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Olsson, Kurt
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Publications (5 of 5) Show all publications
Athanassiadis, T., Olsson, K. A., Kolta, A. & Westberg, K.-G. (2005). Identification of c-Fos immunoreactive brainstem neurons activated during fictive mastication in the rabbit. Experimental Brain Research, 165(4), 478-489
Open this publication in new window or tab >>Identification of c-Fos immunoreactive brainstem neurons activated during fictive mastication in the rabbit
2005 (English)In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 165, no 4, p. 478-489Article in journal (Refereed) Published
Abstract [en]

In the present study we used the expression of the c-Fos-like protein as a "functional marker" to map populations of brainstem neurons involved in the generation of mastication. Experiments were conducted on urethane-anesthetized and paralyzed rabbits. In five animals (experimental group), rhythmical bouts of fictive masticatory-like motoneuron activity (cumulative duration 60-130 min) were induced by electrical stimulation of the left cortical "masticatory area" and recorded from the right digastric motoneuron pool. A control group of five animals (non-masticatory) were treated in the same way as the experimental animals with regard to surgical procedures, anesthesia, paralysis, and survival time. To detect the c-Fos-like protein, the animals were perfused, and the brainstems were cryosectioned and processed immunocytochemically. In the experimental group, the number of c-Fos-like immunoreactive neurons increased significantly in several brainstem areas. In rostral and lateral areas, increments occurred bilaterally in the borderzones surrounding the trigeminal motor nucleus (Regio h); the rostrodorsomedial half of the trigeminal main sensory nucleus; subnucleus oralis-gamma of the spinal trigeminal tract; nuclei reticularis parvocellularis pars alpha and nucleus reticularis pontis caudalis (RPc) pars alpha. Further caudally-enhanced labeling occurred bilaterally in nucleus reticularis parvocellularis and nucleus reticularis gigantocellularis (Rgc) including its pars-alpha. Our results provide a detailed anatomical record of neuronal populations that are correlated with the generation of the masticatory motor behavior.

Keywords
Anesthesia, Animals, Brain Stem/*metabolism, Data Interpretation; Statistical, Efferent Pathways/cytology/physiology, Electric Stimulation, Immunohistochemistry, Male, Mastication/*physiology, Masticatory Muscles/innervation/physiology, Microelectrodes, Motor Cortex/physiology, Motor Neurons/physiology, Neurons/*metabolism, Paralysis/physiopathology, Proto-Oncogene Proteins c-fos/*metabolism, Rabbits
Identifiers
urn:nbn:se:umu:diva-12592 (URN)10.1007/s00221-005-2319-5 (DOI)15887006 (PubMedID)
Available from: 2008-01-09 Created: 2008-01-09 Last updated: 2018-06-09Bibliographically approved
Athanassiadis, T., Westberg, K.-G., Olsson, K. A. & Kolta, A. (2005). Physiological characterization, localization and synaptic inputs of bursting and nonbursting neurons in the trigeminal principal sensory nucleus of the rat. European Journal of Neuroscience, 22(12), 3099-3110
Open this publication in new window or tab >>Physiological characterization, localization and synaptic inputs of bursting and nonbursting neurons in the trigeminal principal sensory nucleus of the rat
2005 (English)In: European Journal of Neuroscience, ISSN 0953-816X, E-ISSN 1460-9568, Vol. 22, no 12, p. 3099-3110Article in journal (Refereed) Published
Abstract [en]

A population of neurons in the trigeminal principal sensory nucleus (NVsnpr) fire rhythmically during fictive mastication induced in the in vivo rabbit. To elucidate whether these neurons form part of the central pattern generator (CPG) for mastication, we performed intracellular recordings in brainstem slices taken from young rats. Two cell types were defined, nonbursting (63%) and bursting (37%). In response to membrane depolarization, bursting cells, which dominated in the dorsal part of the NVsnpr, fired an initial burst followed by single spikes or recurring bursts. Non-bursting neurons, scattered throughout the nucleus, fired single action potentials. Microstimulation applied to the trigeminal motor nucleus (NVmt), the reticular border zone surrounding the NVmt, the parvocellular reticular formation or the nucleus reticularis pontis caudalis (NPontc) elicited a postsynaptic potential in 81% of the neurons tested for synaptic inputs. Responses obtained were predominately excitatory and sensitive to glutamatergic antagonists DNQX and/or APV. Some inhibitory and biphasic responses were also evoked. Bicuculline methiodide or strychnine blocked the IPSPs indicating that they were mediated by GABA(A) or glycinergic receptors. About one-third of the stimulations activated both types of neurons antidromically, mostly from the masseteric motoneuron pool of NVmt and dorsal part of NPontc. In conclusion, our new findings show that some neurons in the dorsal NVsnpr display both firing properties and axonal connections which support the hypothesis that they may participate in masticatory pattern generation. Thus, the present data provide an extended basis for further studies on the organization of the masticatory CPG network.

Keywords
Action Potentials/drug effects/*physiology/radiation effects, Animals, Animals; Newborn, Biotin/analogs & derivatives/metabolism, Dose-Response Relationship; Radiation, Drug Interactions, Electric Stimulation/methods, Evoked Potentials/drug effects/physiology/radiation effects, Excitatory Amino Acid Antagonists/pharmacology, Glycine Agents/pharmacology, Neurons/*classification/drug effects/*physiology/radiation effects, Patch-Clamp Techniques/methods, Quinoxalines/pharmacology, Rats, Rats; Sprague-Dawley, Strychnine/pharmacology, Synaptic Transmission/drug effects/*physiology/radiation effects, Trigeminal Nuclei/*cytology
Identifiers
urn:nbn:se:umu:diva-12591 (URN)10.1111/j.1460-9568.2005.04479.x (DOI)16367776 (PubMedID)
Available from: 2008-01-09 Created: 2008-01-09 Last updated: 2018-06-09Bibliographically approved
Westberg, K.-G., Scott, G., Olsson, K. & Lund, J. P. (2001). Discharge patterns of neurons in the medial pontobulbar reticular formation during fictive mastication in the rabbit. European Journal of Neuroscience, 14(10), 1709-1718
Open this publication in new window or tab >>Discharge patterns of neurons in the medial pontobulbar reticular formation during fictive mastication in the rabbit
2001 (English)In: European Journal of Neuroscience, ISSN 0953-816X, E-ISSN 1460-9568, Vol. 14, no 10, p. 1709-1718Article in journal (Refereed) Published
Abstract [en]

In this study, we describe functional characteristics of neurons forming networks generating oral ingestive motor behaviours. Neurons in medial reticular nuclei on the right side of the brainstem between the trigeminal and hypoglossal motor nuclei were recorded in anaesthetized and paralysed rabbits during two types of masticatory-like motor patterns induced by electrical stimulation of the left (contralateral) or right (ipsilateral) cortical masticatory areas. Sixty-seven neurons in nucleus reticularis pontis caudalis (nPontc), nucleus reticularis parvocellularis (nParv), and nucleus reticularis gigantocellularis (Rgc) were studied. These were classified as phasic or tonic depending on their firing pattern during the fictive jaw movement cycle. Phasic neurons located in the dorsal part of nPontc were active during the jaw opening phase, whilst those in dorsal nParv tended to fire during the closing phase. In most neurons, burst duration and firing frequency changed between the two motor patterns, but there was little change in phase of firing. Tonic units were mainly recorded in the ventral half of nPontc, and at the junction between Rgc and caudal nParv. Cortical inputs with short latency from the contralateral masticatory area were more frequent in phasic (82%) than tonic (44%) neurons, whilst inputs from the ipsilateral cortex were equal in the two subgroups (57% and 56%). Phasic neurons had significantly shorter mean contralateral than ipsilateral cortical latencies, whilst there was no difference among tonic neurons. Intra- and perioral primary afferent inputs activated both types of neurons at oligo-synaptic latencies. Our results show that subpopulations of neurons in medial reticular nuclei extending from the caudal part of the trigeminal motor nucleus to the rostral third of the hypoglossal motor nucleus are active during the fictive masticatory motor behaviour. Unlike masticatory neurons in the lateral tegmentum, the medial subpopulations are spatially organized according to discharge pattern.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2001
Keywords
brainstem, motor control, rhythmical movements, trigeminal system
National Category
Physiology Neurology Neurosciences
Identifiers
urn:nbn:se:umu:diva-82655 (URN)10.1046/j.0953-816x.2001.01782.x (DOI)000172692400013 ()11860465 (PubMedID)
Available from: 2013-11-06 Created: 2013-11-06 Last updated: 2018-06-08Bibliographically approved
Edin, B. B., Essick, G. K., Trulsson, M. & Olsson, K. Å. (1995). Receptor encoding of moving tactile stimuli in humans. I. Temporal pattern of discharge of individual low-threshold mechanoreceptors.. Journal of Neuroscience, 15(1 Pt 2), 830-847
Open this publication in new window or tab >>Receptor encoding of moving tactile stimuli in humans. I. Temporal pattern of discharge of individual low-threshold mechanoreceptors.
1995 (English)In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 15, no 1 Pt 2, p. 830-847Article in journal (Refereed) Published
Abstract [en]

The response of 70 cutaneous, low-threshold mechanoreceptors in the human median, radial and inferior alveolar nerves to well controlled brush stimuli moving across the receptive field was quantitatively studied. Microneurography was used to obtain the response of each to multiple velocities from 0.5 to 32 cm/sec in at least two opposing directions. A high degree of response consistency was observed from the slowly adapting receptors to replication of the same stimulus and to a lesser, but significant degree from the fast adapting receptors. The evoked discharge reflected up to three partially overlapping phases of the moving stimulus: skin compression, indentation, and stretch. Although the overall discharge rate increased with both stimulus velocity and force, the spatial discharge pattern was preserved to a high degrees. In contrast, the discharge patterns differed for opposing and orthogonal directions. Reducing the area of skin surrounding the receptive field that was contacted by the moving stimuli had little effect on the evoked response. Individual mechanoreceptors display highly reliable differences to brush stimuli moving at different velocities. to brush stimuli moving at different velocities. Moreover, different directions of movement evoke differences in the discharge that are consistently observed upon replication of the same stimuli. Despite the richness and consistency in the spatial discharge pattern displayed by individual receptors, it is argued that the details of the patterns are not likely used by the CNS to infer information about direction and velocity of movement across the skin. Rather, the intensity of discharge is proposed as a plausible information-bearing attribute of the stimulus-evoked response.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:umu:diva-32716 (URN)7823184 (PubMedID)
Available from: 2010-03-23 Created: 2010-03-23 Last updated: 2018-06-08Bibliographically approved
Olsson, K. Å. (1979). Hypothalamic and cortical control of jaw reflexes. (Doctoral dissertation). Umeå: Umeå universitet
Open this publication in new window or tab >>Hypothalamic and cortical control of jaw reflexes
1979 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The subject of the thesis is a study of the projections from low threshold oral and face afferents to the cerebral cortex and of descending motor control mechanisms originating in the cerebral cortex or the hypothalamus and influencing the jaw reflexes.Cats anaesthetized with chi oral ose were used for the experiments. Ipsi- and contralateral nerves from the oral cavity and the face were stimulated electrically. Cortical potentials were averaged and recorded. The location of the projections was related to the cytoarchi-tectonic areas of the cerebral cortex. It was found that the afferents projected to separate maximum points in areas 3a, 3b, 5a and 6aß. The projections to areas 3a and 3b were somatotopically organized, but the layout of the projections on the cortex was not facelike.The effect of monopolar anodal stimulation of the cerebral cortex on the monosynaptic jaw closing and the di synaptic jaw opening reflexes was investigated. A sequence of facilitation and inhibition of both reflexes was elicited by cortical stimulation. The effects were of short latency (2.5 ms) and could start with either facilitation or inhibition. The timecourse of the sequence was sinuslike with a period of 10 ms. The largest effect originated in the "sensory" areas 3a and 3b and not in the "motor" areas 4y and 6ag. It is suggested, that a tri gemino-cortico-tri geminai loop via area 3a may function in reflex modulation of jaw movements.The hypothalamic effects on the jaw reflexes were evoked by electrical stimulation in those parts of the hypothalamus, which are w known to generate defence, attack or feeding responses. A tenfold facilitation of the jaw closing reflex and a facilitation followed by almost complete inhibition of the jaw opening reflex were observed in the anaesthetized animal with intact cerebral cortex. The effects remained but were diminished in amplitude after cortical ablation. The descending path was located in the ventral midbrain tegmentum.It is suggested that the observed hypothalamo-tri geminai mechanism may exercise a tonic influence on the trigeminal motoneurones, thereby controlling the set points of the biting force and the rest position. The implications of this hypothesis on the etiology of bruxism and the myofascial pain-dysfunction are discussed.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 1979. p. 59
Series
Umeå University medical dissertations, ISSN 0346-6612 ; New series 52
Keywords
Cat, Oral projections, Cerebral cortex, Cytoarchitecture, Hypothalamus, Defence-Attack area, Jaw reflexes, Bruxism, Myofascial pain dysfunction
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-73597 (URN)
Public defence
1979-12-15, Universitetsbyggnaden LU-0, Umeå universitet, Umeå, 09:00
Projects
digitalisering@umu
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Härtill 3 rapporter.

Available from: 2013-06-25 Created: 2013-06-25 Last updated: 2018-06-08Bibliographically approved
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