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Animal psychophysics

Nabil El Bitar, Bernard Pollin, Elias Georges Karroum, Ivanne Pincedé, Daniel Le Bars
In thermal neutral condition, rats display cyclic variations of the vasomotion of the tail and paws, the most widely used target organs in current acute or chronic animal models of pain. Systemic morphine elicits their vasoconstriction followed by hyperthermia in a naloxone-reversible and dose-dependant fashion. The dose-response curves were steep with ED50 in the 0.5-1 mg/kg range. Given the pivotal functional role of Rostral Ventro-medial Medulla (RVM) in nociception and rostral Medullary Raphe (rMR) in thermoregulation, two largely overlapping brain regions, the RVM/rMR was blocked by muscimol: it suppressed the effects of morphine...
September 7, 2016: Journal of Neurophysiology
Christopher J Plack, Agnès Léger, Garreth Prendergast, Karolina Kluk, Hannah Guest, Kevin J Munro
Cochlear synaptopathy (or hidden hearing loss), due to noise exposure or aging, has been demonstrated in animal models using histological techniques. However, diagnosis of the condition in individual humans is problematic because of (a) test reliability and (b) lack of a gold standard validation measure. Wave I of the transient-evoked auditory brainstem response is a noninvasive electrophysiological measure of auditory nerve function and has been validated in the animal models. However, in humans, Wave I amplitude shows high variability both between and within individuals...
2016: Trends in Hearing
Kelsey N Hom, Meike Linnenschmidt, James A Simmons, Andrea Megela Simmons
Echolocating bats emit trains of intense ultrasonic biosonar pulses and listen to weaker echoes returning from objects in their environment. Identification and categorization of echoes are crucial for orientation and prey capture. Bats are social animals and often fly in groups in which they are exposed to their own emissions and to those from other bats, as well as to echoes from multiple surrounding objects. Sound pressure levels in these noisy conditions can exceed 110 dB, with no obvious deleterious effects on echolocation performance...
August 10, 2016: Journal of Experimental Biology
Gopal Murali, Ullasa Kodandaramaiah
Conspicuous coloration, which presumably makes prey more visible to predators, has intrigued researchers for long. Contrastingly coloured, conspicuous striped patterns are common among lizards and other animals, but their function is not well known. We propose and test a novel hypothesis, the 'redirection hypothesis', wherein longitudinal striped patterns, such as those found on the anterior body parts of most lacertilians, redirect attacks away from themselves during motion towards less vulnerable posterior parts, for example, the autotomous tail...
June 2016: Royal Society Open Science
Leor N Katz, Jacob L Yates, Jonathan W Pillow, Alexander C Huk
During decision making, neurons in multiple brain regions exhibit responses that are correlated with decisions. However, it remains uncertain whether or not various forms of decision-related activity are causally related to decision making. Here we address this question by recording and reversibly inactivating the lateral intraparietal (LIP) and middle temporal (MT) areas of rhesus macaques performing a motion direction discrimination task. Neurons in area LIP exhibited firing rate patterns that directly resembled the evidence accumulation process posited to govern decision making, with strong correlations between their response fluctuations and the animal's choices...
July 14, 2016: Nature
Ronald A Kastelein, Lean Helder-Hoek, Jennifer Covi, Robin Gransier
High intensity underwater sounds may cause temporary hearing threshold shifts (TTSs) in harbor porpoises, the magnitude of which may depend on the exposure duration. After exposure to playbacks of pile driving sounds, TTSs in two porpoises were quantified at 4 and 8 kHz with a psychophysical technique. At 8 kHz, the pile driving sounds caused the highest TTS. Pile driving sounds had the following: pulse duration 124 ms, rate 2760 strikes/h, inter-pulse interval 1.3 s, duty cycle ∼9.5%, average received single-strike unweighted broadband sound exposure level (SELss) 145 dB re 1 μPa(2)s, exposure duration range 15-360 min (cumulative SEL range: 173-187 dB re 1 μPa(2)s)...
May 2016: Journal of the Acoustical Society of America
Joseph Sollini, Ana Alves-Pinto, Christian J Sumner
Psychophysical experiments seek to measure the limits of perception. While straightforward in humans, in animals they are time consuming. Choosing an appropriate task and interpreting measurements can be challenging. We investigated the localization of high-frequency auditory signals in noise using an "approach-to-target" task in ferrets, how task performance should be interpreted in terms of perception, and how the measurements relate to other types of tasks. To establish their general ability to localize, animals were first trained to discriminate broadband noise from 12 locations...
August 2016: Behavioral Neuroscience
Emil A Hoeck, Jens B Marker, Parisa Gazerani, Hjalte H Andersen, Lars Arendt-Nielsen
Pruritus, or simply itch, is a debilitating symptom that significantly decreases the quality of life in a wide range of clinical conditions. While histamine remains the most studied mediator of itch in humans, treatment options for chronic itch, in particular antihistamine-resistant itch, are limited. Relevant preclinical and human surrogate models of non-histaminergic itch are needed to accelerate the development of novel antipruritics and diagnostic tools. Advances in basic itch research have facilitated the development of diverse models of itch and associated dysaesthesiae...
October 2016: Experimental Dermatology
Mohammad-Reza A Dehaqani, Abdol-Hossein Vahabie, Roozbeh Kiani, Majid Nili Ahmadabadi, Babak Nadjar Araabi, Hossein Esteky
Object categories are recognized at multiple levels of hierarchical abstractions. Psychophysical studies have shown a more rapid perceptual access to the mid-level category information (e.g., human faces) than the higher (superordinate; e.g., animal) or the lower (subordinate; e.g., face identity) level. Mid-level category members share many features, whereas few features are shared among members of different mid-level categories. To understand better the neural basis of expedited access to mid-level category information, we examined neural responses of the inferior temporal (IT) cortex of macaque monkeys viewing a large number of object images...
August 1, 2016: Journal of Neurophysiology
Geoffrey A Manley, Pim van Dijk
Frequency selectivity is a key functional property of the inner ear and since hearing research began, the frequency resolution of the human ear has been a central question. In contrast to animal studies, which permit invasive recording of neural activity, human studies must rely on indirect methods to determine hearing selectivity. Psychophysical studies, which used masking of a tone by other sounds, indicate a modest frequency selectivity in humans. By contrast, estimates using the phase delays of stimulus-frequency otoacoustic emissions (SFOAE) predict a remarkably high selectivity, unique among mammals...
June 2016: Hearing Research
Jillian L King, Matthew P Lowe, Kurt R Stover, Aimee A Wong, Nathan A Crowder
Visual adaptation illusions indicate that our perception is influenced not only by the current stimulus but also by what we have seen in the recent past. Adaptation to stimulus contrast (the relative luminance created by edges or contours in a scene) induces the perception of the stimulus fading away and increases the contrast detection threshold in psychophysical tests [1, 2]. Neural correlates of contrast adaptation have been described throughout the visual system including the retina [3], dorsal lateral geniculate nucleus (dLGN) [4, 5], primary visual cortex (V1) [6], and parietal cortex [7]...
May 23, 2016: Current Biology: CB
Alejandro Tabas, Anita Siebert, Selma Supek, Daniel Pressnitzer, Emili Balaguer-Ballester, André Rupp
Communication sounds are typically asymmetric in time and human listeners are highly sensitive to this short-term temporal asymmetry. Nevertheless, causal neurophysiological correlates of auditory perceptual asymmetry remain largely elusive to our current analyses and models. Auditory modelling and animal electrophysiological recordings suggest that perceptual asymmetry results from the presence of multiple time scales of temporal integration, central to the auditory periphery. To test this hypothesis we recorded auditory evoked fields (AEF) elicited by asymmetric sounds in humans...
2016: PloS One
Süay Özmen, Seyhan Dülger, Soner Çoban, Ömer Afşın Özmen, Muhammed Güzelsoy, Özlem Şengören Dikiş, Önder Akdeniz
The studies evaluating the effect of smoking on olfaction reveals opposite results. In vitro and animal studies and epidemiological evidence from volunteers and patients, demonstrated the association between olfaction and erectile functions. In smoking man the reduction of olfactory acuity could adversely affect sexuality. The aim of the present study was to investigate the relationship between erectile dysfunction (ED) and olfactory dysfunction (OD) by comparing a group of healthy adult men with a group of smoking adult men...
June 1, 2016: Physiology & Behavior
Helen M Ditz, Andreas Nieder
The ability to estimate number is widespread throughout the animal kingdom. Based on the relative close phylogenetic relationship (and thus equivalent brain structures), non-verbal numerical representations in human and non-human primates show almost identical behavioural signatures that obey the Weber-Fechner law. However, whether numerosity discriminations of vertebrates with a very different endbrain organization show the same behavioural signatures remains unknown. Therefore, we tested the numerical discrimination performance of two carrion crows (Corvus corone) to a broad range of numerosities from 1 to 30 in a delayed match-to-sample task similar to the one used previously with primates...
March 30, 2016: Proceedings. Biological Sciences
Marilia Pinheiro de Carvalho, Armando Machado, Marco Vasconcelos
Inspired by Spence's seminal work on transposition, we propose a synthetic approach to understanding the temporal control of operant behavior. The approach takes as primitives the temporal generalization gradients obtained in prototypical concurrent and retrospective timing tasks and then combines them to synthetize more complex temporal performances. The approach is instantiated by the learning-to-time (LeT) model. The article is divided into three parts. In the first part, we review the basic findings concerning the generalization gradients observed in fixed-interval schedules, the peak procedure, and the temporal generalization procedure and then describe how LeT explains them...
July 2016: Animal Cognition
Jun Chen, Su-Min Guan, Wei Sun, Han Fu
Melittin is a basic 26-amino-acid polypeptide that constitutes 40-60% of dry honeybee (Apis mellifera) venom. Although much is known about its strong surface activity on lipid membranes, less is known about its pain-producing effects in the nervous system. In this review, we provide lines of accumulating evidence to support the hypothesis that melittin is the major pain-producing substance of bee venom. At the psychophysical and behavioral levels, subcutaneous injection of melittin causes tonic pain sensation and pain-related behaviors in both humans and animals...
June 2016: Neuroscience Bulletin
Bruce G Cumming, Hendrikje Nienborg
How the processing of signals carried by sensory neurons supports perceptual decisions is a long-standing question in neuroscience. The ability to record neuronal activity in awake animals while they perform psychophysical tasks near threshold has been a key advance in studying these questions. Trial-to-trial correlations between the activity of sensory neurons and the decisions reported by animals ('choice probabilities'), even when measured across repeated presentations of an identical stimulus provide insights into this problem...
April 2016: Current Opinion in Neurobiology
Robert H LaMotte
This chapter is an overview of published observations from our laboratory on the psychophysics and neurobiology of the persistent itch and pain of allergic contact dermatitis (ACD). ACD is a clinically significant problem with many features characteristic of other pruritic disorders. Our approach was to produce ACD experimentally in humans and in the mouse. The goal was to use the mouse as an animal model for investigating the peripheral neural mechanisms of itch and pain of ACD in humans. Humans and mice were each sensitized by cutaneous topical application of squaric acid dibutyl ester, a hapten not encountered in the environment...
2016: Advances in Experimental Medicine and Biology
Simon Conway Morris
No chimpanzee knows what a square root is, let alone a complex number. Yet not only our closest ape cousins but even some invertebrates, possess a capacity for numerosity, that is the ability to assess relative numerical magnitudes and distances. That numerosity should confer adaptive advantages, such as social species that choose shoal size, is obvious. Moreover, it is widely assumed that numerosity and mathematics are seamlessly linked, as would be consistent with Darwinian notions of descent and modification...
August 2016: Studies in History and Philosophy of Biological and Biomedical Sciences
Thiago S Gouvêa, Tiago Monteiro, Asma Motiwala, Sofia Soares, Christian Machens, Joseph J Paton
The striatum is an input structure of the basal ganglia implicated in several time-dependent functions including reinforcement learning, decision making, and interval timing. To determine whether striatal ensembles drive subjects' judgments of duration, we manipulated and recorded from striatal neurons in rats performing a duration categorization psychophysical task. We found that the dynamics of striatal neurons predicted duration judgments, and that simultaneously recorded ensembles could judge duration as well as the animal...
2015: ELife
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