Anatomical relationship between mesencephalic trigeminal nucleus and cerebellum in the duck

Bortolami, R.; Callegari, E; Lucchi, Maria Luisa

doi:10.1016/0006-8993(72)90642-7

Cited by 19 publications

(5 citation statements)

References 19 publications

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“…Although a direct projection of MesV to the cerebellar cortex in the duck has been suggested by Bortolami et al (1972), we did not find any evidence for this projection. This result seems to be in agreement with electrophysiological observations on cerebellar units that respond to opening of the lower beak (Azzena et al, 1970): the delay of the response is sufficient to accommodate more than one synapse (5.8 msec).…”

Section: Discussioncontrasting

confidence: 96%

Central connections of the nucleus mesencephalicus nervi trigemini in the mallard (Anas platyrhynchosL.).

1997

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Background In the mallard duck, functionally distinct groups of jaw muscles are each innervated by a different subnucleus of the main trigeminal (mV) or facial (mVII) motor nucleus. The other subnuclei of mV and mVII innervate several head muscles, including lingual muscles. The reticular premotor cells of the trigeminal and facial jaw motor subnuclei occupy different areas in the parvocellular reticular formation (RPc). The cell bodies of jaw muscle spindle afferents are situated in the mesencephalic nucleus (MesV). In the present study, the central connections of MesV with jaw motor subnuclei and their premotor areas are investigated. Methods In a first series of experiments, horseradish peroxidase (HRP) injections were made in electrophysiologically identified trigeminal and facial subnuclei. In a second series of experiments, HRP was delivered iontophoretically at different parts of RPc. Anterograde tracing with tritiated leucine was used to confirm the central connections of MesV. Double labeling with fluorescent tracers was used to investigate whether MesV collaterals reach both the rostral and caudal parts of RPc. Results MesV projects to only two of the five different subnuclei of the trigeminal motor nucleus. The subnuclei that receive spindle afferents innervate jaw adductor muscles (mV2) or pro‐ and retractors of the mandible (pterygoid muscles; mV1). The three other subnuclei innervate jaw‐opener muscles or other head muscles. MesV fibers also project to the rostral part of the dorsolateral RPc (RPcdl), which serves as a premotor area for the motor subnuclei of adductor and pterygoid muscles. The intermediate part of RPcdl does not contain premotor cells of mV or mVII, and a clear projection of MesV to this area is absent. The caudal part of RPcdl projects to the mV and mVII subnuclei that innervate jaw‐opener muscles. This part of RPc receives a projection from the same MesV cells as the rostral RPcdl. The MesV projection to RPc does not include premotor cells of mV and mVII in the ventromedial part of RPc (RPcvm). Conclusions Spindle afferents from jaw‐closer muscles project only to mV subnuclei innervating jaw‐closer muscles (mV1, mV2) and to a population of premotor cells in the rostral RPcdl that innervates these subnuclei. The mixed population of premotor cells in RPcvm, which innervates both jaw‐opener and jaw‐closer subnuclei, does not receive a MesV projection. However, a premotor area for jaw‐opener subnuclei in the caudal part of RPcdl does receive MesV input and may serve as a relay through which proprioceptive information from jaw closer spindles can reach jaw opener muscles. Anat. Rec. 248:554‐565, 1997. © 1997 Wiley‐Liss, Inc.

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Section: Discussioncontrasting

confidence: 96%

Central connections of the nucleus mesencephalicus nervi trigemini in the mallard (Anas platyrhynchosL.).

1997

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“…In the second place, even though it has been mentioned in the literature [e.g. Bortolami et al, 1972], there is no definite evidence of a cerebellar projection from mesV. This could mean that the mesV projection to the cerebellum in mammals is connected with the presence of the second proprioceptive component, the periodontal sense organs.…”

Section: Sensory Input To the Reticular Premotor Areasmentioning

confidence: 60%

The Neural Substrate for ‘Learned’ and ‘Nonlearned’ Activities in Birds: A Discussion of the Organization of Bulbar Reticular Premotor Systems with Side-Lights on the Mammalian Situation

Dubbeldam¹

1998

Cells Tissues Organs

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The reticular formation of the brainstem contains premotor systems for various musculomotor systems. In this paper, the bulbar premotor systems for jaw and tongue movements, head and neck movements, locomotion, and respiration and vocalization in birds are reviewed and compared to premotor systems in mammals. Roughly, the bulbar reticular formation can be subdivided in three longitudinal zones: a dorsolateral (RPcdl) and a ventromedial (RPcvm) parvocellular zone and a gigantocellular zone (RGc). RPcdl contains premotor neurons for the jaw and neck system, RPcvm for the jaw, tongue and neck system, and RGc for the tongue and locomotory system. RPcdl receives input from the descending sensory trigeminal system, parts of RPcvm and RGc from vestibular nuclei, whereas the tectum has a projection to the contralateral RGc. RPcdl and RPcvm receive substantial telencephalic input through the occipitomesencephalic tract. The bulbar part of the respiratory system consists of a series of cell groups in the ventrolateral reticular formation and has connections with motor centers of the vocalization system. The similarities and differences between the avian and mammalian situation are discussed. Musculomotor systems participate in various activities. It is argued that a premotor system should possess sufficient flexibility to control the participation of a motor system in the different activities. This flexibility may permit the occurrence of learning processes in terms of refining basically existing motor patterns. The emergence of new and more complex motor patterns as in vocalization requires the involvement of hierarchically higher brain centers.

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“…An efferent projection of mes. V to the cerebellum is reported in birds (Azzena, Desole & Palmieri 1970;Bortolami, Callegari & Lucchi 1972) and mammals (Voris & Hoerr 1932;Larsell 1936a, b;Brodal & Saugstad 1965) although the functional role of this cerebellar relay is unknown.…”

Section: Introductionmentioning

confidence: 99%

The light microscopical structure of the mesencephalic nucleus of the fifth nerve in the selachian brain

Witkovsky

Roberts

1975

Proc. R. Soc. Lond. B.

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A description is provided of the mesencephalic nucleus of the fifth nerve (mes. V) and its axonal projections in the brains of dogfish ( Scylio - rhinus , Mustelus ) and rays ( Raja ), based upon light microscopic observations. The mes. V nucleus contains 800-1100 cells distributed about the midline at the ventral surface of the optic tectum. Each cell gives rise to a stout axon which courses laterally, then posteriorly on the ipsilateral side; the collected axons divide at the caudal extreme of the tectum into a medial bundle which enters the ventral granular eminence of the anterior cerebellar lobe, and a lateral bundle which enters the medulla and leaves the brain via the fifth nerve root. The medial bundle arises from a cluster of mes. V neurons at the posterior limit of the nucleus which comprise about 15% of the nuclear population. The cerebellar projection ascends the anterior lobe and appears to end in close proximity to Purkinje cell perikarya. A typical mes. V perikaryon is oval, flattened dorsoventrally with average dimensions of 41 µm x 56 µm. It emits a few stout dendrites from its dorsal surface which extend no more than 75 µm from the cell body. Processes from deep tectal cells and collaterals from commissural fibres appear to make synapses upon mes. V perikarya. In addition, neighbouring mes. V neurons often form clusters and also contact each other via short dendrites. A small subpopulation of mes V. neurons gives rise to stout, ventrally directed processes which enter the ependymal layer and ramify within it. These may have a neurosecretory function.

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Anatomical relationship between mesencephalic trigeminal nucleus and cerebellum in the duck

Cited by 19 publications

References 19 publications

Central connections of the nucleus mesencephalicus nervi trigemini in the mallard (Anas platyrhynchosL.).

Central connections of the nucleus mesencephalicus nervi trigemini in the mallard (Anas platyrhynchosL.).

The Neural Substrate for ‘Learned’ and ‘Nonlearned’ Activities in Birds: A Discussion of the Organization of Bulbar Reticular Premotor Systems with Side-Lights on the Mammalian Situation

The light microscopical structure of the mesencephalic nucleus of the fifth nerve in the selachian brain

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