A Novel Subpopulation of Prepositus Hypoglossi Nucleus Neurons Projecting to the Cerebellar Anterior Vermis and Hemisphere in Rats.

The prepositus hypoglossi nucleus (PHN), involved in horizontal gaze control, contributes to this function via cooperation with the vestibulocerebellum (VC). Furthermore, some PHN neurons have been observed to project to cerebellar regions outside the VC. We previously reported a neuronal population in the ventral caudal PHN that projects to lobules III-V of the anterior vermis or to the cerebellar hemispheric crus.

Effect of juvenile social isolation on excitability of prefrontal pyramidal cells with different subcortical axonal projections.

Background: Social experience during development is crucial for the functional maturation of the prefrontal cortex (PFC). Juvenile social isolation (JSI) causes severe PFC dysfunction. JSI reduces intrinsic excitability and excitatory synaptic inputs for a subtype of layer-5 (L5) pyramidal cells showing prominent h-current (PH cells) in the medial PFC.

An Indirect Pathway from the Rat Interstitial Nucleus of Cajal to the Vestibulocerebellum Involved in Vertical Gaze Holding.

The neural network, including the interstitial nucleus of Cajal (INC), functions as an oculomotor neural integrator involved in the control of vertical gaze holding. Impairment of the vestibulocerebellum (VC), including the flocculus (FL), has been shown to affect vertical gaze holding, indicating that the INC cooperates with the VC in controlling this function. However, a network between the INC and VC has not been identified.

Noradrenergic current responses of neurons in rat oculomotor neural integrators.

The prepositus hypoglossi nucleus (PHN) and the interstitial nucleus of Cajal (INC) are involved in the control of horizontal and vertical gaze, respectively. A previous study showed that PHN neurons exhibit depolarized or hyperpolarized responses to noradrenaline (NA). However, the adrenoceptor types that participate in NA-induced responses and the effects of NA on INC neurons have not yet been investigated.

Serotonergic current responses of neurons in rat oculomotor neural integrators.

The prepositus hypoglossi nucleus (PHN) and the interstitial nucleus of Cajal (INC) are involved in controlling horizontal and vertical gaze, respectively. Previous studies have shown that PHN neurons exhibit depolarized or hyperpolarized responses to serotonin (5-hydroxytryptamine, 5-HT). However, serotonergic modulation of INC neurons has not been examined.

Behavioral and Immunohistochemical Evidence for Suppressive Effects of Goshajinkigan on Salicylate-Induced Tinnitus in Rats.

Many people are affected by tinnitus, a sensation of ringing in the ear despite the absence of external sound. Goshajinkigan (GJG) is one of the formulations of Japanese traditional herbal medicine and is prescribed for the palliative treatment of patients with tinnitus. Although GJG is clinically effective in these patients, its behavioral effects and the underlying neuroanatomical substrate have not been modeled in animals.

Distinct purinergic receptor-mediated currents of rat oculomotor integrator neurons characterized by different firing patterns.

The prepositus hypoglossi nucleus (PHN) and the interstitial nucleus of Cajal (INC) are oculomotor neural integrators involved in the control of horizontal and vertical gaze, respectively. We previously reported that local application of adenosine 5'-trisphosphate (ATP) to PHN neurons induced P2X receptor-mediated fast inward currents, P2Y receptor-mediated slow inward currents, and/or adenosine P1 receptor-mediated slow outward currents. In contrast to the findings on PHN neurons, the expression of functional purinergic receptors in INC neurons has not been examined.

Distinct proportions of cholinergic neurons in the rat prepositus hypoglossi nucleus according to their cerebellar projection targets.

Cerebellar functions are modulated by cholinergic inputs, the density of which varies among cerebellar regions. Although the prepositus hypoglossi nucleus (PHN), a brainstem structure involved in controlling gaze holding, is known as one of the major sources of these cholinergic inputs, the proportions of cholinergic neurons in PHN projections to distinct cerebellar regions have not been quantitatively analyzed. In this study, we identified PHN neurons projecting to the cerebellum by applying retrograde labeling with dextran-conjugated Alexa 488 in choline acetyltransferase (ChAT)-tdTomato transgenic rats and compared the proportion of cholinergic PHN neurons in the PHN projections to four different regions of the cerebellum, namely the flocculus (FL), the uvula and nodulus (UN), lobules III-V in the vermis (VM), and the hemispheric paramedian lobule and crus 2 (PC).

Different Activation Mechanisms of Excitatory Networks in the Rat Oculomotor Integrators for Vertical and Horizontal Gaze Holding.

Gaze holding in the horizontal and vertical directions is separately controlled via the oculomotor neural integrators, the prepositus hypoglossi nucleus (PHN) and the interstitial nucleus of Cajal (INC), respectively. Our previous studies demonstrated that transient, high-frequency local stimulation of the PHN and the INC increased the frequency of spontaneous EPSCs that lasted for several seconds. The sustained EPSC response of PHN neurons was attributed to the activation of local excitatory networks primarily mediated via Ca-permeable AMPA (CP-AMPA) receptors and Ca-activated nonselective cation (CAN) channels.

Loss of HCN1 subunits causes absence epilepsy in rats.

Hyperpolarized-activated cyclic nucleotide-gated (HCN) channels underlie hyperpolarization-activated current (I) and are involved in controlling the excitability and electrical responsiveness of neurons. Absence epilepsy is clinically defined by a sudden, brief impairment of consciousness and behavioral arrest. Spike-and-wave discharges (SWDs) on electroencephalograms (EEG) are a diagnostic hallmark of absence epilepsy.

Comparisons of Neuronal and Excitatory Network Properties between the Rat Brainstem Nuclei that Participate in Vertical and Horizontal Gaze Holding.

Gaze holding is primarily controlled by neural structures including the prepositus hypoglossi nucleus (PHN) for horizontal gaze and the interstitial nucleus of Cajal (INC) for vertical and torsional gaze. In contrast to the accumulating findings of the PHN, there is no report regarding the membrane properties of INC neurons or the local networks in the INC. In this study, to verify whether the neural structure of the INC is similar to that of the PHN, we investigated the neuronal and network properties of the INC using whole-cell recordings in rat brainstem slices.

Visual experience regulates the development of long-term synaptic modifications induced by low-frequency stimulation in mouse visual cortex.

Manipulation of visual experience can considerably modify visual responses of visual cortical neurons even in adulthood in the mouse, although the modification is less profound than that observed during the critical period. Our previous studies demonstrated that low-frequency (2Hz) stimulation for 15min applied to layer 4 induces T-type Ca channel-dependent long-term potentiation (LTP) at excitatory synapses in layer 2/3 neurons of visual cortex during the critical period. In this study, we investigated whether low-frequency stimulation could induce synaptic plasticity in adult mice.

Requirement of keratan sulfate proteoglycan phosphacan with a specific sulfation pattern for critical period plasticity in the visual cortex.

Proteoglycans play important roles in regulating the development and functions of the brain. They consist of a core protein and glycosaminoglycans, which are long sugar chains of repeating disaccharide units with sulfation. A recent study demonstrated that the sulfation pattern of chondroitin sulfate on proteoglycans contributes to regulation of the critical period of experience-dependent plasticity in the mouse visual cortex.

TNFα is required for the production of T-type Ca(2+) channel-dependent long-term potentiation in visual cortex.

Monocular deprivation produces depression and potentiation of visual responses evoked in visual cortical neurons by stimulation of deprived and nondeprived eyes, respectively, during the critical period of ocular dominance plasticity. Our previous studies suggested that T-type Ca(2+) channel-dependent long-term potentiation (LTP), induced by 2 Hz stimulation, mediates the potentiation of visual responses. However, it was proposed that the experience-dependent response potentiation is mediated by tumor necrosis factor-α (TNFα)-dependent homeostatic synaptic scaling but not by Hebbian synaptic plasticity, because the potentiation was absent in TNFα knockout (TNFα-KO) mice.