Homonymous Group Research Articles

Lexical homonyms in the Mari language.

The subject of the study is lexical homonyms in the modern Mari language. The material of the scientific work was the data of the 10-volume dictionary of the Mari language, the Mari-Russian dictionary, the author's card file, compiled by selecting materials from Mari works of art, oral folk art and periodicals. The aim of the work is to distinguish lexical homonyms from other groups of homonyms and to determine their conceptual and semantic relationship. At the first stage, a selection of words that belong to the category of lexical homonyms was carried out. At the next stage of the study, all lexical material was analyzed, this group of homonyms was divided into categories, and a quantitative analysis of lexical homonyms was performed. The research method was the analysis of homonyms based on lexicographic sources. A special contribution of the author to the study of the topic is the appeal to a wide range of works and the multidimensional nature of the study of the issue. The novelty of the research lies in the fact that lexical homonyms in the Mari language are analyzed for the first time. The result of the study lies in the conclusion that lexical homonyms are the most common group of homonyms in the Mari language, they can be divided into full and incomplete lexical homonyms, as well as substantive, verbal, adjectival, participial, adverbial and several examples with imitative words were distinguished by their relation to parts of speech. Lexical homonymy occurs among words of the same parts of speech. At the same time, two or more lexical homonyms (full or partial) have an absolute identity of the sound and spelling complex.

ПСИХОЛІНГВІСТИЧНІ АСПЕКТИ ОМОНІМІЇ

This article is devoted to an experimental study of assimilation, storage and functioning features of homonyms in the Ukrainian speaker’s lexicon. One of the effective methods of researching homonymy is an unbound nonrestrictive associative experiment which allows to deepen the knowledge about the assimilation, interpretation, compatibility, functionality and use, including false ones, of homonyms in speech. The main object of analysis was the speakers’ associative reactions to homonymous stimuli obtained during a unbound associative experiment. The content and structure of the associative meaning of lexical homonyms, the types of verbal associative connections of stimuli-homonyms and words-reactions are studied. The analysis outcome of the obtained associative reactions establishes that the number and nature of associative reactions are determined by the degree of relevance of homonymous stimuli for informants. Homonymous stimuli evoke more paradigmatic associative reactions than syntagmatic ones in informants for whom this language is native. There have been identified the factors affecting the actualization (manifestation in the informants’ reactions) of a certain component of the homonymous group. The informant’s age and knowledge of different languages significantly influence the association process. The most frequent were attributive reactions caused by characteristic features of the object such as quality, property, function, significant detail for the speaker, etc., and situational ones where reactions associated with a certain situation or its component. Subjective-definitive reactions containing an explanation of the stimulus word, were also numerous. The strategies of associating homonymous stimuli caused by the influence of age, gender and other informants’ characteristics are analyzed. Due to experimental studies, the homonymy phenomenon receives a more extended interpretation than presented in lexicographic sources.

Agreement in the detection of chiasmal and postchiasmal visual field defects between imo binocular random single-eye test and Humphrey monocular test.

To compare the ability of imo binocular random single-eye test (BRSET) to detect visual field (VF) defects due to chiasmal and postchiasmal lesions (C/PCLs) with a Humphrey Field Analyzer (HFA) monocular test. Prospective multicenter study METHODS: This study enrolled 40 patients with C/PCLs and measured their VFs using both imo BRSET and HFA monocular test. The VFs were classified into three groups using the cluster criterion: 1) bitemporal group, 2) homonymous group, and 3) others. The agreement and correlation of VF results between imo and HFA were analyzed using the Bland-Altman plot and Spearman correlation coefficient. The VFs of 34 patients were analyzed and classified. There were 13 patients in the bitemporal, 6 in the homonymous, and 15 in the others group. BRSET showed a significantly shorter test duration than HFA. The imo systematically yielded a lower sensitivity than HFA. The average sensitivity at each test location correlated well between the perimeters in all groups, with the correlation coefficients ranging from 0.89 to 0.98. Bland-Altman plots showed wider limits of agreement in the affected quadrants compared to the unaffected quadrants in the bitemporal and homonymous groups. The fixation loss rate did not differ between the perimeters, but there were significant differences in the false positive and false negative rates between perimeters. BRSET detected VF defects due to C/PCLs as accurately as the HFA monocular test with a shorter test duration.

ՀԱՄԱՆՈՒՆՈՒԹՅՈՒՆԸ` ՈՐՊԵՍ ՀՈՒՄՈՐԱՅԻՆ ԱԶԴԵՑՈՒԹՅՈՒՆ ՍՏԵՂԾԵԼՈՒ ՄԻՋՈՑ Լ. ՔԵՐՈԼԻ «ԱԼԻՍԱՆ ՀՐԱՇՔՆԵՐԻ ԱՇԽԱՐՀՈՒՄ» ՍՏԵՂԾԱԳՈՐԾՈՒԹՅԱՆ ՄԵՋ / HOMONYMY AS A MEANS OF CREATING HUMOROUS EFFECT IN L. CARROLL’S “ALICE IN WONDERLAND”

The aim of the given article is to scrutinize the use of homonyms as a means of creating puns in Lewis Carroll’s “Alice in Wonderland”. Of special interest is the scrutiny of the paramount role of homonyms in creating humorous effects in the given literary work. It is worth mentioning that ongoing change of the language wordstock leads to the creation of new groups of homonyms. In the current paper, the main focus is on the fact that polysemy serves as a rich source of creating puns. As a result of the scrutiny of homonyms, it comes to light that homonyms have been used in the given literary work not only for creating humorous effects and expressing irony, but also for creating confusion and misunderstanding among characters.

≪现代汉语词典≫中的同音同义词小考

A total of 975 groups of homonyms are included in Modern Chinese Dictionary. There are various ways to interpret them in the dictionary. There are rules to follow, but there are still some places to consider. Homonyms can be produced in dialects, disyllabic words, transliteration words, onomatopoeia, the development of word meaning and even the use of traditional Chinese characters and variant characters. There are 519 groups of homonyms with different characters. Among them, 231 groups have morphological differences, accounting for 45%; 56 groups have phonetic differences, accounting for about 10%; 232 groups have no differences in form and sound symbols, accounting for about 45%.

К вопросу о лакунах в омонимических рядах в толковых словарях русского языка

Homonymic series are presented differently in different dictionaries. The representation dependson the volume of the dictionary and the vocabulary, the approach to reflecting the semantic structure of theword (more general vs. more detailed), and a theoretical approach to homonyms.Comparing the data of different dictionaries, one can find that some of them feature certain groups of homonyms,while some do not. Neologisms, terms and colloquial vocabulary are rarely included in dictionaries, whichalso explains a low share of homonymic series containing such words.The inclusion of neologisms in dictionaries depends on their degree of adoption. Homonyms formed by thedisintegration of a polysemantic word are given in dictionaries very carefully: lexicographers prefer to approachthe division of a polysemantic word conservatively, preserving a single structure and historical perspectiveon the word for as long as possible.The quantitative comparison of the data of the Dictionary of the 21st Century Russian Language and otherexplanatory dictionaries showed a significant discrepancy in the number of homonyms they include: wordsgiven in the Dictionary of the 21st Century Russian Language as homonyms are most often found in otherdictionaries as a single word (the second homonym is missing)—almost 50% of cases; as a polysemousword—5–15%; as homonyms—7–14% (except the New Explanatory and Derivational Dictionary of Russianby T. Efremova, 45%); none of the homonyms are present—15–37% of cases. The presence of the secondhomonym seems to be an important advantage of the Dictionary of the 21st Century Russian Language, sinceit takes into account the actual use of words in the language.

Функциональные омонимы в толковом словаре общего типа (на материале «Словаря русского языка XXI века» под редакцией Г. Н. Скляревской)

The presentation of functional homonyms in explanatory dictionaries varies significantly depending on the lexicographer’s perspective. The Dictionary of the Russian Language (1981–1984) and the Dictionary of the Modern Russian Language (BAS-III, since 2004) tend to avoid the display of functional homonyms in separate vocables. As a rule, such words are given in the dictionary entry of the motivating word with an explanation or just a reference. BAS-III reflects the history of the word meanings, so words that changed their part of speech and still keep semantic affinity with the motivating word are placed in one dictionary entry; this dictionary widely uses such comments as в знач. нареч. (used as an adverb), в знач. сущ. (used as a noun), в знач. предикатива (used as a predicative), в функции сказ. (used as a predicate). The structure of such entries looks quite complex, especially if it includes several morphological and syntactic characteristics and grammatical comments for one word (for example, the Russian word беда). The authors of the Dictionary of the 21st Century Russian Language, supervised by G. N. Sklyarevskaya (SRYA XXI), show a different approach to functional homonyms. What makes the dictionary special is that words are presented in a synchronic aspect, without a historical perspective. The dictionary shows how the word functions in the language, its real use. The dictionary tries to include all possible functional homonyms. They are given as separate vocables with grammatical characteristics, complete explanations based on the words of the same part of speech, and convincing illustrations confirming the active use of the word. Thus, the SRYA XXI dictionary features the following groups of homonyms amply represented as: immutable adjectives formed from nouns (ассорти, брейк-данс, бонсай); impersonal-predicative words ending with -o and predicatives that match the form of nouns (беспокойно, безлюдно, беда, благодать); substantive adjectives, including colloquial ones (бездомный, безнадзорный, белорусский); phrases equivalent to words (без излишеств, без ума), etc. This way to represent homonyms shows the users how words function in the language and makes the dictionary more human-centered.

Nacionalismo, engajamento e música instrumental: a sonoridade do Quarteto Novo

Based on a musical appreciation of the album Quarteto Novo, specifically the phonogram “Algodao”, and discussions on political art and national-popular in the 1960s, this paper aims to contextualize the production of the homonymous group and to verify the way in which a cultural conjuncture is revealed even in instrumental music. The nationalist project assumed by the Quarteto Novo to produce a new music and a new language of improvisation would be closely related to an ideal that encouraged artistic productions with a strong political bias articulated to elements of popular culture. The Quarteto Novo emerges from this context, produces in line with a certain ideal, but its work cannot be reduced to schematic classifications. The group both broke with a type of sound prevalent in instrumental music of the period, and opened new horizons for this music. More than applying ready-made formulas or blindly obeying aesthetic guidelines, this production appropriated different musicalities (local, regional, but also cosmopolitan) to produce a musical synthesis whose legacy seems fundamental to instrumental music in Brazil.

Classification of Homonymic Terms in Medical Terminology of English, Russian and Tatar Languages

This study is undertaken to identify the similarities and differences of classification of homonyms in medical terminology of English, Russian and Tatar languages. In this paper a comparative method was used to identify the common and special in the compared languages. The basis of comparison in the medical terminology of genetically unrelated languages was established. In this study, the method of feature comparison was used, i.e. the phenomenon of homonymy was studied in a comparative aspect. The results of this study contribute to ordering the terms, the selection of the correct, appropriate term when translating medical texts from one language into another. The languages under the consideration have intra-terminological, inter-terminological, inter-system homonymy. Besides, there are homonymic relations between eponyms in all languages. In the medical terminology of the English language, the following groups of homonyms are found: absolute, incomplete, partial (homophones, homographs) homonyms. Incomplete homonyms are divided into lexical and lexical and grammatical, and partial homonyms are divided into lexical, lexical and grammatical, grammatical (homonyms-converse terms). Homophones, in turn, are classified into homophones and near homophones. Homonyms are classified into homonyms of a high degree of homonymity, homonyms of a medium degree of homonymity, homonyms of a low degree of homonymity in Russian medical terminology. In medical terminology of the Tatar language absolute and incomplete homonyms are distinguished. Incomplete homonyms include homoforms that belong to different parts of speech and homographs. Homographs are rare phenomenon in the medical terminology of the Tatar language. Separately, as a special group, homonyms-converse terms are considered. There are three types of functional shift relations in the Tatar language: syntactic, lexical and semantic, the most common of which is syntactic relation. The phenomenon of homonymy affects the Greek-Latin terminological elements, which are international. Comparative analysis of three languages in the matter of homonyms in medical terminology has shown that English and Tatar languages have more similarities than English and Russian ones and Russian and Tatar ones. The English medical terminology is more replete with homonymous acronyms than Russian and Tatar ones.

Genetic Diversity and Structure Analysis Assessed by SSR Markers in a Large Collection of Vitis Cultivars from the Island of Crete, Greece.

The grape (Vitis vinifera L.) cultivars in the island of Crete, Greece represent one of the oldest populations of the species; nevertheless, very scarce information is available about its genetic structure. In this study, Vitis cultivars collected from the island of Crete were characterized using microsatellite markers. A broad germplasm collection representing 44 inferred Vitis cultivars, a total of 163 accessions, from the area of Crete including 37 wine and 7 table cultivars were fingerprinted employing thirteen (13) standardized simple sequence repeat (SSR, microsatellite) loci. SSR allelic analysis and a similarity dendrogram construction (cluster analysis) was followed by a hierarchical STRUCTURE analysis. The mean observed (Ho) and expected heterozygosity (He) were 0.7372 and 0.7686, respectively. The cumulative probability of identity was very low with a value of 3.18 × 10e-15. According to the cluster analysis, twenty-nine of the 44 Vitis cultivars were presented in single clusters and five cultivars were presented as distinct single accessions. In addition, ten (10) cases of synonyms and ten (10) groups of homonyms were also identified. STRUCTURE analysis provided evidence for three genetic groups (putative ancestry groups). Hierarchical STRUCTURE analysis revealed further stratification within each of the three ancestry groups. This work provides the molecular fingerprinting of 44 Vitis cultivars and an initial proposal in their ancestry. In the future, molecular genetic information along with morphological (ampelographic) data will provide an intergraded characterization of existing diversity and will allow for its use in breeding efforts and in commercial viticulture.

Long-latency, inhibitory spinal pathway to ankle flexors activated by homonymous group 1 afferents

Inhibitory feedback from sensory pathways is important for controlling movement. Here, we characterize, for the first time, a long-latency, inhibitory spinal pathway to ankle flexors that is activated by low-threshold homonymous afferents. To examine this inhibitory pathway in uninjured, healthy participants, we suppressed motor-evoked potentials (MEPs), produced in the tibialis anterior (TA), by a prior stimulation to the homonymous common peroneal nerve (CPN). The TA MEP was suppressed by a triple-pulse stimulation to the CPN, applied 40, 50, and 60 ms earlier and at intensities of 0.5-0.7 times motor threshold (average suppression of test MEP was 33%). Whereas the triple-pulse stimulation was below M-wave and H-reflex threshold, it produced a long-latency inhibition of background muscle activity, approximately 65-115 ms after the CPN stimulation, a time period that overlapped with the test MEP. However, not all of the MEP suppression could be accounted for by this decrease in background muscle activity. Evoked responses from direct activation of the corticospinal tract, at the level of the brain stem or thoracic spinal cord, were also suppressed by low-threshold CPN stimulation. Our findings suggest that low-threshold muscle and cutaneous afferents from the CPN activate a long-latency, homonymous spinal inhibitory pathway to TA motoneurons. We propose that inhibitory feedback from spinal networks, activated by low-threshold homonymous afferents, helps regulate the activation of flexor motoneurons by the corticospinal tract.

On the dating of two early 2nd century coin issues from Kos and the IGCH 1320 hoard

This paper presents and discusses the dates of two Koan silver issues, drachms with young Herakles/crab and club in incuse, and hemidrachms with Apollo/lyre. A date in the 190s BC is suggested on several grounds. Weights and diameters correspond with those of HI XII and XIII of the 3rd century, suggesting that the issues discussed here followed shortly thereafter. The other Koan silver issues of the 2nd century were minted on a lower weight-standard. The IGCH 1320 hoard contains examples of both issues, and the other Koan issues in it date to the middle and second half of the 3rd century or the 190s/c. 190. Groups of homonyms occur in issues dating to the end of 3rd/early 2nd century. A connection with Kalymnos seems likely for the hemidrachms, and this may suggest a date early in the 190s during the war with king Philip V of Macedonia.

Statistical analysis on the possibility of distinguishing Chinese homonyms by the contrast of their tones

The present authors have been analyzing statistically the nature of the Chinese tones (Hiki et al., Proc. Int'l Symposium on Tonal Aspects of Languages, 2004, Beijing, 73-74). The letter database used is the Grammatical Knowledge-base of Contemporary Chinese, S-W. Yu, editor, Tsinghua University Press, China, 1998. In this report, the use of contrast of tones for distinguishing words within a group of homonyms is assessed, from the viewpoint of the amount of information transmitted. Among the bisyllabic words having different simplified Chinese character notation, more than 10% of the words belongs to the homonymous groups having the same Pinyin notation. However, the number of words having the same Pinyin notation and combination of tones is not so many, that about 80% of them can be distinguished by the contrast of their tones. Detailed analysis showed some characteristic distribution regarding the type of tones in the contrast, depending on whether the number of words in a homonymous group is two or more, or whether the position of syllable of the contrastive tones in bisyllabic words is first, second or both. This result is useful for guiding the beginners' Chinese tone learning.

Synaptic input from homonymous group I afferents in m. longissimus lumborum motoneurons in the L4 spinal segment in cats.

We examined the relationship between input resistance and amplitude of monosynaptic and polysynaptic EPSPs produced by electrical stimulation of group I muscle afferents innervating the m. longissimus lumborum (Long) at different levels (L1-L4) in Long motoneurons in L4 spinal segments to obtain an insight into the neuronal control of trunk muscles. In the Long motoneuron pool, the amplitude of monosynaptic EPSP was shown to have a close relationship to input resistance. Furthermore, the relation between the amplitude of polysynaptic EPSP after stimulating Long nerves at L3 and input resistance was statistically significant, but the relation between EPSP amplitude evoked by stimulation of Long at L1 or L2 and input resistance was not statistically significant. Our findings suggest a position-dependent control of motoneuron activity by group I muscle afferents. The motoneuron activities carried out by monosynaptic pathways and polysynaptic pathways from adjacent spinal segments are dependent on the intrinsic properties of motoneurons (input resistance, etc.), while the motoneuron activities carried out by polysynaptic pathways from the far spinal segments have independent intrinsic properties.

Recruitment of Cat Motoneurons in the Absence of Homonymous Afferent Feedback

This study provides the first test in vivo of the hypothesis that group Ia muscle-stretch afferents aid in preventing reversals in the orderly recruitment of motoneurons. This hypothesis was tested by studying recruitment of motoneurons deprived of homonymous afferent input. Recruitment order was measured in decerebrate, paralyzed cats from dual intra-axonal records obtained simultaneously from pairs of medial gastrocnemius (MG) motoneurons. Pairs of MG motor axons were recruited in eight separate trials of the reflex discharge evoked by stimulation of the caudal cutaneous sural (CCS) nerve. Some reports suggest that reflex recruitment by this cutaneous input should bias recruitment against order by the size principle in which the axon with the slower conduction velocity (CV) in a pair is recruited to fire before the faster CV axon. Recruitment was studied in three groups of cats: ones with the MG nerve intact and untreated (UNTREATED); ones with the MG nerve cut (CUT); and ones with the MG nerve cut and bathed at its proximal end in lidocaine solution (CUT+). The failure of electrical stimulation to initiate a dorsal root volley and the absence of action potentials in MG afferents demonstrated the effective elimination of afferent feedback in the CUT+ group. Recruitment order by the size principle predominated and was not statistically distinguishable among the three groups. The percentage of pairs recruited in reverse order of the size principle was actually smaller in the CUT+ group (6%) than in CUT (15%) or UNTREATED (19%) groups. Thus homonymous afferent feedback is not necessary to prevent recruitment reversal. However, removing homonymous afferent input did result in the expression of inconsistency in order, i.e., switches in recruitment sequence from one trial to the next, for more axon pairs in the CUT+ group (33%) than for the other groups combined (13%). Increased inconsistency in the absence of increased reversal of recruitment order was approximated in computer simulations by increasing time-varying fluctuations in synaptic drive to motoneurons and could not be reproduced simply by deleting synaptic current from group Ia homonymous afferents, regardless of how that current was distributed to the motoneurons. These findings reject the hypothesis that synaptic input from homonymous group Ia afferents is necessary to prevent recruitment reversals, and they are consistent with the assertion that recruitment order is established predominantly by properties intrinsic to motoneurons.

Integration in descending motor pathways controlling the forelimb in the cat. 15. Comparison of the projection from excitatory C3-C4 propriospinal neurones to different species of forelimb motoneurones.

In the preceding report (Alstermark and Sasaki 1986) it was shown that a stimulus of 500 microA applied in the lateral reticular nucleus (LRN) evokes a maximal or near monosynaptic EPSP (LRN EPSP) in forelimb motoneurones. This EPSP which is assumed to be selectively mediated by C3-C4 propriospinal neurones (PNs), was used to estimate the strength of the excitatory projection from C3-C4 PNs. A systematic comparison was made of the size and time course of the maximal LRN EPSP in various species of forelimb alpha-motoneurones innervating shoulder, elbow, wrist and digit muscles. The LRN EPSP was evoked in all investigated species of forelimb motoneurones. When either the peak amplitude or the underlying area of the LRN EPSP was compared, a three-fold range was found with some tendency for the size to vary in the order of wrist greater than shoulder approximately equal to elbow greater than digit greater than intrinsic paw motor nuclei. Generally, a positive correlation was found in each motor nucleus between the peak amplitude of the LRN EPSP versus the monosynaptic homonymous group Ia EPSP, input resistance and afterhyperpolarization duration respectively (cf. Alstermark and Sasaki 1986). It is therefore postulated, that the LRN EPSP peak amplitude is correlated with motor unit type. Comparison of the time course of the LRN EPSPs was made by measuring the time-to-peak (T-t-p) and half-width (H-w). The finding in the preceding report that the T-t-p and H-w is longer in slow than in fast motoneurones was confirmed and extended to all the investigated motor nuclei. The hypothesis that both fast slow motoneurones receive projection from a group of fast C3-C4 PNs, while slow motoneurones receive an additional projection from a group with lower conduction velocity, can therefore be applied to all forelimb motor nuclei. In addition, it is proposed that some slow shoulder, wrist and digit motoneurones receive projection from a special subpopulation of C3-C4 PNs with very slow conduction velocity.

Integration in descending motor pathways controlling the forelimb in the cat. 14. Differential projection to fast and slow motoneurones from excitatory C3-C4 propriospinal neurones.

The projection of C3-C4 propriospinal neurones (PNs) to alpha-motoneurones of forelimb muscles has been analysed with the aid of antidromic stimulation of the ascending branch of the PNs to the lateral reticular nucleus (LRN). A single stimulus of 500 microA applied in the caudo-dorsal part of the LRN evoked a maximal or greater than 90% maximal monosynaptic EPSP in the motoneurones. Systematic mapping of EPSPs evoked by stimulation of 500 microA in and around the LRN revealed that at this strength there was hardly any co-activation of a medial system (Peterson et al. 1979) which evoked small monosynaptic EPSPs with shorter latency and faster time course. The LRN EPSP amplitude was positively correlated with the homonymous group Ia EPSP amplitude, the input resistance and the afterhyperpolarization (AHP) duration. It is therefore postulated that the LRN EPSP amplitude is correlated with motor unit type (Burke 1967, 1968; Burke et al. 1973) with the largest EPSPs in slow (S), the smallest in fast, fatiguable (FF) and possibly intermediate sized in fast, fatigue resistant (FR) units. There was only a small difference in latency of the LRN EPSP in fast and slow motoneurones, while the time course was considerably slower in the latter. It is suggested that slow motoneurones receive projection both from fast and slowly conducting PNs but fast motoneurones mainly from fast PNs. Comparison of the disynaptic pyramidal EPSPs and the LRN EPSPs revealed a positive correlation, but the amplitude ratio pyramidal EPSP: LRN EPSP was smaller in slow than in fast motoneurones. A negative correlation was found between this amplitude ratio and the latency of the disynaptic pyramidal EPSP. It is suggested that this correlation reflects the excitability level in the PNs and that low excitability is due to inhibition of the PNs.

Plasticity of medial gastrocnemius motor units following cordotomy in the cat.

Experiments were performed in adult cats to determine the effects of lumbar cordotomy on synaptic potentials, motoneuron membrane electrical properties, muscle-unit contractile properties, and whole-muscle histochemical properties of a heterogeneous skeletal muscle. Medial gastrocnemius (MG) motor units were examined 1 wk to 7 mo following complete transection of the lumbar spinal cord (cordotomy). Motor units were classified on the basis of their contractile properties as type FF, FI, FR, or S (8, 68). Muscle fibers were classified as type FG, FOG, or SO on the basis of histochemical staining (59). Motoneuron electrical properties (axonal conduction velocity, action-potential amplitude, rheobase, input resistance, afterhyperpolarization), group I EPSPs, and muscle-unit contractile properties (unpotentiated and potentiated twitch, unfused and fused tetanus, fatigability) were measured. Reduced numbers of type FR motor units and increased numbers of types FI + FF motor units were found in electrophysiological experiments 2 wk to 7 mo following cordotomy. Corroborative data were obtained from histochemical studies of the same MG muscles. Electrical properties of the motoneurons of each motor-unit type were normal following cordotomy. The close correspondence between motoneuron electrical properties and muscle-unit contractile properties found in normal MG muscle (68) was preserved following cordotomy. Contractile strength of muscle units of all types was severely reduced following cordotomy; partial recovery occurred 4-7 mo following cordotomy. Cross-sectional area of muscle fibers was reduced at all times investigated (2 wk to 7 mo). In three cats, homonymous group Ia single-fiber-motoneuron EPSPs were studied 1 or 2 mo following cordotomy at spinal level L4-5 or L5. EPSP amplitude and afferent-to-motoneuron projection frequency were normal. In 12 other cats, composite heteronymous group I EPSPs were studied 2 wk to 7 mo following cordotomy at various levels. Amplitude of these EPSPs was increased, dependent upon level of cordotomy and postoperative time. Hypotheses concerning the influence of motoneurons on muscle, and of muscle on motoneurons, are presented as possible mechanisms whereby the close relation between motoneuron electrical and muscle-unit contractile properties is preserved in the face of redistributed motor-unit populations.

Topographic factors in distribution of homonymous group Ia-afferent input to cat medial gastrocnemius motoneurons.

Experiments were performed to determine whether the topographic relationships between muscle spindles and their surrounding extrafusal fibers are preserved in the pattern of homonymous, monosynaptic connections from Ia-afferents to motoneurons. The medial gastrocnemius (MG) muscle of adult cats was chosen as a model system because previous studies have shown that its muscle nerve divides into several branches, each of which innervates a distinct muscle compartment (20, 27, 28, 38), and that the Ia-afferent fibers innervating muscle spindles within a compartment are found in the same nerve branch (27, 28). Thus, we could make intracellular recordings from MG motoneurons, determine which intramuscular compartment they innervated, and then compare the synaptic input they received from Ia-afferents innervating the same compartment with that which they received from Ia-afferents innervating different compartments. Our results indicate that homonymous Ia-afferent input is "topographically weighted" within the MG motor nucleus such that afferents innervating a given intramuscular compartment exert relatively greater synaptic effects in motoneurons that project to the same compartment than in other homonymous motoneurons. The degree of topographic weighting was quite variable in the different experiments but appeared more prominently in experiments in which a high proportion of the motoneurons studied were characterized by high-rheobase values and low input resistances. This suggests that topographic factors may exert more influence on the distribution of Ia-afferent input to large motoneurons than to small motoneurons. In the DISCUSSION, the extent of topographic weighting within the homonymous motoneuron pool is compared with weighting across synergist motoneuron pools, and alternative models of topographic weighting are proposed and evaluated.

Excitatory and inhibitory effects of repetitive stimulation of group I and II extensor afferents on homonymous motoneurons.

The repetitive firing of functionally isolated 143 extensor alpha motoneurons in response to homonymous group I and II tetanizations was studied in decerebrate cats. Of a total sample of 92 group I activated motoneuronal units, 76 motoneurons (82.6%) discharged phasically and 16 motoneurons (17.4%) discharged tonically at threshold or just suprathreshold tetanizations. Only 6 of the phasic motoneurons fired tonically when the stimulus strength was increased within the group I range. The firing rate of 8 phasic motoneurons increased at group I and II stimulations, but they retained their phasic discharge characteristics. The remaining 46 group I activated phasic motoneurons (60.1%) delivered tonic discharges when group II afferents were stimulated. Another group of 16 phasic motoneurons (21.1%) became tonic at group II tetanus, but their tonic discharge was usually interrupted by an inhibitory period, which coincided with an escape reaction of the animal. Out of 38 group II activated motoneuronal units, only 8 (21.1%) motoneurons discharged tonically at threshold or just suprathreshold tetanizations. The repetitive activity of these motoneurons was usually interrupted by an inhibitory period, which coincided with an escape reaction of the animal. This inhibition disappeared after procain application to the GS nerve, and was attributed to dominant inhibitory action of group II afferents mediating the sensation of pain. The remaining 30 (78,9%) motoneurons discharged phasically. Six of them remained phasic even at high threshold group II tetanus. The others gave tonic discharges when the stimulus strength was increased within the group II range. A great percentage of motoneurons discharged regularly with a fixed decoding ratio reflecting monosynaptic excitation. Some motoneurons discharged in multiple bands of impulse intervals due to a variable decoding ratio, which can be attributed to both monosynaptic and polysynaptic reflex discharge elicited by group I and/or II tetanizations. There were 6 motoneurons (4.2%), which discharged repetitively at stimulations of the GS, DP, and SUR nervers. These motoneurons were referred to "common motoneurons", which may participate in multiple motor actions such as fixation of a limb or as a part of the flexor reflex. SOL motoneurons usually discharged tonically at tetanizations within the group I range. The firing rate of these motoneurons usually decreased at tetanizations of the group II afferents of MG nerve. Conversely, tetanization of the group II afferents of SOL nerve usually exerted facilitatory effects on group II activated MG motoneurons.(ABSTRACT TRUNCATED AT 400 WORDS)