Ventral Paraflocculus Research Articles

Structural study of inferior olivary nucleus of the cat: morphological correlates of electrotonic coupling.

Structural study of inferior olivary nucleus of the cat: morphological correlates of electrotonic coupling.

Eye movements evoked by cerebellar stimulation in the alert monkey.

Eye movements evoked by cerebellar stimulation in the alert monkey.

Vestibulocerebellar Input in the Cat: Anatomy

According to recent studies, the primary vestibularfibres terminate in the nodulus, the adjoining ventral folia of the uvula, the paraflocculus, and the ventral paraflocculus. Within the intracerebellar nuclei, terminations have been established in the small-celled ventral part of the lateral (dentate) nucleus, but a termination in the fastigial nucleus is still conjectural. According to anatomical data, primary vestibular fibers ending in the cerebellum are derived from the semicircular ducts. The primary vestibular fibers end as mossy fibers. These appear to differ in certain respects from the classical type. Secondary vestibular fibers take origin from restricted parts of the vestibular complex only: the group x and the ventrolateral part of the descending vestibular nucleus with a few fibers from the ventral part of the medial nucleus. The fibers appear to terminate in the same regions, as do the primary vestibular fibers. The regions of the vestibular nuclei, which give off secondary vestibular fibers receive few or no primary vestibular afferents. A main source of afferents to these regions is the spinal cord. Accordingly, the secondary vestibular fibers appear to be linked in a spinocerebellar pathway ending in the vestibulocerebellum. Vestibular impulses may reach the cerebellum via other routes.

Firing patterns of abducens neurons of alert monkeys in relationship to horizontal eye movement.

Firing patterns of abducens neurons of alert monkeys in relationship to horizontal eye movement.

Discharge of Purkinje and cerebellar nuclear neurons during rapidly alternating arm movements in the monkey.

Discharge of Purkinje and cerebellar nuclear neurons during rapidly alternating arm movements in the monkey.

Cerebrale Neurofibrome beim Finnwal, Balaenoptera physalus

Two neurofibromas located at the base of the ventral paraflocculus of the cerebellum in an adult fin whale (Balaenoptera physalus) are described histologically. Both tumors were rich in collagenous fibers and related to nervous structures. There were remnants of atrophic myelinated nerve fibers, in loose arrangement, and ganglion cells within the neoplastic tissue.

Relation of pyramidal tract activity to force exerted during voluntary movement.

in a series P of studies of the relation of discharge 01 pyramlda1 tract neurons (PTNs) to voluntary movement. The first of the previous studies (5) showed that PTN activity both at rest and during movement is related to axonal conduction velocity. PTNs with the highest axonal conduction velocities tend to be silent during motor quiescence and to show phasic activity in association with movement. PTNs with lower axonal conduction velocities are for the most part active even in the absence of movement; with movement they show both upward and downward modulation of their resting discharge frequency. A second study (6) was carried out to obtain information as to the point in the interval between stimulus and response at which PTN discharge takes place in association with a conditioned hand movement. It was found that for many PTNs, responses to the conditioned stimulus (the onset of a light) preceded the first peripheral electromyographic correlates of the conditioned response (wrist extension). The fact that these PTN responses preceded the electromyographic response showed that they were not consequent upon feedback resulting from the movement. 1