Pourfour du Petit (1664-1741).

François Pourfour du Petit was a Parisian experimental neuro-anatomist, and ophthalmologist, who investigated his extensive wartime experiences of brain and spinal injuries and verified his conclusions by animal experiments. His results showed with great originality that brain injuries caused weakness or paralysis of the opposite limbs. He also clarified the anatomy of the spinal cord and decussation of the pyramidal tracts, and demonstrated the anatomy and clinical significance of the cervical sympathetic chain.

[Hemiplegia cruciata and severe facial pain due to infarction of the cervicomedullary junction: a case report].

We report the case of a 66-year-old female with hemiplegia cruciata and severe facial pain due to infarction of the cervicomedullary junction. She presented to the hospital with complaints of acute-onset left facial pain and gait disturbance. Neurological examination revealed narrow left palpebral fissure, severe left facial pain and hypothermoesthesia, weakness predominantly in the left upper and right lower extremities, decreased pain and temperature sensation in the right lower extremity, decreased vibration sensation in the left lower extremity, hyperreflexia in the left upper extremity, and mild ataxia in the left upper and lower extremities. Brain MRI revealed a high-intensity lesion in the left cervicomedullary junction on diffusion-weighted and fluid-attenuated inversion recovery images. Hemiplegia cruciata due to the pyramidal tract injury at the cervicomedullary junction is an uncommon clinical manifestation. However, in patients with hemiplegia cruciata, identifying the lesion location may be difficult. Clinicians should consider the possibility of pyramidal decussation lesions. Anatomical differences, in the course of pyramidal tract fibers between the upper and lower limbs have been considered in the pyramidal decussation. Hemiplegia cruciata in this case was primarily caused by the impairment of the left upper limb pyramidal fibers after the pyramidal decussation and the right lower limb pyramidal fibers before the pyramidal decussation.

Abnormal Pyramidal Decussation and Bilateral Projection of the Corticospinal Tract Axons in Mice Lacking the Heparan Sulfate Endosulfatases, Sulf1 and Sulf2.

The corticospinal tract (CST) plays an important role in controlling voluntary movement. Because the CST has a long trajectory throughout the brain toward the spinal cord, many axon guidance molecules are required to navigate the axons correctly during development. Previously, we found that double-knockout (DKO) mouse embryos lacking the heparan sulfate endosulfatases, Sulf1 and Sulf2, showed axon guidance defects of the CST owing to the abnormal accumulation of Slit2 protein on the brain surface. However, postnatal development of the CST, especially the pyramidal decussation and spinal cord projection, could not be assessed because DKO mice on a C57BL/6 background died soon after birth. We recently found that Sulf1/2 DKO mice on a mixed C57BL/6 and CD-1/ICR background can survive into adulthood and therefore investigated the anatomy and function of the CST in the adult DKO mice. In Sulf1/2 DKO mice, abnormal dorsal deviation of the CST fibers on the midbrain surface persisted after maturation of the CST. At the pyramidal decussation, some CST fibers located near the midline crossed the midline, whereas others located more laterally extended ipsilaterally. In the spinal cord, the crossed CST fibers descended in the dorsal funiculus on the contralateral side and entered the contralateral gray matter normally, whereas the uncrossed fibers descended in the lateral funiculus on the ipsilateral side and entered the ipsilateral gray matter. As a result, the CST fibers that originated from 1 side of the brain projected bilaterally in the DKO spinal cord. Consistently, microstimulation of 1 side of the motor cortex evoked electromyogram responses only in the contralateral forelimb muscles of the wild-type mice, whereas the same stimulation evoked bilateral responses in the DKO mice. The functional consequences of the CST defects in the Sulf1/2 DKO mice were examined using the grid-walking, staircase, and single pellet-reaching tests, which have been used to evaluate motor function in mice. Compared with the wild-type mice, the Sulf1/2 DKO mice showed impaired performance in these tests, indicating deficits in motor function. These findings suggest that disruption of Sulf1/2 genes leads to both anatomical and functional defects of the CST.

Pyramidal tract abnormalities in the human fetus and infant with trisomy 18 syndrome.

Trisomy 18 or Edwards syndrome is known to exhibit various developmental abnormalities in the central nervous system. We report dominant uncrossed pyramidal tract in trisomy 18 syndrome, based on the postmortem neuropathologic study of eight consecutive autopsied fetuses and infants with trisomy 18 ranging in age from 16 to 39 weeks of gestation, including six males and two females, along with autopsy cases of a stillborn triploid infant with 69XXX and two stillborn infants without chromosomal or neurodevelopmental abnormalities. Five out of eight cases with trisomy 18 showed a larger proportion of uncrossed than crossed pyramidal tract. All of these cases were male, and the anterior corticospinal tract on one side was constantly larger than the contralateral lateral corticospinal tract in the spinal cord on both sides, while the pyramidal tract was hypoplastic in female cases with trisomy 18 and a case with 69XXX. Abnormal pyramidal decussation has been found in cases with posterior fossa malformations such as occipital encephaloceles, Dandy-Walker malformation, Joubert syndrome and Möbius syndrome, but has not been described in cases with trisomy 18. Our data, together with the previous reports describing uncrossed aberrant ipsilateral pyramidal tract in patients with congenital mirror movements caused by DCC gene mutation in chromosome 18, and hypolasia and hyperplasia of the pyramidal tract in X-linked recessive disorders caused by L1CAM and Kal1 gene mutations, respectively, suggest a role of trisomy 18 in association with X-chromosome in the abnormal development of the pyramidal tract.

Jaw-opening and -closing premotoneurons in the nucleus of the solitary tract making contacts with laryngeal and pharyngeal afferent terminals in rats.

This study clarified the neural mechanisms underlying jaw movements in pharyngolaryngeal reflexes such as swallowing in rats. After retrograde tracer injections into the ventromedial division (Vmovm) of the trigeminal motor nucleus (Vmo) containing jaw-opening (JO) motoneurons or into the dorsolateral division (Vmodl) of Vmo containing jaw-closing (JC) motoneurons, JO and JC premotoneurons were labeled with an ipsilateral predominance in the medial and intermediate subnuclei of the rostrocaudal middle two-thirds of the nucleus of the solitary tract (Sol); JC premotoneurons were also in the lateral subnucleus of Sol. After anterograde tracer injections into the Sol, axons were labeled with an ipsilateral predominance in the Vmovm and Vmodl, prominently in the ipsilateral Vmovm. After transganglionic tracer applications to the superior laryngeal nerve (SLN) or the cervical trunk of the glossopharyngeal nerve (GpN-ct), labeled afferents were seen in the medial, intermediate, lateral and interstitial subnuclei of Sol at the rostral three-fourths of Sol, indicating considerable overlap with the JO and JC premotoneurons in the Sol. Double labeling experiments demonstrated contacts between the afferent terminals and the JO and JC premotoneurons. The present study has for the first time revealed the differential distribution of JO and JC premotoneurons in the Sol and features of their projections from the Sol, as well as their connections with SLN and GpN-ct afferent inputs. The JO and JC premotoneurons in the Sol may play an important role in generation and organization of jaw movements in pharyngolaryngeal reflexes evoked by SLN and GpN-ct inputs, such as swallowing.

Plasma leptin inhibits the response of nucleus of the solitary tract neurons to aortic baroreceptor stimulation.

Leptin receptors have been identified within the nucleus of the solitary tract (NTS) and leptin injections into the caudal NTS inhibit the baroreceptor reflex. However, whether plasma leptin alters the discharge of NTS neurons mediating aortic baroreceptor reflex activity is not known. A series of electrophysiological single unit recording experiments was done in the urethane-chloralose anesthetized, paralyzed and artificially ventilated Wistar and Zucker obese rat with either their neuroaxis intact or with mid-collicular transections. Single units in NTS antidromically activated by electrical stimulation of depressor sites in the caudal ventrolateral medulla (CVLM) were found to display a cardiac cycle-related rhythmicity. These units were tested for their responses to stimulation of the aortic depressor nerve (ADN) and intra-carotid injections of leptin (50-200ng/0.1ml). Of 63 single units tested in NTS, 33 were antidromically activated by stimulation of CVLM depressor sites and 18 of these single units responded with a decrease in discharge rate after intracarotid injections of leptin. Thirteen of these leptin responsive neurons (∼72%) were excited by ADN stimulation. Furthermore, the excitatory response of these single units to ADN stimulation was attenuated by about 50% after the intracarotid leptin injection. Intracarotid injections of leptin (200ng/0.1ml) in the Zucker obese rat did not alter the discharge rate of NTS-CVLM projecting neurons. These data suggest that leptin exerts a modulatory effect on brainstem neuronal circuits that control cardiovascular responses elicited during the reflex activation of arterial baroreceptors.

C-terminals in the mouse branchiomotor nuclei originate from the magnocellular reticular formation.

Large cholinergic synaptic boutons called "C-terminals" contact motoneurons and regulate their excitability. C-terminals in the spinal somatic motor nuclei originate from cholinergic interneurons in laminae VII and X that express a transcription factor Pitx2. Cranial motor nuclei contain another type of motoneuron: branchiomotor neurons. Although branchiomotor neurons receive abundant C-terminal projections, the neural source of these C-terminals remains unknown. In the present study, we first examined whether cholinergic neurons express Pitx2 in the reticular formation of the adult mouse brainstem, as in the spinal cord. Although Pitx2-positive cholinergic neurons were observed in the magnocellular reticular formation and region around the central canal in the caudal medulla, none was present more rostrally in the brainstem tegmentum. We next explored the origin of C-terminals in the branchiomotor nuclei by using biotinylated dextran amine (BDA). BDA injections into the magnocellular reticular formation of the medulla and pons resulted in the labeling of numerous C-terminals in the branchiomotor nuclei: the ambiguous, facial, and trigeminal motor nuclei. Our results revealed that the origins of C-terminals in the branchiomotor nuclei are cholinergic neurons in the magnocellular reticular formation not only in the caudal medulla, but also at more rostral levels of the brainstem, which lacks Pitx2-positive neurons.

The pyramidal syndrome and the pyramidal tract: a brief historical note / A síndrome piramidal e o feixe piramidal: breve nota histórica

The discovery of the pyramidal syndrome and tract is briefly reviewed with emphasis on a few key historical aspects. The pursuit of the relationship between the lateralized deficits resulting from contralateral head trauma begins in the fourth century BC with the Hippocratic School and continues until the present day.

Os autores fazem uma breve nota histórica da síndrome piramidal e do feixe piramidal no homem. Os achados de deficiências motoras decorrentes de traumatismo craniano começam a partir do século IV AC com o pai da medicina Hipócrates (460-377) e vão até os dias atuais.