Cells in and outside the motor trigeminal nucleus projecting to the cerebellar paramedian lobule

To investigate afferent projections to the cerebellar paramedian lobule (PML) from neurones in the motor trigeminal nucleus (Vmt) and the region around it, the method of retrograde transport of HRP, WGA-HRP and FG was employed in the rabbit. After tracer injection into various regions of PML, labelled neurones were observed mainly in the ventral and ventrolateral margins of the beta and gamma parts of Vmt, respectively. In the region just outside Vmt, neurones were labelled mainly in the lateral and dorsolateral parts of region 'h' and in the region adjacent to the root fibres of the facial nerve and even among them. Some neurones were recognized dorsally in region 'm' and in the pars alpha of the parvocellular reticular nucleus. The projection is sparse and bilateral with a slight ipsilateral predominance. Neurones in Vmt send axons to PML sublobules b-f. Projection from regions around Vmt reaches all PML sublobules with sublobules e-f receiving more fibres.     

Learning- and cerebellum-dependent neuronal activity in the lateral pontine nucleus.

The effects of inactivation of cerebellar deep nuclei and the lateral pontine nucleus on classical eyeblink conditioning with tone or lateral reticular nucleus (LRN) stimulation as conditioned stimuli (CSs) were examined. Inactivation of cerebellar deep nuclei abolished eyeblink conditioned responses (CRs) when the CS was either a tone or LRN stimulation. Inactivation of the lateral pontine nucleus prevented only the acquisition and retention of tone-evoked eyeblink CRs. Multiple-unit recording demonstrated that when LRN stimulation was used as the CS, inactivation of the interpositus nucleus abolished learning-related neuronal activity in the lateral pontine nucleus, whereas inactivation of pontine nucleus had little effect on similar activity in the interpositus nucleus. Thus, the learning-induced neuronal activity in the lateral pontine nucleus was most likely driven by the cerebellar interpositus nucleus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of projection neurons in the pontine nuclei and the nucleus reticularis tegmenti pontis of the rat

Dendritic features of identified projection neurons in two precerebellar nuclei, the pontine nuclei (PN) and the nucleus reticularis tegmenti pontis (NRTP) were established by using a combination of retrograde tracing (injection of fluorogold or rhodamine labelled latex micro-spheres into the cerebellum) with subsequent intracellular filling (lucifer yellow) in fixed slices of pontine brainstem. A multivariate analysis revealed that parameters selected to characterize the dendritic tree such as size of dendritic field, number of branching points, and length of terminal dendrites did not deviate significantly between different regions of the PN and the NRTP. On the other hand, projection neurons in ventral regions of the PN were characterized by an irregular coverage of their distal dendrites by appendages while those in the dorsal PN and the NRTP were virtually devoid of them. The NRTP, dorsal, and medial PN tended to display larger somata and more primary dendrites than ventral regions of the PN. These differences, however, do not allow the differentiation of projection neurons within the PN from those in the NRTP. They rather reflect a dorso-ventral gradient ignoring the border between the nuclei. Accordingly, a cluster analysis did not differentiate distinct types of projection neurons within the total sample. In both nuclei, multiple linear regression analysis revealed that the size of dendritic fields was strongly correlated with the length of terminal dendrites while it did not depend on other parameters of the dendritic field. Thus, larger dendritic fields seem not to be accompanied by a higher complexity but rather may be used to extend the reach of a projection neuron within the arrangement of afferent terminals. We suggest that these similarities within dendritic properties in PN and NRTP projection neurons reflect similar processing of afferent information in both precerebellar nuclei.     

The projections of the lateral reticular nucleus to the deep cerebellar nuclei. An experimental analysis in the rat

The projections of the lateral reticular nucleus (LRN) to the cerebellar nuclei were studied using the retrograde axonal transport of tetramethyl rhodamine dextran amine (10% solution in 0.01 M neutral phosphate buffer) in 19 adult Wistar strain rats. The cerebellar nuclei receive topographically organized projections from the LRN. The projections are bilateral with an ipsilateral predominance and they are symmetrical. The contralateral component is progressively larger for projections to the nuclei interpositalis, to the nucleus lateralis and to the nucleus medialis. The projections to the various cerebellar nuclei arise from rostrocaudally oriented columns of neurons located in different (partly overlapping) areas of the magnocellular division of the LRN. The nucleus lateralis receives terminals from the dorsomedial area (mainly from the rostral level of the LRN), the nuclei interpositalis from the dorsolateral area (mainly from the central level) and the nucleus medialis from the intermedioventral area (mainly from the caudal level). Afferent fibres from the small subtrigeminal division were traced to the three cerebellar nuclei and from the parvocellular division to the nuclei interpositalis and medialis. The density of the projections from the LRN to the nuclei interpositalis increases progressively with the shift of the terminal field from the rostrolateral to the caudomedial part of the nucleus. The projections to the nucleus lateralis reach principally the dorsolateral hump, whereas only a few neurons project to the other divisions (parvo- and magnocellular). The projections to the various regions of the nucleus medialis show different densities. The highest density was found for projections to the caudal part, in particular to the dorsolateral protuberance and to the ventrolateral area of the middle division. Conversely, a low density of projections was found for the other areas of the middle division. The regions of the magnocellular division of the LRN which project to the nuclei lateralis (and are thus related to the cerebral cortex), interpositalis (related to the red nucleus) and medialis (related to the spinal cord) also receive afferent terminals from the cerebral cortex, the red nucleus and the spinal cord respectively, in addition to various afferent inputs. Thus, each of these areas is apparently concerned with integrating some spinal and supraspinal information in reverberating circuits.     

Cat pontocerebellar network: numerical capacity and axonal collateral branching of neurones in the pontine nuclei projecting to individual parafloccular folia

We have studied the convergence and divergence in the pontocerebellar pathway. Two or three different fluorescent tracers were injected in separate folia of the parafloccular complex. Retrogradely labelled cells were quantitatively recorded. The estimated total number of labelled neurones in the pontine nuclei contralateral to the injection sites was 18000 (median; range 5000-46000; 14 cell populations, six animals). Using stereological principles, the total number of neurones on one side in the pontine nuclei was estimated to be 490000 (mean; n = 6). Thus, approximately 4% of the total number of neurones in the pontine nuclei would project to a single parafloccular folium. Assuming that the highest estimates of labelled cells are the most representative, the proportion would be 9%. Considering that the volume injected makes up a tiny fraction of the total cerebellar cortical volume, these figures reflect an extreme convergence. After injections in adjacent folia we observed 19-27% double labelling. The double labelling frequency dropped steeply with increasing distance between injections. The strong convergence and limited local axonal branching suggest the existence of extensive branching to widely separated cerebellar regions.     

Classical conditioning of the rabbit eyelid response with a mossy-fiber stimulation CS: II. Lateral reticular nucleus stimulation.

Stimulation of mossy fibers arising from the pontine nuclei can be used as a conditioned stimulus (CS) during classical conditioning of the eyelid/nictitating membrane response (NM). In the present experiment we stimulated another source of mossy fibers, the lateral reticular nucleus (LRN), as a CS for NM conditioning. LRN stimulation was an effective CS, resulting in learning, and the conditioned response to LRN stimulation showed normal extinction. Unpaired presentation of CS and US did not result in pseudo-conditioning. Lesions of the cerebellar dentate-interpositus region abolished the conditioned response but left the unconditioned reflex response intact. We suggest that mossy fibers may normally carry CS information to the cerebellum. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Projections of the nucleus of the basal optic root in pigeons (Columba livia) revealed with biotinylated dextran amine

The nucleus of the basal optic root (nBOR) of the accessory optic system is known to be involved in the analysis of the visual consequences of self-motion. Previous studies have shown that the nBOR in pigeons projects bilaterally to the vestibulocerebellum, the inferior olive, the interstitial nucleus of Cajal, and the oculomotor complex and projects unilaterally to the ipsilateral pretectal nucleus lentiformis mesencephali and the contralateral nBOR. By using the anterograde tracer biotinylated dextran amine, we confirmed these projections and found (previously unreported) projections to the nucleus Darkshewitsch, the nucleus ruber, the mesencephalic reticular formation, and the area ventralis of Tsai as well as ipsilateral projections to the central gray, the pontine nuclei, the cerebellar nuclei, the vestibular nuclei, the processus cerebellovestibularis, and the dorsolateral thalamus. In addition to previous studies, which showed a projection to the dorsomedial subdivision of the contralateral oculomotor complex, we found terminal labelling in the ventral and dorsolateral subdivisions. Individual fibers were reconstructed from serial sections, and collaterals to various nuclei were demonstrated. For example, collaterals of fibers projecting to the vestibulocerebellum terminated in the vestibular or cerebellar nuclei; collaterals of fibers to the inferior olive terminated in the pontine nuclei; many individual neurons projected to the interstitial nucleus of Cajal, the nucleus Darkshewitsch, and the central gray and also projected to the nucleus ruber and the mesencephalic reticular formation; collaterals of fibers to the contralateral nucleus of the basal optic root terminated in the mesencephalic reticular formation and/or the area ventralis of Tsai; neurons projecting to the nucleus lentiformis mesencephali also terminated in the dorsolateral thalamus. The consequences of these data for understanding the visual control of eye movements, neck movements, posture, locomotion, and visual perception are discussed.     

Collateral projections of gamma-aminobutyric acid positive neurons from the lateral superior nucleus to the cochlea and cochlear nucleus in guinea pigs

Collateral projections of gamma-aminobutyric acid (GABA) neurons from the lateral superior olivary nucleus (LSO) to the cochlea and cochlear nuclei in the guinea pigs were studied by injection of two retrograde fluorescent neuronal tracers. For experiments, fast blue (FB) was injected into the scala tympani of one cochlea and diamidine yellow (DY) was injected into cochlear nuclei of the same side. The results showed that the FB-labelled cells and DY-labelled cells constituted approximately 80.8% and 12.4%, respectively; FB and DY double-labelled cells constituted about 6%; FB and DY labelled cells with GABA constituted about 0.7% in the ipsilateral LSO. In the contralateral LSO, the FB and DY labelled cells were less than those of ipsilateral LSO and no FB-DY double-labelled cells could be found. Our results suggest that there are collateral projections of GABA neurons from ipsilateral LSO to the organ of Corti and cochlear nuclei in the guinea pig, even though the numbers are few. The results also show that the efferent projections to the cochlea and cochlear nuclei generally come from two different auditory neuronal nuclei.     

Cerebellar corticonuclear fibers of the paramedian lobule of tree shrew (Tupaia glis) with comments on zones

Following a series of lesions in dorsal (DPML) and ventral (VPML) divisions of tree shrew (Tupaia) paramedian lobule (PML), the distribution of degenerated axons within the deep cerebellar nuclei was determined using the Fink and Heimer ('67) method. Damage to PML produced axonal degeneration in lateral (NL), anterior interposed (NIA), and posterior interposed (NIP) cerebellar nuclei. No degenerated fibers could be traced to either the medial cerebellar nucleus or vestibular complex, via juxtarestiform body, from lesions in PML. Corticonuclear fibers to NL, NIA, and NIP from PML cortex are topographically organized. Subsequent to lesions of lateral DPML, axonal debris is found in rostral and medial NL, while the lateral edge of VPML projects primarily into medial NL. According to the terminology of Voogd ('69) these lateral regions of PML represent the D zone. The NIP receives corticonuclear input from a relatively wide middle area of both portions of PML, interpreted as the C2 zone. There is some evidence which suggests that medial portions of the C2 area of DPML project into more lateral areas of NIP, while lateral regions of this zone in DPML are related to more medial NIP. This projection pattern is invited for the C2 area of VPML; medial C2 to medial NIP, lateral C2 to lateral NIP. Corticonuclear fibers of PML which enter NIA appear to arise from a narrow, irregular, partially discontinuous strip of cortex located at the interface of the D and C2 areas in lateral PML and from a wider, more regular region in the most medial areas of this lobule. These represent, respectively, the C3 and C1 zones. Although an overall pattern of zones is present, there is evidence to suggest that their spatial organization differs from DPML to VPML. The zonal patterns appears to be more obvious in VPML, while this pattern for DPML is less distinct. This is interpreted as indicating that either (1) zones C1--C3 overlap to a greater degree in DPML than in VPML, or (2) zones C1 and C3 may converge in rostral DPML, partially obliterating the intervening zone C2. The different ways in which zonal terminology is applied to both corticonuclear and certain of the afferent cerebellar systems are discussed.     

Projections from the nucleus isthmi to the visual and auditory centres in the frog, Rana esculenta

The lectin Phaseolus vulgaris leucoagglutinin was injected into the nucleus isthmi (NI) in order to study its anterograde and retrograde projections in the frog. The following areas of termination could be discerned in the brainstem: (1) Each of the five subnuclei of the torus semicircularis (TOS) received fibres from the NI. The projection was the most extensive on the three main subnuclei which disclosed also retrogradely labelled neurones on the side of injections. The subependymal subnuclei contained the least number of labelled fibres. (2) Both hemispheres of the optic tectum (TO) were supplied by fibres from the NI. Labelled fibres were more numerous on the side of injections, and preterminal and terminal fibres covered columnar-like areas in layers 8 and 9. Several retrogradely labelled neurones were found in layer 6. Relatively few labelled fibres were seen on the contralateral side. They formed patch-like areas of termination in layer 9. (3) The anterodorsal (AD) and anteroventral (AV) nuclei were reciprocally inter-connected with the NI. The fibre connections were less extensive on the contralateral side. In the rhombencephalon (4) the cochlear nucleus (CN) and (5) the superior olive (SO) were also reciprocally connected with the NI on both sides, but with much weaker projection on the side contralateral to injections. (6) Only a weak anterograde labelling was observed in the contralateral NI and in the ipsilateral reticular formation.     

Connections to cerebellar cortex (Larsell's HVI) in the rabbit: A WGA-HRP study with implications for classical eyeblink conditioning.

Conditioned eyeblink responses are presumably learned in the cerebellum and relayed to motoneurons by way of the red nucleus. Projections from the red nucleus to cerebellar cortex (Larsell's lobule HVI) could be important for shaping temporally adaptive features of the conditioned response. Rabbits that had pipettes containing wheat germ agglutinated horseradish peroxidase (WGA-HRP) implanted unilaterally into HVI showed retrograde labeling of neurons within subregions of the contralateral red nucleus implicated in eyeblink conditioning by lesioning and recording studies. Retrogradely labeled neurons were also observed in the pontine nuclei, inferior olive, and spinal trigeminal nucleus pars oralis. Projections to HVI provide a possible neural substrate for implementing time-derivative computational models of learning in the cerebellum. Time-derivative models are capable of describing the timing and topography of conditioned responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative and somatotopic mapping of neurones in the trigeminal mesencephalic nucleus and ganglion innervating teeth in monkey and baboon

Neurones of the trigeminal mesencephalic nucleus (Mes V) and ganglion innervating the periodontium of incisor, canine and molar teeth in 10 monkeys and 10 baboons were counted and mapped using the horseradish peroxidase (Hrp), retrograde axonal transport method. Periodontal afferent neurones of all these teeth were well represented in the Mes V, although the incisors had a significantly higher number of labelled neurones than the canines or molars. The primary cell bodies of the periodontal afferents were located mainly in the caudal part of the ipsilateral Mes V from the level of the inferior colliculus to the floor of the fourth ventricle in the pons. The caudal periodontal Mes V neurones may be favourably located to make collateral connections with the trigeminal motor nucleus for jaw reflexes. Incisors and canines had a large and predominantly ipsilateral representation of Hrp-labelled neurones in the ganglion. In contrast, molar representation in the ganglion was sparse and all labelled neurones supplied ipsilateral teeth. The maxillary and mandibular teeth had a somatotopic distribution within the respective maxillary (middle) and mandibular (posterolateral) compartments of the trigeminal ganglion. It is suggested that the anterior teeth with greater connections to the Mes V and the ganglion may impart greater sensory perception and be involved in jaw reflexes to ensure a good occlusal relation during mastication, while the afferent connections of the molars may initiate complex jaw reflexes during the occlusal phase of mastication.     

A case of unilateral gustatory disturbance produced by the contralateral midbrain lesion

We reported a case of unilateral gustatory disturbance produced by a lesion in the contralateral midbrain. A 37-year-old man first noticed dysesthesia in the left side of his face. Later, the patient developed dysesthesia of the left part of the lip, muscular weakness on the left lower extremity and gustatory disturbance on the left side. MR scan disclosed a lesion in the tegmentum of the right midbrain, which showed low intensity on a T1-weighted image and high intensity on a T2-weighted image. This lesion could be due to multiple sclerosis. This case suggests that the unilateral gustatory information ascends via the contralateral pathway at the midbrain level. It is suggested that the central gustatory pathways above the ipsilateral pontine taste are ascend via the contralateral projections to the thalamic taste area (parvicellular portion of the ventral posteromedial thalamic nucleus, VPMpc).     

Comparison of in vivo mutagenesis in the endogenous Hprt gene and the lacI transgene of Big Blue(R) rats treated with 7, 12-dimethylbenz[a]anthracene

The lacI transgene of Big Blue(R) (BB) rats was evaluated as a reporter of in vivo mutation by comparing mutant frequencies (MFs) in it and in the endogenous Hprt gene. Seven-week old female BB rats were given single doses of 0, 20, 75 and 130 mg/kg of 7, 12-dimethylbenz(a)anthracene (DMBA) by gavage, and Hprt and lacI MFs in splenic lymphocytes were measured over a period of 18 weeks. The Hprt MFs in treated rats increased for 10 weeks and then declined; 130 mg/kg of DMBA produced a maximum Hprt MF of 168+/-11.4x10-6 clonable lymphocytes, while the MF in control rats was 7.4+/-1. 5x10-6. DMBA exposure of generic F344 rats resulted in a similar time-course of mutant induction but produced about 50% higher Hprt MFs with the 75 and 130 mg/kg doses. In contrast, the lacI MFs increased for 6 weeks and then remained relatively constant; 130 mg/kg of DMBA produced a maximum increase in lacI MF of 341+/-83x10-6 PFU compared with 25+/-5x10-6 PFU in control rats. The Hprt mutant frequencies in DMBA-treated BB and F344 rats were significantly increased over control values for every dose-time combination examined, while only the 130 mg/kg dose consistently produced lacI MFs that were significantly above the controls. In addition, the fold-increase in MF for treated vs. control rats was two times higher for the Hprt gene than the lacI gene due to the higher MFs in the lacI gene of control rats. Differences between the lacI and Hprt genes in the kinetics of mutant induction, in the frequency of induced mutants, and in the sensitivity of mutant detection could be explained at least partially by the properties of these two genes.     

Secondary vestibulo-oculomotor projections in larval sea lamprey: anterior octavomotor nucleus

The ventral octavolateral area of lampreys contains three nuclei: the anterior, intermediate and posterior octavomotor nuclei, formed of large neurons that are contacted by thick primary vestibular fibres. We used horseradish peroxidase (HRP) or fluorescein-dextran-amine (FDA) labelling to study the projections of the anterior octavomotor nucleus (AON) in the larval sea lamprey, Petromyzon marinus. The tracers were injected either in the AON, the oculomotor nucleus or the rostralmost spinal cord. HRP injection in the AON labelled thick axons that coursed to the basal mesencephalic tegmentum, where most decussate and project to the oculomotor nucleus and the third Müller cell. Electron microscopy confirmed that AON axons contact with the contralateral third Müller cell and with oculomotor neurons. Some AON axons run in the mesencephalic tegmentum and the ventral diencephalon. An AON axon was observed to run close to the axon of the contralateral third Müller cell, establishing what appeared to be en passant contacts. HRP injection in the AON also revealed commissural fibres projecting to the contralateral octavolateral area. HRP or FDA injections in the oculomotor nucleus labelled both large and small neurons of the AON, mostly contralateral to the injection site, as well as of cells in the intermediate octavomotor nucleus, mainly ipsilateral. HRP injection in the AON or in the rostral spinal cord did not reveal any projections from the AON to the spinal cord. Our results indicate that the pattern of octavo-oculomotor connections in the lamprey is different from that observed in other vertebrates.     

New methods of rectum and colon x-ray study in patients with constipation

In the 14, 3 and 90 day-experiments with tail-suspended rats, histochemical determination of myosin ATP-ase activity in m. soleus and m. gastrocnemius preincubated in acid and neutral media was followed by measurement of the cross-sectional areas (CSAs) of muscular fibers (MF) and calculation of the percentage of various types of MF. By day 30 of testing atrophy in m. soleus reached maximum and stabilized. By that time, MF CSAs were less than in the control by 69, 62, and 68% in MF-I, -IIA and -IIC, respectively. Slow MF underwent the transformation into fast and intermediate. In slow MF this process peaked by day 3 when the number of these fibers decreased by 28% as compared to the control, and stabilized. The transformation of intermediate fibers into the fast ones was progressing simultaneously. This process was not finished by day 90. Atrophy of m. gastrocnemius was less pronounced than in m. soleus. On day 14 of experiment, MF CSAs, except for IIB, were by 30% smaller than in the control. Type IIB MF were less affected as their CSAs decreased by only 17% as compared with the control. On day 90, CSAs in both slow and IIC-type fast MFs remained approximately same as in the rats investigated on day 14. Fast MF CSAs either tended to (IIA) or regained (IIB) the norm. Hence, atrophy in m. gastrocnemius stabilized earlier than in m. soleus. Besides, longer suspension led to a partial or complete reconstruction of two out of three types of fast fibers. The percent ratio of MFs was unchanged; however, during the ATP-ase determination slow IB-type MFs assumed th color typical of fast MFs.     

Contralateral cortical projection to the mediodorsal thalamic nucleus: origin and synaptic organization in the rat

The origin of the corticothalamic projections to the contralateral mediodorsal nucleus, the collateralization of cortical fibers and their synaptic organization in the ipsi- and contralateral mediodorsal nuclei were investigated in adult rats with double retrograde fluorescent and anterograde tracing. After tracer injections in the mediodorsal nuclei on either side, neurons were retrogradely labeled in all the areas of the contralateral prefrontal cortex in which ipsilateral labeling was also observed. Contralateral corticothalamic cells accounted for 15% of the labeled neurons in the orbital and agranular insular areas, while their proportion was lower (3%) in the anterior cingulate cortex. Up to 70% of the contralateral cortical neurons were double labeled by bilateral injections in the mediodorsal nuclei. At the electron microscopic level, unilateral injections of biotinylated dextran-amine in the orbitofrontal cortex resulted in anterograde labeling of small terminals and a few large boutons in the ipsilateral mediodorsal nucleus, while only small boutons were identified contralaterally. The diameter of postsynaptic dendritic profiles contacted by labeled small cortical endings was significantly larger in the ipsilateral mediodorsal nucleus than contralaterally. These findings demonstrate that dense contralateral cortical projections to the mediodorsal nucleus derive from the orbital and agranular insular areas, and that crossed corticothalamic afferents are mostly formed by collaterals of the ipsilateral connections. Our observations also point out the heterogeneity of corticothalamic boutons in the rat mediodorsal nucleus and morphological differences in the synaptic organization of prefrontal fibers innervating the two sides, indicating that ipsilateral cortical afferents may be more proximally distributed than crossed cortical fibers on dendrites of mediodorsal neurons.     

Behavioural effects of subthalamic nucleus lesions in the hemiparkinsonian marmoset (Callithrix jacchus)

Recent studies in non-human primates support a role for the subthalamic nucleus in the expression of parkinsonian symptomatology, and it has been proposed that subthalamic lesions may provide a surgical treatment for the symptoms of Parkinson's disease in humans. We have applied a broad range of behavioural tests to characterize the effects of lesions of the subthalamic nucleus on parkinsonian symptoms in the unilateral 6-hydroxydopamine (6-OHDA) lesioned marmoset (Callithrix jacchus). Thirteen marmosets were trained on a battery of behavioural tasks that were conducted at regular intervals before and after surgery. All received unilateral 6-OHDA lesions to the medial forebrain bundle. Seven animals were then given an additional N-methyl-D-aspartate lesion of the ipsilateral subthalamic nucleus, whereas the remaining six animals received a variety of control or sham lesions to the nucleus. The 6-OHDA lesions induced a strong ipsilateral bias in head position; mild-moderate ipsilateral rotation spontaneously and after injection of saline or amphetamine; and contralateral rotation after injection of apomorphine. Hemineglect was evident as delayed initiation of reaches on the contralateral side on the staircase reaching task. Additional subthalamic lesions significantly reversed the bias in head position from ipsilateral to contralateral and decreased neglect as evidenced by improved latencies to initiate reaching on the contralateral side at the staircase. However, deficits in skilled movements persisted in the subthalamic nucleus lesion group in that they did not complete the staircase task any faster than the control group and remained impaired on another task which required reaching into tubes. These behavioural effects demonstrate that excitotoxic lesioning of the subthalamic nucleus can ameliorate some, but not all, parkinsonian-like deficits in the unilateral 6-OHDA lesioned marmoset.     

Purification of the hepatic glycogen-associated form of protein phosphatase-1 by microcystin-Sepharose affinity chromatography

Auditory brainstem potential components II and V are delayed in the contralateral recording in comparison with that ipsilateral to the stimulus. Wave III is recorded earlier contralaterally. The effect of increasing stimulus repetition rate on the ipsilateral/contralateral latency differences in these components was examined. There is a progressive increase in latency from Wave I to Wave V ipsilaterally with an increase in stimulus rate; however, contralaterally there is no further increase in latency after Wave III. At 40 Hz stimulus rate, therefore, the ipsi/contra difference in the latency of Wave V disappears, suggesting that there is a differential effect of peripheral and central adaptation on the ipsilateral and contralateral auditory pathways.