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Biomedical subjects

A Takemura

Publications and source records attributed to A Takemura.

At least 19 recordsLinked to original sources
PubMed2003

An algorithm for mapping the catheter tip position on a fluorograph to the three-dimensional position in magnetic resonance angiography volume data.

This paper proposes an algorithm which maps the position of a catheter tip on a fluorograph to the 3D position in magnetic resonance angiography (MRA) data. This algorithm was assessed for its accuracy. We designed an algorithm consisting of a registration step and a recognition step. The registration step registers MRA and fluorography data using a digital subtraction angiography (DSA) image. The recognition step recognizes the position in the MRA data corresponding to the catheter tip position on a fluorograph. We checked the accuracy of the recognition step by employing an artificial data set consisting of 3D image data (64 x 64 x 64 matrix) and its projection image (92 x 92 matrix) and the accuracy of the registration step with the aid of three of the 3D time-of-flight MRA data sets (256 x 256 matrix and 60 slices) and their projection images in the form of DSA images. The accuracy of the recognition step depended upon that of the registration. When there was no misregistration, all of the mean errors were less than 0.2 mm. The mean errors of the registration step were 0.273 mm and 0.226 mm, respectively, for the longitudinal shift along the X and Y axes, 0.478 degrees, 1.203 degrees and 0.208 degrees, respectively, for the rotation angles around the X, Y and Z axes and 0.020 times for the magnification. The mean image error between the projection image of the registered MRA data and that of the MRA data which were employed as the DSA image was 0.034 mm.

Algorithms↗
PubMed2003

Culture conditions affect induction of vitellogenin synthesis by estradiol-17 beta in primary cultures of tilapia hepatocytes.

In vitro synthesis of vitellogenin (VTG), a female-specific protein, after estradiol-17 beta (E(2)) treatment was compared among different culture conditions using the hepatocytes of tilapia, Oreochromis mossambicus. VTG was measured by enzyme-linked immunosorbent assay. Comparison of Leibovitz's L-15 medium (L-15), Williams' medium E (WE) and Medium 199 (M199), which have been used for hepatocyte cultures in certain teleost fishes, showed that monolayer formation of the hepatocytes on the plate in WE and M199 was faster than in L-15 at the beginning of the culture. Morphological differences in the hepatocytes among the culture media were not evident by 96 h after culture. VTG synthesis in L-15 after E(2) treatment was higher than in WE and M199. A concentration of NaHCO(3) at 5 mM in L-15 resulted in faster monolayer formation of the cells and higher VTG synthesis than at 0 and 23 mM. Primary culture of the tilapia hepatocytes at 28 degrees C showed higher synthesis of VTG than at 23 and 33 degrees C. These results suggest that nutritional requirements are vitally different among species, and there are optimal ranges in the pH and the temperature in cultured hepatocytes.

Animals↗
PubMed2003

Requirement of Ca2+ on activation of sperm motility in euryhaline tilapia Oreochromis mossambicus.

Euryhaline tilapia Oreochromis mossambicus acclimates to the external spawning environment by modulating its mechanism for regulating sperm motility. Adaptation of sperm was performed by acclimating fish in various environments. In this paper, regulatory mechanisms of freshwater-acclimated tilapia were studied in detail. Tilapia sperm motility was vigorous in hypotonic conditions and decreased with increasing osmolality. Sperm motility was reduced in hypotonic conditions when extracellular Ca(2+) was chelated; however, extracellular Ca(2+) was not a major factor for motility activation since sperm were motile even when extracellular Ca(2+) levels were nominally depleted by EGTA. The Ca(2+) indicator, fluo 3, showed that intracellular [Ca(2+)] increased on motility activation independently of extracellular [Ca(2+)], accompanied by swelling of the sperm neck region called the sleeve structure. Intracellular [Ca(2+)] was not increased under hypertonic conditions, in which sperm were immotile, even on addition of extracellular Ca(2+). It is possible that Ca(2+) is stored in the neck region. Demembranated sperm were reactivated in the presence of Ca(2+), but cAMP failed to reactivate the motility. Furthermore, we detected phosphorylation and dephosphorylation of three proteins at serine and threonine residues on motility activation. It is likely that hypotonic shock causes an increase in intracellular [Ca(2+)] that activates motility activation via phosphorylation of some flagellar proteins.

Acclimatization↗
PubMed2002

Facial subdermal vascular network flap: anatomic study and clinical application.

Despite the numerous flaps for facial reconstruction that have been described, the search for the ideal flap with good color matching and minimal donor-site morbidity continues. In the past 3 years we have repaired 13 facial defects with success using the lateral genicervical flap - a type of facial subdermal vascular network flap (SVNF) - with a pedicle located on the preauricular region. An anatomic study of the facial SVNF, including blood supply and vascular distribution of the face and anatomic characteristics of facial vessels, based on 14 cadaver dissections, was carried out. The blood supply of the facial skin basically originated from the branches of the facial, superficial temporal and infraorbital arteries. The lateral genicervical skin was supplied basically by the branches of the facial, superficial temporal and occipital arteries, but also by the terminal branches of the superior thyroid artery. The branches diverging from these arteries became superficial and formed a subcutaneous arterial network. The arterioles from the network went to the corium layer and formed a subdermal arterial network whose arterioles anastomosed with each other in a honeycomb-like structure. The vascular distribution presented certain directivity on different areas. The blood supply of the pedicle originated from the subdermal vascular network formed by the perforator branches of these arteries. The arterioles from the facial and superficial temporal arteries anastomosed in the lateral genicervical region. From the anatomic study, we think that the viability of the facial SVNF depends basically on the subdermal vascular network formed by the perforator branches of the pedicle, and that the anastomoses between the facial and superficial temporal arteries provide a solid anatomic basis to the lateral genicervical flap. The clinical data also indicated that this flap is a useful alternative for facial, especially superficial temporal, defects. But the directivity must be taken into account in its clinical application.

Adolescent↗
PubMed2002

Population coding in cortical area MST.

Disparity steps applied to large patterns elicit vergence eye movements at ultrashort latencies. Disparity tuning curves, describing the dependence of the amplitude of the initial vergence responses on the amplitude of the disparity steps, resemble the derivative of a gaussian and indicate that appropriate servo-like behavior occurs only with small disparity steps (<1 degree). Lesion data from monkeys suggest that these vergence responses are mediated, at least in part, by neurons in the medial superior temporal area of the cerebral cortex, and we here review a recent study of the associated single unit activity in that area. Few medial superior temporal neurons have disparity tuning curves whose shapes resemble the tuning curve for vergence. Yet, when the disparity tuning curves for all of the disparity-sensitive cells recorded from a given monkey are summed together, they match the tuning curves for the vergence responses of that monkey very closely, even reproducing that animal's idiosyncracies. When all of the spike trains elicited by a given disparity step are summed together to give an average discharge profile for the whole population of recorded cells, many are noisy, but others that are less so match the temporal profile of the motor response, vergence velocity, quite well. We conclude that the discharges of the disparity-sensitive cells in the medial superior temporal area each represent only a very limited aspect of the sensory stimulus (and/or associated motor response?), but when pooled together, they provide a complete description of the vergence velocity motor response: population coding.

Animals↗
PubMed2001

Assessment of thyroid function in adult medaka (Oryzias latipes) and juvenile rainbow trout (Oncorhynchus mykiss) using immunostaining methods.

The effect of injected bovine TSH on the pattern of anti-T(4) and anti-T(3) immunostaining of the thyroid tissue was examined in rainbow trout (Oncorhynchus mykiss) and medaka (Oryzias latipes) to determine if the previously reported immunostaining of the cytoplasm of thyrocytes is due to the presence of colloid pinocytotic vesicles and is thus indicative of thyroid hormone release. We hypothesized that the number of immunostained thyrocytes should increase following a TSH challenge, and this should parallel other indicators of increased thyroid activity. In medaka, immunostained thyrocytes were only found following the TSH challenge, and were most marked after 24 to 72 hours; the immunostaining was associated with large colloid-filled cytoplasmic vesicles. In trout, the number and staining intensity of immunostained thyrocytes were increased after the TSH challenge; the immunostaining was present throughout the cytoplasm of the thyrocytes. These findings support the working hypothesis that the immunostaining of the thyrocytes is associated with the pinocytosis of thyroglobulin by the thyrocytes in parallel with an increase in release of thyroid hormone, and that this investigational approach provides a reliable indicator of thyroid hormone release activity.

Animals↗
PubMed2001

Effects of estradiol-17beta treatment on in vitro and in vivo synthesis of two distinct vitellogenins in tilapia.

Two distinct vitellogenins (VTG) were purified from the blood of estradiol-17beta (E(2))-injected tilapia, Oreochromis mossambicus. Enzyme-linked immunosorbent assays (ELISA) of each VTG were developed to examine effects of E(2) treatment on induction of VTG synthesis in the primarily cultured tilapia hepatocytes. Two VTG molecules (VTG210 and VTG140) had apparent molecular masses of 370 and 220 kDa by gel filtration and 210 and 140 kDa by SDS-PAGE, respectively. Western blot analyses showed that antibodies raised against the purified VTG210 and VTG140 reacted only with each protein band. Furthermore, ELISA for each VTG was specific for target VTG. When E(2) was added into the media of primarily cultured tilapia hepatocytes, VTG210 and VTG140 were both detected from E(2) concentrations of 1x10(-7) M and 5x10(-7) M, respectively. Time course experiments showed that there was a difference in the detection time of VTG210 and VTG140 after the hormone treatment. Although the injection of different E(2) doses induced both VTGs in the plasma of male tilapia, the concentration of VTG210 was nearly five to eight times higher than that of VTG140. These results suggest that E(2) is a direct inducer of both VTGs in the tilapia hepatocytes in vitro and in vivo, and that there is difference in the hormone response in inducing the VTGs in the tilapia hepatocytes.

Animals↗
PubMed2001

Lunar synchronization of testicular development and steroidogenesis in rabbitfish.

Lunar synchronization of testicular development in the golden rabbitfish, Siganus guttatus, was assessed by measuring changes in sperm motility and conditions in the seminal plasma, and by in vitro production of steroid hormones in testicular fragments and sperm preparations. The duration and percentage of sperm motility was low 1 week before spawning (the new moon), but increased significantly on the day of spawning (the first lunar quarter). During the first lunar quarter, the osmolality decreased, but Ca(2+) concentration increased in the seminal plasma. These results suggest that spermiation occurs rapidly towards the specific lunar phase. Testicular fragments and sperm preparations were incubated with human chorionic gonadotropin (hCG) and two precursor steroid hormones, 17alpha-hydroxyprogesterone (17alpha-OHP) and testosterone (T), during the two lunar phases. The production of 11-ketotestosterone (11-KT) increased significantly when the testicular fragments were incubated with hCG at the first lunar quarter, while incubation of sperm preparations with 17alpha-OHP during the same moon phase resulted in a significant increase in 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP) production in the medium. These results suggest that 11-KT is produced in the somatic cells of the testis under the influence of gonadotropin, and that sperm can convert 17alpha-OHP to DHP. Additionally, steroidogenic activity was considered to increase toward the specific lunar phase. The synchronous increase in testicular activity supports the hypothesis that lunar periodicity is a major factor for the testicular development of S. guttatus.

Animals↗
PubMed2001

Molecular cloning and expression of connexin 32.3 cDNA in the ovary from the red seabream (Pagrus major).

This study examined connexin (Cx) gene activity in relation to oocyte maturation in the red seabream (Pagrus major) ovary. Mixed primers for the polymerase chain reaction (PCR) were designed based on the high sequence homology of selected regions of known Cx genes. PCR-amplified cDNA fragments generated by 3' and 5' rapid amplication of cDNA ends (RACE) were combined to generate full-length cDNA sequences. The 1212-bp cDNA has an open reading frame encoding 282 amino acids, with a molecular mass of 32.3 kDa (red seabream Cx32.3). Hydropathy plots of red seabream Cx32.3 show the four typical major hydrophobic and four major hydrophilic regions of Cx proteins. Typical Cx consensus sequences are observed in the first and second extracellular loops. The ovarian follicles of matured female seabream were incubated in the presence of 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP, 10 ng/ml), gonadotropin (GtH)-I (300 ng/ml) and GtH-II (300 ng/ml). Northern blot analysis of poly(A)(+) RNA extracted from the ovarian follicles were hybridized with red seabream Cx32.3 and beta-actin probes. The transcription level of PmCx32.3 in the presence of DHP, PmGtH-I and PmGtH-II was significantly higher than in the control.

Actins↗
PubMed2001

Estradiol impairs hyposmoregulatory capacity in the euryhaline tilapia, Oreochromis mossambicus.

Freshwater (FW)-adapted tilapia (Oreochromis mossambicus) were treated with estradiol (E(2)) for 4 days to stimulate protein synthesis and sampled at 0, 4, and 24 h after exposure to 50% seawater (SW). E(2) increased circulating vitellogenin (VTG) levels in large amounts, indicative of unusually high rates of hepatic protein synthesis. E(2) treatment prevented the recovery of plasma osmolality in 50% SW that was evident in the sham group. Plasma sodium concentration was significantly elevated with E(2) in FW, but the levels did not change in 50% SW. Gill Na(+)-K(+)-ATPase activity was significantly lower in the E(2) group compared with sham-injected tilapia in 50% SW. No significant differences were noted in plasma cortisol, thyroxine, triiodothyronine, or glucose concentration with E(2) in 50% SW. E(2) significantly lowered several key liver enzyme activities and also decreased gill lactate dehydrogenase and malate dehydrogenase activities over a 24-h period. Together, our results suggest that E(2) impairs ion regulation in tilapia, partially mediated by a decreased metabolic capacity in liver and gill. The decreased tissue metabolic capacity is likely due to E(2)-induced energy repartitioning processes that are geared toward VTG synthesis at the expense of other energy-demanding pathways.

Animals↗
PubMed2001

Single-unit activity in cortical area MST associated with disparity-vergence eye movements: evidence for population coding.

Single-unit discharges were recorded in the medial superior temporal area (MST) of five behaving monkeys. Brief (230-ms) horizontal disparity steps were applied to large correlated or anticorrelated random-dot patterns (in which the dots had the same or opposite contrast, respectively, at the two eyes), eliciting vergence eye movements at short latencies [65.8 +/- 4.5 (SD) ms]. Disparity tuning curves, describing the dependence of the initial vergence responses (measured over the period 50-110 ms after the step) on the magnitude of the steps, resembled the derivative of a Gaussian, the curves obtained with correlated and anticorrelated patterns having opposite sign. Cells with disparity-related activity were isolated using correlated stimuli, and disparity tuning curves describing the dependence of these initial neuronal responses (measured over the period of 40-100 ms) on the magnitude of the disparity step were constructed (n = 102 cells). Using objective criteria and the fuzzy c-means clustering algorithm, disparity tuning curves were sorted into four groups based on their shapes. A post hoc comparison indicated that these four groups had features in common with four of the classes of disparity-selective neurons in striate cortex, but three of the four groups appeared to be part of a continuum. Most of the data were obtained from two monkeys, and when the disparity tuning curves of all the individual neurons recorded from either monkey were summed together, they fitted the disparity tuning curve for that same animal's vergence responses remarkably well (r(2): 0.93, 0.98). Fifty-six of the neurons recorded from these two monkeys were also tested with anticorrelated patterns, and all showed significant modulation of their activity (P < 0.005, 1-way ANOVA). Further, when all of the disparity tuning curves obtained with these patterns from either monkey were summed together, they too fitted the disparity tuning curve for that same animal's vergence responses very well (r(2): 0.95, 0.96). Indeed, the summed activity even reproduced idiosyncratic differences in the vergence responses of the two monkeys. Based on these and other observations on the temporal coding of events, we hypothesize that the magnitude, direction, and time course of the initial vergence velocity responses associated with disparity steps applied to large patterns are all encoded in the summed activity of the disparity-sensitive cells in MST. Latency data suggest that this activity in MST occurs early enough to play an active role in the generation of vergence eye movements at short latencies.

Algorithms↗
PubMed2001

Change in neuronal firing patterns in the process of motor command generation for the ocular following response.

To explore the process of motor command generation for the ocular following response, we recorded the activity of single neurons in the medial superior temporal (MST) area of the cortex, the dorsolateral pontine nucleus (DLPN), and the ventral paraflocculus (VPFL) of the cerebellum of alert monkeys during ocular following elicited by sudden movements of a large-field pattern. Using second-order linear-regression models, we analyzed the quantitative relationships between neuronal firing frequency patterns and eye movements or retinal errors specified by three parameters (position, velocity, and acceleration). We first attempted to reconstruct the temporal waveform of each neuronal response to each visual stimulus and computed the coefficients for each parameter using the least-square error method for each stimulus condition. The temporal firing patterns were generally well reconstructed [coefficient of determination index (CD) > 0.7] from either the retinal error or the associated ocular following response. In the MST and DLPN datasets, however, the fit with the retinal error model was generally better than with the eye-movement model, and the estimated coefficients of acceleration and velocity ranged widely, indicating that temporal patterns in these regions showed considerable diversity. The acceleration component is greater in MST and DLPN than in VPFL, suggesting that an integration occurs in this pathway. When we determined how well the temporal patterns of the neuronal responses of a given cell could be reconstructed for all visual stimuli using a single set of coefficients, good fits were found only for Purkinje cells (P- cells) in the VPFL using the eye-movement model. In these cases, the coefficients of acceleration and velocity for each cell were similar, and the mean ratio of the acceleration and velocity coefficients was close to that of motor neurons. These results indicate that individual MST and DLPN neurons are each encoding some selective aspects of the sensory stimulus (visual motion), whereas the P-cells in VPFL are encoding the complete dynamic command signals for the associated motor response (ocular following). We conclude that the sensory-to-motor transformation for the ocular following response occurs at the P-cells in VPFL.

Animals↗
PubMed2001

The laminar structure of the common opossum masseter (Didelphis marsupialis).

Using three heads of the common opossum (Didelphis marsupialis), which may be considered to have a primitive mammalian form and therefore be appropriate for this study, the laminar structure of the masseter was investigated. We also attempted a comparative anatomical study of the relationships of food habits to the laminar structures of the masseter, zygomatic arch and mandibular ramus. In the common opossum masseter, a total of six layers, the primary and secondary sublayers of the superficial layer, the intermediate layer, and the primary, secondary and third sublayers of the deep layer as a proper masseter, were observed. These layers showed a typical reverse laminar structure, with the layers of tendons and muscles alternating. The maxillomandibularis and zygomaticomandibularis muscles were observed in one layer each, as an improper masseter. The laminar structure of the common opossum masseter was shown to be more similar to that of carnivorous placental animals than that of the herbivorous red kangaroo, a similar marsupial. In regard to the number of layers in the laminar structure of the masseter, the results of both this study and those of our predecessors' showed that differences in food habits affect the deep layer in the proper masseter of marsupials and placental mammals, and that of the maxillomandibularis muscle of placental mammals in the improper masseter.

Adaptation, Physiological↗
PubMed2000

Role of the pretectal nucleus of the optic tract in short-latency ocular following responses in monkeys.

When a large-field image is suddenly moved in front of an observer, an ocular following response (OFR) with short latency (<60 ms in monkey and <85 ms in human) is observed. Previous studies have shown that neurons in the pretectal nucleus of the optic tract (NOT) of the monkey respond to movements of large-field visual stimuli. To understand the potential role of the NOT in the OFR, we first recorded single-unit activity in the NOT of four monkeys (Macaca fuscata). Sixty-six NOT neurons preferred large-field ipsiversive visual motion. In 86% (49/57) of the neurons, optimal directions were distributed over +/-30 degrees from ipsilateral. NOT units were sensitive to the speed of the visual motion; 54% (27/50) preferred slow (< or =20 degrees/s), 22% (11/50) preferred fast (> or =80 degrees/s) and the remainder intermediate speeds. Their response latencies to the moving visual scene were very short (approximately 51 ms), and 44% of them led the onset of the OFR by 10 ms or more. To characterize the response properties of these neurons, we reconstructed the temporal firing patterns of 17 NOT neurons, using the acceleration, velocity, position and bias components of retinal image slip or eye movements during the OFR by a least squares error method. For each stimulus speed fitting condition, using either retinal slip or eye movements, their firing patterns were matched to some extent although the goodness of fit was better using retinal slip than when eye movements were used. Neither of these models could be applied independently of stimulus speed, suggesting that the firing pattern of the NOT neurons represented information associated with retinal slip or eye movements during the OFR, over a limited range. To provide further evidence that the NOT is involved in generating the OFR, we placed unilateral microinjections of muscimol into the NOT. Following the muscimol injection, we observed a approximately 50% decrease in eye velocity of the OFR toward the side of injection regardless of stimulus speed, while only a weak effect was observed in the OFR during contraversive or vertical image motion. These results suggest that the NOT may play a role in the initiation and support of the short-latency ocular following response.

Animals↗
PubMed2000

Efficacy of post operative adjuvant therapy with human interferon beta, MCNU and radiation (IMR) for malignant glioma: comparison among three protocols.

In order to develop ultimate adjuvant therapy for malignant gliomas, we analysed 77 patients with malignant gliomas (29 anaplastic astrocytomas (AAs) and 48 glioblastoma multiformes (GMs)) treated by three protocols of IMR therapy (human interferon-beta (HuIFN-beta), MCNU and radiation). In protocol 1 (n = 45: AA = 13, GM = 32), 1 x 10(6) IU of HuIFN-beta was administrated intravenously once a day for 7 days. On day 2, MCNU was administrated at a dose of 2 mg/kg b.w. intravenously and from day 3, radiation was started in five weekly fractions of 2 Gy for 6 weeks. Total dose was 60 Gy. Protocol 2 (n = 19: AA = 11, GM = 8) was comparable with protocol 1 except HuIFN-beta was administrated twice a day at a dose of 1 x 10(6) IU each. Protocol 3 (n = 13: AA = 5, GM = 8) differed from protocol 2 only in a high dose-hyperfractionated radiation which was given twice a day at a dose of 1.5 Gy each and for a total dose of 66 Gy. Antitumor effects were evaluated by survival and response rate determined by decrease of tumor size. Significant improvement was obtained in patients with AAs by protocol 2 and 3. Response rates of patients with AAs and GMs were 46.2% and 50% in protocol 1, 63.6% and 50% in protocol 2, and 80% and 50% in protocol 3, respectively. One and two year survival rates in AAs were 46.4% and 34.8% in protocol 1, both 75% in protocol 2, and both 100% in protocol 3. Survival rates in GMs were not different among them. Except of radiation necrosis, which was observed in 38.5% of the patients under protocol 3, there was no significant difference in the adverse effects among the three protocols. In the present study, the efficacy of IMR therapy for patients with malignant gliomas, especially for AAs, was cofirmed. We conclude that twice a day administrations of HuIFN-beta in combination with a high dose-hyperfractionated radiation provide increased efficacy in IMR therapy.

Adjuvants, Immunologic↗
PubMed2000

The effect of disparity on the very earliest ocular following responses and the initial neuronal activity in monkey cortical area MST.

Movement of the visual scene evokes tracking movement with the eyes (ocular following response, OFR) at short latency (Miles, F.A., Kawano, K., Optican, L.M., 1986. Short-latency ocular following responses of monkey. I. Dependence on temporospatial properties of visual input. J. Neurophysiol. 56, 1321-1354). We examined the effect of binocular disparity on the initial OFR. The dependence of the OFR on horizontal disparity steps was studied in three monkeys (Macaca fuscata), and the associated unit discharges in the medial superior temporal area (MST) were studied in two of these. Based on the changes in eye position over the period 50-83 ms (measured from stimulus onset), the initial OFR showed clear dependence on the disparity imposed during the preceding centering saccade. The disparity tuning curves were S-shaped with a peak at a small crossed disparity and a trough at uncrossed disparities. Based on the changes in discharge rate over the period 40-73 ms (measured from stimulus onset), almost all OFR-related MST neurons (80/83, 96.4%) showed significant dependence on the disparity step (Student's t-test, P < 0.05). The early neuronal responses of the majority of units (41/75, 55%) had disparity tuning curves resembling those for the OFR, which peaked at small crossed disparities. These findings suggest that the neurons in the MST contain information on binocular disparity in their short-latency discharges, and are involved in the neural basis of the OFR's dependence on horizontal disparity.

Action Potentials↗
PubMed2000

A mathematical analysis of the characteristics of the system connecting the cerebellar ventral paraflocculus and extraoculomotor nucleus of alert monkeys during upward ocular following responses.

Movements of the visual scene evoke short-latency ocular-following-responses (OFR). Many studies suggest that a neural pathway containing the cerebellar-ventral-paraflocculus (VPFL) mediates OFR. The relationship between eye movement and simple-spike firing in the VPFL during OFR has been studied in detail using an inverse dynamics approach. The relationship between eye movement and cell firing in the extraoculomotor nucleus (MN) has already been reported. However, no studies have examined the information transformation that occurs between the VPFL and the MN during OFR. In this paper, using an inverse dynamics approach, we derive a transfer function that represents the characteristics of the structure connecting the VPFL and the MN during upward OFR. This structure appears to contain a kind of neural integrator, which constructs eye-velocity-and-position information from eye-acceleration-and-velocity information. We propose a diagram for the neural integration commonly at work during all types of upward eye movement. This is a closed-loop circuit containing a low-pass filter. The low-pass filter can construct eye-velocity-and-position information from an eye-acceleration-velocity-position command similar to the final motor command used commonly for all upward eye movements. Anatomical and electrophysiological data suggest that the vestibular nuclei-interstitial nucleus of Cajal-vestibular nuclei loop might perform such neural integration.

Action Potentials↗