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Showing papers by "University of Oxford published in 1972"



Journal ArticleDOI

1,798 citations


Journal ArticleDOI
01 Jul 1972

1,641 citations


Journal ArticleDOI
TL;DR: In this article, Hartree-Fock equations for spherical nuclei using Skyrme's density-dependent effective nucleon-nucleon interaction are discussed systematically and the general formula for the mean energy of a spherical nucleus derived.
Abstract: Hartree-Fock calculations for spherical nuclei using Skyrme's density-dependent effective nucleon-nucleon interaction are discussed systematically. Skyrme's interaction is described and the general formula for the mean energy of a spherical nucleus derived. Hartree-Fock equations are obtained by varying the mean energy with respect to the single-particle wave functions of occupied states. Relations between the parameters of the Skyrme force and various general properties of nuclear matter and finite nuclei are analyzed. Calculations have been made for closed-shell nuclei using two rather different sets of parameters, both of which give good binding energies and radii for $^{16}\mathrm{O}$ and $^{208}\mathrm{Pb}$. Both interactions give good binding energies and charge radii for all closed-shell nuclei. Calculated electron scattering angular distributions agree qualitatively with experiment, and for one interaction there is good quantitative agreement. The single-particle energies calculated with the two interactions are somewhat different owing to a different nonlocality of the Hartree-Fock potentials, but both interactions give the correct order and density of single-particle levels near the Fermi level. They differ most strongly in their predictions for the energies of $1s$ single-particle states.

1,340 citations


Journal ArticleDOI
04 Feb 1972-Nature
TL;DR: Observations using electron microscopy and freeze-etching techniques show that both metabolic coupling and ionic coupling in fibroblasts are associated with the appearance of “gap” junctions.
Abstract: Observations using electron microscopy and freeze-etching techniques show that both metabolic coupling and ionic coupling in fibroblasts are associated with the appearance of “gap” junctions.

650 citations


Journal ArticleDOI
TL;DR: In this article, the problem of logistic discrimination when all or most of the observations are qualitative is discussed and the results of Aitchison & Silvey (1958) on constrained maximum likelihood estimation are extended to the situation where separate samples are taken from each population.
Abstract: The problem of discrimination when all or most of the observations are qualitative is discussed. The method of logistic discrimination introduced by Cox (1966) and Day & Kerridge (1967) is extended to the situation where separate samples are taken from each population, using the results of Aitchison & Silvey (1958) on constrained maximum likelihood estimation. The method is further extended to discrimination between three or more populations. The properties of logistic discrimination are investigated by simulation and the method is applied to the differential diagnosis of kerato-conjunctivitis sicca.

631 citations


Journal ArticleDOI
TL;DR: It is concluded that the evidence for the ecological aspect of character displacement is weak and the principal ideas in the original definition given by Brown & Wilson (1956) are retained.
Abstract: Consideration of the possibilities and difficulties of detecting character displacement leads to a re-definition of the phenomenon; character displacement is the process by which a morphological character state of a species changes under Natural Selection arising from the presence, in the same environment, of one or more species similar to it ecologically and/or reproductively. This incorporates the principal ideas in the original definition given by Brown & Wilson (1956), but eliminates the restriction of making comparisons of the character states of a species in sympatry and allopatry. The evidence for the ecological (competitive) aspect of character displacement is assessed by analyzing in detail the best documented and well publicized examples in the literature. Some of the examples either do not exhibit displaced characters or, if they do, the “displacement” can be interpreted in other and perhaps simpler ways; this applies to the so-called classical case of character displacement, Sitta tephronota and S. neumayer in Iran. Other examples, involving lizards and birds, constitute better evidence for character displacement, but in no single study is it entirely satisfactory. It is concluded that the evidence for the ecological aspect of character displacement is weak.

628 citations


Book
01 Jan 1972
TL;DR: The 4th edition of as mentioned in this paper provides a comprehensive introduction to modern particle physics, including developments in elementary particle physics and its connections with cosmology and astrophysics, and the balance between experiment and theory is continually emphasised.
Abstract: This highly-regarded text provides a comprehensive introduction to modern particle physics. Extensively rewritten and updated, this 4th edition includes developments in elementary particle physics, as well as its connections with cosmology and astrophysics. As in previous editions, the balance between experiment and theory is continually emphasised. The stress is on the phenomenological approach and basic theoretical concepts rather than rigorous mathematical detail. Short descriptions are given of some of the key experiments in the field, and how they have influenced our thinking. Although most of the material is presented in the context of the Standard Model of quarks and leptons, the shortcomings of this model and new physics beyond its compass (such as supersymmetry, neutrino mass and oscillations, GUTs and superstrings) are also discussed. The text includes many problems and a detailed and annotated further reading list.

614 citations


Journal ArticleDOI
19 May 1972-Nature
TL;DR: It is still an open question how the genetic polymorphism represented by the principal human histocompatibility system is maintained, but it may have evolved as a consequence of the necessity for cell to cell recognition during development and morphogenesis.
Abstract: It is still an open question how the genetic polymorphism represented by the principal human histocompatibility system is maintained. But it may have evolved as a consequence of the necessity for cell to cell recognition during development and morphogenesis.

502 citations



Journal ArticleDOI
TL;DR: In this article, a general closed function for the tcp dependence of the transverse relaxation times of nuclei exchanging between two sites is described, and the frequency and temperature dependence of this function is examined.

Journal ArticleDOI
TL;DR: The enzyme activities from insect flight muscle confirm and extend much of the earlier work and indicate the type of fuel that can support insect flight and the maximum activity of hexokinase was found to be higher in red than in white vertebrate muscle.
Abstract: 1. The maximum activities of hexokinase, phosphorylase and phosphofructokinase have been measured in extracts from a variety of muscles and they have been used to estimate the maximum rates of operation of glycolysis in muscle. These estimated rates of glycolysis are compared with those calculated for the intact muscle from such information as oxygen uptake, glycogen degradation and lactate formation. Reasonable agreement between these determinations is observed, and this suggests that such enzyme activity measurements may provide a useful method for comparative investigations into quantitative aspects of maximum glycolytic flux in muscle. 2. The enzyme activities from insect flight muscle confirm and extend much of the earlier work and indicate the type of fuel that can support insect flight. The maximum activity of hexokinase in some insect flight muscles is about tenfold higher than that in vertebrate muscles. The activity of phosphorylase is greater, in general, in vertebrate muscle (particularly white muscle) than in insect flight muscle. This is probably related to the role of glycogen breakdown in vertebrate muscle (particularly white muscle) for the provision of ATP from anaerobic glycolysis and not from complete oxidation of the glucose residues. The activity of hexokinase was found to be higher in red than in white vertebrate muscle, thus confirming and extending earlier reports. 3. The maximum activity of the mitochondrial glycerophosphate dehydrogenase was always much lower than that of the cytoplasmic enzyme, indicating that the former enzyme is rate-limiting for the glycerol 3-phosphate cycle. From the maximum activity of the mitochondrial enzyme it can be calculated that the operation of this cycle would account for the reoxidation of all the glycolytically produced NADH in insect flight muscle but it could account for only a small amount in vertebrate muscle. Other mechanisms for this NADH reoxidation in vertebrate muscle are discussed briefly.

Journal ArticleDOI
TL;DR: In this article, a different approach from usual to the formulation of conservation laws and an entropy production inequality was adopted for a single phase continuum and for a mixture of any number of constituents.
Abstract: Within the scope of classical continuum thermodynamics, we elaborate on the basic concepts and adopt a different approach from usual to the formulation of conservation laws and an entropy production inequality, both for a single phase continuum and for a mixture of any number of constituents. These conservation laws and the entropy inequality can be regarded as applicable to both local and nonlocal problems. In the case of a single phase continuum and for a simple material which is homogeneous in its reference configuration, under fairly mild smoothness assumptions, we prove that all the conservation laws reduce to the usual classical ones and the entropy production inequality reduces to the Clausius-Duhem inequality. Some attention is given to possible redundancies in the basic concepts, as well as to alternative forms of the energy equation and the entropy inequality. The latter is particularly significant in regard to different but equivalent formulations of mixture theory.


Journal ArticleDOI
TL;DR: It is shown that small lymphocytes from the thoracic duct of rats are normally a mixture of thymus-derived and marrow-derived cells, and define the traffic areas in lymphoid tissues through which the two populations recirculate, andificially reconstituted mixtures of marrow- derived and thymUS-derived lymphocytes were qualitatively indistinguishable from normal lymphocyte populations.
Abstract: These experiments show that small lymphocytes from the thoracic duct of rats are normally a mixture of thymus-derived and marrow-derived cells, and define the traffic areas in lymphoid tissues through which the two populations recirculate. Thoracic duct lymphocytes were labeled in vitro with uridine-3H and their histological distribution in the lymphoid tissues of normal recipients was demonstrated by radioautography. Labeled lymphocytes occupied two adjacent areas distinguished by a marked difference in the intensity of labeling; heavily labeled cells were found in thymus-dependent traffic areas of lymphocyte recirculation, while lightly labeled cells localized in the thymus-independent follicular areas around germinal centers. A corresponding heterogeneity of uridine uptake among small lymphocytes from normal donors was demonstrated by sedimentation at 1 g ; slowly sedimenting cells incorporated little uridine and localized in follicular areas after transfusion while rapidly sedimenting cells incorporated more uridine and localized in thymus-dependent areas after transfusion. Experimentally prepared marrow-derived small lymphocytes behaved in sedimentation studies and after transfusion like a pure population of the lightly labeled small lymphocytes in normal lymph. Artificially reconstituted mixtures of marrow-derived and thymus-derived lymphocytes were qualitatively indistinguishable from normal lymphocyte populations.

Journal ArticleDOI
TL;DR: Carbonic anhydrases from vertebrates, plants and bacteria have molecular weights of 30,000 (or multiples thereof), contain one zinc atom per 30,,000 molecular weight, and are inhibited by acetazolamide and related compounds.
Abstract: Summary 1. Carbonic anhydrases from vertebrates, plants and bacteria have molecular weights of 30,000 (or multiples thereof), contain one zinc atom per 30,000 molecular weight, and are inhibited by acetazolamide and related compounds. 2. In mammals, there are two major isoenzymes of carbonic anhydrase. The so-called ‘high activity’ carbonic anhydrase possesses a carbon dioxide-hydratase activity many times (in the case of the guinea-pig isoenzymes, 18 times) that of the ‘low activity’ isoenzyme. 3. The mammalian isoenzymes differ from one another in their amino-acid compositions (the difference in serine contents being a consistent finding in a number of species), in their physical properties (isoelectric pH, retention by ion-exchange resins, electrophoretic mobility) and in their kinetic properties. 4. Mammalian carbonic anhydrases also catalyse the hydrolysis of some esters and the hydration of aldehydes. Their relative activities with these other substrates may be substantially different from their relative activities with carbon dioxide as substrate. The discovery that carbonic anhydrase may also catalyse other reactions raises the possibility that the enzyme may have other roles in metabolic pathways (e.g., in certain dehydrogenation reactions). 5. In plants, the role of carbonic anhydrase may be to catalyse the inter-conversion of bicarbonate and carbon dioxide, to provide ‘carbon dioxide’ in the form appropriate for carbon-fixing reactions. A similar role has been suggested for the carbonic anhydrase found in Neissariae. 6. The carbonic anhydrase of vertebrates (the ‘high activity’ isoenzyme of mammals) is found in many ion-transporting epithelia, but its role in them is still uncertain. It occurs in acid-transporting epithelia such as the stomach and kidney, and also in certain bicarbonate-transporting epithelia like the large intestine. There is, however, a poor correlation between the presence of the enzyme and the occurrence of acid or bicarbonate secretion. Thus there is little or no carbonic anhydrase in some tissues noted for their ability to secrete bicarbonate ions, such as the pancreas and ileum. Conversely, carbonic anhydrase-containing tissues like the avian salt gland and the elasmobranch rectal gland form concentrated sodium chloride solutions which are of nearly neutral pH. The correlation between the distribution of carbonic anhydrase and the occurrence of active chloride transport appears similar to that between carbonic anhydrase and bicarbonate ion transport. 7. While the red cells of most mammalian species so far studied contain both ‘high activity’ and ‘low activity’ isoenzymes, the latter is reported to be absent from the erythrocytes of sheep, ox and dog. Presumably the ‘low activity’ isoenzyme is not necessary for an adequate rate of carbon dioxide exchange to occur between tissues and lungs in these species. 8. The ‘low activity’ isoenzyme is present in tissues other than blood, for example, the colon, caecum and ox rumen, and probably also, the gall bladder and kidney medulla. Its distribution differs markedly from that of the ‘high activity’ isoenzyme and presumably it has a particular functional importance of its own. It is not possible to define the role of the ‘low activity’ isoenzyme at present, but attention is drawn to the possibility that it is concerned in the handling of the products of microbial fermentation, such as ammonia and organic acids, by the large intestines and ruminant forestomach. My work on the isoenzymes of carbonic anhydrase was supported by a Medical Research Council Scholarship, and by an equipment grant to Dr D. S. Parsons. I am also grateful to Dr D. S. Parsons for his comments on the manuscript.


Journal ArticleDOI
TL;DR: In this article, a detailed theory of phase transitions has been developed which accounts for the electronic and vibrational Raman spectra, and the lowest four electronic levels of Dy 3+ and Tb 3+ are treated in a pseudospin formalism, discussed in terms of mixed phonon and pseudo-spin excitations.
Abstract: The rare-earth crystals DyVO 4 , DyAsO 4 and TbVO 4 undergo structural phase transitions at 14, 12 and 34 K respectively induced by a cooperative Jahn-Teller effect. An experimental investigation of the phase changes has been made using Raman scattering methods. For purposes of comparison, the Raman spectra of DyPO 4 , YVO 4 and GdVO 4 (which do not undergo phase transitions) have also been measured. A detailed theory of the phase transitions has been developed which accounts for the electronic and vibrational Raman spectra. The lowest four electronic levels of Dy 3+ and Tb 3+ are treated in a pseudospin formalism, and the theory is discussed in terms of mixed phonon and pseudo-spin excitations. The singly degenerate κ ≈ 0 optic phonons are not measurably affected by the transitions, but splittings of up to 20 cm -1 developed in the doubly degenerate E g phonon modes in the Raman spectra owing to anharmonic couplings with the electronic states. Splittings are also observed in the lowest electronic levels of the rate earth ions below the transition temperature; these electronic modes effectively constitute the soft mode which causes the transitions to occur. A molecular field model is first used in the theoretical analysis. The equations of motion of the coupled excitations are then found and the energies, line widths and dispersion of the mixed excitations are discussed. The connexion between the static strain and the acoustic phonon mode coupling is investigated, and a thermodynamic treatment of the elastic constants is given. From the Raman data, it appears that in TbVO 4 the acoustic mode coupling is stronger than the optic mode coupling.

Journal ArticleDOI
TL;DR: In this paper, the authors examined the processes of traumatic degeneration of myelin in the proximal stump of divided rat sciatic nerves with the electron microscope, revealing a complete and coherent series of Schwann cells which are progressively more advanced in the degradation of the myelin.
Abstract: Examination of the processes of traumatic degeneration of myelin in the proximal stump of divided rat sciatic nerves with the electron microscope reveals a complete and coherent series of Schwann cells which are progressively more advanced in the degradation of the myelin. The earlier stages appear to be a wrinkling and distortion of the myelin lamellae, followed by erosion of the circumferential lamellae with subsequent loss of cohesion and fragmentation of the myelin systems. Retraction of the myelin from the region of the node of Ranvier is observed. Myelin debris in the cytoplasm of Schwann cells occurs as vacuoles containing membranous material and pale staining globular inclusions which may develop from the membrane containing vacuoles. Cells containing similar inclusions are present ‘free’ in the endoneurium. The presence of similar cells associated with axons and only partly covered by basement membrane suggests that the cells ‘free’ in the endoneurium are ‘transformed’ Schwann cells digesting their myelin. These cells are most frequent between 3 and 6 days after nerve section and gradually disappear thereafter. We did not see any indications that cells other than Schwann cells were extensively involved in the traumatic degeneration of myelin.

Journal ArticleDOI
TL;DR: Collagenase digestion of human or rabbit subcomponent C1q caused a rapid loss of haemolytic activity which correlated with the breakdown of collagenous regions in the molecule.
Abstract: 1. C1q, a subcomponent of the first component of complement, has been isolated, in a haemolytically active and soluble form, by ion-exchange chromatography and gel filtration, from human and rabbit sera. Yields ranged from 10 to 25mg/litre of serum and the activity of final preparations was consistently in the range 5×103−15×103 C1qH50 units/mg. 2. The molecular weights of human and rabbit subcomponent C1q were 409600 and 417600, as determined by sedimentation equilibrium studies. 3. Subcomponent C1q from both species was shown to be composed of non-covalently linked subunits of approximately 57000 molecular weight as determined by gel-filtration or sedimentation equilibrium studies in 5.3m-guanidinium chloride. Reduction or oxidation of human and rabbit subcomponent C1q yielded three chains each having a molecular weight of approximately 23000 and which differed slightly in amino acid composition but markedly in carbohydrate content. The oxidized chains were separated, on a preparative scale, by ion-exchange chromatography in 8m-urea on DEAE-cellulose. 4. Both human and rabbit subcomponent C1q contained hydroxyproline, hydroxylysine, a high percentage of glycine and approximately 8% carbohydrate. Glutamic acid and aspartic acid were the free N-terminal amino acids of human subcomponent C1q whereas only serine was found in rabbit subcomponent C1q. 5. Collagenase digestion of human or rabbit subcomponent C1q caused a rapid loss of haemolytic activity which correlated with the breakdown of collagenous regions in the molecule.

Journal ArticleDOI
TL;DR: It was concluded that at these stages cell position could determine the development of blastomeres and the segregation of morphogenetic factors at the 4- and 8-cell stages of mouse development.
Abstract: The effect of cell position on cell determination was studied in mouse embryos. Embryos and parts of embryos were combined during early preimplantation development. The differentiation of cells in these composites was followed either by prelabelling some cells with tritiated thymidine or by combining cells which synthesized different electrophoretic variants of glucose phosphate isomerase. It was found that each blastomere of a 4-cell embryo could form both the trophoblast and the inner cell mass of the blastocyst. However, when blastomeres of a 4-cell embryo were placed on the outside of other 4-cell embryos then (a) they tended to form the outside layer of the blastocyst, (b) they tended to develop into the trophoblast and the yolk sac on the 10th day of pregnancy, (c) they tended not to form the coat colour of the foetus. Four- to eight-cell embryos which were completely surrounded by other blastomeres had lost the capacity to form vesicles at the blastocyst stage. We could find no evidence for the segregation of morphogenetic factors at the 4- and 8-cell stages of mouse development and concluded that at these stages cell position could determine the development of blastomeres.

Journal ArticleDOI
TL;DR: The degradation of the majority of amino acids is initiated by an amino transferase reaction, and systematic measurements of the capacity of various amino transferases in rat tissues, and the variations caused by a high-protein or high-carbohydrate diet, are reported.

Journal ArticleDOI
27 Nov 1972-Nature
TL;DR: A reconnaissance age and isotope study of quartzo-feldspathic Amitsoq gneisses of the Godthaab area of West Greenland as discussed by the authors showed that these rocks are older than any other terrestrial rocks yet dated.
Abstract: A RECENT reconnaissance age and isotope study of quartzo-feldspathic Amitsoq gneisses of the Godthaab area of West Greenland1,2 showed that these rocks are older than any other terrestrial rocks yet dated. An Rb-Sr whole rock date of 3,980 ± 170 m.y. and a Pb-Pb whole rock date of 3,620 ± 100 m.y. on fourteen granitic, granodioritic and tonalitic orthogneisses and evidence that some of these rocks contained the least radiogenic lead so far found on Earth, were presented in ref. 1.

Journal ArticleDOI
TL;DR: The effect of atrial systole on valve closure was studied experimentally and theoretically and showed to be due to a ring-vortex occupying the left ventricle together with flow deceleration through the mitral ring during the latter part of diastole.
Abstract: A model of the left ventricle was built incorporating a mitral and an aortic valve. The bicuspid mitral valve was seen to achieve most of its closure during diastole. This was shown to be due to a ring-vortex occupying the left ventricle together with flow deceleration through the mitral ring during the latter part of diastole. The vortex was asymmetrical in the model, because of the shape of the ventricle, and this caused the anterior cusp to close earlier in diastole than the posterior cusp. Enlargement of the ventricle eliminated the vortex and resulted in later closure of the mitral valve. The effect of atrial systole on valve closure was studied experimentally and theoretically.

Book ChapterDOI
A. J. Ayer1
01 Jan 1972
TL;DR: In this article it is argued that if human behaviour is entirely governed by causal laws, it is not clear how any action that is done could ever have been avoided; and it is only when it is believed that I could have acted otherwise that I am held to be morally responsible for what I have done.
Abstract: When I am said to have done something of my own free will it is implied that I could have acted otherwise; and it is only when it is believed that I could have acted otherwise that I am held to be morally responsible for what I have done. For a man is not thought to be morally responsible for an action that it was not in his power to avoid. But if human behaviour is entirely governed by causal laws, it is not clear how any action that is done could ever have been avoided. It may be said of the agent that he would have acted otherwise if the causes of his action had been different, but they being what they were, it seems to follow that he was bound to act as he did. Now it is commonly assumed both that men are capable of acting freely, in the sense that is required to make them morally responsible, and that human behaviour is entirely governed by causal laws: and it is the apparent conflict between these two assumptions that gives rise to the philosophical problem of the freedom of the will.

Journal ArticleDOI
TL;DR: It is concluded that Δ1‐tetrahydrocannabinol (Δ1‐THC) is largely responsible for the effect of cannabis extract on mobility; the potency ratio of Δ1-THC to cannabis extract is between 10 and 20.
Abstract: 1. A bioassay for cannabis, called the ring test, has been developed in which the percentage of the total time spent on a horizontal wire ring during which a mouse remains completely immobile is recorded.2. The effect of cannabis on mobility is a dose-related, graded response.3. Threshold doses of cannabis extract are 12.5 mg/kg when injected intravenously, and 100 mg/kg when injected intraperitoneally or subcutaneously.4. The method provides a measure of the ;cataleptic' effect of cannabis. Chlorpromazine in doses of 1 mg/kg upwards also produces the effect but barbitone does not.5. It is concluded that Delta(1)-tetrahydrocannabinol (Delta(1)-THC) is largely responsible for the effect of cannabis extract on mobility; the potency ratio of Delta(1)-THC to cannabis extract is between 10 and 20. Delta(1)-Tetrahydrocannabidivarol (Delta(1)-THD) also affects mobility but is less active than Delta(1)-THC. Cannabidiol has no effect when injected intraperitoneally in doses up to 100 mg/kg.

Book ChapterDOI
R. M. Hare1
01 Jan 1972
TL;DR: The state of the man who has stopped breathing, and whose heart has stopped beating, but who is subsequently resuscitated, is he alive or dead?
Abstract: Life presents us with many problems; but is ‘What is Life?’ one of them ? Don’t we all know what life is ? Or do we ? Surgeons have recently learnt how, in certain cases, to start a man’s heart working after it has stopped; this has long been possible with the breathing, which was once thought to be a criterion of life — ‘If that her breath will mist or stain the stone, why then she lives’, says King Lear. What then is the state of the man who has stopped breathing, and whose heart has stopped beating, but who is subsequently resuscitated ? Is he alive or dead ? If we say he is alive, why do we not apply the same term to another man, in a precisely similar condition, who does not happen to be lucky enough to have his seizure when there is a surgeon at hand, and who is therefore not resuscitated ? How would we date the death of the second man ? If we say that his life ended when he had the seizure, we ought in consistency to say that the first man, too, died when he had the seizure, and was subsequently brought back to life. But then is death not ‘the undiscover’d country from whose bourn no traveller returns’ ? We feel an aversion to saying that a man has been dead, if he subsequently ‘comes to life again’.

Journal ArticleDOI
TL;DR: That earlier developmental events such as the formation of the blastocoel cavity may in some way trigger polyploidization of trophoblast is not inconsistent with the studies described.
Abstract: 1. Trophoblast development in utero in the first half of gestation is accompanied by a rise in the ploidy levels in giant cell nuclei. Giant cells constitute up to one-third of the trophoblast population over this period. 2. The expression of polyploidy is independent of the maternal environment; the extent of polyploidy and the degree to which trophoblast develops morphologically under various conditions appear to be related. 3. The following events are not necessary for the initiation of polyploidization in trophoblast: (a) hatching from the zona pellucida, (b) oestrogen sensitization, (c) implantation, (d) postimplantation changes in topology. 4. That earlier developmental events such as the formation of the blastocoel cavity may in some way trigger polyploidization of trophoblast is not inconsistent with the studies described.

Journal ArticleDOI
G. Raisman1
TL;DR: The present anatomical findings point to the existence of a separate subdivision of the olfactory system whose connections are quite different from the principal part, and by virtue of its neural connections the accessory ofactory system is ideally placed to mediate the effects of olfaction stimuli on reproduction.
Abstract: The present anatomical findings point to the existence of a separate subdivision of the olfactory system whose connections are quite different from the principal part. The main olfactory bulb has olfactory afferents from the receptors of the general olfactory mucosa, while the accessory bulb has afferents from receptors in the vomeronasal organ. The main bulb projects to the olfactory tubercle and pyriform cortex, while the accessory bulb projects to the amygdala. In turn these areas are further related with the medial forebrain bundle in the case of the pyriform cortex and olfactory tubercle, and with the medial preoptic area and medial hypothalamus in the case of the amygdala. The main and accessory olfactory bulbs are further distinguished by their centrifugal connections, the main bulb receiving fibres from the olfactory tubercle passing through the lateral olfactory tract, and the accessory olfactory bulb receiving fibres from the amygdala through the stria terminalis. The centrifugals to the accessory olfactory bulb resemble those to the main bulb in that both appear to terminate upon granule cells, although further projections to the external plexiform layer or to the periglomerular region have not been demonstrated for the accessory bulb. By virtue of its neural connections the accessory olfactory system is ideally placed to mediate the effects of olfactory stimuli on reproduction.

Journal ArticleDOI
18 Aug 1972-Nature
TL;DR: One subject is reported on, a 20-yr-old girl undergraduate, C. G., who can make smooth eye movements at will in the dark and can change the velocity of these movements on demand, and seem to represent specific voluntary control of the smooth pursuit eye movement system.
Abstract: IT has been shown recently that the eyes can make sustained smooth eye movements indistinguishable from normal pursuit movements in the absence of a moving visual stimulus if an after-image is tracked1–3. This experimental procedure avoids the objections which can be raised against previous demonstrations of smooth eye movements without moving targets which have involved either alternative sources of information about movement4, or closing the eyes5, or changes in subjects' level of arousal6. But it has not yet been shown that smooth eye movements can be made voluntarily, and it is possible that they can be executed by alert, open-eyed subjects only if the saccadic system is inhibited by a visual target. This is a report on one subject, a 20-yr-old girl undergraduate, C. G., who can make smooth eye movements at will in the dark and can change the velocity of these movements on demand. These eye movements are indistinguishable from normal pursuit, do not resemble the eye movements made by the same subject when tracking an after-image, and seem, therefore, to represent specific voluntary control of the smooth pursuit eye movement system.