Jerome Baron

Jerome Baron
Federal University of Minas Gerais | UFMG · Departamento de Fisiologia e Biofísica

DPhil

About

29
Publications
2,876
Reads
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567
Citations
Introduction
Additional affiliations
September 1994 - October 1998
University of Oxford
Position
  • DPhil Student
September 1991 - August 1994
University of Sussex
Position
  • Student

Publications

Publications (29)
Conference Paper
Full-text available
This work presents the main metrics developed so far to correlate physical properties of light and its effects on melatonin suppression. Melatonin is a hormone secreted at night and its production is suppressed by exposure to light. In this context, the negative effects of artificial lighting at night and high exposure to light raise the need for a...
Article
Owls constitute a diverse group of raptors, active at different times of the day with distinct light conditions that might be associated with multiple visual adaptations. We investigated whether shifts in the spectral sensitivity of the L cone visual pigment, as inferred by analysis of gene structure, could be one such adaptive mechanism. Using San...
Conference Paper
Full-text available
Contour elements of static and dynamic visual stimuli are more accurately detected and discriminated when aligned with the horizontal and vertical axes than when obliquely oriented. This phenomenon, known as the "oblique effect", has been observed in a great variety of visual tasks and for animal species as diverse as goldfishes, octopuses, pigeons...
Conference Paper
Full-text available
Gamma oscillations in the retina are transmitted to the lateral geniculate nucleus (LGN) and to the cortex, and are thought to encode stimulus size and continuity. Support for these conjectures were obtained mostly in the anesthetized cat, and visual stimuli were often limited to whole-field flashes. Here, we aim filling this gap by characterizing...
Conference Paper
Full-text available
Cortical gamma oscillations have been implicated in perceptual binding and visual attention. So far, most evidence in support of this hypothesis are based on studies that used artificial, simplified stimuli, such as moving gratings and bars. Recently, a more naturalistic approach led to diverging conclusions. In human subjects required to hold fixa...
Article
The neuronal representation of luminance contrast has not been thoroughly studied in birds. Here, we present a detailed quantitative analysis of the contrast response of 120 individual neurons recorded from the visual wulst of awake burrowing owls, Athene cunicularia. Stimuli were sinewave gratings presented within the cell classical receptive fiel...
Conference Paper
Full-text available
Accumulating evidence suggests that the receptive field (RF) ON/OFF organization of striate cortex (V1) neurons is not fixed but varies depending on how sensory input statistics activate different functional topologies of thalamocorti-cal and intracortical connections. This study was designed to investigate whether such an adaptive feature could al...
Article
The dynamic, accurate measurement of pupil size is extremely valuable for studying a large number of neuronal functions and dysfunctions. Despite tremendous and well-documented progress in image processing techniques for estimating pupil parameters, comparatively little work has been reported on practical hardware issues involved in designing image...
Article
Full-text available
This paper describes a system with potential for identification of sleep deprivation, which, based on our bibliographical survey, has not yet been described in the literature. The system combines two methodologies, i. e., Psychomotor vigilance test (PVT) and pupillometry, which are among the leading methods for the study of sleep deprivation. Howev...
Poster
The visual wulst is the avian telencephalic target of the retinothalamofugal pathway. In owls, this area is known to have a close functional resemblance with mammalian primary visual cortex (V1). In his pioneering study [1], Pettigrew reports that this resemblance also extends to two basic cell types initially described by Hubel and Wiesel [2]: sim...
Article
Full-text available
Previous assessment of verticality by means of rod and rod and frame tests indicated that human subjects can be more (field dependent) or less (field independent) influenced by a frame placed around a tilted rod. In the present study we propose a new approach to these tests. The judgment of visual verticality (rod test) was evaluated in 50 young su...
Article
Full-text available
Previous assessment of verticality by means of rod and rod and frame tests indicated that human subjects can be more (field dependent) or less (field independent) influenced by a frame placed around a tilted rod. In the present study we propose a new approach to these tests. The judgment of visual verticality (rod test) was evaluated in 50 young su...
Article
Light emitting diodes (LEDs) are extensively used as light sources to investigate visual and visually related function and dysfunction. Here, we describe the design of a compact, low-cost, stand-alone LED-based system that enables the configuration, storage and presentation of elaborate visual stimulation paradigms. The core functionality of this s...
Article
The understanding of how neurons interact in the visual cortex and what types of neurons are responsable for each interaction are still open questions. In order to analyse such problem, the spiking activity of neurons in the central visual pathway of awake owls was analyzed with Principal Component Analysis (PCA) and clustering techniques. Further...
Article
Full-text available
The transformation of spatial (SF) and temporal frequency (TF) tuning functions from broad-band/low-pass to narrow band-pass profiles is one of the key emergent properties of neurons in the mammalian primary visual cortex (V1). The mechanisms underlying such transformation are still a matter of ongoing debate. With the aim of providing comparative...
Article
The avian visual wulst is hodologically equivalent to the mammalian primary visual cortex (V1). In contrast to most birds, owls have a massive visual wulst, which shares striking functional similarities with V1. To provide a better understanding of how motion is processed within this area, we used sinusoidal gratings to characterize the spatiotempo...
Article
The avian retinothalamofugal pathway reaches the telencephalon in an area known as visual wulst. A close functional analogy between this area and the early visual cortex of mammals has been established in owls. The goal of the present study was to assess quantitatively the directional selectivity and motion integration capability of visual wulst ne...
Article
Full-text available
The superior colliculus (SC) transforms both visual and nonvisual sensory signals into motor commands that control orienting behavior. Although the afferent and efferent connections of this midbrain nucleus have been well characterized, little is know about the intrinsic circuitry involved in sensorimotor integration. Transmission of visual signals...
Article
Full-text available
Visual responses in the cortex and lateral geniculate nucleus (LGN) are often associated with synchronous oscillatory patterning. In this short review, we examine the possible relationships between subcortical and cortical synchronization mechanisms. Our results obtained from simultaneous multi-unit recordings show strong synchronization of oscilla...
Article
The normal maturation of the auditory space map in the deeper layers of the ferret superior colliculus (SC) depends on signals provided by the superficial visual layers, but it is unknown where or how these signals influence the developing auditory responses. Here we report that tracer injections in the superficial layers label axons with en passan...
Article
Full-text available
To investigate the priming of memories by contextual cues, bees were trained to negotiate two mazes in different places 25 m apart. In the first maze, bees flew leftwards when the inner wall of the maze was covered with 45° stripes or rightwards when the inner wall was coloured yellow. In the second maze, bees flew rightwards on viewing 135° diagon...
Article
Honeybees flying repeatedly over the same trajectory link it to an associated visual stimulus such that on viewing the stimulus they perform a trajectory in the habitual direction. To test if trajectory length can also be linked to a visual stimulus, bees were trained to fly through a multi-comparmented maze. Bees flew through a multi-compartmented...
Article
We investigated the ability of bees to associate a motor parameter with a sensory one. Foragers were trained to fly along a prescribed route through a large box which was partitioned into compartments. Access from one compartment to the next was through a hole in each partition. In two of the compartments, the back wall was covered with a grating o...
Article
Full-text available
MANY hymenopterans use visual landmarks to guide the last stages of their return to a familiar place, moving so that the pattern of landmarks imaged on their retina matches the pattern stored on previous visits to that place1,2. What is the coordinate frame of these landmark memories, and how is it established? On the one hand, bees and flies learn...
Article
Full-text available
The understanding of how neurons interact in the visual cortex and what kinds of neurons are responsible for each interaction are still unanswered questions in the field of neurophysiology. To acquire information on such prob-lems, sixteen neurons were mapped with visual stimulus of different sizes, con-trasts but with similar patterns on their rec...

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Projects

Projects (4)
Project
Our purpose is a meta-analysis on experimental studies methodology about primary visual cortex for identification of parameters that could interfere on those conflicting results that leads to problems on scientific knowledge construction.