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Biomedical subjects

G Gottlieb

Publications and source records attributed to G Gottlieb.

At least 19 recordsLinked to original sources
PubMed1992

Development of brainstem auditory pathway in mallard duck embryos and hatchlings.

The development of the brainstem auditory evoked potential (BAEP) was studied in mallard duck (Anas platyrhynchos) embryos and hatchlings from 5-6 days before hatching through two days after hatching in response to tone pips of different frequencies. BAEPs showed a different time of onset and a different rate of development for low, middle, and high frequencies. Although auditory sensitivity in the mid-frequency range (1.0, 1.5, 2.0, and 3.0 kHz) appeared 1-2 days later than in the low-frequency range, development of the BAEPs in the mid-frequency range was almost complete by hatching. In contrast, the development of auditory sensitivity in the low- and high-frequency ranges continued to develop after hatching. Accelerated development of BAEPs to middle frequencies during the embryonic period and to high frequencies after hatching was correlated with the ducklings' exposure to their own mid-frequency and high-frequency vocalizations before and after hatching, respectively.

Aging↗
PubMed1992

Prospective versus retrospective methods of identifying patients with delirium.

OBJECTIVE: To determine if DSM-III criteria or clinical or discharge diagnoses, reviewed retrospectively, are as accurate an indicator of the presence of delirium as prospective evaluation by a psychiatrist. DESIGN: Selection of delirious patients prospectively by a psychiatrist, followed by retrospective record review of the same patients. SETTING: A referral-based university hospital. PATIENTS: From a sample of 235 consecutive medical patients over age 70, 47 delirious patients were identified prospectively by a research psychiatrist using DSM-III criteria. The medical record of these delirious patients was reviewed after discharge for evidence of delirium. RESULTS: Four patients were assigned ICD-9 codes suggestive of delirium (sensitivity 0.09). Review of physicians' diagnoses correctly identified 8 of 47 (sensitivity 0.17) patients as being delirious or acutely confused. The specific diagnostic criteria necessary to meet a DSM-III diagnosis of delirium could be ascertained from 10 of 47 records (sensitivity 0.21). CONCLUSION: The retrospective medical record review is very imprecise in establishing the diagnosis of delirium. As research in this field moves from descriptive epidemiology to studies of pathogenesis and treatment, prospective designs will be needed.

Abstracting and Indexing↗
PubMed1991

Behavioral pathway to evolutionary change.

The extreme malleability or plasticity of cells early in their development is mirrored to a certain, if lesser, degree in the psychological, behavioral, and neural functioning of developing organisms. The early developmental adaptability of organisms has significance for our understanding of evolution. It is the purpose of the present article to make a case for the extra-genetic or, better, the supra-genetic developmental basis of evolutionary change through the genesis of novel behavioral phenotypes. To make things as clear as possible, I contrast this developmental approach to evolution with the population-genetic model of the modern synthesis. I should say at the outset that the present theory can be integrated with the population-genetic model, with the exception of the radically different role ascribed to genes in the two viewpoints.

Adaptation, Biological↗
PubMed1990

Neophenogenesis: a developmental theory of phenotypic evolution.

An important task for evolutionary biology is to explain how phenotypes change over evolutionary time. Neo-Darwinian theory explains phenotypic change as the outcome of genetic change brought about by natural selection. In the neo-Darwinian account, genetic change is primary; phenotypic change is a secondary outcome that is often given no explicit consideration at all. In this article, we introduce the concept of neophenogenesis: a persistent, transgenerational change in phenotypes over evolutionary time. A theory of neophenogenesis must encompass all sources of such phenotypic change, not just genetic ones. Both genetic and extra-genetic contributions to neophenogenesis have their effect through the mechanisms of development, and developmental considerations, particularly a rejection of the commonly held distinction between inherited and acquired traits, occupy a central place in neophenogenetic theory. New phenotypes arise because of a change in the patterns of organism-environment interaction that produce development in members of a population. So long as these new patterns of developmental interaction persist, the new phenotype(s) will also persist. Although the developmental mechanisms that produce the novel phenotype may change, as in the process known as "genetic assimilation", such changes are not necessary in order for neophenogenesis to occur, because neophenogenetic theory is a theory of phenotypic, not genetic, change.

Animals↗
PubMed1990

Auditory basis of maternal attachment in ducklings (Anas platyrhynchos) under simulated naturalistic imprinting conditions.

The presence of broodmates during the imprinting process results in peer imprinting that interrupts a visually mediated maternal attachment. We sought to determine the conditions in which group-trained mallard ducklings (Anas platyrhynchos) acquire a maternal attachment. At 48 hr of age, ducklings were allowed to follow a vocal, stuffed mallard hen individually or in groups of 4. Individual ducklings showed a preference for the silent, familiar mallard over an unfamiliar pintail. Ducklings trained in groups did not show a preference. When the mallard maternal call was present during testing, group-trained ducklings overwhelmingly responded to it regardless of whether it came from the familiar mallard or an unfamiliar pintail. Training ducklings in groups, which simulates the natural social context of imprinting, results in peer imprinting. Thus, early in development the young become visually imprinted to each other, and the maternal call mediates attachment to the mother.

Animals↗
PubMed1989

Intrathecal baclofen for severe spinal spasticity.

We studied the effect of the intrathecal infusion of baclofen, an agonist of gamma-aminobutyric acid, on abnormal muscle tone and spasms associated with spinal spasticity, in a randomized double-blind crossover study. Twenty patients with spinal spasticity caused by multiple sclerosis or spinal-cord injury who had had no response to treatment with oral baclofen received an intrathecal infusion of baclofen or saline for three days. The infusions were administered by means of a programmable pump implanted in the lumbar subarachnoid space. Muscle tone decreased in all 20 patients (mean [+/- SD] Ashworth score for rigidity, from 4.0 +/- 1.0 to 1.2 +/- 0.4; P less than 0.0001), and spasms were decreased in 18 of the 19 patients who had spasms (mean [+/- SD] score for spasm frequency, from 3.3 +/- 1.2 to 0.4 +/- 0.8; P less than 0.0005). Tests for motor function, neurologic examination, and assessments by the patients correctly indicated when baclofen was being infused in all cases. All patients were then entered in an open long-term trial of continuous infusion of intrathecal baclofen. During a mean follow-up period of 19.2 months (range, 10 to 33), muscle tone has been maintained within the normal range (mean Ashworth score, 1.0 +/- 0.1) and spasms have been reduced to a level that does not interfere with activities of daily living (mean spasm score, 0.3 +/- 0.6). No drowsiness or confusion occurred, one pump failed, and two catheters became dislodged and had to be replaced. No infections were observed. Our observations suggest that intrathecal baclofen is an effective long-term treatment for spinal spasticity that has not responded to oral baclofen.

Adult↗
PubMed1989

Maternal and peer imprinting in mallard ducklings under experimentally simulated natural social conditions.

Previous studies revealed that if socially reared mallard ducklings actively follow a stuffed mallard (Anas platyrhynchos) hen, they later show a visual preference for the familiar mallard hen over an unfamiliar redhead (Aythya americana) hen. The present study determined that the experience of actively following the hen is essential to the induction of a visually controlled, species-typical, maternal preference. Domestic mallard ducklings that had not been given the opportunity to follow the mallard hen were "passively" reared in social groups consisting of a stuffed mallard hen and seven same-aged siblings for either 24, 48, or 72 hr after hatching. These birds were largely unresponsive to the hen in a later choice test, even when they were passively exposed to the mallard hen for as long as 72 hr prior to testing. The question arose as to whether passive exposure to the ducklings induced a preference for them that interfered with establishment of maternal imprinting under these simulated natural nest conditions. Results indicated that socially reared ducklings do prefer stuffed ducklings to a stuffed mallard hen in a simultaneous choice test even when the hen is present and vocalizing during social rearing. Further, even ducklings reared individually with the mallard hen were unresponsive to her in the later choice test. That there is something special about the stimulation provided by ducklings was further demonstrated by the finding that stuffed ducklings were preferred over the mallard hen (1) when the social rearing situation precluded active physical interaction with live ducklings and (2) when reared with inanimate stuffed ducklings. Thus, the ineffectiveness of the stuffed mallard hen in inducing visual imprinting under simulated nesting conditions cannot be attributed to the fact that she was not alive or reciprocally interactive. The present results suggest that mallard ducklings do not become visually imprinted to their hen until after departure from the nest, that the visual component of maternal imprinting likely involves active following subsequent to nest departure, and that early in postnatal development siblings are more visually attractive than is the hen.

Animals↗
PubMed1988

Social specificity: interaction with own species is necessary to foster species-specific maternal preference in ducklings.

Previous studies have shown that if domestic mallard ducklings are allowed social interaction with broodmates after their initial exposure to a stuffed mallard (Anas platyrhynchos) hen, they later show a visual preference for the familiar mallard over an unfamiliar redhead (Aythya americana) hen. Birds kept in social isolation do not make this difficult discrimination. In the present study, we examined whether this social enhancement of imprintability to a natural maternal model is merely the result of social stimulation in its most general sense, or if its effects are specific to social interaction for 30 min (training). This experience resulted in visual preference for the familiar mallard hen over the unfamiliar redhead hen in simultaneous choices tests at 48 hr and 72 hr after hatching only if the birds were allowed social experience with a group of same-age undomesticated mallard hatchings. No visual preference for the familiar mallard hen was found if the ducklings were permitted social experience with a group of same-age chick (Gallus domesticus) hatchlings or muscovy (Cairina moschata) ducklings. Thus, it appears that for ducklings to show a visually imprinted preference for a natural maternal model, they must be allowed social interaction with broodmates of their own species. Social rearing with other precocial bird hatchlings, even other ducklings, is without apparent effect. These results provide further evidence of the importance of nonobvious experimental factors in the development of species-typical behavior. They also suggest that in the evolution of the species-specific learning underlying early species identification, natural selection has operated on the entire (organism-environment) developmental manifold and not merely on genetic, organic, or organismic aspects of that system.

Animals↗
PubMed1988

Development of species identification in ducklings: XV. Individual auditory recognition.

The present experiments examined the ability of domestic mallard ducklings (Anas platyrhynchos) to learn individual mallard maternal calls by either repetition-rate differences or spectral (Hz) differences, both of which are present in such calls recorded in nature. The ducklings could learn both kinds of differences within the first 24 hr after hatching, corresponding to the period prior to the exodus from the nest in nature. The hatchlings were able to learn these differences based upon only 12 min of exposure to the maternal calls during the first day after hatching. They were also able to retain (remember) the familiar call for an additional day after exposure. Embryos, on the other hand, could learn the spectral differences after either 12 or 24 min of exposure but could not retain the information under either exposure condition. An additional difference between the auditory learning competence of hatchlings and embryos was that the hatchlings were capable of learning the spectral features of a maternal call even if it was pulsed at different repetition rates during exposure (familiarization) and the subsequent test for recognition. The evolutionary significance of the results was discussed in terms of the general importance of familiarization as a basic behavioral mechanism underlying not only parental attachment but dietary and habitat preferences and the like.

Animals↗
PubMed1987

Development of species identification in ducklings. XIII: A comparison of malleable and critical periods of perceptual development.

The present experiments sought to determine the relationship of the malleable period--when the mallard duck embryo is most susceptible to alien forms of maternal auditory stimulation--to the critical period, when the embryo must hear its own vocalizations in order to respond normally to the species-typical maternal call after hatching. It was found that a preference for either a wood duck or a chicken maternal call could be induced in devocalized mallard duck embryos by exposing them to either alien call some time between day 24, 0600 to day 26, 0600 hrs. Further experiments showed the height of the malleable period to be between day 24, 1400 hrs and day 25, 0800 hrs of embryonic development. Since the embryonic critical period for maintenance of the species-typical maternal auditory preference spans day 24, 0800 hrs to day 26, 0800 hrs, the malleable period for the induction of a preference for species-atypical maternal stimulation falls inside the critical period. While it is often assumed that malleable and critical periods overlap, this is the first behavioral study to actually demonstrate the temporal relationship of the two periods. It would seem important to further examine malleable and critical periods of development in a broader array of developmental contexts and species to determine whether malleable periods for atypical or abnormal development and critical periods for species-typical or normal development always coincide.

Acoustic Stimulation↗
PubMed1986

Visually imprinted maternal preference in ducklings is redirected by social interaction with siblings.

This study examined the influence of social interaction with broodmates on a visually imprinted maternal preference in domestic mallard ducklings (Anas platyrhynchos) during the first three days of postnatal life. Twenty-four-hour-old ducklings were allowed to follow a stuffed mallard hen for 30 min. This experience resulted in a visually imprinted preference for the familiar stuffed hen over 4 stuffed ducklings in simultaneous choice tests at 48 and 72 hr after hatching, but only if the imprinted birds were kept in social isolation. Imprinted ducklings reared in a social group containing either same-age siblings or the stuffed mallard hen and same-age siblings displayed a visual preference for the stuffed ducklings over the familiar mallard hen at 48 and 72 hr tests. As a first step in the analysis of the features of the social exposure to siblings that are necessary for the redirection of the visually imprinted maternal preference, it was found that direct social interaction is essential to establish the preference for ducklings, but even mere visual exposure to siblings does away with the imprinted maternal preference. These results provide striking evidence of the ready redirection of a species-specific maternal preference in otherwise imprinted ducklings.

Animals↗
PubMed1986

Training ducklings in broods interferes with maternal imprinting.

Under natural conditions, if maternal imprinting is to occur it must occur in a social situation which includes the presence of broodmates. In the laboratory it has been shown that social rearing with siblings prior to maternal imprinting interferes with the establishment of maternal imprinting, whereas social experience with siblings after maternal imprinting enhances the imprinting experience. The present study examined the influence of social experience with broodmates during an imprinting trial on the establishment of a visually imprinted maternal preference in domestic mallard ducklings (Anas platyrhynchos). Twenty-four-hour-old ducklings were allowed to follow a stuffed mallard hen for 30 min either individually or in a brood of four same-aged ducklings. The birds trained alone subsequently showed an imprinted preference for the familiar mallard hen over an unfamiliar pintail hen or four stuffed ducklings in simultaneous choice tests at 48 and 72 hr after hatching. Ducklings trained with broodmates did not show a preference for the familiar mallard hen over the unfamiliar pintail hen and displayed a preference for the stuffed ducklings over the mallard hen at 48 and 72 hr choice tests. These results demonstrate that even brief (30 min) experience with siblings during a maternal imprinting trial results in peer imprinting that interferes with the establishment of maternal imprinting. These and other results of a similar sort render dubious the significance of most laboratory studies of imprinting for an understanding of such events in nature.

Age Factors↗
PubMed1978

Pulmonary function following feeding in low-birth-weight infants.

Determination of functional residual capacity, arterial gas tensions and pH, and arterial-alveolar differences was carried out in a group of nondistressed premature infants to determine if significant alterations in lung volumes or ventilation perfusion relationships sufficiently large to cause cyanosis could be detected after feeding. The only statistically significant changes observed in these parameters were immediately following feeding, a fall of .01 pH units and a fall of 6 mm Hg in arterial oxygen tension; and 15 minutes after feeding, a fall of .01 pH units and a rise in arterial PCO2 of 3 mm Hg. In addition, significant falls in peripheral blood flow were observed five minutes after feeding in association with marked elevations in peripheral vascular resistance. The mild impairment in pulmonary function in association with the more profound changes in limb blood flow are consistent with other studies in premature and full-term infants. These data suggest that cyanotic attacks following feeding may have a complex etiology and require an aggressive multisystem approach for adequate diagnosis and therapy.

Apnea↗
PubMed1978

Development of species identification in ducklings: IV. Change in species-specific perception caused by auditory deprivation.

The purpose of the present experiments was to identify the change in species-specific perception that underlies the aurally deprived ducklings' lack pf preference or discrimination in the mallard versus chicken call test. Among other acoustic differences, the mallard and chicken maternal calls differ in repetition rate (3.7 and 2.3 notes/sec, respectively). The present experiments showed the dimension of repetition rate to be uppermost in the perceptual hierarchy underlying the auditory aspect of species identification in Peking ducklings. The relatively narrow species-typical repetition-rate preferences of normal Peking ducklings (about 4--6 notes/sec) is lacking in the aurally deprived ducklings, and they respond to lower rates than usual (2.3 notes/sec). This broadening of the range of responsiveness on a perceptual dimension (repetition rate) that is basic to species identification accounts for the devocal ducklings' lack of discrimination in the mallard versus chicken call test.

Age Factors↗
PubMed1976

Importance of pulmonary ventilation in respiratory control in the bullfrog.

Pulmonary and cutaneous O2 consumption (Vo2) and CO2 production (Vco2) were measured simultaneously in bullfrogs Rana catesbeiana at 20 degrees C. The lungs were responsible for 77.3-91.0% of the total Vo2 and 28.5-74.9% of the total VCO2. The distribution of the total exchange between the lungs and skin depended on metabolic rate; frogs with higher rates relied more heavily on the pulmonary mode for both Vo2 and Vco2. When prevented from ventilating their lungs in an O2-rich environment, bullfrogs developed severe respiratory acidosis, demonstrating the importance of lung exchange in normal acid-base balance. When frogs were totally submerged in an O2-saturated medium, skin Vco2 increased linearly to a steady-state value which approximated the preapneic total Vco2. In these same animals, arterial Pco2 increased proportionately to the increase in skin Vco2, indicating that skin diffusion capacity for CO2 was unaffected. We conclude that the control of breathing in the bullfrog in response to changes in metabolic rate relies predominantly on changes in lung ventilation while the skin plays a more passive role.

Animals↗