Wernekink Commissure Syndrome: A Rare Cause of Bilateral Cerebellar Syndrome

PURPOSE

Focal signs are a big deal in neurology and are among the most important clues leading to diagnosis and localization. Wernekink commissure syndrome is due to lesions in the caudal paramedian midbrain involving the entire decussation of the superior cerebellar peduncles, resulting in the clinical hallmark of a bilateral cerebellar syndrome.

CASE REPORT

A 79-year-old man presented with sudden, severe unsteadiness associated with slurring of speech, binocular double vision, and bilateral hand tremor. Examination showed right INO, moderately severe dysarthria, bilateral dysmetria and dysdiadochokinesia, with severe truncal ataxia and bilateral upper and lower limb ataxia. Also, bilateral coarse tremor was noted in both hands which was present at rest, action and on reaching for objects. Brain MRI revealed an acute infarction involving the Wernekinck decussation in the right caudal midbrain and mesencephalo-pontine junction.

CONCLUSION

The differential of Wernekink Commissure Syndrome is complex, and localization and lateralization are extremely difficult owing to prominent bilateral cerebellar symptoms. The finding of an associated unilateral INO in some cases makes it possible to confidently narrow the list of differentials and localize the lesion to the paramedian tegmentum ipsilateral to the non-adducting eye.

Hypersomnia due to injury of the ventral ascending reticular activating system following cerebellar herniation: A case report

RATIONALE

We report on a patient with hypersomnia who showed injury of the lower ascending reticular activating system (ARAS) following cerebellar herniation due to a cerebellar infarct, detected on diffusion tensor tractography (DTT).

PATIENT CONCERNS

A 53-year-old male patient was diagnosed as a left cerebellar infarct, and underwent decompressive suboccipital craniectomy due to brain edema at 2 days after the onset of a cerebellar infarct. Three weeks after onset when the patient started rehabilitation, he showed hypersomnia without impairment of consciousness; he fell asleep most of daytime without external stimulation and showed an abnormal score on the Epworth Sleepiness Scale: 15 (full score: 24, cut off for hypersomnia: 10).

DIAGNOSES AND OUTCOMES

On 3-week DTT, narrowing of the upper portion of the lower ventral ARAS between the pontine reticular formation and the hypothalamus was observed on both sides. In addition, partial tearing was observed in the middle portion of the right lower ventral ARAS.

LESSONS

In conclusion, we found injury of the lower ventral ARAS in a patient with hypersomnia following cerebellar herniation due to a cerebellar infarct.

Recovery of consciousness and an injured ascending reticular activating system in a patient who survived cardiac arrest: A case report

We report on a patient who survived cardiac arrest and showed recovery of consciousness and an injured ARAS at the early stage of hypoxic-ischemic brain injury (HI- BI) for 3 weeks, which was demonstrated by diffusion tensor tractography (DTT).A 52-year-old male patient who had suffered cardiac arrest caused by acute coronary syndrome was resuscitated immediately by a layman and paramedics for ∼25 minutes. He was then transferred immediately to the emergency room of a local medical center. When starting rehabilitation at 2 weeks after onset, his consciousness was impaired, with a Glasgow Coma Scale (GCS) score of 8 and Coma Recovery Scale-Revised (GRS-R) score of 8. He underwent comprehensive rehabilitative therapy, including drugs for recovery of consciousness. He recovered well and rapidly so that his consciousness had recovered to full scores in terms of GCS:15 and GRS-R:23 at 5 weeks after onset.The left lower dorsal and right lower ventral ARAS had become thicker on 5-week DTT compared with 2-week DTT (Fig. 1B). Regarding the change of neural connectivity of the thalamic ILN, increased neural connectivity to the basal forebrain and prefrontal cortex was observed in both hemispheres on 5-week DTT compared with 2-week DTT.Recovery of an injured ARAS was demonstrated in a patient who survived cardiac arrest and his consciousness showed rapid and good recovery for 3 weeks at the early stage of HI-BI.

CORRELATION INDICES OF CEREBRAL HEMODYNAMICS AND ELECTRICAL ACTIVITY IN CHILDREN WITH IMPAIRED MOTOR SKILLS

The correlations between the indicators of cerebral hemodynamics and electrical activity in children with impaired motor skills of central origin (children with cerebral palsy) were investigated. There is established a high number of links between indicators of rheoencephalogram (REG) and electroencephalogram (EEG) in the left cerebral hemisphere than in the right. In frontomastoidal allocation 19 correlations and in occipitomastoidal - 59 links. We suppose that poor circulation in vertebroplasty-basilar system leads to the defeat of the brain stem, which, with afferent pathways of the reticular formation, connects the thalamus with the cortex. In the reticular formation there is an inhibition of ascending activators influences, which eland to decreasing of the cortex is tonus. You can talk about the functional immaturity of the system of nonspecific activation by the reticular formation of the brain stem. Children with violation of motor activity had significantly more negative and positive significant and high correlation among the existing indicators of electric brain activity and cerebral hemodynamics, in our opinion, is due to the development of interconnection compensation that is carried out by adjustment of the functional systems and the formation of new forms of adaptive responses in conditions of disontogenetik. Feature correlation pattern of the EEG, of children with disorders of motor activity, is associated with a significantly great number of high and significant correlations between measures of electrical brain activity in the δ- and q- rhythms, especially in the temporal areas of the cerebral cortex. According to visual analysis of EEG there is revealed a common manifestation of changes of bioelectric brain activity in children with disorders of motor activity. This is manifested in the development of paroxysmal activity of action potentials of θ- and δ-rhythms with the focus of activity in the anterior areas of the cerebral cortex; the formation of a mosaic representation of the θ-rhythms in temporal areas; the presence of hypersynchronous a-paroxysms in the posterior areas of the cerebral cortex. The given facts testify to activation of mechanisms of limbic-neocortical systems and synchronizing influences of the reticular formation of the stem and diencephalic structures. There is also detected greater number of correlations when occipitomastoidal registration was lone it reflects compensatory redistribution of cerebral blood flow over the affected structures of brain stem structures that are associated with the provision of cortical functions.

Recovery of Hypersomnia Concurrent With Recovery of an Injured Ascending Reticular Activating System in a Stroke Patient: A Case Report

We report on a stroke patient who showed recovery of hypersomnia concurrent with the recovery of an injured ascending reticular activating system (ARAS), which was demonstrated by diffusion tensor tractography (DTT).A 70-year-old female patient underwent coiling of the left ruptured posterior communicating artery after subarachnoid hemorrhage and both extraventricular drainage for management of an intraventricular hemorrhage. At 2 months after onset, when she started rehabilitation, she exhibited intact consciousness, with the full score on the Glasgow Coma Scale: 15. However, she showed severe hypersomnia: she always fell asleep without external stimulation and the Epworth Sleepiness Scale (EPS) score was 24 (full score: 24, cut off for hypersomnia: 10). She underwent comprehensive rehabilitative therapy, including neurotropic drugs, physical therapy, and occupational therapy. Her hypersomnia has shown improvement as 14 (3 months after onset), 11 (4 months after onset), 7 (12 months after onset), and 6 (24 months after onset), respectively.On 2-month DTT, narrowing of both lower dorsal and ventral ARASs was observed on both sides: in particular, among 4 neural tracts of the lower ARAS, the right lower ventral ARAS was the narrowest. By contrast, on 24-month DTT, the 4 narrowed neural tracts of both lower dorsal and ventral ARASs were thickened compared with those of 2-month DTT.Recovery of hypersomnia with recovery of an injured lower ARAS on DTT was observed in a stroke patient. Our results suggest that evaluation of the lower ARAS using DTT might be useful for stroke patients with hypersomnia.

The Ascending Reticular Activating System in a Patient With Severe Injury of the Cerebral Cortex: A Case Report

We reported on the ascending reticular activating system (ARAS) finding of a patient in whom severe injury of the cerebral cortex was detected following a hypoxic-ischemic brain injury (HIBI).A 67-year-old female patient who suffered from HIBI induced by cardiac arrest after surgery for lumbar disc herniation underwent cardiopulmonary resuscitation approximately 20 to 30 minutes after cardiac arrest. The patient exhibited impaired alertness, with a Glasgow Coma Scale (GCS) score of 4 (eye opening: 2, best verbal response: 1, and best motor response: 1). Approximately 3 years after onset, she began to whimper sometimes and showed improved consciousness, with a GCS score of 10 (eye opening: 4, best verbal response: 2, and best motor response: 4) and Coma Recovery Scale-Revised score of 9 (auditory function: 1, visual function: 1, motor function: 2, verbal function: 2, communication: 1, and arousal: 2).Results of diffusion tensor tractography for the upper connectivity of the ARAS showed decreased neural connectivity to each cerebral cortex in both hemispheres. The right lower ARAS between the pontine reticular formation and the thalamic intralaminar nuclei (ILN) was thinner compared with the left side.Severe injury of the upper portion of the ARAS between the thalamic ILN and cerebral cortex was demonstrated in a patient with some level of consciousness.

Is R2* a new MRI biomarker for the progression of Parkinson's disease? A longitudinal follow-up

Purpose

To study changes of iron content in basal ganglia in Parkinson’s disease (PD) through a three-year longitudinal follow-up of the effective transverse relaxation rate R₂*, a validated MRI marker of brain iron content which can be rapidly measured under clinical conditions.

Methods

Twenty-seven PD patients and 26 controls were investigated by a first MRI (t₀). Longitudinal analysis was conducted among the 18 controls and 14 PD patients who underwent a second MRI (t₁) 3 years after. The imaging protocol consisted in 6 gradient echo images obtained at different echo-times for mapping R₂*. Quantitative exploration of basal ganglia was performed by measuring the variation of R₂* [R₂*(t₁) – R₂*(t₀)] in several regions of interest.

Results

During the three-year evolution of PD, R₂* increased in Substantia nigra (SN) (by 10.2% in pars compacta, p = 0.001, and 8.1% in pars reticulata, p = 0.013) and in the caudal putamen (11.4%, p = 0.011), without significant change in controls. Furthermore, we showed a positive correlation between the variation of R₂* and the worsening of motor symptoms of PD (p = 0.028).

Conclusion

Significant variation of R₂* was longitudinally observed in the SN and caudal putamen of patients with PD evolving over a three-year period, emphasizing its interest as a biomarker of disease progression. Our results suggest that R₂* MRI follow-up could be an interesting tool for individual assessment of neurodegeneration due to PD, and also be useful for testing the efficiency of disease-modifying treatments.

Paralemniscal TIP39 is induced in rat dams and may participate in maternal functions

The paralemniscal area, situated between the pontine reticular formation and the lateral lemniscus in the pontomesencephalic tegmentum contains some tuberoinfundibular peptide of 39 residues (TIP39)-expressing neurons. In the present study, we measured a 4 times increase in the level of TIP39 mRNA in the paralemniscal area of lactating mothers as opposed to nulliparous females and mothers deprived of pups using real-time RT-PCR. In situ hybridization histochemistry and immunolabeling demonstrated that the induction of TIP39 in mothers takes place within the medial paralemniscal nucleus, a cytoarchitectonically distinct part of the paralemniscal area, and that the increase in TIP39 mRNA levels translates into elevated peptide levels in dams. The paralemniscal area has been implicated in maternal control as well as in pain perception. To establish the function of induced TIP39, we investigated the activation of TIP39 neurons in response to pup exposure as maternal, and formalin injection as noxious stimulus. Both stimuli elicited c-fos expression in the paralemniscal area. Subsequent double labeling demonstrated that 95% of neurons expressing Fos in response to pup exposure also contained TIP39 immunoreactivity and 91% of TIP39 neurons showed c-fos activation by pup exposure. In contrast, formalin-induced Fos does not co-localize with TIP39. Instead, most formalin-activated neurons are situated medial to the TIP39 cell group. Our data indicate that paralemniscal neurons may be involved in the processing of maternal and nociceptive information. However, two different groups of paralemniscal neurons participate in the two functions. In particular, TIP39 neurons may participate in the control of maternal functions.

MR imaging findings in the reticular formation in siblings with MPV17-related mitochondrial depletion syndrome

Hepatocerebral MPV17-MDS is quite rare (<30 confirmed cases), with limited findings described on MR imaging. We report 2 siblings having abnormalities within the reticular formation of the lower brain stem and within the reticulospinal tracts at the cervicocranial junction on T2WI. The presence of these MR imaging findings (relative to previous reports) raises the possibility that they represent subtle but characteristic findings corresponding to clinically observed abnormalities of tone encountered with this recently described disorder.

Divergence paralysis caused by acute midbrain infarction

A 41-year-old woman with idiopathic thrombocytopenic purpura and dyslipidemia abruptly developed vertigo, truncal ataxia and divergence paralysis. Cranial magnetic resonance imaging demonstrated the presence of infarction in the left superior paramedian mesencephalic artery involving the vicinity of the periaqueductal gray matter. The symptoms rapidly resolved under the administration of anti-platelet agents. The precise location of the hypothetical divergence center of the ocular motor system remains unclear because the lesions responsible for divergence paralysis are rarely identified on neuroimaging. We emphasize that this is a first reported case of DP caused by acute midbrain infarction and speculate that the mesencephalic reticular formation may be partially involved.

A trigeminoreticular pathway: implications in pain

Neurons in the caudalmost ventrolateral medulla (cmVLM) respond to noxious stimulation. We previously have shown most efferent projections from this locus project to areas implicated either in the processing or modulation of pain. Here we show the cmVLM of the rat receives projections from superficial laminae of the medullary dorsal horn (MDH) and has neurons activated with capsaicin injections into the temporalis muscle. Injections of either biotinylated dextran amine (BDA) into the MDH or fluorogold (FG)/fluorescent microbeads into the cmVLM showed projections from lamina I and II of the MDH to the cmVLM. Morphometric analysis showed the retrogradely-labeled neurons were small (area 88.7 µm(2)±3.4) and mostly fusiform in shape. Injections (20-50 µl) of 0.5% capsaicin into the temporalis muscle and subsequent immunohistochemistry for c-Fos showed nuclei labeled in the dorsomedial trigeminocervical complex (TCC), the cmVLM, the lateral medulla, and the internal lateral subnucleus of the parabrachial complex (PBil). Additional labeling with c-Fos was seen in the subnucleus interpolaris of the spinal trigeminal nucleus, the rostral ventrolateral medulla, the superior salivatory nucleus, the rostral ventromedial medulla, and the A1, A5, A7 and subcoeruleus catecholamine areas. Injections of FG into the PBil produced robust label in the lateral medulla and cmVLM while injections of BDA into the lateral medulla showed projections to the PBil. Immunohistochemical experiments to antibodies against substance P, the substance P receptor (NK1), calcitonin gene regulating peptide, leucine enkephalin, VRL1 (TPRV2) receptors and neuropeptide Y showed that these peptides/receptors densely stained the cmVLM. We suggest the MDH- cmVLM projection is important for pain from head and neck areas. We offer a potential new pathway for regulating deep pain via the neurons of the TCC, the cmVLM, the lateral medulla, and the PBil and propose these areas compose a trigeminoreticular pathway, possibly the trigeminal homologue of the spinoreticulothalamic pathway.

Blockade of opioid receptors in the medullary reticularis nucleus dorsalis, but not the rostral ventromedial medulla, prevents analgesia produced by diffuse noxious inhibitory control in rats with muscle inflammation

Diffuse Noxious Inhibitory Controls (DNIC) involves application of a noxious stimulus outside the testing site to produce analgesia. In human subjects with a variety of chronic pain conditions, DNIC is less effective; however, in animal studies, DNIC is more effective after tissue injury. While opioids are involved in DNIC analgesia, the pathways involved in this opioid-induced analgesia are not clear. The aim of the present study was to test the effectiveness of DNIC in inflammatory muscle pain, and to study which brainstem sites mediate DNIC- analgesia. Rats were injected with 3% carrageenan into their gastrocnemius muscle and responses to cutaneous and muscle stimuli were assessed before and after inflammation, and before and after DNIC induced by noxious heat applied to the tail (45 °C and 47 °C). Naloxone was administered systemically, into rostral ventromedial medulla (RVM), or bilaterally into the medullary reticularis nucleus dorsalis (MdD) prior to the DNIC-conditioning stimuli. DNIC produced a similar analgesic effect in both acute and the chronic phases of inflammation reducing both cutaneous and muscle sensitivity in a dose-dependent manner. Naloxone systemically or microinjected into the MdD prevented DNIC-analgesia, while naloxone into the RVM had no effect on DNIC analgesia. Thus, DNIC analgesia involves activation of opioid receptors in the MdD.

PERSPECTIVE

The current study shows that DNIC activates opioid receptors in the MdD, but not the RVM, to produce analgesia. These data are important for understanding clinical studies on DNIC as well as for potential treatment of chronic pain patients.

One-and-a-half syndrome--two cases

One-and-a-half syndrome is characterized by combination of the clinical features of unilateral horizontal gaze palsy and internuclear ophthalmoplegia. The common symptoms are double vision and oscillopsia. The lesion is located in the paramedian pontine reticular formation, involving the centre of horizontal gaze and medial longitudinal fasciculus. More extensive brainstem damage may result in additional neurological signs. The most frequent underlying diseases are vascular insults, multiple sclerosis, and brainstem tumor. We present two cases of one-and-a-half syndrome. Both patients had lacunar infarction in the paramedian pontine tegmentum, revealed by MRI. The first patient had isolated eye movement disorder, while the second had additional nuclear-type facial paresis. In the first case brainstem evoked potentials indicated brainstem damage, in the second patient it was normal. Ocular symptoms improved within some days in both patients.

Medullary microvessel degeneration in multiple system atrophy

Multiple system atrophy (MSA) is a rare and fatal early-onset autonomic disorder which is characterised by Parkinsonism and orthostatic hypotension (OH). The pathophysiology of MSA is not fully understood but key features include the depletion of medullary autonomic neurons and presence of glial cellular inclusions. We hypothesise that the degeneration of medullary autonomic microvessels is an additional finding in MSA. Using digital pathology we quantified basement membrane collagen (Coll IV), smooth muscle actin (alpha-actin) and endothelial glucose transporter (Glut 1) expression in medullary autonomic nuclei of 8 MSA and 8 OH cases, compared with 12 controls with no autonomic dysfunction. We found decreased Coll IV (p=0.000) and Glut 1 (p=0.000) but not alpha-actin expression, in medullary autonomic nuclei of MSA, but not OH cases compared with control subjects. Medullary microvessel degeneration in MSA may be secondary to the primary neuro-glial pathogenesis of the disorder, and could accelerate its ageing-related progression.

Pontine tuberculoma presenting with horizontal gaze palsy

A 38-year-old immunocompetent man presented with a horizontal supranuclear gaze palsy as the only neurologic manifestation of a pontine tuberculoma. Although a biopsy of the brain lesion was not performed, it was attributed to tuberculosis because of chest x-ray evidence. The patient was given empirical anti-tuberculous therapy. After one month, the gaze palsy had fully recovered and repeat MRI showed a decrease in the size of the lesion. This is the first reported case of supranuclear gaze palsy without diplopia as a manifestation of a tuberculous brain stem lesion.

Enlargement of postoperative aqueductal air due to elevated body temperature. Case report

Pneumocephalus has been reported after posterior fossa surgery especially with procedures performed in the sitting position. The gravitational effect is the decisive factor in the development of pneumocephalus. The entrapped air in the aqueduct may enlarge due to several factors such as elevated body temperature and may cause to deterioration in neurological status. We report a rare case of tension pneumocephalus associated with the enlargement of massive air in aqueduct due to elevated body temperature, following removal of a cervicomedullary tumor. We believe her neurological deterioration was due to the compression of the reticular formation by dilatation of postoperative air in the aqueduct due to the elevation of her body temperature.

Involvement of 5-HT(2) serotonergic receptors of the nucleus raphe magnus and nucleus reticularis gigantocellularis/paragigantocellularis complex neural networks in the antinociceptive phenomenon that follows the post-ictal immobility syndrome

The post-ictal immobility syndrome is followed by a significant increase in the nociceptive thresholds in animals and men. In this interesting post-ictal behavioral response, endogenous opioid peptides-mediated mechanisms, as well as cholinergic-mediated antinociceptive processes, have been suggested. However, considering that many serotonergic descending pathways have been implicated in antinociceptive reactions, the aim of the present work is to investigate the involvement of 5-HT(2)-serotonergic receptor subfamily in the post-ictal antinociception. The analgesia was measured by the tail-flick test in seven or eight Wistar rats per group. Convulsions were followed by statistically significant increase in the tail-flick latencies (TFL), at least for 120 min of the post-ictal period. Male Wistar rats were submitted to stereotaxic surgery for introduction of a guide-cannula in the rhombencephalon, aiming either the nucleus raphe magnus (NRM) or the gigantocellularis complex. In independent groups of animals, these nuclei were neurochemically lesioned with a unilateral microinjection of ibotenic acid (1.0 microg/0.2 microL). The neuronal damage of either the NRM or nucleus reticularis gigantocellularis/paragigantocellularis complex decreased the post-ictal analgesia. Also, in other independent groups, central administration of ritanserin (5.0 microg/0.2 microL) or physiological saline into each of the reticular formation nuclei studied caused a statistically significant decrease in the TFL of seizing animals, as compared to controls, in all post-ictal periods studied. These results indicate that serotonin input-connected neurons of the pontine and medullarly reticular nuclei may be involved in the post-ictal analgesia.

An unusual pathologic feature associated with dermatomyositis

We present a case of juvenile dermatomyositis with unusual histopathologic findings. The child presented with a course consistent with dermatomyositis, a diagnosis confirmed by finding reticulotubular aggregates in endothelial cells on electron microscopy. However, histopathology of his muscle biopsy revealed a striking pattern of glycogen accumulation, to an extent similar to that seen in glycogen storage diseases; this degree of accumulation could potentially confound histopathologic diagnosis.

Increased brainstem volume in panic disorder: a voxel-based morphometric study

Neurocircuitry models of panic disorder have hypothesized that the panic attack itself stems from loci in the brainstem including the ascending reticular system and respiratory and cardiovascular control centers. Voxel-based morphometry with acobian modulation was used to examine gray matter volume changes in 10 panic disorder patients and 23 healthy controls. The panic disorder patients had a relatively increased gray matter volume in the midbrain and rostral pons of the brainstem. Increased ventral hippocampal and decreased regional prefrontal cortex volumes were also noted at a lower significance threshold. This finding has implications for pathophysiologic models of panic disorder, and provides structural evidence for the role of the brainstem in neurocircuitry models of panic disorder.

Pallidoreticular damage in acute carbon monoxide poisoning: diffusion-weighted MR imaging findings

We describe a case of carbon monoxide poisoning that led to pallidoreticular damage and delayed leukoencephalopathy. Serial diffusion-weighted MR imaging was performed. A restricted water diffusion pattern was demonstrated in the globus pallidus and substantia nigra in the early stage. Diffusion-weighted imaging is useful for early identification of the effects of acute carbon monoxide poisoning.

Spinocerebellar ataxias types 2 and 3: degeneration of the pre-cerebellar nuclei isolates the three phylogenetically defined regions of the cerebellum

The pre-cerebellar nuclei act as a gate for the entire neocortical, brainstem and spinal cord afferent input destined for the cerebellum. Since no pathoanatomical studies of these nuclei had yet been performed in spinocerebellar ataxia type 2 (SCA2) or type 3 (SCA3), we carried out a detailed postmortem study of the pre-cerebellar nuclei in six SCA2 and seven SCA3 patients in order to further characterize the extent of brainstem degeneration in these ataxic disorders. By means of unconventionally thick serial sections through the brainstem stained for lipofuscin pigment and Nissl material, we could show that all of the pre-cerebellar nuclei (red, pontine, arcuate, prepositus hypoglossal, superior vestibular, lateral vestibular, medial vestibular, interstitial vestibular, spinal vestibular, vermiform, lateral reticular, external cuneate, subventricular, paramedian reticular, intercalate, interfascicular hypoglossal, and conterminal nuclei, pontobulbar body, reticulotegmental nucleus of the pons, inferior olive, and nucleus of Roller) are among the targets of both of the degenerative processes underlying SCA2 and SCA3. These novel findings are in contrast to the current neuropathological literature, which assumes that only a subset of pre-cerebellar nuclei in SCA2 and SCA3 may undergo neurodegeneration. Widespread damage to the pre-cerebellar nuclei separates all three phylogenetically and functionally defined regions of the cerebellum, impairs their physiological functions and thus explains the occurrence of gait, stance, limb and truncal ataxia, dysarthria, truncal and postural instability with disequilibrium, impairments of the vestibulo-ocular reaction and optokinetic nystagmus, slowed and saccadic smooth pursuits, dysmetrical horizontal saccades, and gaze-evoked nystagmus during SCA2 and SCA3.

C-fos expression in rat brain nuclei following incisor tooth movement

In the rat experimental model, molar tooth movement induced by Waldo's method is known to cause a temporally and spatially defined pattern of brain neuronal activation. Since orthodontic correction usually involves the entire dental arch, we used a spring-activated appliance to extend the investigation to incisors, and we included brain regions related to antinociception. Adjustment of the non-activated appliance on incisors resulted in c-fos expression in the dorsal raphe, peri-aqueductal gray matter, and the locus coeruleus, in addition to trigeminal sensory subnuclei and the parabrachial nucleus, where neuronal activation has already been detected in previous studies on molar tooth movement. Appliance activation with a 70-g force resulted in a further increase in Fos-immunoreactive neurons in the trigeminal sensory subnucleus caudalis and in the dorsal raphe. This result suggests that there is a recruitment of neurons related to nociception and to antinociception when tooth movement is increased.

Expression of pro-inflammatory cytokine and caspase genes promotes neuronal apoptosis in pontine reticular formation after spinal cord transection

We identified apoptotic neurons in pontine reticular formation (PRF), the origin of pontine reticulospinal fibers, in adult Sprague-Dawley rats after complete spinal cord transection (SCT) at T8 level. SCT also increased the expression in PRF of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, caspase-1, or caspase-3 mRNA. This was followed by an augmented expression of activated caspase-3 protein, an increase in caspase-3 activity, and expression of a cleaved fragment of poly(ADP-ribose) polymerase (PARP), a proteolytic substrate of the activated caspase-3. Microinjection bilaterally into the PRF of an antiserum against TNF-alpha attenuated the expression of IL-6 mRNA and up-regulation of caspase-3 mRNA, and a caspase-3 inhibitor, DEVD-CHO, suppressed the augmentation in activated caspase-3 or cleaved PARP expression after SCT. Both treatments also reduced the number of SCT-induced apoptotic PRF neurons. We conclude that PRF neurons in adult mammalian brain may actively degrade themselves after SCT through apoptosis, via signaling processes that involve activation of proinflammatory cytokine genes and the intracellular caspase-3 pathway.

Neuroanatomical correlates of brainstem coma

The brainstem tegmentum, including the reticular formation, contains distinct nuclei, each of which has a set of chemical, physiological and anatomical features. Damage to the brainstem tegmentum is known to cause coma, the most radical disturbance of consciousness. However, it has remained unclear which nuclei within the tegmentum are crucial for the maintenance of consciousness in humans. Accordingly, we initiated a retrospective study of MRIs obtained from 47 patients with brainstem stroke. The lesion boundaries were charted on patient MRIs and transferred onto a corresponding series of 4.7 T MRIs obtained from a control brainstem specimen that later was cut on a freezing microtome and analysed histologically. In addition, medical charts and available post-mortem materials were used to obtain relevant clinical and anatomical data to verify the MRI readings in each case. We found that in the 38 patients who did not have coma, brainstem damage either was located outside the tegmentum (n = 29) or produced a very small and unilateral compromise of the tegmentum (n = 9). In contrast, in patients who had coma (n = 9), the lesions in the tegmentum were mostly bilateral (n = 7) and were located either in the pons alone (n = 4) or in the upper pons and the midbrain (n = 5). The maximum overlap territory of the lesions coincided with the location of the rostral raphe complex, locus coeruleus, laterodorsal tegmental nucleus, nucleus pontis oralis, parabrachial nucleus and the white matter in between these nuclei. We also found that four coma subjects developed hyperthermia and died in the absence of any infections. In these cases, the maximum lesion overlap was centred in the core of pontine tegmentum. Our findings suggest that lesions confined to the upper pons can cause coma in humans even in the absence of damage to the midbrain. The findings also point to the brainstem nuclei whose lesions are likely to be associated with loss of consciousness and fatal hyperthermia in humans.

Spinocerebellar ataxia type 3 (Machado-Joseph disease): severe destruction of the lateral reticular nucleus

The lateral reticular nucleus (LRT) of the medulla oblongata is a precerebellar nucleus involved in proprioception and somatomotor automatisms. We investigated this nucleus in five individuals with clinically diagnosed and genetically confirmed spinocerebellar ataxia type 3 (SCA3, Machado-Joseph disease). Polyethylene glycol-embedded 100 micro m thick sections stained for lipofuscin granules and Nissl material as well as Nissl-stained paraffin-embedded sections revealed severe destruction of the LRT in all SCA3 brains examined. Some of the few surviving neurones contained ataxin-3-immunopositive intranuclear inclusion bodies, as noted in other affected brain regions in SCA3. Along with the severe neuronal depletion, obvious astrogliosis was seen in the LRT of all SCA3 patients. The findings suggest that the LRT is a consistent target of the pathological process underlying SCA3. In view of its afferent and efferent connections, destruction of the LRT probably contributes to gait ataxia in individuals suffering from SCA3.

Where does parkinson disease pathology begin in the brain?

The substantia nigra is not the induction site in the brain of the neurodegenerative process underlying Parkinson disease (PD). Instead, the results of this semi-quantitative study of 30 autopsy cases with incidental Lewy body pathology indicate that PD in the brain commences with the formation of the very first immunoreactive Lewy neurites and Lewy bodies in non-catecholaminergic neurons of the dorsal glossopharyngeus-vagus complex, in projection neurons of the intermediate reticular zone, and in specific nerve cell types of the gain setting system (coeruleus-subcoeruleus complex, caudal raphe nuclei, gigantocellular reticular nucleus), olfactory bulb, olfactory tract, and/or anterior olfactory nucleus in the absence of nigral involvement. The topographical parcellation of the nuclear grays described here is based upon known architectonic analyses of the human brainstem and takes into consideration the pigmentation properties of a few highly susceptible nerve cell types involved in PD. In this sample and in all 58 age- and gender-matched controls, Lewy bodies and Lewy neurites do not occur in any of the known prosencephalic predilection sites (i.e. hippocampal formation, temporal mesocortex, proneocortical cingulate areas, amygdala, basal nucleus of Meynert, interstitial nucleus of the diagonal band of Broca, hypothalamic tuberomamillary nucleus).

New findings on the neuropathology of multiple system atrophy

Multiple system atrophy (MSA) provides a typical example of the integrative role of the central autonomic network in controlling cardiovascular, respiratory, bladder and gastrointestinal functions. There is increasing evidence that neurochemically defined neuronal groups of the brainstem are selectively affected in MSA to a much greater degree than in Parkinson's disease. These include the catecholaminergic neurons of the rostral ventrolateral medulla (C1 group) which project to the intermediolateral cell column and are involved in modulation of sympathetic vasomotor outflow, and noradrenergic neurons of the caudal ventrolateral medulla (A1 group) projecting to the magnocellular nuclei of the hypothalamus and regulating vasopressin (AVP) release. Loss of these groups of neurons may, at least in part, explain the development of orthostatic hypotension, baroreflex dysfunction, and impaired reflex AVP release in response to hypotension. There is preliminary evidence that cardiovagal neurons of the ventrolateral portion of the nucleus ambiguus, distinct from the branchimotor neurons of the compact region, may also be affected in MSA. Loss of cholinergic neurons in the medullary arcuate nucleus, considered by some to be the homologous to the central chemosensitive region of the ventral medullary surface, may contribute to disturbances in automatic ventilation, particularly during sleep, in patients with MSA.

Progressive supranuclear palsy: neuronal and glial cytoskeletal pathology in the higher order processing autonomic nuclei of the lower brainstem

The medial and lateral parabrachial nuclei (MPB, LPB), the gigantocellular reticular nucleus (GI), the raphes magnus (RMG) and raphes obscurus nuclei (ROB), as well as the intermediate reticular zone (IRZ) represent pivotal subordinate brainstem centres, all of which control autonomic functions. In this study, we investigated the occurrence and severity of the neuronal and glial cytoskeletal pathology in these six brainstem nuclei from 17 individuals with clinically diagnosed and neuropathologically confirmed progressive supranuclear palsy (PSP). The association between the severity of the pathology and the duration of the disease was investigated by means of correlation analysis. The brainstem nuclei in all of the PSP cases were affected by the neuronal cytoskeletal pathology, with the IRZ and GI regularly showing severe involvement, the MPB, RMG, and ROB marked involvement, and the LPB mild involvement. In the six nuclear greys studied, glial cells undergo alterations of their cytoskeleton on an irregular basis, whereby diseased oligodendrocytes predominantly presented as coiled bodies and affected astrocytes as thorn-shaped astrocytes. In all six nuclei, the severity of the neuronal or glial cytoskeletal pathology showed no correlation with the duration of PSP. In view of their functional role, the neuronal pathology in the nuclei studied offers a possible explanation for the autonomic dysfunctions that eventually develop in the course of PSP.

Disturbance of phasic chin muscle activity during rapid-eye-movement sleep

In patients with Rett syndrome (RS), a peculiar type of disturbance in phasic chin muscle activity during rapid-eye-movement sleep (REMS) (e.g. an elevation of phasic inhibition index (PII) without an affection of tonic inhibition index (TII)) has been reported. The similar disturbance in REMS was reported not only in child patients with infantile spasms, severe myoclonic epilepsy in infancy (SMEI), severe nocturnal enuresis, and autism but also in adult patients with Parkinson's disease (PD). Except for SMEI and PD, patients with the other four clinical entities including RS could express autistic tendency. Since the responsible lesion for the occurrence of an elevation of PII with a normal TII value is likely to be in the pontine tegmentum, this subcortical structure is hypothesized to be involved in the appearance of autistic tendency.

Ocular flutter associated with a localized lesion in the paramedian pontine reticular formation

Ocular flutter is a rare horizontal eye movement disorder characterized by rapid saccadic oscillations. It has been hypothesized that it is caused by loss of "pause" neuronal inhibition of "burst" neuron function in the paramedian pontine reticular formation (PPRF); however, there have been no imaging studies confirming such anatomical localization. We report the case of a woman with an acute attack of multiple sclerosis associated both with ocular flutter and a circumscribed pontine lesion, mainly involving the PPRF on magnetic resonance imaging. As she recovered from the attack, both the midline pontine lesion and the ocular flutter dramatically improved. This case is the first clear evidence that at least some cases of ocular flutter are due to lesions involving the PPRF.

Central neuropathology of equine grass sickness

Equine grass sickness (EGS) is an acquired disease of unknown aetiology affecting horses kept at grass. The disease is characterised by postganglionic sympathetic and parasympathetic neuronal pathology and is categorised as a dysautonomia. This study undertook a systematic examination of brain stem cranial nerve nuclei in 59 cases of EGS. Pathology consisting of neuronal chromatolysis was most consistently noted in the lower motor neurons of the general visceral efferent nucleus of CN III and X and the general somatic efferent nuclei of CN III, V, VII and XII. The prevalence of chromatolysis differed significantly between the diagnostic categories and was inversely related to the age of the animal. Duration of disease had a small but significant negative effect on the proportion of nuclei with chromatolytic neurons in chronic cases. The distribution of chromatolytic neurons is unlike that reported in any other equine or human disease; however, it appears to be equivalent to that in other animals with primary dysautonomias. EGS should be classified as a multisystem disease.

Early involvement of the tegmentopontine reticular nucleus during the evolution of Alzheimer's disease-related cytoskeletal pathology

The tegmentopontine reticular nucleus (nucleus of Bechterew) plays a crucial role in the generation of horizontal saccades and smooth pursuit movement of the eyes. The evolution of Alzheimer's disease-related cytoskeletal pathology was studied of this nucleus was studied in 27 autopsy cases at different stages of the cortical neurofibrillary pathology (NFT/NT stages I--VI). The first cytoskeletal changes were seen at stages I and II (preclinical Alzheimer's disease). At stages III and IV (incipient Alzheimer's disease), the nucleus exhibited a marked pathology, and it was severely involved at stages V and VI (clinically overt Alzheimer's disease). Damage to the tegmentopontine reticular nucleus most probably contributes to the hypometrie of horizontal saccades and the slowing of smooth pursuits that characteristically develop in patients suffering from Alzheimer's disease. Given the fact that pathological alterations of the tegmentopontine reticular nucleus begin early during the evolution of the underlying process, the question arises as to whether dysfunctional horizontal saccades and abnormal smooth pursuits could be employed as means of screening or diagnosing Alzheimer's patients in the very earliest stages of the disease.

Reduced gating of middle-latency auditory evoked potentials (P50) in migraine patients: another indication of abnormal sensory processing?

Habituation of cortical evoked responses to repetitive stimuli is reduced in migraine between attacks. To explore another aspect of information processing, we measured auditory sensory gating. The amplitude of the P50 response to the second of two homologous stimuli was significantly less reduced in migraineurs than in healthy volunteers. This lack of auditory sensory gating may be due to a hypofunction of monoaminergic subcortico-cortical pathways, which is also supposed to cause the interictal deficit of cortical habituation to repetitive stimuli.

The autonomic higher order processing nuclei of the lower brain stem are among the early targets of the Alzheimer's disease-related cytoskeletal pathology

The nuclei of the pontine parabrachial region (medial parabrachial nucleus, MPB; lateral parabrachial nucleus, LPB; subpeduncular nucleus, SPP) together with the intermediate zone of the medullary reticular formation (IRZ) are pivotal relay stations within central autonomic regulatory feedback systems. This study was undertaken to investigate the evolution of the Alzheimer's disease-related cytoskeletal pathology in these four sites of the lower brain stem. We examined the MPB, LPB, SPP and IRZ in 27 autopsy cases and classified the cortical Alzheimer-related cytoskeletal anomalies according to an established staging system (neurofibrillary tangle/neuropil threads [NFT/NT] stages I-VI). The lesions were visualized either with the antibody AT8, which is immunospecific for the abnormally phosphorylated form of the cytoskeletal protein tau, or with a modified Gallyas silver iodide stain. The MPB, SPB, and IRZ display cytoskeletal pathology in stage I and the LPB in stage II, whereby bothstages correspond to the preclinical phase of Alzheimer's disease (AD). In stages III-IV (incipient AD), the MPB and SPP are severely affected. In all of the stage III-IV cases, the lesions in the LPB and IRZ are well developed. In stages V and VI (clinical phase of AD), the MPB and SPP are filled with the abnormal intraneuronal material. At stages V-VI, the LPB is moderately involved and the IRZ shows severe damage. The pathogenesis of the AD-related cytoskeletal lesions in the nuclei of the pontine parabrachial region and in the IRZ conforms with the cortical NFT/NT staging sequence I-VI. In the event that the cytoskeletal pathology observed in this study impairs the function of the nerve cells involved, it is conceivable that autonomic mechanisms progressively deteriorate with advancing cortical NFT/NT stages. This relationship remains to be established, but it could provide insights into the illusive correlation between the AD-related cytoskeletal pathology and the function of affected neurons.

Chronically injured supraspinal neurons exhibit only modest axonal dieback in response to a cervical hemisection lesion

This study examined the extent of axon retraction (dieback) exhibited by injured brain stem neurons in a chronic spinal cord injury (SCI) condition. Adult female rats subjected to a cervical (C3) hemisection lesion were sacrificed 1, 4, 8, or 14 weeks after injury and the spinal cord from C1 to the lesion cavity was removed. One week prior to sacrifice, a microinjection of biotinylated dextran amine (BDA, 0.5 microliter) was made into the red nucleus, lateral vestibular nucleus, or medullary reticular formation of each animal. Horizontal cryostat sections were processed with avidin-HRP to detect supraspinal axons anterogradely labeled with BDA. Terminal end bulbs of axons were identified and their distance from the lesion site was measured by a computerized image analysis program. At all postinjury intervals, numerous rubrospinal, vestibulospinal, and reticulospinal tract axons were found immediately adjacent to the lesion site and over 60% of all terminals were within 500 micrometer at 1 and 4 weeks. The mean axonal distance of 450-500 micrometer from the lesion indicated that many injured axons had retracted farther than 500 micrometer from the lesion site; however, long-term maintenance of the mean axonal distance from the lesion at less than 500 micrometer indicated the absence of progressive dieback after SCI. While some modest changes occur in specific supraspinal pathways following SCI, axonal retraction does not appear to be a contributing factor to the diminished regenerative effort by certain brain stem neurons that has been observed at long postinjury intervals.

The organisation of spinal projecting brainstem neurons in an animal model of muscular dystrophy. A retrograde tracing study on mdx mutant mice

Previous studies we performed on the mdx mouse demonstrated marked central nervous system alterations in this model of human Duchenne muscular dystrophy, such as reduction in number and pathological changes of cortico-spinal neurons. Prompted by these findings we extended the survey of the mdx brain to the major brainstem-descending pathways: the rubro-, vestibulo-, reticulo-, and raphe-spinal projections. Horseradish peroxidase microinjections were performed in the cervical spinal cord of mdx and control mice. The rubro-spinal neurons were found to be significantly reduced in mutants compared to controls. The vestibulo-spinal, reticulo-spinal, and raphe-spinal cell populations, though less numerous in mdx than in control mice, were instead substantially spared. Our data further unveil the selective nature of mdx brain damage indicating a marked and selective involvement of the highest centers for motor control.

Kainic acid lesions to the lateral tegmental field of medulla: effects on cough, expiration and aspiration reflexes in anesthetized cats

We have tested the hypothesis that neurons of both the ventral reticular nucleus and the adjacent parts of the lateral tegmental field (LTF) may be important for the production of motor programs associated with cough, expiration and aspiration reflexes. Our studies were conducted on non-decerebrate, spontaneously breathing cats under pentobarbitone anesthesia. Dysfunction of the medullary LTF region above the obex, produced by uni- or bilateral injections of kainic acid (a neurotoxin), regularly abolished the cough reflex evoked by mechanical stimulation of both the tracheobronchial and laryngeal regions and in most cases also the expiration reflex induced from the glottal area. However, some electrical activity still occurred in the neurogram of the recurrent laryngeal nerve during probing the laryngeal and glottal regions. Interestingly, the aspiration reflex elicited from the nasopharynx regularly persisted, although with lower intensity after the LTF lesion. Nevertheless, successive midcollicular decerebration performed in four cats also abolished the aspiration reflex. These experiments demonstrate the importance of medullary LTF neurons for the normal occurrence of cough and expiration reflexes. One possible explanation for the elimination of these expulsive processes is that the blockade of the LTF neurons may remove an important source of a facilitatory input to the brainstem circuitries that mediate cough and expiration reflexes. In addition, the potential importance of the mesencephalic reticular formation for the occurrence of the aspiration reflex and the role of the LTF in modulating both the eupnoeic breathing and the blood pressure are also discussed.

alpha-synuclein immunopositive Parkinson's disease-related inclusion bodies in lower brain stem nuclei

Advanced silver stains and immunohistochemical reactions against alpha-synuclein were used to detect Parkinson's disease-related cytoskeletal abnormalities in select lower brain stem nuclei. Various types of inclusion bodies including inconspicuous and heretofore unnoted granular particles and thread-like Lewy neurites were visualized. Of the nuclei investigated (gigantocellular reticular nucleus, bulbar raphe nuclei, coeruleus-subcoeruleus area), only lipofuscin- or neuromelanin-laden neuronal types showed a propensity to develop the pathological changes. Neuronal types devoid of pigment deposits remained free of the cytoskeletal abnormalities. Fine, dust-like particles and small globular Lewy bodies were encountered solely within the limits of intraneuronal lipofuscin or neuromelanin deposits.

Eye deviation in patients with one-and-a-half syndrome

To understand malalignments of the visual axes in one-and-a-half syndrome, we measured eye positions in 4 patients with this syndrome under two conditions: with Frenzel goggles to prevent eye fixation and without Frenzel goggles. When fixation was prevented with the Frenzel goggles, all patients showed mild outward deviation in both eyes. Removal of the Frenzel goggles elicited adduction of the eye ipsilateral to the side of the lesion for fixation, with greater outward deviation of the contralateral eye (acute stage), or adduction of both eyes to midposition for biocular fixation (convalescent stage). In 3 patients whose outward eye deviation with Frenzel goggles was greater on the ipsilateral side, a transition from one-and-a-half syndrome to ipsilateral internuclear ophthalmoplegia was noted, whereas a transition to ipsilateral gaze palsy was seen in the one patient whose deviation was greater on the contralateral side. These findings suggest that in one-and-a-half syndrome patients, the eyes tend to be in divergent positions when fixation is prevented; ipsilateral eye deviation may result from medial longitudinal fasciculus involvement, and contralateral eye deviation may result from paramedian pontine reticular formation involvement. Viewing a target may lead to a secondary deviation or adaptation of eye positions for fixation.

A mouse genetic locus with death clock and life clock features

A senility syndrome, with weight loss and priapism, occurs in CBAT6/T6 mice, an exceptionally long-lived strain. Instead of dying at the expected time, these mice get senile weight loss and priapism and go on living. We have postulated that a mutant death clock kills the wrong neurons. Crosses with the NZW and C57BL/6 strains show causation by a single genetic locus (Priap1), with a pronounced gene dosage effect on timing. We report here that various cancers were the cause of death in 31 of 32 NZW mice, compared to only five of 22 CBAT6/T6 mice, a highly significant difference (P<0.001). The longevity of (CBAT6/T6xNZW)F1 hybrids, and the segregation of longevity with priapism and senile weight loss in (CBAT6/T6xNZW) F2 hybrids, indicates that Priap1, or a linked gene, inhibits the cancers that usually shorten the lives of NZW mice. If a timer gene is involved, the cancer resistance action could be because the locus impedes the normal mid-life regression of anti-cancer defence. The priapism suggests loss of the medullary reticular formation neurons which normally inhibit male spinal sexual reflexes. In this region of the medulla there are also the respiratory and cardiac control centres, where apoptotic neuron destruction by the wild-type locus could govern maximal life-span. The CBAT6/T6 locus may be a mutant life-stage control clock. Its discovery could be the revelation of a new, major class of aetiology of disease.

Arteether-induced brain injury in Macaca mulatta. I. The precerebellar nuclei: the lateral reticular nuclei, paramedian reticular nuclei, and perihypoglossal nuclei

Malaria poses a threat across several continents: Eurasia (Asia and parts of Eastern Europe), Africa, Central and South America. Bradley (1991) estimates human exposure at 2,073,000,000 with infection rates at 270,000,000, illnesses at 110,000,000, and deaths at 1,000,000. Significant mortality rates are attributed to infection by the parasite Plasmodium falciparum, with an estimated 90% among African children. A worldwide effort is ongoing to chemically and pharmacologically characterize a class of artemisinin compounds that might be promising antimalarial drugs. The U.S. Army is studying the efficacy and toxicity of several artemisinin semi-synthetic compounds: arteether, artemether, artelinic acid, and artesunate. The World Health Organization and the U.S. Army selected arteether for drug development and possible use in the emergency therapy of acute, severe malaria. Male Rhesus monkeys (Macaca mulatta) were administered different daily doses of arteether, or the vehicle alone (sesame oil), for a period of either 14 days, or 7 days. Neuropathological lesions were found in 14-day arteether treated monkeys in the precerebellar nuclei of the medulla oblongata, namely: (1) the lateral reticular nuclei (subnuclei magnocellularis, parvicellularis, and subtrigeminalis), (2) the paramedian reticular nuclei (subnuclei accessorius, dorsalis, and ventralis), and the perihypoglossal nuclei (n. intercalatus of Staderini, n. of Roller, n. prepositus hypoglossi). The data demonstrate that the simina meduallry precerebellar nuclei have a high degree of vulnerability when arteether is given for 14 days at dose levels between 8mg/kg per day and 24 mg/kg per day. The neurological consequences of this treatment regimen could profoundly impair posture, gait, and autonomic regulation, while eye movement disorders might also be anticipated.

Effects of acute and chronic midthoracic spinal cord injury on neural circuits for male sexual function. II. Descending pathways

In normal animals, microstimulation of the medullary reticular formation (MRF) has two effects on efferent neurons in the motor branch of the pudendal nerve (PudM). MRF microstimulation depresses motoneuron reflex discharges (RD) elicited by dorsal nerve of the penis (DNP) stimulation and produces long latency sympathetic fiber responses (SFR). The midthoracic spinal location of these descending MRF-PudM projections was studied electrophysiologically using a variety of acute and chronic lesions. Chronic lesions, in 27 mature male rats, included dorsal (DHx) or lateral (LHx) hemisections or moderate/severe contusions (Cx) at spinal level T(8). Behavioral data (sexual reflex latency, bladder voiding) obtained throughout the recovery period revealed a significant impairment of urogenital function for the DHx and severe Cx groups of animals. Microstimulation-induced PudM-RDs and PudM-SFRs, obtained in terminal electrophysiological experiments 30 days postinjury in the same 27 rats (urethan-anesthetized), were tested for a combined total of 1,404 bilateral MRF sites. PudM-RD was obtained for LHx and moderate Cx groups of animals but not for DHx or severe Cx groups. PudM-SFRs were obtained for LHx, DHx (although significantly weakened) and moderate Cx groups but not for those having received either an over-DHx or a severe Cx injury. PudM responses also were tested for 6 MRF sites in six intact control rats both before and after various select acute spinal cord lesions. For MRF sites producing a robust PudM-RD and PudM-SFR, acute bilateral lesions confined to the dorsolateral quadrant (DLQ) eliminated the PudM-RD but failed to eliminate PudM-SFRs. A deeper lesion encompassing additional white matter located dorsally in the ventrolateral quadrant (VLQ) was necessary to eliminate PudM-SFRs. Overall, these electrophysiological results provide evidence for descending projections conveying information between MRF and the lower thoracic/lumbosacral male urogenital circuitry within the DLQ and the dorsal-most aspect of VLQ at the midthoracic level of spinal cord. The alterations of supraspinal projections observed after chronic injury are likely of important clinical significance for functional recovery in cases of clinically incomplete spinal cord injury at midthoracic spinal cord.

Parkinson's disease: affection of brain stem nuclei controlling premotor and motor neurons of the somatomotor system

Pathological changes which consistently develop in the lower brain stem of patients suffering from Parkinson's disease are described against the background of the internal organization and interconnections of the involved nuclei, i.e., the gigantocellular reticular nucleus, bulbar raphe nuclei, and coeruleus-subcoeruleus area. Immunoreactions against the presynaptic protein alpha-synuclein reveal not only the voluminous forms of Lewy bodies and Lewy neurites but also the otherwise inconspicuous dot- or thread-like types. These lesions develop solely in specific neuronal types. Lipofuscin- or neuromelanin-laden projection cells which at the same time generate a long, unmyelinated or sparsely myelinated axon are particularly susceptible to developing the changes. The bulbar nuclei under consideration receive strong input from supramedullary sources, above all from higher order centers of the limbic system such as the central amygdalar nucleus, periaqueductal gray, and parabrachial nuclei. In turn, they generate descending projections to premotor and motor neurons of the somatomotor system. The disease-related deterioration of both the supramedullary limbic centers and the bulbar brain stem nuclei reduces the limbic influence and markedly impairs the control of premotor and motor neurons. This functional deficit most probably contributes to the overall dysfunction of the motor system typically evolving in the course of Parkinson's disease.

Projections from basal ganglia to tegmentum: a subcortical route for explaining the pathophysiology of Parkinson's disease signs?

Functional changes in the organisation of neuronal circuitries are generally used to explain parkinsonian motor symptoms and levodopa-induced dyskinesias. Based on information from histology and neurophysiological microrecordings of specific basal ganglia nuclei, the most widely accepted scheme is based on a central loop which starts in the cerebral cortex, makes multiple relays in the basal ganglia, and returns to the cerebral cortex. Transcranial magnetic stimulation studies, however, reveal no significant differences in the excitability of the motor cortex between normal subjects and patients with Parkinson's disease. Furthermore, electrophysiological and audiospinal facilitation studies indicate that the activity of reticular nuclei is altered in Parkinson's disease. It therefore appears that a circuit with the cortex as the only recipient of basal ganglia output is an oversimplification. This paper explores the relationships between various basal ganglia nuclei and proposes a subcortical pathway via which modifications in the basal ganglia may influence motor function.

[The clinico-pathological findings of the patients grouped as respiratory motor paralysis preceded type of ALS]

We reported five autopsied patients grouped as respiratory motor paralysis preceded type of ALS (R-ALS) classified as one clinical type of ALS from the patients living beyond respiratory failure reported in the previous paper, in which ALS the ontogenetically new motor functions in the "first motor system" proposed by Holstege involved first. The neuropathological changes of five patients were not limited in the degeneration of conventional "motor system" such as corticospinal tract and spinal and cranial motoneurons, but extended into the realm of "non-motor system", which could show the anterolateral myelin pallor in spinal cord by myelin staining, and detect the fibrillary gliosis of the anterior commissural area, the spinal grey matter of intemediate zone and anterior horn in all patients, and of medullary reticular formation in three one by Holzer staining. These pathological lesions could be included in the "first motor system". Considered from this study of the clinico-pathological findings of R-ALS based on "a new view of ALS", which respiratory failure in ALS is not terminus in ALS and total course of ALS might be TLS, it might be concluded that the clinico-pathologically involved initial lesions of ALS might be in the "first motor system", and include not only degenerations of "motor system", but also those of "non-motor system", which is the basically pathological lesions in ALS. Furthermore, the hitherto clinico-pathological ALS findings, which respiratory failure in ALS is terminus in ALS, could be included in this group, and showed as a part of ALS discussed from this study. Total clinico-pathological on ALS from the initial ones (R-type) to the advanced ones (TLS) including ALS-dementia should be considered further based on "the second and the third motor systems in addition to the first one".