scholarly journals Mosaic Evolution of Brainstem Motor Nuclei in Catarrhine Primates

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Seth D. Dobson ◽  
Chet C. Sherwood
Keyword(s):  
Brain Evolution ◽  
Motor Nucleus ◽  
Regression Analyses ◽  
Facial Nucleus ◽  
Developmental Constraints ◽  
Catarrhine Primates ◽  
Facial Motor Nucleus ◽  
Motor Nuclei ◽  
Additional Support ◽  
Nucleus Volume

Facial motor nucleus volume coevolves with both social group size and primary visual cortex volume in catarrhine primates as part of a specialized neuroethological system for communication using facial expressions. Here, we examine whether facial nucleus volume also coevolves with functionally unrelated brainstem motor nuclei (trigeminal motor and hypoglossal) due to developmental constraints. Using phylogenetically informed multiple regression analyses of previously published brain component data, we demonstrate that facial nucleus volume is not correlated with the volume of other motor nuclei after controlling for medulla volume. Our results show that brainstem motor nuclei can evolve independently of other developmentally linked structures in association with specific behavioral ecological conditions. This finding provides additional support for the mosaic view of brain evolution.

An Electron Microscopic Study of Developing Synapses in Facial and Hypoglossal Motor Nuclei of the Brazilian Opossum.

1997 ◽  
Vol 3 (S2) ◽  
pp. 181-182
Author(s):  
T.M. Pepper ◽  
J.J. Swanson ◽  
M.C. Kuehl-Kovarik ◽  
CD. Jacobson
Keyword(s):  
Methylene Blue ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Motor Nucleus ◽  
Electron Microscopic ◽  
Initial Analysis ◽  
Facial Motor Nucleus ◽  
Associated Proteins ◽  
Motor Nuclei

Previously, we have shown the apparent development of synapses utilizing immunohistochemistry (IHC) for synapse-associated proteins in the facial and hypoglossal motor nuclei of the Brazilian opossum. This study suggests that synaptogenesis is delayed in the facial motor nucleus (FMN) as compared to the hypoglossal motor nucleus (HMN). In the present study we plan to confirm and extend these findings at the electron microscopic (EM) level.We have examined the ultrastructure of the developing FMN from animals 5 to 25 days of postnatal age (PN). The specific nuclei were identified using methylene blue stained 150 μm thick vibratome cut sections. The FMN and HMN were then dissected out for processing, guaranteeing that visualization at the EM level would be confined to areas specific to the nuclei of interest.Initial analysis of the FMN indicates a marked increase of detectable synapses between 5 and 15PN.

scholarly journals Face to face with the social brain

2012 ◽  
Vol 367 (1597) ◽  
pp. 1901-1908 ◽  
Author(s):  
Seth Dobson
Keyword(s):  
Motor Control ◽  
Brain Size ◽  
Quantitative Relationship ◽  
Motor Nucleus ◽  
Facial Nucleus ◽  
Face To Face ◽  
Facial Motor Nucleus ◽  
The Social ◽  
Group Members ◽  
Facial Expressivity

Recent comparative evidence suggests that anthropoid primates are the only vertebrates to exhibit a quantitative relationship between relative brain size and social group size. In this paper, I attempt to explain this pattern with regard to facial expressivity and social bonding. I hypothesize that facial motor control increases as a secondary consequence of neocortical expansion owing to cortical innervation of the facial motor nucleus. This is supported by new analyses demonstrating correlated evolution between relative neocortex size and relative facial nucleus size. I also hypothesize that increased facial motor control correlates with enhanced emotional expressivity, which provides the opportunity for individuals to better gauge the trustworthiness of group members. This is supported by previous evidence from human psychology, as well as new analyses demonstrating a positive relationship between allogrooming and facial nucleus volume. I suggest new approaches to the study of primate facial expressivity in light of these hypotheses.

The development of facial motoneurones in the mouse — neuronal death and the innervation of the facial muscles

Development ◽  
1983 ◽  
Vol 77 (1) ◽  
pp. 117-141
Author(s):  
K. W. Ashwell ◽  
C. R. R. Watson
Keyword(s):  
Cell Death ◽  
Neuronal Death ◽  
Indirect Evidence ◽  
Motor Nucleus ◽  
Neuromuscular System ◽  
Facial Nucleus ◽  
Facial Muscles ◽  
Facial Musculature ◽  
Facial Motor Nucleus ◽  
Horseradish Peroxide

The relationship between neuronal death and the formation of patterned connections was studied in the facial neuromuscular system of foetal, neonatal, and adult mice. The facial neuromuscular system was selected because two large, widely separated, facial muscles (the nasolabial and posterior auricular muscles) are innervated by clearly separated partsof the the facial motor nucleus in the adult mouse. The number of motorneurones in the facial nucleus was counted in Nissl-stained sections at different stages of development. Over 6400 neurones were present in the facial nucleus at day 17 p.c. (post-coitum). After day 17 p.c. the number of neurones fell rapidly and only 2000 cells remain in the adult nucleus. This represents a loss of 68%, most of which occurs between days 18 and 20 p.c. Neurones with pyknotic nuclei are seen on day 17 p.c. and are most numerous on day 18 p. c. This leads us to believe that the fall in neurone numbers is due to cell death. Indirect evidence provided by acetylcholinesterase histochemistry (time of earliest reaction in the facial muscles) and horseradish peroxide (HRP) tracing studies (time of earliest transport) indicate that facial motorneurone axons innervate the facial musculature before the period of cell death: diffuse acetylcholinesterase activity first appeared inthe auricular muscles at day 15 p.c. and in the nasolabial muscles at day 17 p.c.; retrograde transport of HRP from the auricular and nasolabial muscles to the facial nucleus cannot be reliably demonstrated before day 17 p.c. We assessed the topography of early facial neuromuscular innervation by making HRP injections into nasolabial and posterior auricular muscles of embryonic and neonatal mice. Injections of HRP at day 17 p.c. (the day before cell loss commenced) showed that the nasolabial muscle and posterior auricular muscles were innervated by the same subnuclei of the facial nucleus as in the adult - except that there was a small number (1–5 %) of labelled cells located in parts of the nucleus not consistent with the adult innervation pattern. These data indicate that, except for a small number of neurones, topographically organized connections in the facial neuromuscular system are established before the period of cell death. We conclude that motoneurone cell death does not play a major role in the establishment of topographically organized connections inthis system.

The organization and activity patterns of the anterior and posterior heads of the guinea pig digastric muscle

1987 ◽  
Vol 58 (3) ◽  
pp. 496-509 ◽  
Author(s):  
A. Lev-Tov ◽  
M. Tal
Keyword(s):  
Guinea Pig ◽  
Activity Patterns ◽  
Motor Nucleus ◽  
Digastric Muscle ◽  
Fiber Types ◽  
Jaw Movements ◽  
Cross Sectional ◽  
Trigeminal Motor Nucleus ◽  
Facial Motor Nucleus ◽  
Early Activity

The structure and activity patterns of the anterior and posterior heads of the guinea pig digastric muscle (DG) were studied in ketamine-anesthetized guinea pigs. Collagen staining of longitudinal and transverse sections of the muscle revealed that the guinea pig DG is comprised of a unicompartmental anterior head (ADG) and a multicompartmental posterior head (PDG). The two heads are separated by a thin tendinous inscription that, unlike the intermediate tendon of the DG in humans, is not attached to the hyoid bone. The motor nuclei of the guinea pig DG were reconstructed using retrograde labeling with horseradish peroxidase. The motoneurons of the ADG were clustered in a longitudinal column within the trigeminal motor nucleus. The motoneurons of the PDG were segregated into two clusters within the facial motor nucleus. The cross-sectional areas of the ADG and PDG motoneuron somata exhibited unimodal frequency distributions and the average soma area was larger for ADG than PDG motoneurons. Histochemical characterization of ADG and PDG revealed that the two muscle heads contained the three main histochemical types of muscle fibers identified in limb muscles. The frequency distribution of fiber types in ADG and PDG were not significantly different. Both muscle heads were predominantly fast with slow oxidative fibers accounting for only 1.1 and 0.3% of the fibers in narrow dorsal regions of ADG and PDG, respectively, and 13.6 and 12.9% in the more ventral regions of ADG and PDG, respectively. Simultaneous recordings of EMGs from the ADG and PDG were carried out during spontaneously occurring rhythmical jaw movements. These recordings revealed a high degree of synchrony between the activities of the two heads, although differences were observed in the onset and duration of the EMG bursts. Activity in the PDG preceded activity in the ADG in most of the rhythmical cycles and persisted longer. The differences in latencies of time-locked EMGs evoked in the ADG and PDG by four-pulse cortical stimulation were much smaller than those observed between the activity bursts of the two heads during rhythmical jaw movements. It is suggested that the early activity in the PDG is accounted for by shorter central conduction times in the pathways onto it and/or by higher recruitability of its motor units. The early activity in PDG may serve to optimize the location of ADG on its length-tension curve prior to and during the active state.

Somatotopic Organization of Perioral Musculature Innervation within the Pig Facial Motor Nucleus

2005 ◽  
Vol 66 (1) ◽  
pp. 22-34 ◽  
Author(s):  
Christopher D. Marshall ◽  
Ron H. Hsu ◽  
Susan W. Herring
Keyword(s):  
Motor Nucleus ◽  
Somatotopic Organization ◽  
Facial Motor Nucleus

Effects of perinatal undernourishment on neuronal development of the facial motor nucleus in the rat

2001 ◽  
Vol 905 (1-2) ◽  
pp. 54-62 ◽  
Author(s):  
Esther Perez-Torrero ◽  
Carmen Torrero ◽  
Manuel Salas
Keyword(s):  
Neuronal Development ◽  
Motor Nucleus ◽  
Facial Motor Nucleus

The Respiratory Centre in the Tench (Tinca Tinca L.)

1961 ◽  
Vol 38 (1) ◽  
pp. 79-92
Author(s):  
G. SHELTON
Keyword(s):  
Grey Matter ◽  
Rhythmic Activity ◽  
Motor Nucleus ◽  
Rhythmic Movements ◽  
Tinca Tinca ◽  
Large Numbers ◽  
Respiratory Centre ◽  
Potential Activity ◽  
Motor Nuclei ◽  
Tench Tinca Tinca

1. The medulla of the tench brain was searched systematically by means of needle electrodes for rhythmic bursts of action potential activity coinciding with the breathing movements. 2. The neurones which produced these rhythmic bursts of activity were located in the grey matter, mainly beneath the IXth and Xth motor nuclei and in the region round the VIIth motor nucleus. This type of activity was also found in some of the neurones forming the Vth and VIIth motor nuclei. 3. The respiratory neurones were not arranged in a discrete and homogenous nucleus anywhere in the medulla, but were scattered through the grey matter. The distribution was not uniform, the neurones tending to occur in very small groups. There was also a relatively higher density of respiratory neurones in the central, as compared with the more anterior and posterior, parts of the respiratory region. The possibility that variations may occur in the constitution of the respiratory centre, in different individuals and in the same individual at different times, is considered. 4. The manner in which neurones of the respiratory centre function to produce the rhythmic activity is discussed. Localized destruction of active respiratory regions, over a wide area of the medulla in different fish, was never followed by a breakdown in the rhythmic movements. This is interpreted as evidence against the existence of a pacemaker and favouring the hypothesis that the rhythm is produced by a general reciprocal interaction of large numbers of respiratory neurones.

Regulation of CD44 in the Regenerating Mouse Facial Motor Nucleus

1997 ◽  
Vol 9 (9) ◽  
pp. 1854-1863 ◽  
Author(s):  
Leonard L. Jones ◽  
Georg W. Kreutzberg ◽  
Gennadij Raivich
Keyword(s):  
Motor Nucleus ◽  
Facial Motor Nucleus
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