山东首次发现晚始新世哺乳动物化石地点

本文报道了鲁西曲阜董庄、泗水拓沟间黄庄一带发现的哺乳动物化石.描述了含哺乳动物化石的地层,建立了黄庄组.依据所产化石对黄庄组的时代进行了讨论,认为是晚始新世.     

内蒙古脑木根地区渐新世啮齿类及相关地层问题

描述了脑木根敖包顶部岩层中所产的啮齿类化石：阿尔泰查干鼠(Tsaganomys altaicus)和中间圆柱鼠(Cyclomylus intermedius)。脑木根敖包顶部地层最初被归人巴润索组。研究表明该层共含5种哺乳动物化石(Tsaganomys altaicus、Cyclomylus intermedius、Paracerotherium tran-souralicum、Ardynia kaxachstanensis和Etelodn gobiensis），其时代为早渐新世晚期。巴润索组的层型是巴润索平台顶部的砂砾岩，其时代为晚始新世。脑木根敖包顶部岩层不应归人巴润索组，而与额尔登敖包顶部的上脑岗代组在岩性上接近，时代相同，因此应归人上脑岗代组。     

伊朗西北部 Varzeghan 附近晚中新世一些新化石地点的大哺乳动物(英文)

首次报道了伊朗西北部 Varzeghan 附近发现的大型哺乳动物化石,材料包括三趾马和恐象。根据个体大小和形态特征,将三趾马标本暂时分为一个小至中型类似 Hipparion moldavicum 的种和一个中至大型类似 H. prostylum 或 H. dietrichi 的种。Deinotherium giganteum 也出现于这一地区。依据与其他晚中新世地点哺乳动物化石的对比,这些新化石地点的时代推测为吐洛里期( Turolian) 中期或相当于欧洲哺乳动物带的 MN12。     

四川炉霍县虾拉沱晚更新世哺乳类化石

本文简记了在四川省炉霍县虾拉沱附近鲜水河左岸发现的十三种哺乳动物化石.根据动物群的性质和 C~(14) 年代的测定,初步确定含化石层的时代为晚更新世最晚期.     

许家窑遗址1977年出土的人类化石

<正> 1976年,在许家窑遗址发掘获得9件人类化石、大量的哺乳动物化石和石器。这些遗骸和遗物已由贾兰坡教授等进行了研究和报道(1979)。1977年7—9月,我们对许家窑遗址又作了进一步发掘,共获得人类化石8件及大量的石器和骨器,还有丰富的哺乳动物化石。本文仅对1977年发现的人类化石报告如下:     

内蒙古阿左旗乌兰塔塔尔地区渐新世地层剖面及动物群初步观察

内蒙古阿左旗乌兰塔塔尔地区的渐新世地层中,哺乳动物化石丰富,种类繁多。本文是这个动物群研究的初步报道,除对动物群中各成员和地层概况做了简单介绍外,还对化石层的时代作了初步探讨。     

晚中新世晚期土城子小哺乳动物组合及土城子动物群在内蒙古中部地区新近纪哺乳动物群序列中的位置（英文）

近百年来,在内蒙古中部地区发现了丰富的新近纪哺乳动物化石,命名和描述了10余个哺乳动物群,其时代跨越早中新世至早上新世。它们已经成为建立中国北方新近纪哺乳动物生物年代地层框架的重要依据。早在1959年中苏古生物联合考察过程中就已经发现土城子地区有丰富的哺乳动物化石,但这些化石以大–中型哺乳动物为主,缺乏小哺乳动物。土城子动物群的构成和其在中国北方新近纪哺乳动物年代地层框架中的位置长期以来不是特别明确。报道了在土城子新发现的6种小哺乳动物化石。根据Lophocricetus grabaui–Sinocricetus zdanskyi–Prosiphneus licenti–Hansdebruijnia pusilla–Moschus grandaevus的组合特点,认为土城子动物群的年代应该可以很好地约束在晚中新世(或者保德期)的晚期。土城子动物群明显比内蒙古的宝格达乌拉动物群要进步一些,与二登图动物群非常相似,时代上晚于前者,略早于后者。依据动物群整体面貌,推测在晚中新世晚期土城子地区存在森林和草原混合的环境。     

华北几个地点的上新世哺乳动物化石

本文记述1959年和1960年中苏古生物考察队在内蒙和甘肃采集的上新世哺乳动物化石,并对各地点化石组合性质和各动物群所代表的时代进行了分析。化石包括窑沟原貂Proputorius yaogouensis)、化德无角犀(Aceratherium huadeensis)和化德上新鹿(Cervocerushuadeensis)三个新种。     

内蒙古阿拉善左旗克克阿木中渐新世早期哺乳动物化石的发现

本文简要报道了在内蒙古阿左旗克克阿木地点发现的哺乳动物化石,计4目10科11属12种.动物群的时代可能为中渐新世早期.     

内蒙古苏尼特左旗第三纪中期哺乳动物化石新地点

报道了内蒙古自治区苏尼特左旗白音宝力道乡嘎顺音阿得格地区一个第三纪中期哺乳动物化石新地点。对哺乳动物化石的初步研究表明,该区覆盖于晚古生代花岗岩基底上的第三纪沉积物时代可能为晚渐新世─早中新世的过渡层位,而不是过去认为的中中新世通古尔组。     

Uncovering the spatio-temporal dynamics of value-based decision-making in the human brain: a combined fMRI–EEG study

While there is a growing body of functional magnetic resonance imaging (fMRI) evidence implicating a corpus of brain regions in value-based decision-making in humans, the limited temporal resolution of fMRI cannot address the relative temporal precedence of different brain regions in decision-making. To address this question, we adopted a computational model-based approach to electroencephalography (EEG) data acquired during a simple binary choice task. fMRI data were also acquired from the same participants for source localization. Post-decision value signals emerged 200 ms post-stimulus in a predominantly posterior source in the vicinity of the intraparietal sulcus and posterior temporal lobe cortex, alongside a weaker anterior locus. The signal then shifted to a predominantly anterior locus 850 ms following the trial onset, localized to the ventromedial prefrontal cortex and lateral prefrontal cortex. Comparison signals between unchosen and chosen options emerged late in the trial at 1050 ms in dorsomedial prefrontal cortex, suggesting that such comparison signals may not be directly associated with the decision itself but rather may play a role in post-decision action selection. Taken together, these results provide us new insights into the temporal dynamics of decision-making in the brain, suggesting that for a simple binary choice task, decisions may be encoded predominantly in posterior areas such as intraparietal sulcus, before shifting anteriorly.     

SURFACE MORPHOLOGY OF THE FOREBRAIN OF THE BOWHEAD WHALE, BALAENA MYSTICETUS

Observations were made on 11 brains from bowhead whales subsistence-harvested by Alaskan Eskimos under International Whaling Commission guidelines. This study is part of a larger project to determine the basic morphology of this endangered species. The bowhead brain is similar to other cetacean brains, particularly that of the southern right whale. Long olfactory peduncles are reflected upon the rostrodorsal surface of the cerebral hemispheres. Olfactory bulbs have not been recovered but are presumed to exist since nerve fibers have been identified histologically in the olfactory peduncles. The induseum griseum is evident on the corpus callosum. The hippocampus proper is small but protrudes into the lateral ventricle. The cruciate sulcus runs diagonally across the rostral surface, limiting a small frontal lobe. The structure of the floor of the sylvian fissure varies from a few short gyri radiating toward the circular sulcus to a more extensive and complex two-tiered arrangement including numerous gyri perpendicular to the gyrus bordering the paleocortex. Pineal-body-like tissue was present in one specimen. There is no interthalamic adhesion. The lateral geniculate body is elevated but smaller than the large medial geniculate body. The neurohypophysis was adherent on most brain specimens received.     

Cranial nerves in the Australian lungfish,Neoceratodus forsteri,and in fossil relatives (Osteichthyes: Dipnoi)

Three systems, two sensory and one protective, are present in the skin of the living Australian lungfish, Neoceratodus forsteri, and in fossil lungfish, and the arrangement and innervation of the sense organs is peculiar to lungfish. Peripheral branches of nerves that innervate the sense organs are slender and unprotected, and form before any skeletal structures appear. When the olfactory capsule develops, it traps some of the anterior branches of cranial nerve V, which emerged from the chondrocranium from the lateral sphenotic foramen. Cranial nerve I innervates the olfactory organ enclosed within the olfactory capsule and cranial nerve II innervates the eye. Cranial nerve V innervates the sense organs of the snout and upper lip, and, in conjunction with nerve IX and X, the sense organs of the posterior and lateral head. Cranial nerve VII is primarily a motor nerve, and a single branch innervates sense organs in the mandible. There are no connections between nerves V and VII, although both emerge from the brain close to each other. The third associated system consists of lymphatic vessels covered by an extracellular matrix of collagen, mineralised as tubules in fossils. Innervation of the sensory organs is separate from the lymphatic system and from the tubule system of fossil lungfish.     

Neural representation of auditory size in the human voice and in sounds from other resonant sources

The size of a resonant source can be estimated by the acoustic-scale information in the sound [1-3]. Previous studies revealed that posterior superior temporal gyrus (STG) responds to acoustic scale in human speech when it is controlled for spectral-envelope change (unpublished data). Here we investigate whether the STG activity is specific to the processing of acoustic scale in human voice or whether it reflects a generic mechanism for the analysis of acoustic scale in resonant sources. In two functional magnetic resonance imaging (fMRI) experiments, we measured brain activity in response to changes in acoustic scale in different categories of resonant sound (human voice, animal call, and musical instrument). We show that STG is activated bilaterally for spectral-envelope changes in general; it responds to changes in category as well as acoustic scale. Activity in left posterior STG is specific to acoustic scale in human voices and not responsive to acoustic scale in other resonant sources. In contrast, the anterior temporal lobe and intraparietal sulcus are activated by changes in acoustic scale across categories. The results imply that the human voice requires special processing of acoustic scale, whereas the anterior temporal lobe and intraparietal sulcus process auditory size information independent of source category.     

The brain structure of selected trypanorhynch tapeworms

The brain architecture in four species of tapeworms from the order Trypanorhyncha has been studied. In all species, the brain consists of paired anterior and lateral lobes, and an unpaired central lobe. The anterior lobes connect by dorsal and ventral semicircular commissures; the central and lateral lobes connect by a median and an X-shaped crisscross commissure. In the center of the brain, five well-developed compact neuropils are present. The brain occupies a medial position in the scolex pars bothrialis. The ventral excretory vessels are situated outside the lateral lobes of the brain; the dorsal excretory vessels are located inside the brain and dorsal to the median commissure. The brain gives rize four anterior proboscis nerves and four posterior bulbar nerves with myelinated giant axons (GAs). The cell bodies of the GAs are located within the X-commissure and in the bulbar nerves. Highly developed serotonergic neuropils are present in the anterior and lateral lobes; numerous 5-HT neurons are found in the brain lobes including the central unpaired lobe. The X-cross commissure consists of the α-tub-immunoreactive and 5-HT-IR neurites. Eight ultrastructural types of neurons were found in the brain of the three species investigated. In addition, different types of synapses were present in the neuropils. Glial cells ensheath the brain lobes, the neuropils, the GAs, and the bulbar nerves. Glia cell processes form complex branching patterns of thin cytoplasmic sheets sandwiched between adjacent neural processes and filling the space between neurons. Multilayer myelin-like envelopes and a mesaxon-like structure have been found in Trypanorhyncha nervous system. We compared the brain architecture of Trypanorhyncha with that of an early basal cestode taxon, that is, Diphyllobothriidea, and present a hypothesis about the homology of the anterior brain lobes in order Trypanorhyncha; and the lateral lobes and median commissure are homologous brain structures within Eucestoda.     

Neuronal reactions of the olfactory centers of the forebrain during stimulation of the hypothalamic structures in rabbits]

During stimulation of phylogenetically ancient parts of the hypothalamus (the anterior and lateral), neuronal reactions have been recorded in the prepyriform lobe and tuberculum olfactorium. These reactions are characterized by a short latent period (6-25 msec) and high stability to rhythmic stimulation. Neuronal reactions in the same olfactory centers during stimulation of phylogenetically more recent hypothalamic structures (the posterior and medial) exhibit a long latent period (30-120 msec) and are readily exhausted by rhythmic stimulation.     

Morphological patterns of the intraparietal sulcus and the anterior intermediate parietal sulcus of Jensen in the human brain

Distinct parts of the intraparietal sulcal cortex contribute to sensorimotor integration and visual spatial attentional processing. A detailed examination of the morphological relations of the different segments of the complex intraparietal sulcal region in the human brain in standard stereotaxic space, which is a prerequisite for detailed structure-to-function studies, is not available. This study examined the intraparietal sulcus (IPS) and the related sulcus of Jensen in magnetic resonance imaging brain volumes registered in the Montreal Neurological Institute stereotaxic space. It was demonstrated that the IPS is divided into two branches: the anterior ramus and the posterior ramus of the IPS, often separated by a submerged gyral passage. The sulcus of Jensen emerges between the anterior and posterior rami of the IPS, and its ventral end is positioned between the first and second caudal branches of the superior temporal sulcus. In a small number of brains, the sulcus of Jensen may merge superficially with the first caudal branch of the superior temporal sulcus. The above morphological findings are discussed in relation to previously reported functional neuroimaging findings and provide the basis for future exploration of structure-to-function relations in the posterior parietal region of individual subjects.     

Central connections of the olfactory bulb in the weakly electric fish,Gnathonemus petersii

Summary We have investigated the central connections of the classical olfactory system in the weakly electric fish Gnathonemus petersii using HRP and cobalt labelling techniques. The olfactory bulb projects bilaterally via the medial and lateral olfactory tracts to restricted areas of the telencephalon, namely to its rostromedial, lateral and posterior medial parts. The most extensive telencephalic target is the posterior terminal field, which arcs around the lateral forebrain bundle at levels posterior to the anterior commissure. Projections to the contralateral hemisphere cross in the ventral telencephalon rostral to the anterior commissure and via the posterior dorsal part of the anterior commissure; endings are also present within the anterior commissure. Bilateral projections to the preoptic area, to the nucleus posterior tuberis and to an area in the thalamus are apparent. In all cases, contralateral projections are less extensive than those on the side ipsilateral to the injected bulb. A projection via the medial olfactory tract can be followed to the contralateral bulb. Following injections into the olfactory bulb, retrogradely labelled neurons are found in the contralateral bulb and in six telencephalic areas; they are also present in the periventricular diencephalon and in an area lateral to the nucleus posterior tuberis. The present results support the suggestion that a reduction in olfactory input to the telencephalon occurs together with increased telencephalic differentiation in actinopterygian fishes.     

Characterization of the synaptic properties of olfactory bulb projections

The olfactory bulb directly projects to several diverse telencephalic structures, but, to date, few studies have investigated the physiological characteristics of most of these areas. As an initial step towards understanding the odor processing functions of these secondary olfactory structures, we recorded evoked field potentials in response to lateral olfactory tract stimulation in vivo in urethane-anesthetized Sprague-Dawley rats in the following brain structures: anterior olfactory nucleus, ventral and dorsal tenia tecta, olfactory tubercle, anterior and posterior piriform cortex, the anterior cortical nucleus of the amygdala, and lateral entorhinal cortex. Using paired-pulse stimulation with interpulse intervals of 25-1000 ms, we observed facilitation of the response to the second pulse in every structure examined, although the degree of facilitation varied among the target structures. Additionally, pulse train stimulation at three different frequencies (40, 10 and 2 Hz) produced facilitation of evoked field potentials that also varied among target structures. We discuss the potential utility of such short-term facilitation in olfactory processing.     

Central connections of the olfactory bulb in the goldfish,Carassius auratus

Summary The central connections of the goldfish olfactory bulb were studied with the use of horseradish peroxidase methods. The olfactory bulb projects bilaterally to ventral and dorsolateral areas of the telencephalon; further targets include the nucleus praeopticus periventricularis and a caudal olfactory nucleus near the nucleus posterior tuberis in the diencephalon, bilaterally. The contralateral bulb and the anterior commissure also receive an input from the olfactory bulb. Contralateral projections cross in rostral and caudal portions of the anterior commissure and in the habenular commissure. Retrogradely labeled neurons are found in the contralateral bulb and in three nuclei in the telencephalon bilaterally; the neurons projecting to the olfactory bulb are far more numerous on the ipsilateral side than in the contralateral hemisphere. Afferents to the olfactory bulb are found to run almost entirely through the lateral part of the medial olfactory tract, while the bulb efferents are mediated by the medial part of the medial olfactory tract and the lateral olfactory tract. Selective tracing of olfactory sub-tracts reveals different pathways and targets of the three major tract components. Reciprocal connections between olfactory bulb and posterior terminal field suggest a laminated structure in the dorsolateral telencephalon.