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Q X Yu

Publications and source records attributed to Q X Yu.

29 records · Page 2Linked to original sources
PubMed1991

[Stimulation of the dorsal raphe nucleus induced depressive effect on cerebellar Purkinje cell responses to mossy and climbing fiber afferent inputs in rat].

In anaesthetized and paralyzed rats, the effect of dorsal raphe (DR) conditioning stimulation on cerebellar Purkinje cell (PC) responses to mossy fiber and climbing fiber inputs were examined. The main results are as follows: (1) Stimulation of cerebral sensorimotor cortex elicits widespread activation of mossy and climbing fiber inputs to PCs in contralateral VI and VII lobules of the cerebellum and generates two kinds of evoked responses, i.e. the simple spike (SS) and the complex spike (CS) responses with respectively a latency 8-25 and 12-30 ms. (2) These PC responses could be markedly suppressed by stimulation of DR at intensities which by themselves were subthreshold for directly affecting PC's spontaneous SS and CS activities. (3) This DR-induced depressive effects on evoked PC's SS and CS excitations could be attenuated or blocked by systemic administration of 5-HT receptor blocker methysergide. These results demonstrate that serotonergic fiber input from DR can suppress the efficacy of mossy and climbing fiber synaptic action on PC, or decrease the responsiveness of PC itself to afferent synaptic action. The findings of this study also suggest that the raphe-cerebellar serotonergic fiber afferent system may be involved in some of the important neuronal processing in the cerebellum.

Afferent Pathways↗
PubMed1989

[Electrophysiological study of the corticonuclear projection in the lobule VII of cat cerebellum].

Antidromic field potentials and antidromic unit responses of Purkinje cells (PCs) to the stimulation of fastigial nucleus (FN), interposed nucleus (IN) and dentate nucleus (DN) were respectively recorded from the lobule VII of posterior cortex of decerebrated cats, to identify the corticonuclear projection in the lobule VII. After antidromically identified, simple and complex spike responses of PCs to natural peripheral forepaw extension-flexion stimuli were observed. All data were analysed by a computer, and average field potentials and poststimulus time histograms (PSTHs) were constructed. The results show that the corticonuclear zones are sharply demarcated on the lobule VII of posterior cortex. The boundary between the fastigial zone (FZ) and the interposed zone (IZ) on the lobule VII is not straight, but bends. Among sublobule VII Aa-VII Ad the FZ-IZ boundary bends from 2.8 mm to 1.5 mm laterally to the midline. The boundary between IZ and dentata zone (DZ) was about 5.0 mm away from the midline. The PSTHs of the simple and complex spike activities showed that part of PCs in all three different corticonuclear zones responded to the forepaw flexion-extension stimulation, but proportion of the cells affected was quite different among the three zones. In the IZ 84% PCs were modulated by the forepaw stimulation, while in the FZ and DZ it was 59% and 20% respectively. These results support previous finding that information processing involved in the modulation of Purkinje cell activity in response to the forepaw stimulation occurs in all 3 zones examined.

Animals↗
PubMed1989

[Hippocampus-cerebellar cortex-cerebellar nuclei projection in the rat: electrophysiological and HRP studies].

The spatial distribution of the hippocampus-cerebellar projection and the connection between the projection area of hippocampus in the cerebellum and cerebellar nuclei were studied by means of electrophysiological and HRP labelling techniques. Polysynaptic responses of Purkinje cell's simple and complex spike in the lobule VI could be evoked by stimulation of the area CA1/CA3 of the dorsal hippocampus. These results suggest that there are polysynaptic projections from CA1 and CA3 areas of dorsal hippocampus to the lobule VI of cerebellar cortex, and the last relay fibers for these projections are mossy fiber and/or climbing fiber. It is also shown that this hippocampus-cerebellar projection predominantly terminates at the lobule VI of cerebellar cortex, 0.8-1.4 mm lateral to the midline. The projection from CA1 area is mainly contralateral, whereas the projection from CA3 area is mainly ipsilateral. The results with HRP labelling indicate that the projection area of hippocampus is an interpositus zone of the lobule VI. Reciprocal connections may exist between this cortical area and the interpositus nucleus.

Animals↗
PubMed1987

[Pattern recognition on the trace element spectrum in gastric cancer and peptic ulcer].

The trace element spectrum of gastric tissue and whole blood specimens from gastric cancer and peptic ulcer patients was recognized with pattern recognition technique in order to obtain the chemical information of gastric cancer. Thirty specimens were obtained from cancer patients in each of the 58 gastric tissues and 54 whole blood specimens. Five pathological types were divided into two groups: peptic ulcer and dysplasia as the ulcer group; well-differentiated, undifferentiated and mucinous carcinoma as the cancer group. The accuracy of recognizing the several spectra was 90%: nine trace element spectra (Cu, Zn, Ni, Co, Cr, Cd, Mn, Fe and Mg) for the tissue specimens from the cancer and ulcer groups; six (Cu, Zn, Mn, Co, Cr and Cd) for dysplasia and well-differentiated adenocarcinoma tissues; five (Cu, Ni, Cr, Cd and Fe) for the whole blood specimens from these two groups and six (Cu, Zn, Cr, Cd, Fe and Ni) for the whole blood specimens from dysplasia and peptic ulcer (including 10 normal individuals). The data were treated by non-linear mapping method and calculated by TRS-80 III type microcomputer.

Adenocarcinoma↗
PubMed1985

Electrophysiological study of the corticonuclear projection in the cat cerebellum.

Experiments were designed to examine the relationship between the responses of Purkinje cells to natural peripheral stimuli and the location of these neurons within identified zones of the corticonuclear projection in lobule V of the cat cerebellar cortex. It was hypothesized that the corticonuclear zones are sharply demarcated and that the responses of Purkinje cells to a restricted natural stimulus is not localized to only one zone but rather is present and varies in character across these 3 zones. Initially the spatial distribution of the antidromic field potential evoked by stimulating in the fastigial (FN), lateral vestibular (LVN), and anterior interposed nuclei (AIN) was determined in sublobules Va-Vc in unanesthetized decerebrate cats. In some animals the corticonuclear projection was further examined by evaluating the location of Purkinje cells responding antidromically to stimuli in the FN, LVN and AIN, or FN, AIN and the posterior interposed nuclei (PIN). Once a Purkinje cell was identified, its simple and complex spike responses to a step-like flexion-extension passive movement of the ipsilateral forepaw were determined. The boundary based on the antidromic activation of Purkinje cells between the fastigial zone (FZ) and the anterior interposed zone (AIZ) in sublobules Va-Vc of the cerebellar cortex was highly reproducible from cat to cat, although there was a slight overlap between these zones based on the antidromic field potential. The FZ-AIZ border was located at 2.1 +/- 0.12 mm lateral and parallel to the midline. The FZ also contained a few cells projecting to the LVN. However, the AIZ only contained neurons projecting to the AIN. The boundary between AIZ and PIZ in lobule Va-Vc was between 3.3 and 3.8 mm from the midline and ran parallel to it. The peristimulus time histograms (PSTHs) of the simple and complex spike activity to a passive forepaw displacement revealed extensive modulation of neurons located across the mediolateral extent of the AI and PIZ. Both the simple and complex spike discharge of Purkinje cells projecting to the FN also were modulated, but to a lesser degree than cells in AIZ or PIZ. The spatial distribution of simple and complex spike responses recorded from Purkinje cells overlapped extensively. The data support previous findings that the corticonuclear projection is organized into longitudinally oriented sagittal zones. Electrophysiologically the boundaries were remarkably reproducible from animal to animal. The results also show that information processing involving the modulation of Purkinje cell activity in response to the forepaw stimulus occurs in all 3 zones examined.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Increase in Purkinje cell gain associated with naturally activated climbing fiber input.

These experiments were designed to test the hypothesis that climbing fiber inputs evoked by a peripheral stimulus increase the responsiveness of Purkinje cells to mossy fiber inputs. This hypothesis was based on a previous series of observations demonstrating that spontaneous climbing fiber inputs are associated with an accentuation of the Purkinje cell responses to subsequent mossy fiber inputs (10, 12). Furthermore, short-term nonpersistent interactions between climbing and mossy fiber inputs have been an important aspect of many theories of cerebellar function (5, 7, 8, 12, 36). Extracellular unitary recordings were made from Purkinje cells in lobule V of decerebrate, unanesthetized cats. To activate mossy and climbing fiber inputs, the forepaw was passively flexed by a Ling vibrator system. A data analysis was developed to sort the simple spike trials into two groups, based on the presence or absence of complex spikes activated by the stimulus. In addition, during those trials in which complex spikes were activated, the simple spike train was aligned on the occurrence of the complex spike. For each simple spike response to the forepaw input, the average firing rate during the response was compared to background both in those trials in which complex spikes were activated and in those in which they were not. The ratio of the response amplitudes in the histograms constructed from these two groups of trials permitted a quantification of the change in responsiveness when climbing fiber inputs were activated. The results show that both excitatory and inhibitory simple spike responses are accentuated when associated with the activation of a complex spike. Using an arbitrary level of a gain change ratio of 120% as indicating a significant modification, 64% of the response components analyzed increased their amplitude when climbing fiber input was present. Simple spike response components occurring prior to complex spike activation were usually not accentuated, although in a few cells the amplitude of this component of the response increased. In addition, in a small number of cells the occurrence of complex spikes was associated with a new simple spike component. For excitatory responses, the magnitude of the gain change ratio was shown to be inversely related to the amplitude of the simple spike response evoked by the mossy fiber inputs. The data obtained is consistent with the hypothesis that the climbing fiber input is associated with an increase in the responsiveness of Purkinje cells to mossy fiber inputs. The increased responsiveness occurs whether the simple spike modulation evoked by the peripheral stimulus is excitatory or inhibitory. The change in responsiveness is short term and nonpersistent. It is argued that the activation of climbing fiber inputs to the cerebellar cortex is associated with an increase in the gain of Purkinje cells to mossy fiber inputs activated by natural peripheral stimuli.

Afferent Pathways↗