Helmut Hirsch
SUNY: University at Albany, Biology, Faculty Member
We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their... more
We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their Pb loads at different stages of development (larvae, eclosion, newly-eclosed adults, and mature adults). Pb loads were tested using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). We found that D. melanogaster readily accumulated Pb throughout their lifespan and the levels of accumulation increased with Pb exposure in the medium. Wandering third-instar larvae accumulated more Pb than mature adults; this phenomenon may be due to elimination of Pb in the pupal cases during eclosion and/or depuration in adults post-eclosion. The accumulated Pb in mature adults was not transferred to F1 mature adult offspring. Using a set of recombinant inbred strains, we identified a quantitative trait locus for adult Pb loads and found that genetic variation a...
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We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their... more
We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their Pb loads at different stages of development (larvae, eclosion, newly-eclosed adults, and mature adults). Pb loads were tested using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). We found that D. melanogaster readily accumulated Pb throughout their lifespan and the levels of accumulation increased with Pb exposure in the medium. Wandering third-instar larvae accumulated more Pb than mature adults; this phenomenon may be due to elimination of Pb in the pupal cases during eclosion and/or depuration in adults post-eclosion. The accumulated Pb in mature adults was not transferred to F1 mature adult offspring. Using a set of recombinant inbred strains, we identified a quantitative trait locus for adult Pb loads and found that genetic variation a...
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Novel Activities Enhance Performance of the Aging Brain. by Mark A. Hirsch , Helmut VB Hirsch Two roads diverged in a wood, and I - I took the one less traveled by, And that has made all the difference. - Robert Frost (Frost, 1916)... more
Novel Activities Enhance Performance of the Aging Brain. by Mark A. Hirsch , Helmut VB Hirsch Two roads diverged in a wood, and I - I took the one less traveled by, And that has made all the difference. - Robert Frost (Frost, 1916) Traditio.
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EJ493739 - Educators Look at Contemporary Science Teaching.
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In unequal alternating monocular exposure (unequal AME), each eye receives normal patterned visual input but on alternate days and for unequal periods. It has been shown previously that this imbalance in stimulation produces a deficit in... more
In unequal alternating monocular exposure (unequal AME), each eye receives normal patterned visual input but on alternate days and for unequal periods. It has been shown previously that this imbalance in stimulation produces a deficit in the nasal visual field of the less experienced eye (LEE). The effect of subsequent binocular exposure on these visual deficits has now been examined. No evidence of recovery was found. Instead, visual fields remained the same or became smaller. In cats reared with little or no imbalance (8 hr/day vs 7 hr/day or 1 hr/day vs 1 hr), subsequent binocular exposure had no effect on visual fields. In cats reared with a moderate or large imbalance (8 hr/day vs 4 hr/day or 8 hr/day vs 1 hr/day), subsequent binocular exposure led to a suppression of the LEE: when tested binocularly, these cats rarely responded to targets presented in the monocular field of the LEE. The deficits became progressively more severe throughout the period of binocular exposure, unti...
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ABSTRACT Here, we show that in a skeleton photoperiod where all midday light is removed from a standard laboratory 12:12 LD photoperiod, a large diurnal peak of activity is revealed that is continuous with the E peak seen in constant dark... more
ABSTRACT Here, we show that in a skeleton photoperiod where all midday light is removed from a standard laboratory 12:12 LD photoperiod, a large diurnal peak of activity is revealed that is continuous with the E peak seen in constant dark (DD). We further show that the circadian clock gene tim regulates light-dependent masking of daytime activity, but the clock gene per does not. Finally, relative to wild-type flies, mutants for both of these clock genes showed increased nighttime activity in the skeleton photoperiod but not in the standard photoperiod. This result suggests that nighttime activity is suppressed by the intact circadian clock, and in its absence, by exposure to a standard photoperiod. These results support and extend the literature addressing the complex interactions between masking and clock-controlled components of overt circadian rhythms.
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Page 103. Tunable Seers Activity-Dependent Development of Vision in Fly and Cat HELMUT VB HIRSCH, SUZANNAH BLISS TIEMAN, MARTIN EARTH, AND HELEN GHIRADELLA INTRODUCTION Programs guiding nervous system development must achieve two goals. ...
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To test whether visual experience can affect development of visual behavior in the fruitfly, Drosophila, we measured the visually-guided choice behavior of groups of flies reared in complete darkness, compared with controls reared in a... more
To test whether visual experience can affect development of visual behavior in the fruitfly, Drosophila, we measured the visually-guided choice behavior of groups of flies reared in complete darkness, compared with controls reared in a normal light/dark cycle. We used a simple visual preference test, i.e. choice among four different visual targets each consisting of vertical black lines of a particular width on a white background, using a blind testing procedure so that the individual rearing histories were not known by the tester. Both groups of flies were strongly attracted to the vertical lines; however, generally the dark-reared flies were more attracted to the wider stimulus lines than were the control flies. Control experiments in which normally reared adults were kept for several days in darkness showed that the effects of dark-rearing were not simply due to being in darkness, but depended upon the timing of the deprivation. The results indicate that the development of visual behavior can be affected by visual experience in Drosophila and thus open the possibility of using Drosophila for genetic dissection of mechanisms of visual plasticity.
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ABSTRACT We present a primer on the adaptability of the brain. We start with a brief historical overview of the biology of neuroplasticity. Environmental enrichment, social stimulation, exercise, and pharmacologic interventions (eg,... more
ABSTRACT We present a primer on the adaptability of the brain. We start with a brief historical overview of the biology of neuroplasticity. Environmental enrichment, social stimulation, exercise, and pharmacologic interventions (eg, antidepressant drugs) have all been reported to influence neuroplasticity. Since adaptive changes in the brain involve changes in how genes are expressed, we look at some approaches to that. Next, we consider a vital, but often overlooked, factor in brain development throughout life—social interactions. We conclude with a future perspective.
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Kittens were reared so that each eye received normal patterned vision on alternate days. If the eyes received equal periods of stimulation, the visual fields were normal. If one eye received much more experience than the other, the field... more
Kittens were reared so that each eye received normal patterned vision on alternate days. If the eyes received equal periods of stimulation, the visual fields were normal. If one eye received much more experience than the other, the field of the less experienced eye was restricted to the temporal hemifield. This change, which differs from that observed when one or both eyes are deprived continuously of patterned input, suggests that an imbalance in the duration of stimulation can influence the outcome of the normal competitive interaction between pathways from the two eyes and can cause a selective suppression of a portion of the input from the less experienced eye. This suppression may involve the ipsilateral retino-geniculo-cortical pathways or it may involve the entire cortical pathway from the less experienced eye, leaving the colliculus to control responses to visual targets.
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Abstract The controversy of the low dose effects, ie health effects of small amounts of ionizing radiation on human beings which do not produce any short-term effects, can serve as exemplification of (a) the existing trend of growing... more
Abstract The controversy of the low dose effects, ie health effects of small amounts of ionizing radiation on human beings which do not produce any short-term effects, can serve as exemplification of (a) the existing trend of growing political integration of science and ...
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Research Interests: Genetics, Animal Behavior, Drosophila melanogaster, Gene expression, Neural Development, and 15 moreBiological Sciences, Endocrine disruptors, Female, Animals, Male, Model System, Neuronal Activity, Locomotor Activity, Endocrine Disruptors, Fruit Fly, Neuromuscular Junction, Organometallic Compounds, Environmental Exposure, Intracellular Calcium, and Motor activity
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We present data on the effects of various concentrations of the organophosphorus insecticide, fenitrothion, on development, reproduction and eggshell structure of Spodoptera exigua. The insecticide did not change the male/female ratio in... more
We present data on the effects of various concentrations of the organophosphorus insecticide, fenitrothion, on development, reproduction and eggshell structure of Spodoptera exigua. The insecticide did not change the male/female ratio in tested populations. The ...
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Considerable progress has been made over the past couple of decades concerning the molecular bases of neurobehavioral function and dysfunction. The field of neurobehavioral genetics is becoming mature. Genetic factors contributing to... more
Considerable progress has been made over the past couple of decades concerning the molecular bases of neurobehavioral function and dysfunction. The field of neurobehavioral genetics is becoming mature. Genetic factors contributing to neurologic diseases such as Alzheimer's disease have been found and evidence for genetic factors contributing to other diseases such as schizophrenia and autism are likely. This genetic approach can also benefit the field of behavioral neurotoxicology. It is clear that there is substantial heterogeneity of response with behavioral impairments resulting from neurotoxicants. Many factors contribute to differential sensitivity, but it is likely that genetic variability plays a prominent role. Important discoveries concerning genetics and behavioral neurotoxicity are being made on a broad front from work with invertebrate and piscine mutant models to classic mouse knockout models and human epidemiologic studies of polymorphisms. Discovering genetic factors of susceptibility to neurobehavioral toxicity not only helps identify those at special risk, it also advances our understanding of the mechanisms by which toxicants impair neurobehavioral function in the larger population. This symposium organized by Edward Levin and Annette Kirshner, brought together researchers from the laboratories of Michael Aschner, Douglas Ruden, Ulrike Heberlein, Edward Levin and Kathleen Welsh-Bohmer conducting studies with Caenorhabditis elegans, Drosophila, fish, rodents and humans studies to determine the role of genetic factors in susceptibility to behavioral impairment from neurotoxic exposure.
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Research Interests: Drosophila melanogaster, Neurotoxicology, Female, Animals, Male, and 12 moreInductively Coupled Plasma Mass Spectrometry, Model System, Distilled Water, Cognitive Function, Human Activity, Locomotor Activity, Nervous System, Organometallic Compounds, Neurosciences, Environmental Exposure, Linear System and Response, and Motor activity
Long term or chronic exposure to lead is associated with cognitive and other deficits in humans, which may reflect lead-induced changes in synaptic development and function. We believe that Drosophila has great potential as a model system... more
Long term or chronic exposure to lead is associated with cognitive and other deficits in humans, which may reflect lead-induced changes in synaptic development and function. We believe that Drosophila has great potential as a model system for studying such changes. To test this, we compared the structure of single, identified synapses between identified axons (axons 1 and 2) and muscle fibers (fibers 6 and 7) in untreated 3rd instar larvae, and in larvae reared on medium made with 100 microM lead acetate in distilled water. We used three approaches to examine the motor terminals on muscle fibers 6 and 7 in segment 2: (1) all terminals were stained with an antibody to HRP; (2) only the terminals of axon 1 were stained by injecting biotinylated Lucifer yellow into it; and (3) the regions of the terminal containing synaptic vesicles were stained with an antibody to synaptotagmin, which provides an estimate of "synaptic" terminal area. Lead burdens were determined by inductively coupled plasma mass spectrometry; hemolymph lead levels at the neuromuscular junction were likely to be micromolar. We observed that lead exposure did not significantly affect the average terminal area or the average muscle fiber area, but did significantly affect the uniformity of the matching between muscle area and motor terminal size that normally occurs during development. There was a significant positive correlation between motor terminal size and muscle area in control, but not in lead-exposed larvae. The sensitivity of Drosophila larval synaptic development to lead opens the way to using the powerful genetic and molecular tools available for this system to study the underlying mechanisms of this sensitivity. We would hope that from such an understanding may come strategies for dealing with lead-induced deficits in children.
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Cats reared with their visual world restricted to vertical lines for one eye and horizontal lines for the other had, in their visual cortices, units with elongated receptive fields that were either vertically or horizontally oriented.... more
Cats reared with their visual world restricted to vertical lines for one eye and horizontal lines for the other had, in their visual cortices, units with elongated receptive fields that were either vertically or horizontally oriented. These receptive fields could be mapped only using that eye which had seen lines of the same orientation during development. Other units had diffuse,
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Thirty-four kittens reared by allowing each eye patterned visual input, but on alternate days and for unequal periods of time (unequal alternating monocular exposure (AME)), were tested for their ability to orient to targets at different... more
Thirty-four kittens reared by allowing each eye patterned visual input, but on alternate days and for unequal periods of time (unequal alternating monocular exposure (AME)), were tested for their ability to orient to targets at different positions in visual space. In all unequal AME cats, the visual field of the more experienced eye (MEE) was normal, while that of the less experienced eye (LEE) was restricted. In contrast, in 14 cats reared with equal AME, the fields of both eyes were equal and of normal size. The field deficits observed in the unequal AME cats must therefore be due to the imbalance in stimulation and thus result from a competitive interaction between the afferents from the MEE and the LEE. The field deficits observed in the unequal AME cats differed from those observed in two monocularly deprived (MD) cats. Neither of the MD cats ever responded to targets presented in the region of normal binocular overlap when tested with the deprived eye (DE). The unequal AME cats all showed a nasal field loss in the LEE, but responded normally to targets throughout the temporal portion of the binocular visual field. When the imbalance in stimulation was large (8 to 1) or moderate (8 to 4), there was an abrupt drop in responsiveness (from 100% to zero) as the position of the target was changed from temporal to nasal. When the imbalance was slight (8 to 7), the drop in responsiveness was more gradual and occurred within the nasal field. Our results demonstrate that (1) the paradigm of unequal AME is a useful one for studying binocular competition quantitatively, (2) even the slightest imbalance in stimulation of the two eyes can affect the outcome of the competitive interaction, and (3) the pathways serving binocular vision are not uniformly affected by binocular competition: the ipsilateral pathway is more sensitive than the contralateral pathway.
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Research Interests: Psychophysics, Cats, Higher Order Thinking, Visual Cortex, Form perception, and 14 moreCellular and Molecular Neurobiology, Orientation, Sensory processing, Animals, Visual System, First-Order Logic, Lateral Geniculate Nucleus, Sensory Deprivation, Orientation Selectivity, Retinal Ganglion Cells, Neurosciences, Gamma-Aminobutyric Acid, Biochemistry and cell biology, and Striate Cortex
Eye alignment was measured in neonatal callosum-sectioned cats that were 1-3 years old. Alignment was measured from photographs of the cat's corneal reflex when alert, anesthetized and paralyzed, and by plotting to optic disc... more
Eye alignment was measured in neonatal callosum-sectioned cats that were 1-3 years old. Alignment was measured from photographs of the cat's corneal reflex when alert, anesthetized and paralyzed, and by plotting to optic disc separation during paralysis. The callosal alignment was equally divergent when alert and paralyzed and was identical to the control alignment under paralysis. Therefore, the alert callosal divergence results from a failure to converge the eyes.
Research Interests: Cognitive Science, Cornea, Strabismus, Cats, Brain, and 4 moreCorpus Callosum, Animals, Reflex, and Neurosciences
... HELMUT VB HIRSCH, DOREEN POTTER, DARIUSZ ZAWIERUCHA, TANVIR CHOUDHRI, ADRIAN GLASSER, AND DUNCAN BYERS Neurobiology Research Center and ... between dark-reared and control flies was small but significant (N = 1263 flies; chi-square =... more
... HELMUT VB HIRSCH, DOREEN POTTER, DARIUSZ ZAWIERUCHA, TANVIR CHOUDHRI, ADRIAN GLASSER, AND DUNCAN BYERS Neurobiology Research Center and ... between dark-reared and control flies was small but significant (N = 1263 flies; chi-square = 58.44, df = ...
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Neurons in the visual cortex that respond preferentially to diagonal contours are present only in cats exposed to diagonal lines early in life. In contrast, cells that prefer horizontal or vertical contours are found following exposure to... more
Neurons in the visual cortex that respond preferentially to diagonal contours are present only in cats exposed to diagonal lines early in life. In contrast, cells that prefer horizontal or vertical contours are found following exposure to horizontal, to vertical, and to diagonal lines. Such cells do not require a specific visual input for maintenance or for development; neurons responding preferentially to diagonal lines do.
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To determine whether selective exposure to lines of one orientation modifies the shape of the dendritic fields of cells in visual cortex, we examined the dendritic morphology of neurons in area 17 of five normally reared cats, five cats... more
To determine whether selective exposure to lines of one orientation modifies the shape of the dendritic fields of cells in visual cortex, we examined the dendritic morphology of neurons in area 17 of five normally reared cats, five cats reared viewing only vertical lines, and three cats reared viewing only horizontal lines. Kittens were placed with their mothers into a totally dark room before their eyes had opened. Beginning at 4 weeks of age, the kittens were brought out for daily periods of exposure wearing masks that limited the vision of each eye to a field of three vertical lines or three horizontal lines. After a minimum of 170 hours of exposure, the animals were killed and blocks of visual cortex were impregnated by the Golgi-Kopsch procedure and cut tangential to the pial surface. Complete neurons from layers III and IV were drawn with the aid of a camera lucida, and the orientations of the dendritic fields wer analyzed using Sholl diagrams. In normal cats, the distributions of the orientations of dendritic fields were uniform, whereas in strip-reared cats, the distributions for the layer III pyramidal cells were shifted. The direction of this shift varied with the experience of the cat: In cats reared viewing only vertical lines, the dendritic fields were oriented orthogonal to the representation of the vertical meridian, and in cats reared viewing only horizontal lines, the fields were oriented parallel to the representation of the vertical meridian. In contrast, the distribution of dentritic orientations for the stellate cells was not affected by stripe-rearing. These results demonstrate a morphological effect of early visual experience that is specific to the particular stimulus presented during rearing and suggest that (1) cortical cells differ in the degree to which they can be modified by such experience, and (2) the dendritic morphology of cortical neurons is related to their preferred orientations.
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Page 1. Exp. Brain l~es. 15, 405~423 (1972) ~) by Springer-Verlag 1972 Visual Perception in Cats After Environmental Surgery HELMUT VB HIRSC]~* Department of Psychology, Stanford University, Stanford, California (USA) Received December... more
Page 1. Exp. Brain l~es. 15, 405~423 (1972) ~) by Springer-Verlag 1972 Visual Perception in Cats After Environmental Surgery HELMUT VB HIRSC]~* Department of Psychology, Stanford University, Stanford, California (USA) Received December 29, 1971 Summary. ...
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Different types of visual deprivation lead to different patterns of deficits determined neurophysiologically. This study attempted to determined whether these d.
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Cats were raised from birth with one eye viewing horizontal lines and one eye viewing vertical lines. Elongated receptive fields of cells in the visual cortex were horizontally or vertically oriented-no oblique fields were found. Units... more
Cats were raised from birth with one eye viewing horizontal lines and one eye viewing vertical lines. Elongated receptive fields of cells in the visual cortex were horizontally or vertically oriented-no oblique fields were found. Units with horizontal fields were activated only by the eye exposed to horizontal lines; units with vertical fields only by the eye exposed to vertical lines.