The role of anatomy demonstrators: A surgical trainees' perspective.

Core Surgical Trainees (CST) in the London (UK) Postgraduate School of Surgery receive clinical anatomy teaching in their first year of training, and, in their second year, give 30 sessions of anatomy teaching to medical and other students. This study set out to investigate the role of demonstrators from the perspective of the trainees. A focus group was convened to ascertain trainees' perspectives on demonstrating anatomy and to identify problems and improvement strategies to optimize their ability to enhance students' learning. A questionnaire was formulated and all second-year CST (n = 186-from two cohorts) in the London Postgraduate School of Surgery were invited. A total of 109 out of 186 trainees completed the questionnaire. A high percentage (98%) of trainees that completed the questionnaire responded that demonstrating was an invaluable part of their training. Sixty-two per cent responded that anatomy teaching they received in their first year of core surgical training helped them in their teaching role and 80% responded that it helped them prepare for surgical training. The study also revealed the need for improved communication between trainees and the London Postgraduate School of Surgery/Medical Schools/National Health Service Trusts to address issues such as trainees' perceived difficulty in fulfilling their teaching session requirement. The stakeholders have acknowledged and addressed the outcomes to improve the experience for both surgical trainees and students. The results indicate that anatomy demonstrating delivers important benefits to early surgical trainees, in addition to those received by the students that they teach. Clin. Anat. 31:409-416, 2018. © 2017 Wiley Periodicals, Inc.

A morphometric analysis of the suitability of the transverse cervical artery as a recipient artery in head and neck free flap microvascular reconstruction.

PURPOSE: Gold standard recipient arteries in head and neck free flap microvascular reconstruction are currently branches of the external carotid. However, these arteries can be compromised by neck dissection or radiotherapy, resulting in 'vessel-depleted neck' and 'frozen neck' respectively. In such cases, the transverse cervical artery (TCA) may be a suitable recipient artery. METHODS: The origin, course and diameter of the TCA were determined in 46 sides of neck from 23 cadavers. The distances from the origin of the TCA to the angle of the mandible, floor of the mouth and mandibular symphysis were measured to determine the pedicle length required for free flap anastomosis. RESULTS: The TCA was present bilaterally in all subjects investigated and its course across the posterior triangle of the neck was constant between individuals. The mean distances from the origin of the TCA to the angle of mandible, floor of mouth and mandibular symphysis were 10.0, 9.2 and 12.6 cm, respectively. There were no significant differences in these distances between the left and right sides of the neck (p > 0.05 for all comparisons). The distances from the TCA origin to the angle of the mandible and floor of the mouth were significantly longer in males than in females (p = 0.004) and correlated directly with the greater height of males compared to females (p = 0.0004). The mean diameter of the TCA measured 2 cm from its origin was 2.2 mm. CONCLUSION: The TCA is a suitable and reliable recipient artery for free flap microvascular reconstruction, when branches of the external carotid artery are unavailable.

The Anatomical Society core regional anatomy syllabus for undergraduate medicine.

The Anatomical Society's core syllabus for anatomy (2003 and later refined in 2007) set out a series of learning outcomes that an individual medical student should achieve on graduation. The core syllabus, with 182 learning outcomes grouped in body regions, referenced in the General Medical Council's Teaching Tomorrow's Doctors, was open to criticism on the grounds that the learning outcomes were generated by a relatively small group of anatomists, albeit some of whom were clinically qualified. We have therefore used a modified Delphi technique to seek a wider consensus. A Delphi panel was constructed involving 'experts' (n = 39). The revised core syllabus of 156 learning outcomes presented here is applicable to all medical programmes and may be used by curriculum planners, teachers and students alike in addressing the perennial question: 'What do I need to know ?'

GFAP immunoreactivity within the rat nucleus ambiguus after laryngeal nerve injury.

Changes that occur in astroglial populations of the nucleus ambiguus after recurrent (RLN) or superior (SLN) laryngeal nerve injury have hitherto not been fully characterised. In the present study, rat RLN and SLN were lesioned. After 3, 7, 14, 28 or 56 days of survival, the nucleus ambiguus was investigated by means of glial fibrillary acidic protein (GFAP) immunofluorescence or a combination of GFAP immunofluorescence and the application of retrograde tracers. GFAP immunoreactivity was significantly increased 3 days after RLN resection and it remained significantly elevated until after 28 days post injury (dpi). By 56 dpi it had returned to basal levels. In contrast, following RLN transection with repair, GFAP immunoreactivity was significantly elevated at 7 dpi and remained significantly elevated until 14 dpi. It had returned to basal levels by 28 dpi. Topographical analysis of the distribution of GFAP immunoreactivity revealed that after RLN injury, GFAP immunoreactivity was increased beyond the area of the nucleus ambiguus within which RLN motor neuron somata were located. GFAP immunoreactivity was also observed in the vicinity of neuronal somata that project into the uninjured SLN. Similarly, lesion of the SLN resulted in increased GFAP immunoreactivity around the neuronal somata projecting into it and also in the vicinity of the motor neuron somata projecting into the RLN. The increase in GFAP immunoreactivity outside of the region containing the motor neurons projecting into the injured nerve, may reflect the onset of a regenerative process attempting to compensate for impairment of one of the laryngeal nerves and may occur because of the dual innervation of the posterior cricoarytenoid muscle. This dual innervation of a very specialised muscle could provide a useful model system for studying the molecular mechanisms underlying axonal regeneration process and the results of the current study could provide the basis for studies into functional regeneration following laryngeal nerve injury, with subsequent application to humans.

Proof-of-concept prototype drill-guide for use in medial patello-femoral ligament (MPFL) reconstruction surgery.

For surgical reconstruction of the medial patello-femoral ligament (MPFL) a variety of techniques are used for fixation of the graft to the medial border of the patella. The bone bridge or V-shaped tunnel technique utilises two tunnels drilled from the medial aspect of the patella that converge centrally creating a tunnel through which the graft is threaded. This technique has advantages: it avoids hardware (bone anchors) and their associated complications, creates a broad attachment of the ligament approximating normal anatomy and the tunnel does not breach the lateral cortex of the patella reducing the risk of patella fracture. In current practice the bony tunnels are created using freehand techniques. These rely on estimation of the patella centre by the surgeon and is subject to wide variation. Additionally this technique can be inefficient, inaccurate and time consuming. To address these disadvantages a new drill-guide device was developed. A prototype drill-guide was constructed using CAD and 3D printing methods. The device was designed to allow the surgeon to accurately and efficiently drill the required v-shaped bone tunnel. To assess the efficacy of the prototype drill guide, an experiment designed to assess a group of ten surgeons with an average of 4.2 years experience performing the task of creating a v-shaped bone tunnel using a free-hand technique and the drill-guide. To determine the accuracy of the tunnel placement, the angle between drill holes, distance from centre of the patella and the amount of over-drill were measured. Procedure duration was also compared. The results revealed that the prototype drill-guide created a more accurate bone bridge than the traditional free hand method. The root mean square error for the distance from centre was 0.50 mm vs 2.12 mm and the angle between tunnels was 2.6O vs 15.9O for the prototype and traditional methods respectively. There was a mean of 8.9 mm over-drill with the traditional method, which was negated when using the guide. Surgeons using the guide were approximately 25% faster than using the traditional free-hand technique. The prototype drill-guide improved the accuracy, reduced the variability, and reduced procedure duration compared to the traditional free-hand technique.

Neonatal stimulation of 5-HT(2) receptors reduces androgen receptor expression in the rat anteroventral periventricular nucleus and sexually dimorphic preoptic area.

Masculinization of the brain is dependent upon a perinatal surge in testosterone. It also requires a transient decrease in hypothalamic 5-HT concentration and turnover and an increase in androgen receptor (AR) expression during the second postnatal week. We have previously shown that increasing 5-HT activity over this period in male or androgenized female rats feminizes their adult behaviour and also feminizes the size of their anteroventral periventricular nucleus (AVPV) and sexually dimorphic nucleus of the preoptic area (SDN-POA). To investigate the role of 5-HT in sexual differentiation of the brain, 5-HT activity was raised over postnatal days 8-16 in male, female and androgenized female rats by daily administration of the 5-HT(2) receptor agonist (-)[2,5 dimethoxy-4-iodophenyl]-2-amino propane hydrochloride [(-)DOI]. By postnatal day 18, the size of the AVPV and SDN-POA was sexually dimorphic; their sizes were feminized by (-)DOI treatment. In the absence of (-)DOI treatment, there were significantly more AR-immunoreactive cells in the AVPV of males, and in the SDN-POA of males and androgenized females, than in those of females on postnatal day 18. (-)DOI treatment reduced the number of AR-immunoreactive cells in the AVPV and SDN-POA of males and androgenized females, but not of females, by postnatal day 18. These results suggest that 5-HT(2) receptor activation can influence sexual differentiation of the brain by controlling AR expression.

High-resolution MRI in evaluation of the surgical anatomy of the esophagus and posterior mediastinum.

OBJECTIVE: The purpose of this study was to use high-resolution MRI to evaluate the surgical anatomy of the posterior mediastinum, in particular the esophagus and its relation to the surrounding structures. The aim was to familiarize radiologists with the appearance of structures considered important in planning surgical resection of the esophagus. MATERIALS AND METHODS: The thoraces of two cadavers were imaged with a 1.5-T magnet using a high-resolution T2-weighted sequence. Axial cadaveric sections of the posterior mediastinum were cut with a band saw at levels determined from the MR images, and histologic whole-mount sections of the esophagus and surrounding tissue were prepared from the cadaveric sections. The appearance of structures identified on the MR images was compared with the findings on corresponding gross anatomic and histologic whole-mount sections. RESULTS: The MR images depicted the esophagus and structures in close anatomic relation: the pleural reflections and pericardium. The technique enabled visualization of structures to our knowledge not previously described on cross-sectional imaging: the individual layers of the esophageal wall, the thoracic duct, a connective tissue layer attaching the esophagus to the anterior wall of the aorta, and a fascial plane passing between layers of the right and left parietal pleura posterior to the esophagus. CONCLUSION: High-resolution MRI of the posterior mediastinum provides detailed anatomic information, delineating structures not visible on other forms of cross-sectional imaging. It can provide important information for planning surgical intervention.

Induction of CD80 expression in low-grade B cell lymphoma--a potential immunotherapeutic target.

The CD80 antigen (B7) is expressed on activated B lymphocytes. It is thought to be important in eliciting a T cell response via its ligands CD28 and CTLA-4 when antigen is presented in the presence of the MHC-1 peptide. Low-grade B cell lymphomas analysed by flow cytometry express CD80 very poorly. However, when grown in vitro using the IL-4/anti-CD40 stromal cell culture system, following depletion of T and IgD-bearing cells, a monoclonal B cell expansion occurs. Cells harvested at days 10-13 express the antigen strongly, regardless of the histological subtype of lymphoma. Further investigation of CD80-mediated immune functions may be possible using this system as a basis for testing immunotherapy.

Blood brain barrier in ageing and Alzheimer's disease.

A blood-brain barrier deficit may play a role in age-related deterioration and neurodegenerative diseases of the central nervous system. Strategies for testing this hypothesis by investigating the structure, barrier and transport functions of brain capillary endothelium are described and discussed.

Axonal loss from the olfactory tracts in Alzheimer's disease.

Senile dementia of the Alzheimer type has been shown to be associated with impaired olfactory function early in the course of the disease. Neuropathology in the olfactory system is also a feature of Alzheimer's disease (AD) and it has been suggested that the disease may be caused by a pathogen entering the brain via olfactory pathways. To investigate this hypothesis, the effect of AD on the olfactory tract was investigated. There was a 40% decrease in the cross-sectional area of the olfactory tract and a 52% loss of myelinated axons from the tract in AD. These results, together with those of previous studies suggest that peripheral regions of the olfactory system, i.e., the olfactory bulb and primary sensory olfactory neurons are less affected by the pathology of AD than more central parts, i.e., cortical regions, the anterior olfactory nuclei, and olfactory tract. This less severe pathology at the periphery argues against a pathogen entering the brain via the peripheral olfactory apparatus and suggests a central pathogenesis which spreads centrifugally along olfactory pathways.

Cerebral Glycoprotein Synthesis and Long-term Memory Formation in the Chick (Gallus domesticus) Following Passive Avoidance Training Depends on the Nature of the Aversive Stimulus.

Chicks that peck a small bright bead coated in a distateful substance can learn in a single trial to subsequently avoid a similar bead. The taste aversant commonly used is methyl anthranilate, which also has a strong pervasive odour. We have compared the efficacy of methyl anthranilate and the apparently odourless quinine as aversants. Methyl anthranilate-trained chicks learnt the task and the memory apparently persisted undiminished for at least 24 h. Quinine-trained chicks exhibited a memory for the task similar to that of methyl anthranilate-trained chicks 45 min after training, this thereafter declined until, at 24 h after training, they showed no recall. We investigated the incorporation of a radio-labelled synaptic membrane glycoprotein precursor, [3H]fucose, into three regions of the chick forebrain; two of these regions have previously been implicated in learning using methyl anthranilate as the aversant. There was a significant increase in [3H]fucose incorporation into the left lateral cerebral area and numerically similar, but non-significant, increases in the intermediate part of the medial hyperstriatum ventrale and lobus parolfactorius. There were no such increases in the right hemisphere of methyl anthranilate-trained chicks or any region of either hemisphere of quinine-trained chicks. Thus, the memory for methyl anthranilate is longer-lasting than that for quinine and is associated with increased fucosylation in the left cerebral hemisphere and although in the short-term, chicks can retain a memory of the one-trial passive avoidance task with quinine as the aversant, this does not result in a localized increase in cerebral [3H]fucose incorporation.

Termination pattern of medial hyperstriatum ventrale efferents in the archistriatum of the domestic chick.

The chick archistriatum receives afferents from the intermediate part of the medial hyperstriatum ventrale (IMHV) and projects to the lobus parolfactorius (LPO). There is functional evidence to suggest that the IMHV and the LPO are connected, but there is no anatomical evidence for a direct connection between the two structures. The aim of the current study was to characterize the termination pattern of medial hyperstriatal afferents within the archistriatum to determine whether the archistriatum may act as a relay between the IMHV and LPO. Following iontophoresis of Phaseolus vulgaris leucoagglutinin into the medial hyperstriatum ventrale (including the IMHV) of 1-week-old domestic chicks, anterogradely labelled fibers were observed to descend through the medial neostriatum and paleostriatum to enter the archistriatum. These medial hyperstriatum ventrale afferents arborised profusely to give varicose axon branches within all except the anterior part of the archistriatum. However, the greatest density was present in the ventral part of the intermediate archistriatum. Electron microscope examination of Phaseolus lectin immunocytochemistry and Golgi impregnation revealed that medial hyperstriatum ventrale axons formed multiple asymmetric synapses with dendritic spines (head and neck regions) on the terminal and preterminal dendritic segments of densely spiny archistriatal projection neurons. Medial hyperstriatum ventrale afferents were not observed to contact calbindin immunoreactive, presumptive "local circuit" neurons, within the archistriatum, despite a spatial overlap in their distribution. These results suggest that the archistriatum may be capable of mediating the transfer of information from the IMHV to the LPO.

Efferent connections of the domestic chick archistriatum: a phaseolus lectin anterograde tracing study.

The archistriatum of the domestic chick has been implicated in both fear behaviour and learning. However, relatively little is known about its organisation. The efferent connections of discrete anatomical regions of the chick archistriatum were therefore investigated by iontophoresis of the anterograde tracer Phaseolus vulgaris leucoagglutinin into its anterior, dorsal intermediate, ventral intermediate, medial, and posterior parts. The results of this study suggest that the chick archistriatum can be divided into two basic divisions according to whether they project to the following limbic structures: the hippocampal formation, septal areas, lobus parolfactorius, nucleus accumbens, ventral paleostriatum, and dorsomedial thalamus. The limbic archistriatum includes the posterior archistriatum and extends rostrally through the ventral intermediate archistriatum into the anterior archistriatum. The non-limbic archistriatum comprises the dorsal intermediate and medial archistriatum and largely gives rise to specific sensory, somatosensory, and motor telencephalofugal efferents. There may not be distinct borders between these two divisions of the chick archistriatum.

Distribution of CGRP-like immunoreactivity in the chick and quail brain.

Calcitonin gene-related peptide (CGRP)-containing neurones have been implicated in the transmission of visceral sensory information to the cortex and in the control of arterial blood pressure in mammals. However, little is known about its function in other vertebrates. As a first step toward investigating the function of CGRP in birds, its distribution was studied in the domestic chick and quail brain by means of immunocytochemistry, by using antibodies against rat CGRP. The distribution of CGRP immunoreactivity in the chick and quail central nervous system was found to be similar. CGRP-immunoreactive (CGRPi) perikarya were not present in the telencephalon. In the diencephalon, CGRPi perikarya were present mainly in the shell of the thalamic nucleus ovoidalis, the nucleus semilunaris paraovoidalis, the nucleus dorsolateralis posterior thalami, and in the hypothalamic nucleus of the ansa lenticularis. In the brainstem, CGRPi perikarya were present in the nucleus mesencephalicus nervi trigemini, the nucleus tegmenti ventralis, the locus coeruleus, the nucleus linearis caudalis and in the parabrachial region. In addition CGRPi perikarya were found in the motor nuclei of the III, IV, V, VI, VII, IX, X, and XII cranial nerves. The telencephalon contained CGRPi fibres within the paleostriatal complex (mainly in the ventral paleostriatum), parts of the neostriatum and ventral hyperstriatum, parts of the archistriatum, and the septum. In the diencephalon, the densest plexus of CGRPi fibres was observed in the dorsal reticular thalamus. A less dense CGRPi innervation was present in some dorsal thalamic nuclei and in the medial and periventricular hypothalamus. The pretectum and midbrain tegmentum also contained CGRPi fibres, whereas the optic tectum was virtually devoid of immunolabelling. Scattered CGRPi fibres were observed in the central grey and neighbouring pontine areas. Some of the sensory fibres of the trigeminal, vagal, glossopharyngeal, and spinal nerves were also CGRPi. The results of comparative studies indicate that the presence of CGRP in some thalamo-telencephalic projections is a primitive feature of the forebrain of amniotes. Therefore, the brain areas giving rise to and receiving such a projection in different vertebrates, are likely to be homologous.

Clinical experience with antithrombin III concentrate in treatment of congenital and acquired deficiency of antithrombin. The Antithrombin III Study Group.

Phase I clinical studies of antithrombin III (ATIII) concentrate demonstrated a mean in vivo incremental recovery of functional activity of 1.4 percent per unit/kg administered, an initial 50 percent disappearance time of 22 hours, and a biologic half-life of 3.8 days. Based on these observations, a treatment regimen designed to maintain plasma ATIII levels between 75 and 120 percent of normal has been developed. None of 10 subjects with congenital ATIII deficiency treated prophylactically had evidence of thromboembolism, including four pregnant women at the time of delivery. Five subjects treated for acute thrombosis and/or thromboembolism, four of whom were pregnant, recovered without further thrombotic extension or recurrence. Heparin resistance was reversed in two subjects, both pregnant. Nine subjects with acquired ATIII deficiency also received ATIII treatment for venous or arterial thrombosis or disseminated intravascular coagulation, all with low plasma ATIII levels. Two subjects with disseminated intravascular coagulation demonstrated improvement, one clinically, the other biochemically. All patients with congenital ATIII deficiency survived, but only five of nine with acquired deficiency survived, highlighting the importance in acquired ATIII deficiency of the underlying disease in prognosis. Survival rate was especially poor in subjects with arterial thrombosis in the setting of low plasma ATIII. Administration of ATIII concentrate was well tolerated. None of the subjects who received ATIII concentrate demonstrated evidence of an infectious transmissible agent. These studies demonstrate that it is now feasible to safely replace the deficient protein in congenital ATIII deficiency, either prophylactically or therapeutically.

Noradrenaline and learning: effects of the noradrenergic neurotoxin DSP4 on imprinting in the domestic chick.

The effects of the noradrenergic neurotoxin DSP4 on imprinting in domestic chicks were investigated. Chicks received either DSP4 or distilled water and were trained 60 hr after hatching by exposing them to either a rotating red box or a stuffed jungle fowl. Noradrenaline concentration was determined in Wulst and medial and basal forebrain samples. The medial forebrain sample comprised mainly the intermediate part of the medial hyperstriatum ventrale, a region previously shown to be intimately involved in imprinting. The DSP4 treatment reduced forebrain noradrenaline levels by about 65%. DSP4 profoundly impaired imprinting in box-trained chicks but not in fowl-trained chicks. In box-trained chicks, the strength of imprinting was positively correlated with noradrenaline concentration in both medial and basal forebrain samples. It is suggested on the basis of these and previous studies that some of the neural structures and mechanisms involved in imprinting on the fowl differ from those involved in imprinting on the box.

Immunolabelling of hippocampal microvessel glucose transporter protein is reduced in Alzheimer's disease.

Changes in cerebral microvessel ultrastructure have been reported to occur in Alzheimer's disease (AD). In order to investigate whether these changes are associated with compromised blood-brain transport mechanisms, hippocampal formation sections from AD and age-matched normal brains were immunolabelled with an antibody to the GLUT-1 glucose transporter protein. GLUT-1 immunolabelling of microvessel endothelium was significantly reduced in the AD compared to normal hippocampal formation. Thus, AD is associated with a reduction in cerebral microvessel endothelium glucose transporter content, which may result in decreased glucose availability to the brain.

The effect of archistriatal lesions on 'open field' and fear/avoidance behaviour in the domestic chick.

The chick archistriatum has been implicated in avoidance learning and filial imprinting. However, its role in these learning paradigms may be due to the inhibition of normal avoidance responses, since the avian archistriatum has been shown to play a role in fear/avoidance behaviour. The involvement of the archistriatum in the expression of unlearned fear/avoidance behaviour was therefore investigated in two day-old chicks. Chicks were exposed individually to a novel 'open field' for 5 min. Behaviour was recorded on videotape for analysis. In a separate but concurrent experiment, bilateral archistriatal lesions, sham archistriatal lesions or lateral cerebral lesions were made in day-old chicks which were then exposed to the 'open field' arena. At the end of each exposure a novel object was dropped near the chick. Chicks with archistriatal lesions generally displayed greater movement, more pecking behaviour and spent more time near the centre of the 'open field' than other chicks. There were no differences between the treatment groups in latencies to move or begin peeping. The behaviour of untreated chicks in the 'open field' was similar to that of sham-lesioned chicks and there was no effect of hatch on behaviour. Upon exposure to a novel object, indices of fear and avoidance were not changed in lesioned chicks. These results demonstrate that in the young chick, the archistriatum may be involved in the response to mild or intermediate levels of environment or isolation-related stress, but does not appear to be important for overt fear responses or avoidance of novel objects. Taken together with the results of previous work, the data suggests that the archistriatum may be directly involved in avoidance learning and imprinting.

Differentiation of alpha-adrenergic responsiveness in the neonatal rat iris after decentralization or extirpation of the superior cervical ganglion.

The effects of stimulating alpha-adrenergic receptors in the iris of neonatal rats (up to 30 days of age) whose superior cervical ganglion (SCG) has been decentralized or extirpated 3 days after birth were investigated by measuring changes in pupil diameter. The responses of these experimental animals were compared with those of normal animals of similar age. Alpha-adrenergic stimulation was effected by topical application of noradrenaline (NA) after blockade of beta-adrenoceptors with dichlorisoproterenol and cholinoceptors with atropine. The results reveal that although decentralization of the SCG depletes the NA content of the ipsilateral iris as demonstrated by radio-chemical assay and formaldehyde-induced fluorescence, it does not affect the development of alpha-adrenoceptor responsiveness. Even the more severe disruption of the innervation caused by extirpation of the SCG did not affect the responsiveness of the ipsilateral iris.

Changes in telencephalic catecholamine levels in the domestic chick. Effects of age and visual experience.

The concentrations of adrenaline, dopamine and noradrenaline were measured in 3 regions of the domestic chick telencephalon: (a) the Wulst; (b) a medial forebrain sample comprising mainly the intermediate part of the medial hyperstriatum ventrale (IMHV); and (c) a basal forebrain sample comprising mainly paleostriatum augmentatum. There was no significant left/right hemispheric asymmetry in the concentration of any of these catecholamines in any region studied. Adrenaline was undetectable in the Wulst and medial forebrain samples and only trace amounts were found in the basal forebrain samples of 1-day-old, light-reared chicks. Dopamine concentrations of 9.13 +/- 1.13 (S.E.M.) ng/g were present in the Wulst, 16.66 +/- 2.56 ng/g in the medial forebrain and 121.19 +/- 33.06 ng/g in the basal forebrain samples at hatching. These levels did not alter with age or with visual experience of an imprinting stimulus during the first 50 h post-hatch. At hatching, noradrenaline concentrations of 35.83 +/- 8.61 ng/g were present in the Wulst, 26.09 +/- 3.75 ng/g in the medial forebrain and 53.13 +/- 7.85 in the basal forebrain samples. The noradrenaline concentrations in the Wulst and medial forebrain samples increased significantly over the first 50 h post-hatch in dark-reared chicks. Visual experience increased noradrenaline levels in all 3 regions of the telencephalon studied.