollinators on mango flowers and number of pollen grains adhering to their bodies determined pollinator efficiency for reproductive success of the crop. Chok Anan failed to produce any fruit set in the absence of pollinators. In natural condition, we found that Sala produced 4.8% fruit set per hermaphrodite flower while Chok Anan produced 3.1% per flower. Hand pollination tremendously increased fruit set of naturally pollinated flower for Sala (>100%), but only 33% for Chok Anan. Pollinator contribution to mango fruit set was estimated at 53% of total fruit set production. Our results highlighted the importance of insect pollinations in mango production. Large size flies Eristalinus spp. and Chrysomya spp. were found to be effective pollen carriers and visited more mango flowers compared with other flower visitors.
    Matched MeSH terms: Diptera/physiology; Insects/physiology*; Mangifera/physiology*; Flowers/physiology
  13. Diet and internal physiological changes of female orange mud crabs, Scylla olivacea (Herbst, 1796) in different ovarian maturation stages
    Hidir A, Aaqillah-Amr MA, Noordiyana MN, Ikhwanuddin M
    Anim. Reprod. Sci., 2018 Aug;195:216-229.
    PMID: 29861342 DOI: 10.1016/j.anireprosci.2018.05.026
    Recently, there has been a growing interest in the ovarian maturation of mud crabs, genus Scylla. Studies regarding the factors that affect ovarian maturation in mud crabs, however, are still lacking. This study, therefore, evaluates the relationship between diet and internal physiological changes of female orange mud crabs, Scylla olivacea. Sixty female adult S. olivacea were sampled from Setiu Wetland, Malaysia. Foreguts were sampled to study fullness and content. The hepatopancreas was sampled to study digestive enzyme activity, biochemical composition, and histology. Ovaries were sampled to study ovarian biochemical composition and histology. Foregut fullness data suggest that there is an increase in feeding with advancing ovarian maturation in mud crabs. Data for foregut contents indicated that when the ovary was in Stage 3 of maturation the diet was animal-based. The activity of amylase, cellulase, lipase, and trypsin during Stages 1 and 4 of ovarian maturation were less than during Stage 3 of ovarian maturation. Biochemical composition (protein and lipid) was greater during Stage 3 of ovarian maturation. Histological analysis of the hepatopancreas indicated an increase in hepatopancreas tubules, B and R cells during Stage 3 as compared with Stage 1 of ovarian maturation. Histological analysis of the ovary indicated increases in oocyte diameter due to concentrated large yolk globules. Based on these results, it is concluded that vitellogenesis mainly occurred during Stage 3 of ovarian maturation, based on evidence of increased feeding with the diet being predominantly animal-based. Likewise, digestive enzyme activities, proteins, lipids, B cells, and R cells were all greater during Stage 3 of ovarian maturation.
    Matched MeSH terms: Brachyura/physiology*; Feeding Behavior/physiology*; Ovary/physiology*; Gastrointestinal Tract/physiology
  14. Review of numerical methods for simulation of mechanical heart valves and the potential for blood clotting
    Zakaria MS, Ismail F, Tamagawa M, Aziz AFA, Wiriadidjaja S, Basri AA, et al.
    Med Biol Eng Comput, 2017 Sep;55(9):1519-1548.
    PMID: 28744828 DOI: 10.1007/s11517-017-1688-9
    Even though the mechanical heart valve (MHV) has been used routinely in clinical practice for over 60 years, the occurrence of serious complications such as blood clotting remains to be elucidated. This paper reviews the progress that has been made over the years in terms of numerical simulation method and the contribution of abnormal flow toward blood clotting from MHVs in the aortic position. It is believed that this review would likely be of interest to some readers in various disciplines, such as engineers, scientists, mathematicians and surgeons, to understand the phenomenon of blood clotting in MHVs through computational fluid dynamics.
    Matched MeSH terms: Blood Coagulation/physiology*; Blood Flow Velocity/physiology; Heart Valves/physiology*; Pulsatile Flow/physiology
  15. A systematic review of muscle activity assessment of the biceps brachii muscle using mechanomyography
    Talib I, Sundaraj K, Lam CK, Sundaraj S
    J Musculoskelet Neuronal Interact, 2018 12 01;18(4):446-462.
    PMID: 30511949
    This systematic review aims to categorically analyses the literature on the assessment of biceps brachii (BB) muscle activity through mechanomyography (MMG). The application of our search criteria to five different databases identified 319 studies. A critical review of the 48 finally selected records, revealed the diversity of protocols and parameters that are employed in MMG-based assessments of BB muscle activity. The observations were categorized into the following: muscle torque, fatigue, strength and physiology. The available information on the muscle contraction protocol, sensor(s), MMG signal parameters and obtained results were then tabulated based on these categories for further analysis. The review affirms that - 1) MMG is suitable for skeletal muscle activity assessment and can be employed potentially for further investigation of the BB muscle activity and condition (e.g., force, torque, fatigue, and contractile properties), 2) a majority of the records focused on static contractions of the BB, and the analysis of dynamic muscle contractions using MMG is thus a research gap, and 3) very few studies have focused on the analysis of BB muscle activity under externally stimulated contractions. Taken together, the findings of this review on BB activity assessment using MMG affirm the potential of MMG as an alternative tool.
    Matched MeSH terms: Biomechanical Phenomena/physiology; Muscle Contraction/physiology*; Muscle, Skeletal/physiology*; Muscle Fatigue/physiology*
  16. Fulltext Gliding saves time but not energy in Malayan colugos
    Byrnes G, Libby T, Lim NT, Spence AJ
    J Exp Biol, 2011 Aug 15;214(Pt 16):2690-6.
    PMID: 21795564 DOI: 10.1242/jeb.052993
    Gliding is thought to be an economical form of locomotion. However, few data on the climbing and gliding of free-ranging gliding mammals are available. This study employed an animal-borne three-dimensional acceleration data-logging system to collect continuous data on the climbing and gliding of free-ranging Malayan colugos, Galeopterus variegatus. We combined these movement data with empirical estimates of the metabolic costs to move horizontally or vertically to test this long-standing hypothesis by determining whether the metabolic cost to climb to sufficient height to glide a given distance was less than the cost to move an equivalent distance horizontally through the canopy. On average, colugos climb a short distance to initiate glides. However, due to the high energetic cost of climbing, gliding is more energetically costly to move a given horizontal distance than would be predicted for an animal travelling the same distance through the canopy. Furthermore, because colugos spend a small fraction of their time engaged in locomotor activity, the high costs have little effect on their overall energy budget. As a result, the energetic economy hypothesis for the origins of gliding is not supported. It is likely that other ecologically relevant factors have played a greater role in the origins of gliding in colugos and other mammals.
    Matched MeSH terms: Energy Metabolism/physiology*; Flight, Animal/physiology*; Lemur/physiology*; Locomotion/physiology
  17. Fulltext In vivo bone strain and finite element modeling of a rhesus macaque mandible during mastication
    Panagiotopoulou O, Iriarte-Diaz J, Wilshin S, Dechow PC, Taylor AB, Mehari Abraha H, et al.
    Zoology (Jena), 2017 10;124:13-29.
    PMID: 29037463 DOI: 10.1016/j.zool.2017.08.010
    Finite element analysis (FEA) is a commonly used tool in musculoskeletal biomechanics and vertebrate paleontology. The accuracy and precision of finite element models (FEMs) are reliant on accurate data on bone geometry, muscle forces, boundary conditions and tissue material properties. Simplified modeling assumptions, due to lack of in vivo experimental data on material properties and muscle activation patterns, may introduce analytical errors in analyses where quantitative accuracy is critical for obtaining rigorous results. A subject-specific FEM of a rhesus macaque mandible was constructed, loaded and validated using in vivo data from the same animal. In developing the model, we assessed the impact on model behavior of variation in (i) material properties of the mandibular trabecular bone tissue and teeth; (ii) constraints at the temporomandibular joint and bite point; and (iii) the timing of the muscle activity used to estimate the external forces acting on the model. The best match between the FEA simulation and the in vivo experimental data resulted from modeling the trabecular tissue with an isotropic and homogeneous Young's modulus and Poisson's value of 10GPa and 0.3, respectively; constraining translations along X,Y, Z axes in the chewing (left) side temporomandibular joint, the premolars and the m1; constraining the balancing (right) side temporomandibular joint in the anterior-posterior and superior-inferior axes, and using the muscle force estimated at time of maximum strain magnitude in the lower lateral gauge. The relative strain magnitudes in this model were similar to those recorded in vivo for all strain locations. More detailed analyses of mandibular strain patterns during the power stroke at different times in the chewing cycle are needed.
    Matched MeSH terms: Bone and Bones/physiology*; Macaca mulatta/physiology*; Mandible/physiology*; Mastication/physiology*
  18. The limits of stability and muscle activity in middle-aged adults during static and dynamic stance
    Ku PX, Abu Osman NA, Wan Abas WAB
    J Biomech, 2016 Dec 08;49(16):3943-3948.
    PMID: 27865478 DOI: 10.1016/j.jbiomech.2016.11.006
    Balance control plays an important role in maintaining daily activity. However, studies on postural control among middle-aged adults are scarce. This study aims (i) to examine directional control (DCL) and electromyography activity (EMG) for different stability levels, and (ii) to determine left-right asymmetry for DCL and muscle activity among sedentary middle-aged adults. Twenty healthy, middle-aged adults (10 males, 10 females; age=50.0±7.5yrs; body height: 1.61±0.10m; body mass: 70.0±14.5kg) participated in the study. EMG for left and right side of rectus femoris (RF), biceps femoris (BF), and medial gastrocnemius (MG) were recorded. Two-way repeated measures analysis of variance was used to assess the effect of dynamic level on DCL and EMG, whereas independent sample t-test was conducted to analyse the asymmetries of DCL and EMG for the left and right leg. When the dynamic tilt surface increased, DCL scores significantly decreased (except forward, forward-rightward, and backward-leftward direction) and only RF muscle indicated significant differences. Left-right asymmetry was found in BF and MG muscles. No significant gender difference was observed in DCL and EMG. These data demonstrated that increased dynamic tilt surface may increase the displacement of center of pressure of certain directions, and stimulate RF activity in dynamic stance among sedentary middle-aged adults. Further studies should be conducted to examine the dynamic stance and muscle activity of the lower limb in age-matched patient groups with balance abnormalities.
    Matched MeSH terms: Postural Balance/physiology; Leg/physiology; Posture/physiology*; Muscle, Skeletal/physiology*
  19. Newborns are sensitive to the correspondence between auditory pitch and visuospatial elevation
    Walker P, Bremner JG, Lunghi M, Dolscheid S, D Barba B, Simion F
    Dev Psychobiol, 2018 03;60(2):216-223.
    PMID: 29355921 DOI: 10.1002/dev.21603
    Amodal (redundant) and arbitrary cross-sensory feature associations involve the context-insensitive mapping of absolute feature values across sensory domains. Cross-sensory associations of a different kind, known as correspondences, involve the context-sensitive mapping of relative feature values. Are such correspondences in place at birth (like amodal associations), or are they learned from subsequently experiencing relevant feature co-occurrences in the world (like arbitrary associations)? To decide between these two possibilities, human newborns (median age = 44 hr) watched animations in which two balls alternately rose and fell together in space. The pitch of an accompanying sound rose and fell either congruently with this visual change (pitch rising and falling as the balls moved up and down), or incongruently (pitch rising and falling as the balls moved down and up). Newborns' looking behavior was sensitive to this congruence, providing the strongest indication to date that cross-sensory correspondences can be in place at birth.
    Matched MeSH terms: Child Development/physiology*; Motion Perception/physiology*; Pattern Recognition, Visual/physiology*; Pitch Perception/physiology*
  20. Sensory adaptation and inhibition of return: dissociating multiple inhibitory cueing effects
    Lim A, Eng V, Janssen SMJ, Satel J
    Exp Brain Res, 2018 05;236(5):1369-1382.
    PMID: 29520444 DOI: 10.1007/s00221-018-5225-3
    Inhibition of return (IOR) refers to an increase in reaction times to targets that appeared at a previously cued location relative to an uncued location, often investigated using a spatial cueing paradigm. Despite numerous studies that have examined many aspects of IOR, the neurophysiological mechanisms underlying IOR are still in dispute. The objective of the current research is to investigate the plausible mechanisms by manipulating the cue and target types between central and peripheral stimuli in a traditional cue-target paradigm with saccadic responses to targets. In peripheral-cueing conditions, we observed inhibitory cueing effects across all cue-target onset asynchronies (CTOAs) with peripheral targets, but IOR was smaller and arose later with central targets. No inhibition was observed in central-cueing conditions at any CTOAs. Empirical data were simulated using a two-dimensional dynamic neural field model. Our results and simulations support previous work demonstrating that, at short CTOAs, behavioral inhibition is only observed with repeated stimulation-an effect of sensory adaptation. With longer CTOAs, IOR is observed regardless of target type when peripheral cueing is used. Our findings suggest that behaviorally exhibited inhibitory cueing effects can be attributed to multiple mechanisms, including both attenuation of visual stimulation and local inhibition in the superior colliculus.
    Matched MeSH terms: Adaptation, Physiological/physiology*; Attention/physiology*; Reaction Time/physiology*; Saccades/physiology
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