Biomedical subjects

L J Rogers

Publications and source records attributed to L J Rogers.

At least 37 records · Page 2Linked to original sources

PubMed1999

Light experience and lateralization of the two visual pathways in the chick.

Using retrograde labelling with the fluorescent tracer rhodamine B isocyanate (RITC), we have examined the organisation of the thalamofugal and tectofugal visual projections to the forebrain of the young chick. In addition, we have investigated the influence of light exposure prior to hatching on the development of the tectofugal visual projections. Our results for the thalamofugal projections confirm those found previously; viz., that there are more projections from the left side of the thalamus to the right hyperstriatum of the forebrain than from the right side of the thalamus to the left hyperstriatum in males and females. The organisation of the tectofugal visual projections to the rotundal nuclei was more symmetrical (males only examined) although there was a trend towards a greater number of projections from the left optic tectum to its ipsilateral nucleus rotundus than from the right optic tectum to its ipsilateral nucleus rotundus. There are numerous projections from the optic tecta to their contralateral rotundal nuclei but, in contrast to reports for the pigeon, no marked asymmetry was present in these. The ratio of contralateral to ipsilateral projections revealed significant asymmetry for projections from the ventral regions of the optic tecta and symmetry from the dorsal regions. Thus both visual pathways of the chick have asymmetrical organisation but the asymmetry is much greater in the thalamofugal pathway. The slight asymmetry in the tectofugal projections may be determined by exposing the embryo to light just before hatching, as known to be the case for thalamofugal projections.

Animals↗

PubMed1999

Possible evolutionary origins of cognitive brain lateralization.

Despite the substantial literature on the functional architecture of the asymmetries of the human brain, which has been accumulating for more than 130 years since Dax and Broca's early reports, the biological foundations of cerebral asymmetries are still poorly understood. Recent advances in comparative cognitive neurosciences have made available new animal models that have started to provide unexpected insights into the evolutionary origins and neuronal mechanisms of cerebral asymmetries. Animal model-systems, particularly those provided by the avian brain, highlight the interrelations of genetic, hormonal and environmental events to produce neural and behavioural asymmetries. Novel evidences showing that functional and structural lateralization of the brain is widespread among vertebrates (including fish, reptiles and amphibians) have accumulated rapidly. Perceptual asymmetries, in particular, seem to be ubiquitous in everyday behaviour of most species of animals with laterally placed eyes; in organisms with wider binocular overlap (e.g., amphibians), they appear to be retained for initial detection of stimuli in the extreme lateral fields. We speculate that adjustment of head position and eye movements may play a similar role in mammals with frontal vision as does the choice for right or left lateral visual fields in animals with laterally placed eyes. A first attempt to trace back the origins of brain asymmetry to early vertebrates is presented, based on the hypothesis that functional incompatibility between the logical demands associated with very basic cognitive functions is central to the phenomenon of cerebral lateralization.

Animals↗

PubMed1999

Light exposure of chick embryo influences lateralized recall of imprinting memory.

Environmental cues, such as light during the later part of incubation, are known to establish lateralization of some forms of visually guided behaviors in birds. The authors investigated the effect of light on lateralized recall of imprinting memory in chicks. On Day E19 of incubation, one eye was occluded for 24 hr. The other eye received stimulation by light. Chicks were imprinted and then tested for their imprinting preferences after administration of a low dose (500 ng) of glutamate into either hemisphere. Chicks that had the right eye exposed to light during incubation showed recall of the imprinting stimulus after injection of the left hemisphere but not after injection into the right hemisphere. The reverse was found for chicks that had the left eye exposed to light. Hence, the hemisphere ipsilateral to the eye exposed to light before hatching became essential for recall of imprinting memory. The hemisphere used in recall of imprinting memory received indirect visual inputs and was determined by environmental stimulation (asymmetrical light input).

Animals↗

PubMed1998

Complementary right and left hemifield use for predatory and agonistic behaviour in toads.

Cerebral lateralization, the differing specializations of the right and left sides of the brain once thought to be unique of humans, is now well known to occur in both birds and mammals. Here we report that in toads the right hemisfield of vision guides predatory tongue-striking responses towards moving prey and the left hemisfield guides agnostic tongue-striking responses towards conspecifics. This indicates, for the first time, complementary cerebral specializations for visual processing in anurans, and strongly supports the hypothesis that lateralized brain functions in birds and mammals may have arisen from a common lateralized ancestor. Complementary specializations in visual processing may have originally evolved to avoid problem of response competition during control of medial organs such as the tongue in organisms with laterally placed eyes and, in organisms with wider binocular overlap, it appears to be retained for initial detection of stimuli in the extreme lateral fields.

Agonistic Behavior↗

PubMed1998

Bilaterally projecting neurons in the two visual pathways of chicks.

By means of a double-labeling technique, we have investigated the organization of the bilateral thalamo-Wulst and tecto-rotundal projections in 2-day old chicks. After injecting fluorogold (FG) into one side of the visual Wulst and rhodamine B isothiocyanate (RITC) into the other side of the visual Wulst, the labeled neurons in the nucleus geniculatus lateralis pars dorsalis (GLd) were examined. Although the distribution areas of ipsilaterally and contralaterally labeled neurons overlap partly, very few double-labeled neurons were found (only 0.01% double-labeled neurons). This suggests that the ipsilateral and contralateral projections to the Wulst come from different neuronal populations of the thalamus. The FG and RITC were also injected into the rotundal nuclei (Rt) on each side of the thalamus and the labeled neurons in the optic tectum (TeO) were examined. In the TeO, the distribution areas of the neurons labeled ipsilaterally and contralaterally to Rt overlap completely and we found that up to 45% of the tectal cells were double-labeled by both FG and RITC. Therefore, many tectal neurons have axon collaterals so that they project to the Rt on both sides of the thalamus and must send information simultaneously to both sides of the brain. The differences in the structural organization of the two visual pathways are discussed with reference to the transmission of information to higher centers on both sides of the brain.

Animals↗

PubMed1998

Organisation of the tectorotundal and SP/IPS-rotundal projections in the chick.

The organisation of the neural projections from the optic tectum and pretectal nuclei complex, n. subpretectalis / n. interstitio-pretecto-subpretectalis (SP/IPS), to the nucleus rotundus (Rt) in chicks was studied by using retrograde tracing techniques. After the injection of fluorescent retrograde tracers, rhodamine-conjugated latex microspheres, fluorescein-conjugated latex microspheres, True Blue, Fluoro-Gold, or rhodamine B isothiocyanate, into different regions of Rt and its middorsal extension, the nucleus triangularis (T), the distribution of retrogradely labelled neuronal cell bodies in the tectum and pretectal nuclei was assessed. Both the ipsilateral and contralateral tectorotundal projections were found to be organised topographically in as much as different sublaminas of the stratum griseum centrale (SGC) project in an orderly manner to Rt and T. The deepest stratum of SGC overlapping into the stratum album centrale projects to T. Deep SGC projects to the dorsal Rt and superficial SGC to the ventral Rt. A band running through the centre of Rt receives input from the central sublamina of SGC, and the caudal central Rt receives input from a deeper sublamina than does the rostral central Rt. The SP/IPS projects to the ipsilateral Rt only and the projection order is dorsal SP to dorsal Rt, ventral SP to ventral Rt and middle SP to the central band of Rt. The neurones in IPS and the nucleus of the tractus tectothalamicus project to T. Thus, Rt and T receive topographically both tecto- (excitatory) and SP/IPS- (inhibitory) projections. The possible functional implications for parallel information processing in these projections are discussed.

Animals↗

PubMed1998

Lateralized use of the mouth in production of vocalizations by marmosets.

We have found that the common marmoset, Callithrix jacchus, displays a larger left hemimouth during production of fear expressions, with or without vocalization, and a larger right hemimouth when producing a social contact call. Thus, marmosets have right hemisphere specialization for the production of negative emotional expressions and vocalizations and left hemisphere specialization for the production of social contact communication. These hemispheric specializations for social communication in marmosets are the same as those found in humans for speech production and for the control of emotional expressions. We suggest that hemispheric specializations for communication in humans may well have precursors in primate evolution.

Animals↗

PubMed1998

Right hemisphere involvement in imprinting memory revealed by glutamate treatment.

The lateralized use of the forebrain hemispheres during recall of imprinting memory was investigated using unilateral intrahemispheric injections of glutamate. Administration of glutamate to the right hemisphere 1.3, or 6 h after exposure to the imprinting stimulus disrupted recall 8 h after the end of training, whereas the same treatment of the left hemisphere had no effect. Imprinted chicks treated with glutamate injected into the right hemisphere did not approach the imprinting stimulus in preference to an alternative, unfamiliar stimulus during a simultaneous choice test, whereas imprinted chicks treated with glutamate injected into the left hemisphere showed a preference for the imprinting stimulus. Thus, the left and right hemispheres are involved differentially in the recall of imprinting memory. Fear behavior or activity levels were not altered by glutamate treatment of either the right or left hemisphere, indicating that the effects of glutamate were specific to recall of imprinting memory. However, the amnestic effect of treatment of the right hemisphere with glutamate was transient: it was no longer evident by 48 h after the end of training. Also, glutamate had no effect when the chicks were treated 9 h after the end of training. These results suggest that regions in right hemisphere of the chick brain are involved in early (0-8 h after training) recall of imprinting memory.

Animals↗

PubMed1998

The origins of cerebral asymmetry: a review of evidence of behavioural and brain lateralization in fishes, reptiles and amphibians.

Early evidence for lateralization at a population and/or individual level in 'lower' vertebrates is reviewed. The lateralities include structural asymmetries in the epithalamus of several species of fish and amphibians, asymmetries in the location of both eyes on the same side of the head and of the dorsal/ventral crossing at optic-chiasma in flatfish, asymmetries in copulatory organs of several species of fishes, asymmetries in lung size and direction of coiling in reptiles, and asymmetrical distribution of scarring in whitefish. More recent data on functional lateralization at population level in lower vertebrates are also reviewed. These include: lateral asymmetries in the direction of turning during escape behaviour and in eye use in poeciliid fish; lateralization of pectoral stridulation sounds in catfish; neural lateralization for control of vocalization in the frogs; pawedness in toads; lateralization of courtship behaviour in newts; and lateralization of aggressive responses in lizards. Several cases of behavioural asymmetries at the individual level are also described, and possible relationships between lateralization at the individual level and fluctuating asymmetries arising from reduced heterozygosity are discussed. It is argued that the overall evidence now available supports the hypothesis of an early origin of brain lateralization in vertebrates.

Amphibians↗

PubMed1998

Light exposure of the embryo and development of behavioural lateralisation in chicks, I: olfactory responses.

Chicks exposed to light during late foetal life experience stimulation of the right eye only and, in consequence, develop asymmetries of the crossed visual projections from thalamus to forebrain and differences in performance of some visual tasks when using the right or left eye. The present study compared dark- and light-incubated chicks in a test of olfaction in which clove oil odour was presented together with a coloured bead. When the chicks were tested with a blue bead and using the right nostril (left nostril occluded by wax), head shaking and pecking were elevated, compared to pretest responses to an unscented, white bead. No significant elevation of head shaking occurred in chicks tested with the blue bead and using the left nostril, although pecking increased, which indicates that these chicks attended to the visual parameters of the bead but not the odour. It appears that, when the left nostril is used, attention to an attractive visual stimulus suppresses responses to olfactory input to the left hemisphere. When the clove oil odour was presented together with a less attractive, red bead, no significant lateralisation emerged. Light or dark experience prior to hatching had no effect on the lateralised performance of the blue-bead test.

Animals↗

PubMed1998

Eye preferences in common marmosets (Callithrix jacchus): influence of age, stimulus, and hand preference.

Eye preferences of the common marmoset ( Callithrix jacchus ) were examined, taking into account age, arousal, and hand preference. Monocular eye use for looking through a small hole at a stimulus was recorded. Of 21 marmosets, 20 displayed right-eye preferences for viewing a piece of familiar food. In subjects tested at 3-8, 12, 15-18, and 22 months, eye preferences were consistent across age. A group bias, indicative of right-eyedness, was also found for viewing other stimuli. The stimuli included a watch, mirror, model of a beetle, and the experimenter's hand. However, when the marmosets viewed a threatening stimulus, a model resembling two rearing snakes, they displayed increased arousal (indicated by longer duration between monocular viewing events and increased incidence of aroused vocalisations) and the eye preferences shifted away from a preference for the right eye to either no preference or a left-eye preference. No relationship between eye preference and hand preference for holding food was found. Therefore, we suggest that eye preferences may reflect hemispheric specialisations for perceptual processing, according to the emotional valence of the stimulus.

Journal Article↗

PubMed1998

Teat preference for suckling in common marmosets: relationship to side of being carried and hand preference.

Mother-infant interaction in common marmosets ( Callithrix jacchus jacchus ) was scored for the first 60 days post parturition. Teat preference was compared to hand preference for picking up and holding food over the same ages and at 18 months. All infants, except one, exhibited strong preferences for one of the mother's teats. Preference for a teat was maintained when twins suckled separately as well as together. Infants suckled separately for a mean 42% of the time of all suckling bouts being observed. There was a significant correlation between teat preference and the side of being carried by the mother. This correlation was maintained despite the fact that the father also carried the infants. There was no significant relationship between teat preference and hand preference from 0 to 2 months or later life.

Journal Article↗

PubMed1997

Exposure to light prior to hatching induces asymmetry of receptor binding in specific regions of the chick forebrain.

This paper describes neurochemical asymmetries present in forebrain regions of the newly hatched chick that result from environmental conditions; specifically from asymmetrical exposure of the chick embryo to light prior to hatching. Quantitative autoradiography was used to determine GABA and glutamate receptor subtype binding in a number of regions of the left and right forebrain hemispheres of chicks that had either the left (LES), or the right (RES), eye system exposed to light prior to hatching. On day 19 of incubation the embryo's head was withdrawn from the egg and the left or the right eye was occulded until hatching. [3H]MK-801, [3H]AMPA and [3H]muscimol binding assays were performed on frozen sections from 2 different coronal regions of the forebrain, sampled on day-1 posthatching. Significant [3H]MK-801, [3H]AMPA and [3H]muscimol binding asymmetries were determined in forebrain regions from chicks that had their RES exposed to light prior to hatching, particularly in forebrain regions which are known to receive afferent visual input. The reverse pattern of asymmetry was found for all 3 ligands in regions such as the ectostriatum of chicks that had their LES exposed to light, while asymmetry of muscimol and AMPA binding, present in many regions in right eye system chicks was not present in chicks that had the left eye system exposed to light during incubation. Thus, the presence and pattern of experience-dependent neurochemical asymmetries in the chick forebrain are specific to both region and receptor type.

Animals↗

PubMed1997

Glutamate affects the development of the thalamofugal visual projection of the chick.

Examination of the thalamofugal visual projections of the chick following treatment of the hyperstriatal regions with glutamate was undertaken to investigate whether structural change underlies slowed learning known to follow such treatment. On the second day after hatching from eggs exposed to light, chicks were injected bilaterally with 5 microl of 100 mM glutamate or physiological saline. On post-hatching day 8, retrograde fluorescence labelling of the thalamofugal projections with True Blue and FluoroGold led to the labelling of thalamic cells which project to the visual hyperstriatum. The number of contralateral and ipsilateral projections relative to each dye injection site was determined. Glutamate prevented the development of the structural asymmetry which is present in control chicks. The resultant symmetry of the thalamofugal projections in glutamate-treated chicks may cause deficits in visual discrimination.

Aging↗

PubMed1997

Relative importance of odour and taste in the one-trial passive avoidance learning bead task.

The relative importance of taste and odour cues in a one-trial passive avoidance learning (PAL) task was examined. One-day-old chicks were presented with a small bead and different combinations of the taste and odour of methyl anthranilate (MeA). The chicks had received three consecutive pretraining trials where they were presented with white, red, and blue beads. They were then trained with a red bead presented in one of four possible conditions: dry and unscented, with the odour but not the taste of MeA, with the bitter taste but not the odour of MeA (the chicks' nostrils were occluded with a wax preparation), or with the taste and odour of MeA. Recall was tested 10 min after training by presenting a red and then a blue bead with no odour or taste added. The number of pecks made at the bead and the number of bouts of head shaking during each of the trials were scored. During testing, chicks that were trained with the odour of MeA alone pecked less at a red bead than at a blue bead, compared with chicks trained with a dry and unscented bead, indicating that they discriminated between the training bead and a bead of a different colour. There was no significant difference between the discrimination ratio of chicks trained with the odour, taste, or taste and odour of MeA. These results demonstrate that chicks can perform PAL using taste and/or odour cues.

Animals↗

PubMed1997

Pharmacological extension of the sensitive period for imprinting in Gallus domesticus.

Precocial animals, such as the chick, exhibit a form of learning termed filial imprinting. The chick's sensitive period for filial imprinting is restricted to the first few days after hatching. The neural mechanism that terminates the sensitive period is not fully understood. It is thought to be an experience-dependent event because once a chick has imprinted, it will not readily imprint on another stimulus. However, even dark-reared chicks eventually lose the ability to imprint, which suggests that the ending of the sensitive period may not be entirely experience-dependent. The present study investigates factors that may contribute to the ending of the sensitive period. In our experiments, dark-reared chicks were unable to imprint after Day 2 posthatching, but chicks treated 10 h after hatching with an intramuscular injection of the noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist ketamine (55 mg/kg) and the alpha2-adrenoceptor agonist xylazine (6 mg/kg) (KX) imprinted on a stuffed hen 8 days after hatching. Similarly treated chicks did not imprint on a red and black box, although the box was an effective imprinting stimulus for Day 2 chicks. Chicks treated with KX at 20 or 40 h posthatching or on Day 4 or 7 as well as controls treated with pyrogen-free saline were unable to imprint on Day 8.

Adrenergic alpha-Agonists↗

PubMed1997

Differential contributions of the two visual pathways to functional lateralization in chicks.

The contribution of the two visual pathways to lateralization of visual behaviour in chicks was assessed using unilateral injections of 0.5 microliters of 100 mM monosodium glutamate into localized regions of the forebrain. Chicks treated with glutamate in the left visual hyperstriatum made more errors in a visual discrimination task (pebble-floor test) than did chicks treated in the right visual hyperstriatum. Glutamate injection into the left visual hyperstriatum also elevated attack and copulation scores, but this did not occur following injection of the right visual hyperstriatum. The performance of chicks treated in the right visual hyperstriatum did not differ from that of sham-operated controls. Thus, only the left visual hyperstriatum is involved in the control of these three visually guided behaviours. By contrast, glutamate injections of the left ectostriatum affected only the attack behavior and not performance in the pebble-floor test or copulation responses. Glutamate treatment of the right ectostriatum had no affect on any of the behaviours tested and this was also the case for glutamate treatment of both the left and right neostriata. Although injecting glutamate in a larger volume that allows glutamate to spread over a wide area of the left hemisphere is known to retard auditory habituation, localized injection of glutamate in the areas chosen for this study had no effect on auditory habituation. The results suggest that the tectofugal and thalamofugal pathways have different roles in the lateralization of visual functions. The forebrain region which receives input from the thalamofugal visual system has a lateralized role in categorising pebbles as different from food grains, and also a role in controlling attack and copulation responses. The forebrain region which receives input from the tectofugal visual system is involved in the control of attack responses only.

Agonistic Behavior↗

PubMed1997

Pawedness and motor asymmetries in toads.

Pawedness was investigated in three species of toads, Bufo bufo , Bufo viridis , and Bufo marinus. Samples from natural populations were collected in two successive years and tested during attempts to remove a strip of paper stuck onto the snout ( Bufo bufo and Bufo viridis ) or during attempts to remove an elastic balloon wrapped around the head ( Bufo bufo ). A preferential right forelimb use at the population level was observed in Bufo bufo in both tests, whereas no clear pawedness was observed in Bufo viridis. Bufo marinus also showed no laterality in the paper-strip test, but it appeared to be strongly lateralised in another test that investigated which side the toad rotated when turned on its back underwater. Preferentially turning to the toad's left side as part of a righting response, Bufo marinus released the left forelimb first, using the right forelimb to control the roll to the upright position, and push to the surface. These results suggest that preferential limb use has a long evolutionary history, which dates back to early tetrapods.

Journal Article↗