Endocannabinoid (eCB), 2-arachidonoyl-glycerol (2-AG), the most abundant eCB in the brain, regulates diverse neural functions. Here we linked multiple homozygous loss-of-function mutations in 2-AG synthase diacylglycerol lipase beta (DAGLB) to an early onset autosomal recessive Parkinsonism. DAGLB is the main 2-AG synthase in human and mouse substantia nigra (SN) dopaminergic neurons (DANs). In mice, the SN 2-AG levels were markedly correlated with motor performance during locomotor skill acquisition. Genetic knockdown of Daglb in nigral DANs substantially reduced SN 2-AG levels and impaired locomotor skill learning, particularly the across-session learning. Conversely, pharmacological inhibition of 2-AG degradation increased nigral 2-AG levels, DAN activity and dopamine release and rescued the locomotor skill learning deficits. Together, we demonstrate that DAGLB-deficiency contributes to the pathogenesis of Parkinsonism, reveal the importance of DAGLB-mediated 2-AG biosynthesis in nigral DANs in regulating neuronal activity and dopamine release, and suggest potential benefits of 2-AG augmentation in alleviating Parkinsonism.
        
Title: Oxidative stress and detoxification mechanisms of earthworms (Eisenia fetida) after exposure to flupyradifurone in a soil-earthworm system Qiao Z, Li P, Tan J, Peng C, Zhang F, Zhang W, Jiang X Ref: J Environ Manage, 322:115989, 2022 : PubMed
Flupyradifurone (FLU) has great application potential in agricultural production as a new generation of neonicotinoid insecticide after imidacloprid. Nevertheless, the toxic effects of FLU on non-target soil organisms remain unclear, resulting in considerable environmental risks. We evaluated the acute and subchronic toxicities of FLU to earthworms. The results of acute toxicity show that the median lethal concentration (LC(50)) values (14 d) of FLU were 186.9773 mg kg(-1) for adult earthworms and 157.6502 mg kg(-1) for juveniles, respectively. The subchronic toxicity of FLU that focused on the activities of antioxidant and detoxication enzymes showed the superoxide dismutase (SOD), catalase (CAT), and glutathione-S transferase (GST) activities in earthworms increased while the peroxidase (POD) and acetylcholinesterase (AChE) activities decreased after exposure to FLU. Oxidative damage analyses revealed that the reactive oxygen species (ROS) level and malonaldehyde (MDA) content in earthworms were increased by FLU, resulting in DNA damage. Transcriptomics and RT-qPCR confirmed that FLU influenced the expression of genes related to antioxidant response and detoxification of earthworms. Ultimately detoxification metabolism, environmental information processing, cell processes, and immune system pathways are significantly enriched to respond jointly to FLU. Our study fills the gaps in the toxicity of FLU to earthworms, providing a basis for its risk assessment of soil ecosystems and non-target biological toxicity.
        
Title: Thyroid endocrine disruption and neurotoxicity of gestodene in adult female mosquitofish (Gambusia affinis) Tan J, Liang C, Guo Y, Zou H, Ye J, Hou L, Wang X Ref: Chemosphere, :137594, 2022 : PubMed
The frequent detection of progestins in various aquatic environments and their potential endocrine disruptive effects in fish have attracted increasing attention worldwide. However, data on their effects on thyroid function and neurotoxicity in fish are limited, and the underlying mechanisms remain unclear. Here, the effects of gestodene (GES, a common progestin) on the thyroid endocrine and nervous systems of mosquitofish (Gambusia affinis) were studied. Adult female fish were exposed to GES at environmentally relevant concentrations (4.4-378.7 ng/L) for 60 days. The results showed that exposure to 378.7 ng/L GES caused a significant decrease in fish growth compared with the control and a marked reduction in the total distance traveled (50.6%) and swimming velocity (40.1-61.9%). The triiodothyronine (T3) levels were significantly increased by GES in a dose-dependent manner, whereas those of tetraiodothyronine (T4) were significantly decreased only at the G500 concentration. The acetylcholinesterase (AChE) activity was decreased significantly in the 4.42 ng/L GES treatments, but increased significantly at 378.67 ng/L. In the brain, a strong increase in the transcriptional levels of bdnf, trh, and dio2 was observed in fish after the 378.7 ng/L treatment. In addition, chronic exposure to GES caused colloid depletion with a concentration-dependent manner in the thyroid, and angiectasis, congestion, and vacuolar necrosis in the brain. These findings provide a better understanding of the effects of GES and associated underlying mechanisms in G. affinis.
        
Title: UHPLC With On-Line Coupled Biochemical Detection for High Throughput Screening of Acetylcholinesterase Inhibitors in Coptidis Rhizoma and Cortex Phellodendri Tan J, Zhang X, Fang J, Shen H, Ding X, Zheng G Ref: Journal of Chromatography Sci, :, 2021 : PubMed
We developed a new on-line method of ultra-performance liquid chromatography coupled with biochemical detection (UHPLC-BCD) to screen acetylcholinesterase (AChE) inhibitors in complex matrixes. Chromatography separation was performed using an Xtimate UHPLC C18 column (100 mm x 2.1 mm, 1.8 microm) and a gradient elution with methanol-0.1% formic acid at a flow rate of 0.08 mL/min. The BCD was based on a colorimetric method using Ellman's reagent, and the detection wavelength was at 405 nm. Galanthamine was used as a positive reference to validate the methodology. The detection and quantitation limits of the UHPLC-BCD method were 0.018 and 0.060 microg, respectively. A functional equation was generated in terms of the negative peak area (X) and galanthamine concentration (Y, microg/mL). The regression equation was Y = 0.0028X2 + 0.4574X + 50.7776, R2 = 0.9993. UHPLC-fourier-transform mass spectrometry detection results revealed that five alkaloids showed obvious AChE inhibitory activities including coptisin, epiberberine, jatrorrhizine, berberine and palmatine. The relative AChE inhibitory activities of jatrorrhizine, berberine and palmatine in the Coptidis Rhizoma sample were equal to that of 257.0, 2355 and 283.9 microg/mL of galanthamine, respectively. This work demonstrated that the UHPLC-BCD method was convenient and feasible, and could be widely used for the screening and activity evaluation of the bioactive components in the complex extracts.
        
Title: Enhancing the thermostability of a mono- and diacylglycerol lipase from Malassizia globose by stabilizing a flexible loop in the catalytic pocket Xing YN, Tan J, Wang Y, Wang J Ref: Enzyme Microb Technol, 149:109849, 2021 : PubMed
A lipase from Malassizia globose, named SMG1, is highly desirable for industrial application due to its substrate specificity towards mono- and diacylglycerol. To improve its thermostability, we constructed a mutant library using an error-prone polymerase chain reaction, which was screened for both initial and residual enzymatic activity. Selected mutants were further studied using purified proteins for their kinetic thermostability at 45 degC, T(50) (the temperature at which the enzyme loses half of its activity), and the optimal reaction temperature. Results showed that the majority of mutations with improved thermostability were on the protein surface. D245N and L270P showed the most significant thermostability enhancement with an approximately 3 degC increase in T(50) compared to wild-type (WT). In addition, combining these two mutations resulted in an increase of T(50) by 5 degreesC. Also, the optimal reaction temperatures of L270P and this double mutant are 10 degC higher than WT. The double mutant showed an approximately 100-fold increase in half-life at 45 degC and higher enzymatic activities at 30 degC and above compared to WT. High-temperature unfolding molecular dynamics simulation suggested that the double mutant stabilized a flexible loop in the catalytic pocket.
OBJECTIVE Respiratory dysfunction is the leading cause of mortality following upper cervical spinal cord injury (SCI). The authors' previous study suggested that vagus nerve (VN) and phrenic nerve (PN) anastomosis could partially improve respiratory function in rabbits that had been subjected to PN transection. As a branch of the VN and a motor fiber-dominated nerve, the recurrent laryngeal nerve (RLN) seems a better choice to anastomose with the PN for respiratory function restoration after upper cervical SCI. This study was designed to determine whether RLN-PN anastomosis could restore the respiratory function after upper cervical SCI in rabbits. METHODS Twelve male New Zealand rabbits were randomly divided into 3 groups: 1) sham group (no injury), 2) transection group (right RLN and PN were transected), and 3) bridge group (transected right RLN and PN were immediately anastomosed). Spontaneous discharges of the RLN and PN were compared using a bio-signal collection system. RLN and PN cross sections were stained for acetylcholinesterase (AChE), and the numbers of motor fibers were compared. Three months after the initial surgical procedures, the movement of the diaphragm was assessed using a digital subtraction angiography (DSA) system, and discharges from the right diaphragm muscle were recorded. Toluidine blue staining, electron microscopy, and staining for AChE were used to assess whether motor fibers from the RLN regenerated into the PN, and sections of diaphragm were examined after AChE staining to assess the motor endplates. RESULTS Both the RLN and PN exhibited highly rhythmic discharges, synchronized with respiration, and most fibers in the RLN and PN were found to be motor fibers. Numerous myelinated fibers were observed in anastomosed PN using toluidine blue staining and electron microscopy. Staining for AChE showed that those regenerated fibers had typical characteristics of motor fibers, and motor endplates with typical morphological characteristics were observed in the diaphragm. Reestablished rhythmic contraction of the hemidiaphragm was directly observed using the DSA system, and rhythmic spontaneous discharge was recorded from the reinnervated hemidiaphragm using the bio-signal collection system. CONCLUSIONS Motor fibers from the RLN could regenerate into the PN after end-to-end anastomosis and reinnervate the denervated hemidiaphragm in rabbits. Those regenerated motor fibers restored rhythmic and autonomic movement of the paralyzed diaphragm. These results suggest that the RLN is an optimal donor nerve to anastomose with the PN in order to reestablish the autonomic movement of paralyzed diaphragms after high-level SCI.
Heteroatom-rich organoboron compounds have attracted attention as modulators of enzyme function. Driven by the unmet need to develop chemoselective access to boron chemotypes, we report herein the synthesis of alpha- and beta-aminocyano(MIDA)boronates from borylated carbonyl compounds. Activity-based protein profiling of the resulting beta-aminoboronic acids furnishes selective and cell-active inhibitors of the (ox)lipid-metabolizing enzyme alpha/beta-hydrolase domain 3 (ABHD3). The most potent compound displays nanomolar in vitro and in situ IC50 values and fully inhibits ABHD3 activity in human cells with no detectable cross-reactivity against other serine hydrolases. These findings demonstrate that synthetic methods that enhance the heteroatom diversity of boron-containing molecules within a limited set of scaffolds accelerate the discovery of chemical probes of human enzymes.
Date palm (Phoenix dactylifera L.) is a cultivated woody plant species with agricultural and economic importance. Here we report a genome assembly for an elite variety (Khalas), which is 605.4 Mb in size and covers >90% of the genome (~671 Mb) and >96% of its genes (~41,660 genes). Genomic sequence analysis demonstrates that P. dactylifera experienced a clear genome-wide duplication after either ancient whole genome duplications or massive segmental duplications. Genetic diversity analysis indicates that its stress resistance and sugar metabolism-related genes tend to be enriched in the chromosomal regions where the density of single-nucleotide polymorphisms is relatively low. Using transcriptomic data, we also illustrate the date palm's unique sugar metabolism that underlies fruit development and ripening. Our large-scale genomic and transcriptomic data pave the way for further genomic studies not only on P. dactylifera but also other Arecaceae plants.
        
Title: Posttraumatic Stress Disorder Exacerbation with Cholinesterase Inhibitor in a Patient with Dementia Kolli V, Dickson J, Amani M, Tan J Ref: Innov Clin Neurosci, 10:11, 2013 : PubMed
Strigolactones (SLs), a newly discovered class of carotenoid-derived phytohormones, are essential for developmental processes that shape plant architecture and interactions with parasitic weeds and symbiotic arbuscular mycorrhizal fungi. Despite the rapid progress in elucidating the SL biosynthetic pathway, the perception and signalling mechanisms of SL remain poorly understood. Here we show that DWARF 53 (D53) acts as a repressor of SL signalling and that SLs induce its degradation. We find that the rice (Oryza sativa) d53 mutant, which produces an exaggerated number of tillers compared to wild-type plants, is caused by a gain-of-function mutation and is insensitive to exogenous SL treatment. The D53 gene product shares predicted features with the class I Clp ATPase proteins and can form a complex with the alpha/beta hydrolase protein DWARF 14 (D14) and the F-box protein DWARF 3 (D3), two previously identified signalling components potentially responsible for SL perception. We demonstrate that, in a D14- and D3-dependent manner, SLs induce D53 degradation by the proteasome and abrogate its activity in promoting axillary bud outgrowth. Our combined genetic and biochemical data reveal that D53 acts as a repressor of the SL signalling pathway, whose hormone-induced degradation represents a key molecular link between SL perception and responses.
Optogenetic methods have emerged as powerful tools for dissecting neural circuit connectivity, function and dysfunction. We used a bacterial artificial chromosome (BAC) transgenic strategy to express the H134R variant of channelrhodopsin-2, ChR2(H134R), under the control of cell type-specific promoter elements. We performed an extensive functional characterization of the newly established VGAT-ChR2(H134R)-EYFP, ChAT-ChR2(H134R)-EYFP, Tph2-ChR2(H134R)-EYFP and Pvalb(H134R)-ChR2-EYFP BAC transgenic mouse lines and demonstrate the utility of these lines for precisely controlling action-potential firing of GABAergic, cholinergic, serotonergic and parvalbumin-expressing neuron subsets using blue light. This resource of cell type-specific ChR2(H134R) mouse lines will facilitate the precise mapping of neuronal connectivity and the dissection of the neural basis of behavior.
        
Title: High-level secretion and purification of recombinant acetylcholinesterase from human cerebral tissue in P. pastoris and identification by chromogenic reaction Ma X, Tan J, Wei D, Zhu P, Sun M Ref: Applied Microbiology & Biotechnology, 72:316, 2006 : PubMed
The gene encoding human cerebral tissue acetylcholinesterase (AChE) was cloned from an 18-week fetal cerebral tissue and expressed in Pichia pastoris. Twenty-two positive transformants were obtained by Mut(+)/Mut(s) phenotypes screening in MD/MM medium and polymerase chain reaction amplification, and four recombinant P. pastoris strains that could secrete active AChE at high level were identified by simple and specific development reaction with indoxyl acetate as the chromogenic substrate. In shake-flask culture induced with methanol, the recombinant human AChE (rhAChE) content was about 76% of the total secreted proteins, and rhAChE activity in supernatant was 40 U/ml. The enzyme was purified through anion-exchange and affinity chromatography. Purity of the rhAChE was up to 96% after the simple purification procedure. The enzymatic activity reached 200 U/mg.
We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000-40,000. Only 2%-3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family.
Chronic brain inflammation is the common final pathway in the majority of neurodegenerative diseases and central to this phenomenon is the immunological activation of brain mononuclear phagocyte cells, called microglia. This inflammatory mechanism is a central component of HIV-associated dementia (HAD). In the healthy state, there are endogenous signals from neurons and astrocytes, which limit excessive central nervous system (CNS) inflammation. However, the signals controlling this process have not been fully elucidated. Studies on the peripheral nervous system suggest that a cholinergic anti-inflammatory pathway regulates systemic inflammatory response by way of acetylcholine acting at the alpha7 nicotinic acetylcholine receptor (alpha7nAChR) found on blood-borne macrophages. Recent data from our laboratory indicates that cultured microglial cells also express this same receptor and that microglial anti-inflammatory properties are mediated through it and the p44/42 mitogen-activated protein kinase (MAPK) system. Here we report for the first time the creation of an in vitro model of HAD composed of cultured microglial cells synergistically activated by the addition of IFN-gamma and the HIV-1 coat glycoprotein, gp120. Furthermore, this activation, as measured by TNF-alpha and nitric oxide (NO) release, is synergistically attenuated through the alpha7 nAChR and p44/42 MAPK system by pretreatment with nicotine, and the cholinesterase inhibitor, galantamine. Our findings suggest a novel therapeutic combination to treat or prevent the onset of HAD through this modulation of the microglia inflammatory mechanism.
The objective of our study was to investigate the effects of ultrasonic energy on tissues, using a porcine model, performed under various instrumental and procedural parameters. Domestic pigs were anesthetized and prepared for surgery. An incision was made on the side of the hip randomly assigned to the right or left side. Tumescence solution was infiltrated via a blunt tip, small diameter cannula, followed by performance of standard liposuction. On the contralateral side, a similar incision was made. For ultrasonic liposuction experiments without the sheath, a percutaneous introducer was inserted into the incision, which was protected at the entry site from contact with the cannula. Tumescence solution was infiltrated via a blunt tip, small diameter cannula, and then the site was treated with ultrasonic energy at maximum output from the machine with liposuction concurrent through the hollow cannula. The experiments with the sheath did not require a pretreatment with tumescence solution but consisted of tumescence solution pumped through the sheath at a low infusion rate, with concurrent treatment utilizing ultrasonically assisted liposuction through the central lumen of the cannula. In all cases, the lipoaspirate was preserved for biochemical analysis. After treatment, the pigs were euthanized, and samples for histopathology were taken. The pigs were then perfused with a radio-opaque solution through the left ventricle following preperfusion with saline. The groups were ultrasound-assisted liposuction with sheath (n = 3), ultrasound-assisted without sheath (n = 4), and tumescence alone (n = 1), with standard liposuction performed on the contralateral side for all ultrasound-assisted liposuction animals. The lipoaspirates from the ultrasonically assisted liposuction with the sheath showed significantly less blood loss (measured as hemoglobin in the aspirate) than standard liposuction (p = 0.012) at comparable levels of fat (measured as triglycerides in the aspirate). The lipoaspirates from ultrasound-assisted liposuction without the sheath showed blood loss comparable to that experienced with standard liposuction. The ratio of hemoglobin to triglyceride was lowest in the ultrasound-assisted group with (p = 0.01) and without (p = 0.06) the sheath when compared to traditional liposuction. In both of these treated groups, the radiograms of the perfused areas showed significantly less vascular disruption when compared with suction-assisted liposuction. Histopathologic examination of specimens taken from various treated areas showed substantial tissue damage comparable in ultrasound- and suction-assisted liposuction treated groups. This preliminary experimental study showed that ultrasound-assisted lipoplasty is comparable to traditional suction-assisted lipoplasty. Treatment with ultrasound provided more significant hemoglobin/triglyceride ratios, indicative of more lipid aspirated per hemoglobin lost, and better preservation of vascular tissues as demonstrated by our perfusion studies. Treatment with the sheath showed a significantly lower hemoglobin release with a diminished volume infused into the subcutaneous space during the procedure.
        
Title: Anatomical compartments in the white matter of the rabbit flocculus Tan J, Simpson JI, Voogd J Ref: Journal of Comparative Neurology, 356:1, 1995 : PubMed
The white matter of the rabbit flocculus is subdivided into five compartments by narrow sheets of densely staining acetylcholinesterase-positive fibers. The most lateral compartment is continuous with the C2 compartment of the paraflocculus and contains the posterior interposed nucleus. The other four compartments are numbered from lateral to medial as floccular compartments 1, 2, 3, and 4 (FC1-4). FC1-3 continue across the posterolateral fissure into the adjacent folium (folium p) of the ventral paraflocculus. FC4 is present only in the rostral flocculus. In the caudal flocculus FC1 and FC3 abut dorsal to FC2. Fibers of FC1-4 can be traced into the lateral cerebellar nucleus and the floccular peduncle. The presence of acetylcholinesterase in the deep stratum of the molecular layer of the flocculus and ventral paraflocculus distinguishes them from the dorsal paraflocculus. The topographical relations to the flocculus and the floccular peduncle with group y and the cerebellar nuclei are discussed.
        
Title: Zonal organization of the climbing fiber projection to the flocculus and nodulus of the rabbit: a combined axonal tracing and acetylcholinesterase histochemical study Tan J, Gerrits NM, Nanhoe R, Simpson JI, Voogd J Ref: Journal of Comparative Neurology, 356:23, 1995 : PubMed
The localization and termination of olivocerebellar fibers in the flocculus and nodulus of the rabbit were studied with anterograde axonal transport methods [wheatgerm agglutinin-horseradish peroxidase (WGA-HRP) and tritiated leucine] and correlated with the compartments in the white matter of these lobules delineated with acetylcholinesterase histochemistry (Tan et al. J. Comp. Neurol., 1995, this issue). Olivocerebellar fibers originating from the caudal dorsal cap travel through floccular compartments FC2 and FC4 to terminate as climbing fibers in floccular zones FZII and FZIV. Fibers from the rostral dorsal cap and the ventrolateral outgrowth traverse compartments FC1 and FC3, which are interleaved with compartments FC2 and FC4, and terminate in zones FZI and FZIII. Fibers from the rostral pole of the medial accessory olive traverse the C2 compartment and terminate in the C2 zone. FZI-III extend into the adjoining folium (folium p) of the ventral paraflocculus. The C2 zone continues across folium p into other folia of the ventral paraflocculus and into the dorsal paraflocculus. Four compartments and five zones were distinguished in the nodulus. Medial compartment XC1 contains olivocerebellar fibers from the caudal dorsal cap and subnucleus beta that terminate in the XZI zone. Olivocerebellar fibers from the rostral dorsal cap and the ventrolateral outgrowth occupy XC2 and terminate in XZII. The XC4 compartment contains fibers from both the caudal dorsal cap and from the rostral dorsal cap and the ventrolateral outgrowth. The latter terminate in a central portion of the XZIV zone. The dorsomedial cell column projects to the XZIII zone, which is present only in the dorsal part of the nodulus. The rostral medial accessory olive projects to the XZV zone, which occupies the lateral border of the nodulus. These results confirm and extend the conclusions of Katayama and Nisimaru ([1988] Neurosci. Res. 5:424-438) on the zonal pattern in the olivo-nodular projection in the rabbit. Additional observations were made on the presence of a lateral A zone (Buisseret-Delmas [1988] Neurosci. Res. 5:475-493) in the hemisphere of lobules VI and VII. Retrograde labeling of the nucleo-olivary tract of Legendre and Courville ([1987] Neuroscience 21:877-891) was observed after WGA-HRP injections into the inferior olive including the rostral dorsal cap and the ventrolateral outgrowth. The anatomical and functional implications of these observations are discussed.
        
Title: Zonal organization of the flocculovestibular nucleus projection in the rabbit: a combined axonal tracing and acetylcholinesterase histochemical study Tan J, Epema AH, Voogd J Ref: Journal of Comparative Neurology, 356:51, 1995 : PubMed
With the use of retrograde transport of horseradish peroxidase we confirmed the observation of Yamamoto and Shimoyama ([1977] Neurosci Lett. 5:279-283) that Purkinje cells of the rabbit flocculus projecting to the medial vestibular nucleus are located in two discrete zones, FZII and FZIV, that alternate with two other Purkinje cell zones, FZI and FZIII, projecting to the superior vestibular nucleus. The retrogradely labeled axons of these Purkinje cells collect in four bundles that occupy the corresponding floccular white matter compartments, FC1-4, that can be delineated with acetylcholinesterase histochemistry (Tan et al. [1995a] J. Comp. Neurol., this issue). Anterograde tracing from small injections of wheat germ agglutin-horseradish peroxidase in single Purkinje cell zones of the flocculus showed that Purkinje cell axons of FZII travel in FC2 to terminate in the medial vestibular nucleus. Purkinje cell axons from FZI and FZIII occupy the FC1 and FC3 compartments, respectively, and terminate in the superior vestibular nucleus. Purkinje cell axons from all three compartments pass through the floccular peduncle and dorsal group y. In addition, some fibers from FZI and FZII, but not from FZIII, arch through the cerebellar nuclei to join the floccular peduncle more medially. No anterograde tracing experiments were available to determine the projections of the FZIV and C2 zones. The functional implications of these results are discussed.