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Sample records for cingulate pyramidal neurons

  1. Characterization of intrinsic properties of cingulate pyramidal neurons in adult mice after nerve injury

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    Chen Tao

    2009-12-01

    Full Text Available Abstract The anterior cingulate cortex (ACC is important for cognitive and sensory functions including memory and chronic pain. Glutamatergic excitatory synaptic transmission undergo long-term potentiation in ACC pyramidal cells after peripheral injury. Less information is available for the possible long-term changes in neuronal action potentials or intrinsic properties. In the present study, we characterized cingulate pyramidal cells in the layer II/III of the ACC in adult mice. We then examined possible long-term changes in intrinsic properties of the ACC pyramidal cells after peripheral nerve injury. In the control mice, we found that there are three major types of pyramidal cells according to their action potential firing pattern: (i regular spiking (RS cells (24.7%, intrinsic bursting (IB cells (30.9%, and intermediate (IM cells (44.4%. In a state of neuropathic pain, the population distribution (RS: 21.3%; IB: 31.2%; IM: 47.5% and the single action potential properties of these three groups were indistinguishable from those in control mice. However, for repetitive action potentials, IM cells from neuropathic pain animals showed higher initial firing frequency with no change for the properties of RS and IB neurons from neuropathic pain mice. The present results provide the first evidence that, in addition to synaptic potentiation reported previously, peripheral nerve injury produces long-term plastic changes in the action potentials of cingulate pyramidal neurons in a cell type-specific manner.

  2. NK-3 receptor activation depolarizes and induces an after-depolarization in pyramidal neurons in gerbil cingulate cortex

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    Rekling, Jens C

    2004-01-01

    The involvement of tachykinins in cortical function is poorly understood. To study the actions of neurokinin-3 (NK3) receptor activation in frontal cortex, whole cell patch clamp recordings were performed from pyramidal neurons in slices of cingulate cortex from juvenile gerbils. Senktide (500n......M), a selective NK3 receptor agonist, induced a transient increase in spontaneous EPSPs in layer V pyramidal neurons, accompanied by a small depolarization ( approximately 4 mV). EPSPs during senktide had a larger amplitude and faster 10-90% rise time than during control. Senktide induced a transient...... depolarization in layer II/III pyramidal neurons, which often reached threshold for spikes. The depolarization ( approximately 6 mV) persisted in TTX, and was accompanied by an increase in input resistance. Senktide also transiently induced a slow after-depolarization, which appeared following a depolarizing...

  3. In vivo whole-cell patch-clamp recording of sensory synaptic responses of cingulate pyramidal neurons to noxious mechanical stimuli in adult mice

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    Descalzi Giannina

    2010-09-01

    Full Text Available Abstract The anterior cingulate cortex (ACC plays important roles in emotion, learning, memory and persistent pain. Our previous in vitro studies have demonstrated that pyramidal neurons in layer II/III of the adult mouse ACC can be characterized into three types: regular spiking (RS, intermediate (IM and intrinsic bursting (IB cells, according to their action potential (AP firing patterns. However, no in vivo information is available for the intrinsic properties and sensory responses of ACC neurons of adult mice. Here, we performed in vivo whole-cell patch-clamp recordings from pyramidal neurons in adult mice ACC under urethane anesthetized conditions. First, we classified the intrinsic properties and analyzed their slow oscillations. The population ratios of RS, IM and IB cells were 10, 62 and 28%, respectively. The mean spontaneous APs frequency of IB cells was significantly greater than those of RS and IM cells, while the slow oscillations were similar among ACC neurons. Peripheral noxious pinch stimuli induced evoked spike responses in all three types of ACC neurons. Interestingly, IB cells showed significantly greater firing frequencies than RS and IM cells. In contrast, non-noxious brush did not induce any significant response. Our studies provide the first in vivo characterization of ACC neurons in adult mice, and demonstrate that ACC neurons are indeed nociceptive. These findings support the critical roles of ACC in nociception, from mice to humans.

  4. Differential emotional experience induces elevated spine densities on basal dendrites of pyramidal neurons in the anterior cingulate cortex of Octodon degus.

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    Helmeke, C; Poeggel, G; Braun, K

    2001-01-01

    It appears likely that, in analogy to the synaptic development of sensory and motor cortices, which critically depends on sensory or motor stimulation (Rosenzweig and Bennett, 1996), the synaptic development of limbic cortical regions are modulated by early postnatal cognitive and emotional experiences. The very first postnatal experience, which takes place in a confined and stable familial environment, is the interaction of the newborn individual with the parents and siblings (Gray, 1958). The aim of this quantitative morphological study was to analyze the impact of different degrees of juvenile emotional experience on the synaptic development in a limbic cortical area, the dorsal anterior cingulate cortex, a region which is involved in the perception and regulation of emotions. We study the precocious trumpet-tailed rat (Octodon degus) as the animal model, because, like human babies, this species is born with functional visual and acoustic systems and the pups are therefore capable of detecting even subtle environmental changes immediately after birth (Reynolds and Wright, 1979; Poeggel and Braun, 1996; Braun et al., 2000; Ovtscharoff and Braun, 2001). The results demonstrate that already a subtle disturbance of the familial environment such as handling induced significantly elevated spine densities on the basal dendrites of layer III cortical pyramidal neurons. More severe disturbances of the emotional environment, such as periodic parental deprivation with or without subsequent chronic social isolation, resulted in an elevation of spine densities of similar magnitude as seen after handling and in addition, altered spine densities confined to specific dendritic segments were observed in these groups. These observations unveil the remarkable sensitivity of the dorsal anterior cingulate cortex towards environmental influences and behavioral experiences during phases of postnatal development. The behavioral consequences of these experience-induced synaptic changes

  5. 芍药苷对急性缺氧前扣带回锥体神经元的影响%Effect of Paeoniflorin on Anterior Cingulate Cortex Pyramidal Neurons After Acute Hypoxia

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    李果; 杜永平; 张月萍; 徐晖; 胡三觉

    2011-01-01

    Objective: To investigate the neuroprotective effect of paeoniflorin (PF) on the anterior cingulate cortex(ACC) pyramidal neurons after acute hypoxia. Methods: Before and after the application of PF,variations of frequencies on the neuronal miniature excitatory postsynaptic current (mEPSC) in ACC were recorded by the whole-cell patch clamp techniques of rat brain slices following acute hypoxia. Results: After acute hypoxic insult,the frequence of the mEPSC was significantly increased in the pyramidal neurons of the ACC. When perfusion with 300μmol/L PF of artificial cerebrospinal fluid,the frequency of the mEPSC was remarkably reduced in comparison with the frequency determined following acute hypoxia. Conclusion: PF may modulate the plasticity of synaptic activities through decreasing the frequency of the neuronal mEPSC induced by acute hypoxic insult. All these results indicate that PF may have neuroprotective effects.%目的 探讨芍药昔对急性缺氧形成的前扣带回(ACC)锥体神经元损伤的保护作用.方法 应用全细胞膜片钳技术记录急性缺氧ACC锥体神经元微小兴奋性突触后电流(mEPSC)频率的变化,观察芍药苷对急性缺氧后mEPSC的影响.结果 急性缺氧后,ACC锥体神经元的mEPSC频率明显增加;灌流含有芍药苷(300μmol/L)的正常人工脑脊液(ACSF),神经元的mEPSC频率与急性缺氧后相比明显降低.结论 芍药苷可能通过抑制急性缺氧ACC锥体神经元mEPSC的频率,调节突触活动的可塑性变化,达到神经保护作用.

  6. Neurochemical, morphologic, and laminar characterization of cortical projection neurons in the cingulate motor areas of the macaque monkey

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    Nimchinsky, E. A.; Hof, P. R.; Young, W. G.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

    1996-01-01

    The primate cingulate gyrus contains multiple cortical areas that can be distinguished by several neurochemical features, including the distribution of neurofilament protein-enriched pyramidal neurons. In addition, connectivity and functional properties indicate that there are multiple motor areas in the cortex lining the cingulate sulcus. These motor areas were targeted for analysis of potential interactions among regional specialization, connectivity, and cellular characteristics such as neurochemical profile and morphology. Specifically, intracortical injections of retrogradely transported dyes and intracellular injection were combined with immunocytochemistry to investigate neurons projecting from the cingulate motor areas to the putative forelimb region of the primary motor cortex, area M1. Two separate groups of neurons projecting to area M1 emanated from the cingulate sulcus, one anterior and one posterior, both of which furnished commissural and ipsilateral connections with area M1. The primary difference between the two populations was laminar origin, with the anterior projection originating largely in deep layers, and the posterior projection taking origin equally in superficial and deep layers. With regard to cellular morphology, the anterior projection exhibited more morphologic diversity than the posterior projection. Commissural projections from both anterior and posterior fields originated largely in layer VI. Neurofilament protein distribution was a reliable tool for localizing the two projections and for discriminating between them. Comparable proportions of the two sets of projection neurons contained neurofilament protein, although the density and distribution of the total population of neurofilament protein-enriched neurons was very different in the two subareas of origin. Within a projection, the participating neurons exhibited a high degree of morphologic heterogeneity, and no correlation was observed between somatodendritic morphology and

  7. Characterization of neuronal intrinsic properties and synaptic transmission in layer I of anterior cingulate cortex from adult mice

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    Li Xiang-Yao

    2012-07-01

    Full Text Available Abstract The neurons in neocortex layer I (LI provide inhibition to the cortical networks. Despite increasing use of mice for the study of brain functions, few studies were reported about mouse LI neurons. In the present study, we characterized intrinsic properties of LI neurons of the anterior cingulate cortex (ACC, a key cortical area for sensory and cognitive functions, by using whole-cell patch clamp recording approach. Seventy one neurons in LI and 12 pyramidal neurons in LII/III were recorded. Although all of the LI neurons expressed continuous adapting firing characteristics, the unsupervised clustering results revealed five groups in the ACC, including: Spontaneous firing neurons; Delay-sAHP neurons, Delay-fAHP neurons, and two groups of neurons with ADP, named ADP1 and ADP2, respectively. Using pharmacological approaches, we found that LI neurons received both excitatory (mediated by AMPA, kainate and NMDA receptors, and inhibitory inputs (which were mediated by GABAA receptors. Our studies provide the first report characterizing the electrophysiological properties of neurons in LI of the ACC from adult mice.

  8. Dendritic potassium channels in hippocampal pyramidal neurons.

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    Johnston, D; Hoffman, D A; Magee, J C; Poolos, N P; Watanabe, S; Colbert, C M; Migliore, M

    2000-05-15

    Potassium channels located in the dendrites of hippocampal CA1 pyramidal neurons control the shape and amplitude of back-propagating action potentials, the amplitude of excitatory postsynaptic potentials and dendritic excitability. Non-uniform gradients in the distribution of potassium channels in the dendrites make the dendritic electrical properties markedly different from those found in the soma. For example, the influence of a fast, calcium-dependent potassium current on action potential repolarization is progressively reduced in the first 150 micrometer of the apical dendrites, so that action potentials recorded farther than 200 micrometer from the soma have no fast after-hyperpolarization and are wider than those in the soma. The peak amplitude of back-propagating action potentials is also progressively reduced in the dendrites because of the increasing density of a transient potassium channel with distance from the soma. The activation of this channel can be reduced by the activity of a number of protein kinases as well as by prior depolarization. The depolarization from excitatory postsynaptic potentials (EPSPs) can inactivate these A-type K+ channels and thus lead to an increase in the amplitude of dendritic action potentials, provided the EPSP and the action potentials occur within the appropriate time window. This time window could be in the order of 15 ms and may play a role in long-term potentiation induced by pairing EPSPs and back-propagating action potentials.

  9. Adolescent maturation of inhibitory inputs onto cingulate cortex neurons is cell-type specific and TrkB dependent

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    Angela eVandenberg

    2015-02-01

    Full Text Available The maturation of inhibitory circuits during adolescence may be tied to the onset of mental health disorders such as schizophrenia. Neurotrophin signaling likely plays a critical role in supporting inhibitory circuit development and is also implicated in psychiatric disease. Within the neocortex, subcircuits may mature at different times and show differential sensitivity to neurotrophin signaling. We measured miniature inhibitory and excitatory postsynaptic currents (mIPSC and mEPSCs in Layer 5 cell-types in the mouse anterior cingulate across the periadolescent period. We differentiated cell-types mainly by Thy1 YFP transgene expression and also retrobead injection labeling in the contralateral cingulate and ipsilateral pons. We found that YFP- neurons and commissural projecting neurons had lower frequency of mIPSCs than neighboring YFP+ neurons or pons projecting neurons in juvenile mice (P21-25. YFP- neurons and to a lesser extent commissural projecting neurons also showed a significant increase in mIPSC amplitude during the periadolescent period (P21-25 vs. P40-50, which was not seen in YFP+ neurons or pons projecting neurons. Systemic disruption of tyrosine kinase receptor B (TrkB signaling during P23-50 in TrkBF616A mice blocked developmental changes in mIPSC amplitude, without affecting miniature excitatory post synaptic currents (mEPSCs. Our data suggest that the maturation of inhibitory inputs onto layer 5 pyramidal neurons is cell-type specific. These data may inform our understanding of adolescent brain development across species and aid in identifying candidate subcircuits that may show greater vulnerability in mental illness.

  10. Intrinsic oscillations of neocortex generated by layer 5 pyramidal neurons.

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    Silva, L R; Amitai, Y; Connors, B W

    1991-01-25

    Rhythmic activity in the neocortex varies with different behavioral and pathological states and in some cases may encode sensory information. However, the neural mechanisms of these oscillations are largely unknown. Many pyramidal neurons in layer 5 of the neocortex showed prolonged, 5- to 12-hertz rhythmic firing patterns at threshold. Rhythmic firing was due to intrinsic membrane properties, sodium conductances were essential for rhythmicity, and calcium-dependent conductances strongly modified rhythmicity. Isolated slices of neocortex generated epochs of 4- to 10-hertz synchronized activity when N-methyl-D-aspartate receptor-mediated channels were facilitated. Layer 5 was both necessary and sufficient to produce these synchronized oscillations. Thus, synaptic networks of intrinsically rhythmic neurons in layer 5 may generate or promote certain synchronized oscillations of the neocortex.

  11. Intrinsic Oscillations of Neocortex Generated by Layer 5 Pyramidal Neurons

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    Silva, Laurie R.; Amitai, Yael; Connors, Barry W.

    1991-01-01

    Rhythmic activity in the neocortex varies with different behavioral and pathological states and in some cases may encode sensory information. However, the neural mechanisms of these oscillations are largely unknown. Many pyramidal neurons in layer 5 of the neocortex showed prolonged, 5- to 12-hertz rhythmic firing patterns at threshold. Rhythmic firing was due to intrinsic membrane properties, sodium conductances were essential for rhythmicity, and calcium-dependent conductances strongly modified rhythmicity. Isolated slices of neocortex generated epochs of 4- to 10-hertz synchronized activity when N-methyl-D-aspartate receptor-mediated channels were facilitated. Layer 5 was both necessary and sufficient to produce these synchronized oscillations. Thus, synaptic networks of intrinsically rhythmic neurons in layer 5 may generate or promote certain synchronized oscillations of the neocortex.

  12. Pyramidal neurons of the prefrontal cortex in post-stroke, vascular and other ageing-related dementias.

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    Foster, Vincent; Oakley, Arthur E; Slade, Janet Y; Hall, Roslyn; Polvikoski, Tuomo M; Burke, Matthew; Thomas, Alan J; Khundakar, Ahmad; Allan, Louise M; Kalaria, Raj N

    2014-09-01

    Dementia associated with cerebrovascular disease is common. It has been reported that ∼30% of elderly patients who survive stroke develop delayed dementia (post-stroke dementia), with most cases being diagnosed as vascular dementia. The pathological substrates associated with post-stroke or vascular dementia are poorly understood, particularly those associated with executive dysfunction. Three separate yet interconnecting circuits control executive function within the frontal lobe involving the dorsolateral prefrontal cortex, anterior cingulate cortex and the orbitofrontal cortex. We used stereological methods, along with immunohistological and related cell morphometric analysis, to examine densities and volumes of pyramidal neurons of the dorsolateral prefrontal cortex, anterior cingulate cortex and orbitofrontal cortex in the frontal lobe from a total of 90 elderly subjects (age range 71-98 years). Post-mortem brain tissues from post-stroke dementia and post-stroke patients with no dementia were derived from our prospective Cognitive Function After Stroke study. We also examined, in parallel, samples from ageing controls and similar age subjects pathologically diagnosed with Alzheimer's disease, mixed Alzheimer's disease and vascular dementia, and vascular dementia. We found pyramidal cell volumes in layers III and V in the dorsolateral prefrontal cortex of post-stroke and vascular dementia and, of mixed and Alzheimer's disease subjects to be reduced by 30-40% compared to post-stroke patients with no dementia and controls. There were no significant changes in neuronal volumes in either the anterior cingulate or orbitofrontal cortices. Remarkably, pyramidal neurons within the orbitofrontal cortex were also found to be smaller in size when compared to those in the other two neocortical regions. To relate the cell changes to cognitive function, we noted significant correlations between neuronal volumes and total CAMCOG, orientation and memory scores and clinical

  13. Housing under the pyramid reduces susceptibility of hippocampal CA3 pyramidal neurons to prenatal stress in the developing rat offspring.

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    Murthy, Krishna Dilip; George, Mitchel Constance; Ramasamy, Perumal; Mustapha, Zainal Arifin

    2013-12-01

    Mother-offspring interaction begins before birth. The foetus is particularly vulnerable to environmental insults and stress. The body responds by releasing excess of the stress hormone cortisol, which acts on glucocorticoid receptors. Hippocampus in the brain is rich in glucocorticoid receptors and therefore susceptible to stress. The stress effects are reduced when the animals are placed under a model wooden pyramid. The present study was to first explore the effects of prenatal restraint-stress on the plasma corticosterone levels and the dendritic arborisation of CA3 pyramidal neurons in the hippocampus of the offspring. Further, to test whether the pyramid environment would alter these effects, as housing under a pyramid is known to reduce the stress effects, pregnant Sprague Dawley rats were restrained for 9 h per day from gestation day 7 until parturition in a wire-mesh restrainer. Plasma corticosterone levels were found to be significantly increased. In addition, there was a significant reduction in the apical and the basal total dendritic branching points and intersections of the CA3 hippocampal pyramidal neurons. The results thus suggest that, housing in the pyramid dramatically reduces prenatal stress effects in rats.

  14. Active dendrites support efficient initiation of dendritic spikes in hippocampal CA3 pyramidal neurons

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    Kim, Sooyun; Guzman, Segundo J.; Hu, Hua; Jonas, Peter

    2012-01-01

    CA3 pyramidal neurons are important for memory formation and pattern completion in the hippocampal network. It is generally thought that proximal synapses from the mossy fibers activate these neurons most efficiently, whereas distal inputs from the perforant path have a weaker modulatory influence. We used confocally targeted patch-clamp recording from dendrites and axons to map the activation of rat CA3 pyramidal neurons at the subcellular level. Our results reveal two distinct dendritic dom...

  15. Location-dependent excitatory synaptic interactions in pyramidal neuron dendrites.

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    Bardia F Behabadi

    Full Text Available Neocortical pyramidal neurons (PNs receive thousands of excitatory synaptic contacts on their basal dendrites. Some act as classical driver inputs while others are thought to modulate PN responses based on sensory or behavioral context, but the biophysical mechanisms that mediate classical-contextual interactions in these dendrites remain poorly understood. We hypothesized that if two excitatory pathways bias their synaptic projections towards proximal vs. distal ends of the basal branches, the very different local spike thresholds and attenuation factors for inputs near and far from the soma might provide the basis for a classical-contextual functional asymmetry. Supporting this possibility, we found both in compartmental models and electrophysiological recordings in brain slices that the responses of basal dendrites to spatially separated inputs are indeed strongly asymmetric. Distal excitation lowers the local spike threshold for more proximal inputs, while having little effect on peak responses at the soma. In contrast, proximal excitation lowers the threshold, but also substantially increases the gain of distally-driven responses. Our findings support the view that PN basal dendrites possess significant analog computing capabilities, and suggest that the diverse forms of nonlinear response modulation seen in the neocortex, including uni-modal, cross-modal, and attentional effects, could depend in part on pathway-specific biases in the spatial distribution of excitatory synaptic contacts onto PN basal dendritic arbors.

  16. Morphology cluster and prediction of growth of human brain pyramidal neurons

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    Chao Yu; Zengxin Han; Wencong Zeng; Shenquan Liu

    2012-01-01

    Predicting neuron growth is valuable to understand the morphology of neurons, thus it is helpful in the research of neuron classification. This study sought to propose a new method of predicting the growth of human neurons using 1 907 sets of data in human brain pyramidal neurons obtained from the website of NeuroMorpho.Org. First, we analyzed neurons in a morphology field and used an expectation-maximization algorithm to specify the neurons into six clusters. Second, naive Bayes classifier was used to verify the accuracy of the expectation-maximization algorithm. Experiment results proved that the cluster groups here were efficient and feasible. Finally, a new method to rank the six expectation-maximization algorithm clustered classes was used in predicting the growth of human pyramidal neurons.

  17. Early establishment of multiple release site connectivity between interneurons and pyramidal neurons in the developing hippocampus.

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    Groc, Laurent; Gustafsson, Bengt; Hanse, Eric

    2003-05-01

    The strength of the synaptic transmission between two neurons critically depends on the number of release sites connecting the neurons. Here we examine the development of connectivity between gamma-aminobutyric acid (GABA)ergic interneurons and CA1 pyramidal neurons in the hippocampus. GABAergic postsynaptic currents (PSCs) were recorded in whole-cell voltage-clamped CA1 pyramidal neurons. By comparing spontaneous and miniature (action potential-independent) GABAergic PSCs, we found that multiple release site connectivity is established already at the first postnatal day and that the degree of connectivity remains unaltered into adulthood. During the same time there is a dramatic increase in the number of GABAergic synapses on each pyramidal neuron as indicated by the increase in frequency of miniature GABAergic PSCs. These results indicate that during development a given interneuron contacts an increasing number of target pyramidal neurons but with the same multiple release site connectivity. It has been shown previously that the connectivity between CA3 and CA1 pyramidal neurons is initially restricted to one release site, and develops gradually. The present result thus suggests different mechanisms to govern the maturation of excitatory and inhibitory synaptic transmissions.

  18. Thrombin modulates persistent sodium current in CA1 pyramidal neurons of young and adult rat hippocampus.

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    Lunko, O O; Isaev, D S; Krishtal, O O; Isaeva, E V

    2015-01-01

    Serine protease thrombin, a key factor of blood coagulation, participates in many neuronal processes important for normal brain functioning and during pathological conditions involving abnormal neuronal synchronization, neurodegeneration and inflammation. Our previous study on CA3 pyramidal neurons showed that application ofthrombin through the activation of specific protease-activated receptor 1 (PAR1) produces a significant hyperpolarizing shift of the activation of the TTX-sensitive persistent voltage-gated Na+ current (I(Nap)) thereby affecting membrane potential and seizure threshold at the network level. It was shown that PAR1 is also expressed in CA1 area of hippocampus and can be implicated in neuronal damage in this area after status epilepticus. The aim of the present study was to evaluate the effect of thrombin on I(NaP) in CA1 pyramidal neurons from adult and young rats. Using whole cell patch-clamp technique we demonstrate that thrombin application results in the hyperpolarization shift of I(NaP) activation as well as increase in the I(NaP) amplitude in both age groups. We have found that I(NaP) in pyramidal neurons of hippocampal CA 1 region is more vulnerable to the thrombin action than I(NaP) in pyramidal neurons of hippocampal CA3 region. We have also found that the immature hippocampus is more sensitive to thrombin action which emphasizes the contribution of thrombin-dependent pathway to the regulation of neuronal activity in immature brain.

  19. Brief dopaminergic stimulations produce transient physiological changes in prefrontal pyramidal neurons.

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    Moore, Anna R; Zhou, Wen-Liang; Potapenko, Evgeniy S; Kim, Eun-Ji; Antic, Srdjan D

    2011-01-25

    In response to food reward and other pertinent events, midbrain dopaminergic neurons fire short bursts of action potentials causing a phasic release of dopamine in the prefrontal cortex (rapid and transient increases in cortical dopamine concentration). Here we apply short (2s) iontophoretic pulses of glutamate, GABA, dopamine and dopaminergic agonists locally, onto layer 5 pyramidal neurons in brain slices of the rat medial prefrontal cortex (PFC). Unlike glutamate and GABA, brief dopaminergic pulses had negligible effects on the resting membrane potential. However, dopamine altered action potential firing in an extremely rapid (iontophoresis current artifact. Our present data imply that one population of PFC pyramidal neurons receiving direct synaptic contacts from midbrain dopaminergic neurons would stall during the 0.5s of the phasic dopamine burst. The spillover dopamine, on the other hand, would act as a positive stimulator of cortical excitability (30% increase) to all D2-receptor carrying pyramidal cells, for the next 40s.

  20. De novo expression of the neurokinin 1 receptor in spinal lamina I pyramidal neurons in polyarthritis.

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    Almarestani, L; Waters, S M; Krause, J E; Bennett, G J; Ribeiro-da-Silva, A

    2009-05-20

    Spinal lamina I (LI) neurons play a major role in the transmission and integration of pain-related information that is relayed to higher centers. Alterations in the excitability of these neurons influence chronic pain development, and expression of the neurokinin 1 receptor (NK-1r) is thought to play a major role in such changes. Novel expression of NK-1r may underlie hyperexcitability in new populations of LI neurons. LI projection neurons can be classified morphologically into fusiform, pyramidal, and multipolar cells, differing in their functional properties, with the pyramidal type being nonnociceptive. In agreement with this, we have shown that spinoparabrachial pyramidal neurons seldom express NK-1r, in contrast with the other two cell types. In this study we investigated in the rat the long-term changes in NK-1r expression by spinoparabrachial LI neurons following the unilateral injection in the hindpaw plantar surface of complete Freund's adjuvant (CFA). Cholera toxin subunit B (CTb) was injected unilaterally into the parabrachial nucleus. Our results revealed that, ipsilaterally, pyramidal neurons were seldom immunoreactive for NK-1r both in saline-injected and in CFA-injected rats, up to 10 days post-CFA. However, a considerable number of pyramidal cells were immunoreactive for NK-1r at 15, 21, and 30 days post-CFA. Our data raise the possibility -- which needs to be confirmed by electrophysiology -- that most LI projection neurons of the pyramidal type are likely nonnociceptive in naive animals but might become nociceptive following the development of arthritis.

  1. Pyramidal cells make specific connections onto smooth (GABAergic neurons in mouse visual cortex.

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    Rita Bopp

    2014-08-01

    Full Text Available One of the hallmarks of neocortical circuits is the predominance of recurrent excitation between pyramidal neurons, which is balanced by recurrent inhibition from smooth GABAergic neurons. It has been previously described that in layer 2/3 of primary visual cortex (V1 of cat and monkey, pyramidal cells filled with horseradish peroxidase connect approximately in proportion to the spiny (excitatory, 95% and 81%, respectively and smooth (GABAergic, 5% and 19%, respectively dendrites found in the neuropil. By contrast, a recent ultrastructural study of V1 in a single mouse found that smooth neurons formed 51% of the targets of the superficial layer pyramidal cells. This suggests that either the neuropil of this particular mouse V1 had a dramatically different composition to that of V1 in cat and monkey, or that smooth neurons were specifically targeted by the pyramidal cells in that mouse. We tested these hypotheses by examining similar cells filled with biocytin in a sample of five mice. We found that the average composition of the neuropil in V1 of these mice was similar to that described for cat and monkey V1, but that the superficial layer pyramidal cells do form proportionately more synapses with smooth dendrites than the equivalent neurons in cat or monkey. These distributions may underlie the distinct differences in functional architecture of V1 between rodent and higher mammals.

  2. Sensory deprivation differentially impacts the dendritic development of pyramidal versus non-pyramidal neurons in layer 6 of mouse barrel cortex.

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    Chen, Chia-Chien; Tam, Danny; Brumberg, Joshua C

    2012-04-01

    Early postnatal sensory experience can have profound impacts on the structure and function of cortical circuits affecting behavior. Using the mouse whisker-to-barrel system we chronically deprived animals of normal sensory experience by bilaterally trimming their whiskers every other day from birth for the first postnatal month. Brain tissue was then processed for Golgi staining and neurons in layer 6 of barrel cortex were reconstructed in three dimensions. Dendritic and somatic parameters were compared between sensory-deprived and normal sensory experience groups. Results demonstrated that layer 6 non-pyramidal neurons in the chronically deprived group showed an expansion of their dendritic arbors. The pyramidal cells responded to sensory deprivation with increased somatic size and basilar dendritic arborization but overall decreased apical dendritic parameters. In sum, sensory deprivation impacted on the neuronal architecture of pyramidal and non-pyramidal neurons in layer 6, which may provide a substrate for observed physiological and behavioral changes resulting from whisker trimming.

  3. Pyramidal Cells in Prefrontal Cortex of Primates: Marked Differences in Neuronal Structure Among Species

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    Elston, Guy N.; Benavides-Piccione, Ruth; Elston, Alejandra; Manger, Paul R.; DeFelipe, Javier

    2010-01-01

    The most ubiquitous neuron in the cerebral cortex, the pyramidal cell, is characterized by markedly different dendritic structure among different cortical areas. The complex pyramidal cell phenotype in granular prefrontal cortex (gPFC) of higher primates endows specific biophysical properties and patterns of connectivity, which differ from those in other cortical regions. However, within the gPFC, data have been sampled from only a select few cortical areas. The gPFC of species such as human and macaque monkey includes more than 10 cortical areas. It remains unknown as to what degree pyramidal cell structure may vary among these cortical areas. Here we undertook a survey of pyramidal cells in the dorsolateral, medial, and orbital gPFC of cercopithecid primates. We found marked heterogeneity in pyramidal cell structure within and between these regions. Moreover, trends for gradients in neuronal complexity varied among species. As the structure of neurons determines their computational abilities, memory storage capacity and connectivity, we propose that these specializations in the pyramidal cell phenotype are an important determinant of species-specific executive cortical functions in primates. PMID:21347276

  4. BDNF has opposite effects on the quantal amplitude of pyramidal neuron and interneuron excitatory synapses.

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    Rutherford, L C; Nelson, S B; Turrigiano, G G

    1998-09-01

    Recently, we have identified a novel form of synaptic plasticity that acts to stabilize neocortical firing rates by scaling the quantal amplitude of AMPA-mediated synaptic inputs up or down as a function of neuronal activity. Here, we show that the effects of activity blockade on quantal amplitude are mediated through the neurotrophin brain-derived neurotrophic factor (BDNF). Exogenous BDNF prevented, and a TrkB-IgG fusion protein reproduced, the effects of activity blockade on pyramidal quantal amplitude. BDNF had opposite effects on pyramidal neuron and interneuron quantal amplitudes and modified the ratio of pyramidal neuron to interneuron firing rates. These data demonstrate a novel role for BDNF in the homeostatic regulation of excitatory synaptic strengths and in the maintenance of the balance of cortical excitation and inhibition.

  5. Spiking patterns of neocortical L5 pyramidal neurons in vitro change with temperature

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    Tristan eHedrick

    2011-01-01

    Full Text Available A subset of pyramidal neurons in layer 5 of the mammalian neocortex can fire action potentials in brief, high-frequency bursts while others fire spikes at regularly-spaced intervals. Here we show that individual layer 5 pyramidal neurons in acute slices from mouse primary motor cortex can adopt both regular and burst spiking patterns. During constant current injection at the soma, neurons displayed a regular firing pattern at 36-37 °C, but switched to burst spiking patterns upon cooling the slice to 24-26 °C. This change in firing pattern was reversible and repeatable and was independent of the somatic resting membrane potential. Hence these spiking patterns are not inherent to discrete populations of pyramidal neurons and are more interchangeable than previously thought. Burst spiking in these neurons is the result of electrical interactions between the soma and distal apical dendritic tree. Presumably the interactions between soma and distal dendrite are temperature-sensitive, suggesting that the manner in which layer 5 pyramidal neurons translate synaptic input into an output spiking pattern is fundamentally altered at sub-physiological temperatures.

  6. Dense and overlapping innervation of pyramidal neurons by neocortical chandelier cells

    Science.gov (United States)

    Inan, Melis; Blázquez-Llorca, Lidia; Merchán-Perez, Angel; Anderson, Stewart A.; DeFelipe, Javier; Yuste, Rafael

    2013-01-01

    Chandelier (or axo-axonic) cells are a distinct group of GABAergic interneurons that innervate the axon initial segments of pyramidal cells and thus could have an important role controlling the activity of cortical circuits. To understand their connectivity we labeled upper layers chandelier cells (ChCs) from mouse neocortex with a genetic strategy and studied how their axons contact local populations of pyramidal neurons, using immunohistochemical detection of axon initial segments. We studied ChCs located in the border of layers 1 and 2 from primary somatosensory cortex and find that practically all ChC axon terminals contact axon initial segments with an average of 3–5 boutons per cartridge. By measuring the number of putative synapses in initial segments we estimate that each pyramidal neuron is innervated, on average, by at least 4 ChCs. Additionally, each individual ChC contacts 35–50% of pyramidal neurons within its axonal arbor, with pockets of high innervation density. Finally, we find that ChC axons seems to have a conserved innervation pattern at different postnatal ages (P18–90), with only relatively small lateral expansions of their arbor and increases in the total number of their cartridges during the developmental period analyzed. We conclude that ChCs innervate neighboring pyramidal neurons in a dense and overlapping manner, an innervation pattern which could enable ChCs exert a widespread influence on their local circuits. PMID:23365230

  7. Modelling the Somatic Electrical Response of Hippocampal Pyramidal Neurons

    Science.gov (United States)

    1989-09-01

    non-linear, time-varying conductances in the soma, including those that underly three putative sodium currents , (IN.-tr,, INa-tail, and INa-rep), a...for excitation and propagation of the nerve impulse. Biophysics Journal. 6:, 1966. [12] C. French and P. Gage. A threshold sodium current in pyramidal

  8. EFFECTS OF GLUTAMATE ON SODIUM CHANNEL IN ACUTELY DISSOCIATED HIPPOCAMPAL CA1 PYRAMIDAL NEURONS OF RATS

    Institute of Scientific and Technical Information of China (English)

    高宾丽; 伍国锋; 杨艳; 刘智飞; 曾晓荣

    2011-01-01

    Objective To observe the effects of glutamate on sodium channel in acutely dissociated hippocampal CA1 pyramidal neurons of rats.Methods Voltage-dependent sodium currents (INa) in acutely dissociated hippocampal CA1 pyramidal neurons of neonate rats were recorded by whole-cell patchclamp of the brain slice technique when a series of doses of glutamate (100-1000μmol/L) were applied.Results Different concentrations of glutamate could inhibit INa,and higher concentration of glutamate affected greater inhibitio...

  9. Turtle Dorsal Cortex Pyramidal Neurons Comprise Two Distinct Cell Types with Indistinguishable Visual Responses.

    Directory of Open Access Journals (Sweden)

    Thomas Crockett

    Full Text Available A detailed inventory of the constituent pieces in cerebral cortex is considered essential to understand the principles underlying cortical signal processing. Specifically, the search for pyramidal neuron subtypes is partly motivated by the hypothesis that a subtype-specific division of labor could create a rich substrate for computation. On the other hand, the extreme integration of individual neurons into the collective cortical circuit promotes the hypothesis that cellular individuality represents a smaller computational role within the context of the larger network. These competing hypotheses raise the important question to what extent the computational function of a neuron is determined by its individual type or by its circuit connections. We created electrophysiological profiles from pyramidal neurons within the sole cellular layer of turtle visual cortex by measuring responses to current injection using whole-cell recordings. A blind clustering algorithm applied to these data revealed the presence of two principle types of pyramidal neurons. Brief diffuse light flashes triggered membrane potential fluctuations in those same cortical neurons. The apparently network driven variability of the visual responses concealed the existence of subtypes. In conclusion, our results support the notion that the importance of diverse intrinsic physiological properties is minimized when neurons are embedded in a synaptic recurrent network.

  10. Anatomy and Physiology of the Thick-tufted Layer 5 Pyramidal Neuron

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    Srikanth eRamaswamy

    2015-06-01

    Full Text Available The thick-tufted layer 5 (TTL5 pyramidal neuron is one of the most extensively studied neuron types in the mammalian neocortex and has become a benchmark for understanding information processing in excitatory neurons. By virtue of having the widest local axonal and dendritic arborization, the TTL5 neuron encompasses various local neocortical neurons and thereby defines the dimensions of neocortical microcircuitry. The TTL5 neuron integrates input across all neocortical layers and is the principal output pathway funneling information flow to subcortical structures. Several studies over the past decades have investigated the anatomy, physiology, synaptology, and pathophysiology of the TTL5 neuron. This review summarizes key discoveries and identifies potential avenues of research to facilitate an integrated and unifying understanding on the role of a central neuron in the neocortex.

  11. Electrophysiological actions of cyclosporin A and tacrolimus on rat hip-pocampal CA1 pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    Yong YU; Xue-qin CHEN; Yao-yuan CUI; Guo-yuan HU

    2007-01-01

    Aim: The aim of the present study was to investigate the electrophysiological actions of cyclosporin A (CsA) and tacrolimus (FK506) on neurons in the brain, and to elucidate the relevant mechanisms. Methods: Whole-cell current-clamp recording was made in CA1 pyramidal neurons in rat hippocampal slices; whole- cell voltage-clamp recording was made in dissociated hippocampal CA1 pyrami- dal neurons of rats. Results: CsA (100 μmol/L) and FKS06 (50 μmol/L) did not significantly alter the passive electrical properties of hippocampal CA1 pyramidal neurons, but slowed down the repolarizing phase of the action potential. CsA (10-100 μmol/L) selectively inhibited the delayed rectifier K~ current (IK,) in a concentration-dependent manner. CsA did not affect the kinetic properties of IK. Intracellular dialysis of CsA (100 μmol/L) had no effect on IK. The inhibition of IK by CsA (100/μmol/L) persisted under the low Ca2+ conditions that blocked the basal activity of calcineurin. Conclusion: CsA exerted calcineurin-independent inhibition on the IK in rat hippocampal pyramidal neurons. Taken together with our previous finding with FK506, it is conceivable that the spike broadening caused by the immunosuppressant drugs is due to direct inhibition on the IK.

  12. Layer 4 pyramidal neurons exhibit robust dendritic spine plasticity in vivo after input deprivation.

    Science.gov (United States)

    Miquelajauregui, Amaya; Kribakaran, Sahana; Mostany, Ricardo; Badaloni, Aurora; Consalez, G Giacomo; Portera-Cailliau, Carlos

    2015-05-06

    Pyramidal neurons in layers 2/3 and 5 of primary somatosensory cortex (S1) exhibit somewhat modest synaptic plasticity after whisker input deprivation. Whether neurons involved at earlier steps of sensory processing show more or less plasticity has not yet been examined. Here, we used longitudinal in vivo two-photon microscopy to investigate dendritic spine dynamics in apical tufts of GFP-expressing layer 4 (L4) pyramidal neurons of the vibrissal (barrel) S1 after unilateral whisker trimming. First, we characterize the molecular, anatomical, and electrophysiological properties of identified L4 neurons in Ebf2-Cre transgenic mice. Next, we show that input deprivation results in a substantial (∼50%) increase in the rate of dendritic spine loss, acutely (4-8 d) after whisker trimming. This robust synaptic plasticity in L4 suggests that primary thalamic recipient pyramidal neurons in S1 may be particularly sensitive to changes in sensory experience. Ebf2-Cre mice thus provide a useful tool for future assessment of initial steps of sensory processing in S1.

  13. Synaptic integration in tuft dendrites of layer 5 pyramidal neurons: a new unifying principle.

    Science.gov (United States)

    Larkum, Matthew E; Nevian, Thomas; Sandler, Maya; Polsky, Alon; Schiller, Jackie

    2009-08-07

    Tuft dendrites are the main target for feedback inputs innervating neocortical layer 5 pyramidal neurons, but their properties remain obscure. We report the existence of N-methyl-D-aspartate (NMDA) spikes in the fine distal tuft dendrites that otherwise did not support the initiation of calcium spikes. Both direct measurements and computer simulations showed that NMDA spikes are the dominant mechanism by which distal synaptic input leads to firing of the neuron and provide the substrate for complex parallel processing of top-down input arriving at the tuft. These data lead to a new unifying view of integration in pyramidal neurons in which all fine dendrites, basal and tuft, integrate inputs locally through the recruitment of NMDA receptor channels relative to the fixed apical calcium and axosomatic sodium integration points.

  14. Changes in membrane properties of CA1 pyramidal neurons after transient forebrain ischemia in vivo.

    Science.gov (United States)

    Gao, T M; Pulsinelli, W A; Xu, Z C

    1999-03-01

    We have previously identified three distinct populations of CA1 pyramidal neurons after reperfusion based on differences in synaptic response, and named these late depolarizing postsynaptic potential neurons (enhanced synaptic transmission), non-late depolarizing postsynaptic potential and small excitatory postsynaptic neurons (depressed synaptic transmission). In the present study, spontaneous activity and membrane properties of CA1 neurons were examined up to 48 h following approximately 14 min ischemic depolarization using intracellular recording and staining techniques in vivo. In comparison with preischemic properties, the spontaneous firing rate and the spontaneous synaptic activity of CA1 neurons decreased significantly during reperfusion; spontaneous synaptic activity ceased completely 36-48 h after reperfusion, except for a low level of activity which persisted in non-late depolarizing postsynaptic potential neurons. Neuronal hyperactivity as indicated by increasing firing rate was never observed in the present study. The membrane input resistance and time constant decreased significantly in late depolarizing postsynaptic potential neurons at 24-48 h reperfusion. In contrast, similar changes were not observed in non-late depolarizing postsynaptic potential neurons. The rheobase, spike threshold and spike frequency adaptation in late depolarizing postsynaptic potential neurons increased progressively following reperfusion. Only a transient increase in rheobase and spike threshold was detected in non-late depolarizing postsynaptic potential neurons and spike frequency adaptation remained unchanged in these neurons. The amplitude of fast afterhyperpolarization increased in all neurons after reperfusion, with the smallest increment in non-late depolarizing postsynaptic potential neurons. Small excitatory postsynaptic potential neurons shared similar changes to those of late depolarizing postsynaptic potential neurons. These results suggest that the enhancement

  15. The facilitatory influence of anterior cingulate cortex on ON-OFF response of tactile neuron in thalamic ventrobasal nucleus

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The structures of limbic system have been found to modulate the auditory, visual and pain afferent signals in the related nuclei of thalamus. One of those structures is anterior cingulate cortex (ACC) that influences nocuous response of the pain-sensitive neurons in the ventropostero-lateral nucleus of thalamus. Thus, we inferred that ACC would also modulate tactile information at the thalamic level. To test this assumption, single units were recorded extracellularly from thalamic ventrobasal nucleus (VB). Tactile ON-OFF response and the relationship between different patterns of the responses and the parameters of tactile stimulation were examined. Furthermore, the influence of ACC on the tactile ON-OFF response was studied. ACC stimulation was found to produce a facilitatory effect on the OFF-response of ON-OFF neurons. It lowered the threshold of the off-response of that neuron, and therefore changed the response pattern or enhanced the firing rate of the OFF-response of the neuron. The study on receptive fields of ON-OFF neurons showed that the excitation of the ACC could change an ON-response on the verge of a receptive field into an ON-OFF response. The above results suggest that the ACC modulation sharpens the response of a VB neuron to a moving stimulus within its receptive field, indicating that the limbic system can modulate tactile ascending sensory information.

  16. Distinctive transcriptome alterations of prefrontal pyramidal neurons in schizophrenia and schizoaffective disorder

    Science.gov (United States)

    Arion, Dominique; Corradi, John P.; Tang, Shaowu; Datta, Dibyadeep; Boothe, Franklyn; He, Aiqing; Cacace, Angela M.; Zaczek, Robert; Albright, Charles F.; Tseng, George; Lewis, David A.

    2014-01-01

    Schizophrenia is associated with alterations in working memory that reflect dysfunction of dorsolateral prefrontal cortex (DLPFC) circuitry. Working memory depends on the activity of excitatory pyramidal cells in DLPFC layer 3, and to a lesser extent in layer 5. Although many studies have profiled gene expression in DLPFC gray matter in schizophrenia, little is known about cell type-specific transcript expression in these two populations of pyramidal cells. We hypothesized that interrogating gene expression specifically in DLPFC layer 3 or 5 pyramidal cells would reveal new and/or more robust schizophrenia-associated differences that would provide new insights into the nature of pyramidal cell dysfunction in the illness. We also sought to determine the impact of other variables, such as a diagnosis of schizoaffective disorder or medication use at time of death, on the patterns of gene expression in pyramidal neurons. Individual pyramidal cells in DLPFC layers 3 or 5 were captured by laser microdissection from 36 subjects with schizophrenia or schizoaffective disorder and matched normal comparison subjects. The mRNA from cell collections was subjected to transcriptome profiling by microarray followed by qPCR validation. Expression of genes involved in mitochondrial (MT) or ubiquitin-proteasome system (UPS) functions were markedly down-regulated in the patient group (p values for MT-related and UPS-related pathways were <10−7 and <10−5 respectively). MT-related gene alterations were more prominent in layer 3 pyramidal cells, whereas UPS-related gene alterations were more prominent in layer 5 pyramidal cells. Many of these alterations were not present, or found to a lesser degree, in samples of DLPFC gray matter from the same subjects, suggesting that they are pyramidal cell-specific. Furthermore, these findings principally reflected alterations in the schizophrenia subjects, were not present or present to a lesser degree in the schizoaffective disorder subjects

  17. Loss of glutathione homeostasis associated with neuronal senescence facilitates TRPM2 channel activation in cultured hippocampal pyramidal neurons

    Directory of Open Access Journals (Sweden)

    Belrose Jillian C

    2012-04-01

    Full Text Available Abstract Background Glutathione (GSH plays an important role in neuronal oxidant defence. Depletion of cellular GSH is observed in neurodegenerative diseases and thereby contributes to the associated oxidative stress and Ca2+ dysregulation. Whether depletion of cellular GSH, associated with neuronal senescence, directly influences Ca2+ permeation pathways is not known. Transient receptor potential melastatin type 2 (TRPM2 is a Ca2+ permeable non-selective cation channel expressed in several cell types including hippocampal pyramidal neurons. Moreover, activation of TRPM2 during oxidative stress has been linked to cell death. Importantly, GSH has been reported to inhibit TRPM2 channels, suggesting they may directly contribute to Ca2+ dysregulation associated with neuronal senescence. Herein, we explore the relation between cellular GSH and TRPM2 channel activity in long-term cultures of hippocampal neurons. Results In whole-cell voltage-clamp recordings, we observe that TRPM2 current density increases in cultured pyramidal neurons over time in vitro. The observed increase in current density was prevented by treatment with NAC, a precursor to GSH synthesis. Conversely, treatment of cultures maintained for 2 weeks in vitro with L-BSO, which depletes GSH by inhibiting its synthesis, augments TRPM2 currents. Additionally, we demonstrate that GSH inhibits TRPM2 currents through a thiol-independent mechanism, and produces a 3.5-fold shift in the dose-response curve generated by ADPR, the intracellular agonist for TRPM2. Conclusion These results indicate that GSH plays a physiologically relevant role in the regulation of TRPM2 currents in hippocampal pyramidal neurons. This interaction may play an important role in aging and neurological diseases associated with depletion of GSH.

  18. Dopamine control of pyramidal neuron activity in the primary motor cortex via D2 receptors

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    Clément eVitrac

    2014-02-01

    Full Text Available The primary motor cortex (M1 is involved in fine voluntary movements control. Previous studies have shown the existence of a dopamine (DA innervation in M1 of rats and monkeys that could directly modulate M1 neuronal activity. However, none of these studies have described the precise distribution of DA terminals within M1 functional region nor have quantified the density of this innervation. Moreover, the precise role of DA on pyramidal neuron activity still remains unclear due to conflicting results from previous studies regarding D2 effects on M1 pyramidal neurons.In this study we assessed in mice the neuroanatomical characteristics of DA innervation in M1 using unbiased stereological quantification of dopamine transporter-immunostained fibers. We demonstrated for the first time in mice that DA innervates the deep layers of M1 targeting preferentially the forelimb representation area of M1. To address the functional role of the DA innervation on M1 neuronal activity, we performed electrophysiological recordings of single neurons activity in vivo and pharmacologically modulated D2 receptors activity. Local D2 receptors activation by quinpirole enhanced pyramidal neurons spike firing rate without changes in spike firing pattern. Altogether, these results indicate that DA innervation in M1 can increase neuronal activity through D2 receptors activation and suggest a potential contribution to the modulation of fine forelimb movement. Given the demonstrated role for DA in fine motor skill learning in M1, our results suggest that altered D2 modulation of M1 activity may be involved in the pathophysiology of movement disorders associated with disturbed DA homeostasis.

  19. De novo expression of neurokinin-1 receptors by spinoparabrachial lamina I pyramidal neurons following a peripheral nerve lesion.

    Science.gov (United States)

    Saeed, Abeer W; Ribeiro-da-Silva, Alfredo

    2013-06-01

    Lamina I of the spinal dorsal horn is a major site of integration and transmission to higher centers of nociceptive information from the periphery. One important primary afferent population that transmits such information to the spinal cord expresses substance P (SP). These fibers terminate in contact with lamina I projection neurons that express the SP receptor, also known as the neurokinin-1 receptor (NK-1r). Three types of lamina I projection neurons have been described: multipolar, fusiform, and pyramidal. Most neurons of the first two types are thought to be nociceptive and express the NK-1r, whereas most pyramidal neurons are nonnociceptive and do not express the NK-1r. In this immunocytochemical and behavioral study, we induced a neuropathic pain-like condition in the rat by means of a polyethylene cuff placed around in the sciatic nerve. We document that this lesion led to a de novo expression of NK-1r on pyramidal neurons as well as a significant increase in SP-immunoreactive innervation onto these neurons. These phenotypic changes were evident at the time of onset of neuropathic pain-related behavior. Additionally, we show that, after a noxious stimulus (intradermal capsaicin injection), these NK-1r on pyramidal neurons were internalized, providing evidence that these neurons become responsive to peripheral noxious stimulation. We suggest that the changes following nerve lesion in the phenotype and innervation pattern of pyramidal neurons are of significance for neuropathic pain and/or limb temperature regulation.

  20. On learning time delays between the spikes from different input neurons in a biophysical model of a pyramidal neuron.

    Science.gov (United States)

    Koutsou, Achilleas; Bugmann, Guido; Christodoulou, Chris

    2015-10-01

    Biological systems are able to recognise temporal sequences of stimuli or compute in the temporal domain. In this paper we are exploring whether a biophysical model of a pyramidal neuron can detect and learn systematic time delays between the spikes from different input neurons. In particular, we investigate whether it is possible to reinforce pairs of synapses separated by a dendritic propagation time delay corresponding to the arrival time difference of two spikes from two different input neurons. We examine two subthreshold learning approaches where the first relies on the backpropagation of EPSPs (excitatory postsynaptic potentials) and the second on the backpropagation of a somatic action potential, whose production is supported by a learning-enabling background current. The first approach does not provide a learning signal that sufficiently differentiates between synapses at different locations, while in the second approach, somatic spikes do not provide a reliable signal distinguishing arrival time differences of the order of the dendritic propagation time. It appears that the firing of pyramidal neurons shows little sensitivity to heterosynaptic spike arrival time differences of several milliseconds. This neuron is therefore unlikely to be able to learn to detect such differences.

  1. Cytoarchitecture of mouse and rat cingulate cortex with human homologies.

    Science.gov (United States)

    Vogt, Brent A; Paxinos, George

    2014-01-01

    A gulf exists between cingulate area designations in human neurocytology and those used in rodent brain atlases with a major underpinning of the former being midcingulate cortex (MCC). The present study used images extracted from the Franklin and Paxinos mouse atlas and Paxinos and Watson rat atlas to demonstrate areas comprising MCC and modifications of anterior cingulate (ACC) and retrosplenial cortices. The laminar architecture not available in the atlases is also provided for each cingulate area. Both mouse and rat have a MCC with neurons in all layers that are larger than in ACC and layer Va has particularly prominent neurons and reduced neuron densities. An undifferentiated ACC area 33 lies along the rostral callosal sulcus in rat but not in mouse and area 32 has dorsal and ventral subdivisions with the former having particularly large pyramidal neurons in layer Vb. Both mouse and rat have anterior and posterior divisions of retrosplenial areas 29c and 30, although their cytology is different in rat and mouse. Maps of the rodent cingulate cortices provide for direct comparisons with each region in the human including MCC and it is significant that rodents do not have a posterior cingulate region composed of areas 23 and 31 like the human. It is concluded that rodents and primates, including humans, possess a MCC and this homology along with those in ACC and retrosplenial cortices permit scientists inspired by human considerations to test hypotheses on rodent models of human diseases.

  2. Intracellular activities related to in vitro hippocampal sharp waves are altered in CA3 pyramidal neurons of aged mice.

    Science.gov (United States)

    Moradi-Chameh, H; Peng, J; Wu, C; Zhang, L

    2014-09-26

    Pyramidal neurons in the hippocampal CA3 area interconnect intensively via recurrent axonal collaterals, and such CA3-to-CA3 recurrent circuitry plays important roles in the generation of hippocampal network activities. In particular, the CA3 circuitry is able to generate spontaneous sharp waves (SPWs) when examined in vitro. These in vitro SPWs are thought to result from the network activity of GABAergic inhibitory interneurons as SPW-correlating intracellular activities are featured with strong IPSPs in pyramidal neurons and EPSPs or spikes in GABAergic interneurons. In view of accumulating evidence indicating a decrease in subgroups of hippocampal GABAergic interneurons in aged animals, we test the hypothesis that the intracellular activities related to in vitro SPWs are altered in CA3 pyramidal neurons of aged mice. Hippocampal slices were prepared from adult and aged C57 black mice (ages 3-6 and 24-28months respectively). Population and single-cell activities were examined via extracellular and whole-cell patch-clamp recordings. CA3 SPW frequencies were not significantly different between the slices of adult and aged mice but SPW-correlating intracellular activities featured weaker IPSC components in aged CA3 pyramidal neurons compared to adult neurons. It was unlikely that this latter phenomenon was due to general impairments of GABAergic synapses in the aged CA3 circuitry as evoked IPSC responses and pharmacologically isolated IPSCs were observed in aged CA3 pyramidal neurons. In addition, aged CA3 pyramidal neurons displayed more positive resting potentials and had a higher propensity of burst firing than adult neurons. We postulate that alterations of GABAergic network activity may explain the reduced IPCS contributions to in vitro SPWs in aged CA3 pyramidal neurons. Overall, our present observations are supportive of the notion that excitability of hippocampal CA3 circuitry is increased in aged mice.

  3. The facilitatory influence of anterior cingulate cortex on ON-OFF response of tactile neuron in thalamic ventrobasal nucleus

    Institute of Scientific and Technical Information of China (English)

    曹晓华; 卢湘岳; 周绍慈

    2000-01-01

    The structures of limbic system have been found to modulate the auditory, visual and pain afferent signals in the related nuclei of thalamus. One of those structures is anterior cingulate cortex (ACC) that influences nocuous response of the pain-sensitive neurons in the ventropos-tero-lateral nucleus of thalamus. Thus, we inferred that ACC would also modulate tactile information at the thalamic level. To test this assumption, single units were recorded extracellularly from thalamic ventrobasal nucleus (VB). Tactile ON-OFF response and the relationship between different patterns of the responses and the parameters of tactile stimulation were examined. Furthermore, the influence of ACC on the tactile ON-OFF response was studied. ACC stimulation was found to produce a facilitatory effect on the OFF-response of ON-OFF neurons. It lowered the threshold of the off-response of that neuron, and therefore changed the response pattern or enhanced the firing rate of the OFF-response of the neuron. The study on rec

  4. Mitochondrial DNA copy numbers in pyramidal neurons are decreased and mitochondrial biogenesis transcriptome signaling is disrupted in Alzheimer's disease hippocampi.

    Science.gov (United States)

    Rice, Ann C; Keeney, Paula M; Algarzae, Norah K; Ladd, Amy C; Thomas, Ravindar R; Bennett, James P

    2014-01-01

    Alzheimer's disease (AD) is the major cause of adult-onset dementia and is characterized in its pre-diagnostic stage by reduced cerebral cortical glucose metabolism and in later stages by reduced cortical oxygen uptake, implying reduced mitochondrial respiration. Using quantitative PCR we determined the mitochondrial DNA (mtDNA) gene copy numbers from multiple groups of 15 or 20 pyramidal neurons, GFAP(+) astrocytes and dentate granule neurons isolated using laser capture microdissection, and the relative expression of mitochondrial biogenesis (mitobiogenesis) genes in hippocampi from 10 AD and 9 control (CTL) cases. AD pyramidal but not dentate granule neurons had significantly reduced mtDNA copy numbers compared to CTL neurons. Pyramidal neuron mtDNA copy numbers in CTL, but not AD, positively correlated with cDNA levels of multiple mitobiogenesis genes. In CTL, but not in AD, hippocampal cDNA levels of PGC1α were positively correlated with multiple downstream mitobiogenesis factors. Mitochondrial DNA copy numbers in pyramidal neurons did not correlate with hippocampal Aβ1-42 levels. After 48 h exposure of H9 human neural stem cells to the neurotoxic fragment Aβ25-35, mtDNA copy numbers were not significantly altered. In summary, AD postmortem hippocampal pyramidal neurons have reduced mtDNA copy numbers. Mitochondrial biogenesis pathway signaling relationships are disrupted in AD, but are mostly preserved in CTL. Our findings implicate complex alterations of mitochondria-host cell relationships in AD.

  5. Functional changes in piriform cortex pyramidal neurons in the chronic methamphetamine-treated rat.

    Science.gov (United States)

    Hori, Nobuaki; Kadota, Tomoko; Akaike, Norio

    2015-01-01

    Chronic treatment of rats with methamphetamine (MAP) causes a range of functional changes to the central nervous system (CNS), including a toxicity that is widespread throughout the brain (Frost and Cadet 2000; Fasihpour et al. 2013). In this report, we examined the effect of chronic MAP treatment on pyramidal neurons of the rat piriform cortex, an area involved in sensory processing, associative learning and a model system for studies on synaptic plasticity. MAP treatment significantly depolarized the membrane potential and decreased neuronal input resistance. Furthermore, the voltage-dependence of both AMPA and NMDA responses was disturbed by chronic MAP treatment, and the extent of long-term potentiation (LTP) was decreased. Morphological changes of MAP-treated rat pyramidal neurons were observed as blebbing of the dendrite trees. The changes we observed represent detrimental effects on the function of piriform cortical neurons further illustrating deficits in synaptic plasticity extend beyond the hippocampus. These changes may contribute to behavioural deficits in chronic MAP-treated animals.

  6. Thalamocortical input onto layer 5 pyramidal neurons measured using quantitative large-scale array tomography

    Directory of Open Access Journals (Sweden)

    Jong-Cheol eRah

    2013-11-01

    Full Text Available The subcellular locations of synapses on pyramidal neurons strongly influences dendritic integration and synaptic plasticity. Despite this, there is little quantitative data on spatial distributions of specific types of synaptic input. Here we use array tomography (AT, a high-resolution optical microscopy method, to examine thalamocortical (TC input onto layer 5 pyramidal neurons. We first verified the ability of AT to identify synapses using parallel electron microscopic analysis of TC synapses in layer 4. We then use large-scale AT to measure TC synapse distribution on L5 pyramdial neurons in a 1.00 x 0.83 x 0.21 mm^3 volume of mouse somatosensory cortex. We found that TC synapses primarily target basal dendrites in layer 5, but also make a considerable input to proximal apical dendrites in L4, consistent with previous work. Our analysis further suggests that TC inputs are biased towards certain branches and, within branches, synapses show significant clustering with an excess of TC synapse nearest neighbors within 5-15 μm compared to a random distribution. Thus, we show that AT is a sensitive and quantitative method to map specific types of synaptic input on the dendrites of entire neurons. We anticipate that this technique will be of wide utility for mapping functionally-relevant anatomical connectivity in neural circuits.

  7. Membrane Potential Dynamics of CA1 Pyramidal Neurons during Hippocampal Ripples in Awake Mice.

    Science.gov (United States)

    Hulse, Brad K; Moreaux, Laurent C; Lubenov, Evgueniy V; Siapas, Athanassios G

    2016-02-17

    Ripples are high-frequency oscillations associated with population bursts in area CA1 of the hippocampus that play a prominent role in theories of memory consolidation. While spiking during ripples has been extensively studied, our understanding of the subthreshold behavior of hippocampal neurons during these events remains incomplete. Here, we combine in vivo whole-cell and multisite extracellular recordings to characterize the membrane potential dynamics of identified CA1 pyramidal neurons during ripples. We find that the subthreshold depolarization during ripples is uncorrelated with the net excitatory input to CA1, while the post-ripple hyperpolarization varies proportionately. This clarifies the circuit mechanism keeping most neurons silent during ripples. On a finer timescale, the phase delay between intracellular and extracellular ripple oscillations varies systematically with membrane potential. Such smoothly varying delays are inconsistent with models of intracellular ripple generation involving perisomatic inhibition alone. Instead, they suggest that ripple-frequency excitation leading inhibition shapes intracellular ripple oscillations.

  8. Zbtb20-Induced CA1 Pyramidal Neuron Development and Area Enlargement in the Cerebral Midline Cortex of Mice

    DEFF Research Database (Denmark)

    Nielsen, Jakob V; Blom, Jonas B; Noraberg, Jens

    2010-01-01

    that are innervated by Schaffer collateral projections in ectopic strata oriens and radiatum. The Zbtb20-transformed neurons express Bcl11B, Satb2, and Calbindin-D28k, which are markers of adult CA1 pyramidal neurons. Downregulation of Zbtb20 expression by RNA interference impairs the normal maturation of CA1...... pyramidal neurons resulting in deficiencies in Calbindin-D28k expression and in reduced apical dendritic arborizations in stratum lacunosum moleculare. Overall, the results show that Zbtb20 is required for various aspects of CA1 pyramidal neuron development such as the postnatal extension of apical...... dendritic arbors in the distal target zone and the subtype differentiation of Calbindin-D28k-positive subsets. They further suggest that Zbtb20 plays a role in arealization of the midline cortex....

  9. Ammonia inhibits long-term potentiation via neurosteroid synthesis in hippocampal pyramidal neurons.

    Science.gov (United States)

    Izumi, Y; Svrakic, N; O'Dell, K; Zorumski, C F

    2013-03-13

    Neurosteroids are a class of endogenous steroids synthesized in the brain that are believed to be involved in the pathogenesis of neuropsychiatric disorders and memory impairment. Ammonia impairs long-term potentiation (LTP), a synaptic model of learning, in the hippocampus, a brain region involved in memory acquisition. Although mechanisms underlying ammonia-mediated LTP inhibition are not fully understood, we previously found that the activation of N-methyl-d-aspartate receptors (NMDARs) is important. Based on this, we hypothesize that metabolic stressors, including hyperammonemia, promote untimely NMDAR activation and result in neural adaptations that include the synthesis of allopregnanolone (alloP) and other GABA-potentiating neurosteroids that dampen neuronal activity and impair LTP and memory formation. Using an antibody against 5α-reduced neurosteroids, we found that 100 μM ammonia acutely enhanced neurosteroid immunostaining in pyramidal neurons in the CA1 region of rat hippocampal slices. The enhanced staining was blocked by finasteride, a selective inhibitor of 5α-reductase, a key enzyme required for alloP synthesis. Finasteride also overcame LTP inhibition by 100 μM ammonia, as did picrotoxin, an inhibitor of GABA-A receptors. These results indicate that GABA-enhancing neurosteroids, synthesized locally within pyramidal neurons, contribute significantly to ammonia-mediated synaptic dysfunction. These results suggest that the manipulation of neurosteroid synthesis could provide a strategy to improve cognitive function in individuals with hyperammonemia.

  10. Persistent sodium current drives conditional pacemaking in CA1 pyramidal neurons under muscarinic stimulation.

    Science.gov (United States)

    Yamada-Hanff, Jason; Bean, Bruce P

    2013-09-18

    Hippocampal CA1 pyramidal neurons are normally quiescent but can fire spontaneously when stimulated by muscarinic agonists. In brain slice recordings from mouse CA1 pyramidal neurons, we examined the ionic basis of this activity using interleaved current-clamp and voltage-clamp experiments. Both in control and after muscarinic stimulation, the steady-state current-voltage curve was dominated by inward TTX-sensitive persistent sodium current (I(NaP)) that activated near -75 mV and increased steeply with depolarization. In control, total membrane current was net outward (hyperpolarizing) near -70 mV so that cells had a stable resting potential. Muscarinic stimulation activated a small nonselective cation current so that total membrane current near -70 mV shifted to become barely net inward (depolarizing). The small depolarization triggers regenerative activation of I(NaP), which then depolarizes the cell from -70 mV to spike threshold. We quantified the relative contributions of I(NaP), hyperpolarization-activated cation current (I(h)), and calcium current to pacemaking by using the cell's own firing as a voltage command along with specific blockers. TTX-sensitive sodium current was substantial throughout the entire interspike interval, increasing as the membrane potential approached threshold, while both Ih and calcium current were minimal. Thus, spontaneous activity is driven primarily by activation of I(NaP) in a positive feedback loop starting near -70 mV and providing increasing inward current to threshold. These results show that the pacemaking "engine" from I(NaP) is an inherent property of CA1 pyramidal neurons that can be engaged or disengaged by small shifts in net membrane current near -70 mV, as by muscarinic stimulation.

  11. Action potential modulation in CA1 pyramidal neuron axons facilitates OLM interneuron activation in recurrent inhibitory microcircuits of rat hippocampus.

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    Sooyun Kim

    Full Text Available Oriens-lacunosum moleculare (O-LM interneurons in the CA1 region of the hippocampus play a key role in feedback inhibition and in the control of network activity. However, how these cells are efficiently activated in the network remains unclear. To address this question, I performed recordings from CA1 pyramidal neuron axons, the presynaptic fibers that provide feedback innervation of these interneurons. Two forms of axonal action potential (AP modulation were identified. First, repetitive stimulation resulted in activity-dependent AP broadening. Broadening showed fast onset, with marked changes in AP shape following a single AP. Second, tonic depolarization in CA1 pyramidal neuron somata induced AP broadening in the axon, and depolarization-induced broadening summated with activity-dependent broadening. Outside-out patch recordings from CA1 pyramidal neuron axons revealed a high density of α-dendrotoxin (α-DTX-sensitive, inactivating K+ channels, suggesting that K+ channel inactivation mechanistically contributes to AP broadening. To examine the functional consequences of axonal AP modulation for synaptic transmission, I performed paired recordings between synaptically connected CA1 pyramidal neurons and O-LM interneurons. CA1 pyramidal neuron-O-LM interneuron excitatory postsynaptic currents (EPSCs showed facilitation during both repetitive stimulation and tonic depolarization of the presynaptic neuron. Both effects were mimicked and occluded by α-DTX, suggesting that they were mediated by K+ channel inactivation. Therefore, axonal AP modulation can greatly facilitate the activation of O-LM interneurons. In conclusion, modulation of AP shape in CA1 pyramidal neuron axons substantially enhances the efficacy of principal neuron-interneuron synapses, promoting the activation of O-LM interneurons in recurrent inhibitory microcircuits.

  12. Action potential modulation in CA1 pyramidal neuron axons facilitates OLM interneuron activation in recurrent inhibitory microcircuits of rat hippocampus.

    Science.gov (United States)

    Kim, Sooyun

    2014-01-01

    Oriens-lacunosum moleculare (O-LM) interneurons in the CA1 region of the hippocampus play a key role in feedback inhibition and in the control of network activity. However, how these cells are efficiently activated in the network remains unclear. To address this question, I performed recordings from CA1 pyramidal neuron axons, the presynaptic fibers that provide feedback innervation of these interneurons. Two forms of axonal action potential (AP) modulation were identified. First, repetitive stimulation resulted in activity-dependent AP broadening. Broadening showed fast onset, with marked changes in AP shape following a single AP. Second, tonic depolarization in CA1 pyramidal neuron somata induced AP broadening in the axon, and depolarization-induced broadening summated with activity-dependent broadening. Outside-out patch recordings from CA1 pyramidal neuron axons revealed a high density of α-dendrotoxin (α-DTX)-sensitive, inactivating K+ channels, suggesting that K+ channel inactivation mechanistically contributes to AP broadening. To examine the functional consequences of axonal AP modulation for synaptic transmission, I performed paired recordings between synaptically connected CA1 pyramidal neurons and O-LM interneurons. CA1 pyramidal neuron-O-LM interneuron excitatory postsynaptic currents (EPSCs) showed facilitation during both repetitive stimulation and tonic depolarization of the presynaptic neuron. Both effects were mimicked and occluded by α-DTX, suggesting that they were mediated by K+ channel inactivation. Therefore, axonal AP modulation can greatly facilitate the activation of O-LM interneurons. In conclusion, modulation of AP shape in CA1 pyramidal neuron axons substantially enhances the efficacy of principal neuron-interneuron synapses, promoting the activation of O-LM interneurons in recurrent inhibitory microcircuits.

  13. Fractal dimension of apical dendritic arborization differs in the superficial and the deep pyramidal neurons of the rat cerebral neocortex.

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    Puškaš, Nela; Zaletel, Ivan; Stefanović, Bratislav D; Ristanović, Dušan

    2015-03-04

    Pyramidal neurons of the mammalian cerebral cortex have specific structure and pattern of organization that involves the presence of apical dendrite. Morphology of the apical dendrite is well-known, but quantification of its complexity still remains open. Fractal analysis has proved to be a valuable method for analyzing the complexity of dendrite morphology. The aim of this study was to establish the fractal dimension of apical dendrite arborization of pyramidal neurons in distinct neocortical laminae by using the modified box-counting method. A total of thirty, Golgi impregnated neurons from the rat brain were analyzed: 15 superficial (cell bodies located within lamina II-III), and 15 deep pyramidal neurons (cell bodies situated within lamina V-VI). Analysis of topological parameters of apical dendrite arborization showed no statistical differences except in total dendritic length (p=0.02), indicating considerable homogeneity between the two groups of neurons. On the other hand, average fractal dimension of apical dendrite was 1.33±0.06 for the superficial and 1.24±0.04 for the deep cortical neurons, showing statistically significant difference between these two groups (pfractal dimension values, apical dendrites of the superficial pyramidal neurons tend to show higher structural complexity compared to the deep ones.

  14. Ephrin-B1 controls the columnar distribution of cortical pyramidal neurons by restricting their tangential migration.

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    Dimidschstein, Jordane; Passante, Lara; Dufour, Audrey; van den Ameele, Jelle; Tiberi, Luca; Hrechdakian, Tatyana; Adams, Ralf; Klein, Rüdiger; Lie, Dieter Chichung; Jossin, Yves; Vanderhaeghen, Pierre

    2013-09-18

    Neurons of the cerebral cortex are organized in layers and columns. Unlike laminar patterning, the mechanisms underlying columnar organization remain largely unexplored. Here, we show that ephrin-B1 plays a key role in this process through the control of nonradial steps of migration of pyramidal neurons. In vivo gain of function of ephrin-B1 resulted in a reduction of tangential motility of pyramidal neurons, leading to abnormal neuronal clustering. Conversely, following genetic disruption of ephrin-B1, cortical neurons displayed a wider lateral dispersion, resulting in enlarged ontogenic columns. Dynamic analyses revealed that ephrin-B1 controls the lateral spread of pyramidal neurons by limiting neurite extension and tangential migration during the multipolar phase. Furthermore, we identified P-Rex1, a guanine-exchange factor for Rac3, as a downstream ephrin-B1 effector required to control migration during the multipolar phase. Our results demonstrate that ephrin-B1 inhibits nonradial migration of pyramidal neurons, thereby controlling the pattern of cortical columns.

  15. IKCa channels are a critical determinant of the slow AHP in CA1 pyramidal neurons.

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    King, Brian; Rizwan, Arsalan P; Asmara, Hadhimulya; Heath, Norman C; Engbers, Jordan D T; Dykstra, Steven; Bartoletti, Theodore M; Hameed, Shahid; Zamponi, Gerald W; Turner, Ray W

    2015-04-14

    Control over the frequency and pattern of neuronal spike discharge depends on Ca2+-gated K+ channels that reduce cell excitability by hyperpolarizing the membrane potential. The Ca2+-dependent slow afterhyperpolarization (sAHP) is one of the most prominent inhibitory responses in the brain, with sAHP amplitude linked to a host of circuit and behavioral functions, yet the channel that underlies the sAHP has defied identification for decades. Here, we show that intermediate-conductance Ca2+-dependent K+ (IKCa) channels underlie the sAHP generated by trains of synaptic input or postsynaptic stimuli in CA1 hippocampal pyramidal cells. These findings are significant in providing a molecular identity for the sAHP of central neurons that will identify pharmacological tools capable of potentially modifying the several behavioral or disease states associated with the sAHP.

  16. Glia-derived ATP inversely regulates excitability of pyramidal and CCK-positive neurons

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    Tan, Zhibing; Liu, Yu; Xi, Wang; Lou, Hui-fang; Zhu, Liya; Guo, Zhifei; Mei, Lin; Duan, Shumin

    2017-01-01

    Astrocyte responds to neuronal activity with calcium waves and modulates synaptic transmission through the release of gliotransmitters. However, little is known about the direct effect of gliotransmitters on the excitability of neuronal networks beyond synapses. Here we show that selective stimulation of astrocytes expressing channelrhodopsin-2 in the CA1 area specifically increases the firing frequency of CCK-positive but not parvalbumin-positive interneurons and decreases the firing rate of pyramidal neurons, phenomena mimicked by exogenously applied ATP. Further evidences indicate that ATP-induced increase and decrease of excitability are caused, respectively, by P2Y1 receptor-mediated inhibition of a two-pore domain potassium channel and A1 receptor-mediated opening of a G-protein-coupled inwardly rectifying potassium channel. Moreover, the activation of ChR2-expressing astrocytes reduces the power of kainate-induced hippocampal ex vivo gamma oscillation. Thus, through distinct receptor subtypes coupled with different K+ channels, astrocyte-derived ATP differentially modulates the excitability of different types of neurons and efficiently controls the activity of neuronal network. PMID:28128211

  17. Transient increase in Zn2+ in hippocampal CA1 pyramidal neurons causes reversible memory deficit.

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    Atsushi Takeda

    Full Text Available The translocation of synaptic Zn(2+ to the cytosolic compartment has been studied to understand Zn(2+ neurotoxicity in neurological diseases. However, it is unknown whether the moderate increase in Zn(2+ in the cytosolic compartment affects memory processing in the hippocampus. In the present study, the moderate increase in cytosolic Zn(2+ in the hippocampus was induced with clioquinol (CQ, a zinc ionophore. Zn(2+ delivery by Zn-CQ transiently attenuated CA1 long-term potentiation (LTP in hippocampal slices prepared 2 h after i.p. injection of Zn-CQ into rats, when intracellular Zn(2+ levels was transiently increased in the CA1 pyramidal cell layer, followed by object recognition memory deficit. Object recognition memory was transiently impaired 30 min after injection of ZnCl(2 into the CA1, but not after injection into the dentate gyrus that did not significantly increase intracellular Zn(2+ in the granule cell layer of the dentate gyrus. Object recognition memory deficit may be linked to the preferential increase in Zn(2+ and/or the preferential vulnerability to Zn(2+ in CA1 pyramidal neurons. In the case of the cytosolic increase in endogenous Zn(2+ in the CA1 induced by 100 mM KCl, furthermore, object recognition memory was also transiently impaired, while ameliorated by co-injection of CaEDTA to block the increase in cytosolic Zn(2+. The present study indicates that the transient increase in cytosolic Zn(2+ in CA1 pyramidal neurons reversibly impairs object recognition memory.

  18. Metrifonate decreases sI(AHP) in CA1 pyramidal neurons in vitro.

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    Power, J M; Oh, M M; Disterhoft, J F

    2001-01-01

    Metrifonate, a cholinesterase inhibitor, has been shown to enhance learning in aging rabbits and rats, and to alleviate the cognitive deficits observed in Alzheimer's disease patients. We have previously determined that bath application of metrifonate reduces the spike frequency adaptation and postburst afterhyperpolarization (AHP) in rabbit CA1 pyramidal neurons in vitro using sharp electrode current-clamp recording. The postburst AHP and accommodation observed in current clamp are the result of four slow outward potassium currents (sI(AHP), I(AHP), I(M), and I(C)) and the hyperpolarization activated mixed cation current, I(h). We recorded from visually identified CA1 hippocampal pyramidal neurons in vitro using whole cell voltage-clamp technique to better isolate and characterize which component currents of the AHP are affected by metrifonate. We observed an age-related enhancement of the slow component of the AHP tail current (sI(AHP)), but not of the fast decaying component of the AHP tail current (I(AHP), I(M), and I(C)). Bath perfusion of metrifonate reduced sI(AHP) at concentrations that cause a reduction of the AHP and accommodation in current-clamp recordings, with no apparent reduction of I(AHP), I(M), and I(C). The functional consequences of metrifonate administration are apparently mediated solely through modulation of the sI(AHP).

  19. Dynamic Expression Patterns of Progenitor and Pyramidal Neuron Layer Markers in the Developing Human Hippocampus.

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    Cipriani, Sara; Nardelli, Jeannette; Verney, Catherine; Delezoide, Anne-Lise; Guimiot, Fabien; Gressens, Pierre; Adle-Biassette, Homa

    2016-03-01

    The molecular mechanisms underlying the formation of hippocampus are unknown in humans. To improve our knowledge of molecules that potentially regulate pyramidal neurogenesis and layering in various hippocampal fields, we investigated the expression of progenitor markers and cell fate molecules from gestational week (GW) 9 to GW 20. At GW 9, the progenitor cell compartment of the hippocampal formation mainly consisted of PAX6(+) cells in the ventricular zone. Between GW 9 and 11, a second germinal area, the subventricular zone (SVZ), was formed, as shown by TBR2 labeling. Postmitotic markers (TBR1, CTIP2, SATB2, and CUX1) might reflect the inside-out layering of the plate from GW 11 onwards. TBR1(+) neurons appeared in the deep plate, whereas CTIP2(+), SATB2(+), and CUX1(+) neurons occupied the upper layers. From GW 16, differences in layer segregation were observed between the ammonic and subicular plates. Moreover, an ammonic-to-subicular maturation gradient was observed in germinal/postmitotic areas. Taken together, these findings demonstrate for the first time the presence of an SVZ in the hippocampus of human fetuses and laminar differences in transcription factor expression in the pyramidal layer of the human ammonic and subicular plate, and provide new information to further investigate the connectivity of the hippocampal formation.

  20. Electrophysiological effects of SKF83959 on hippocampal CA1 pyramidal neurons: potential mechanisms for the drug's neuroprotective effects.

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    Hong-Yuan Chu

    Full Text Available Although the potent anti-parkinsonian action of the atypical D₁-like receptor agonist SKF83959 has been attributed to the selective activation of phosphoinositol(PI-linked D₁ receptor, whereas the mechanism underlying its potent neuroprotective effect is not fully understood. In the present study, the actions of SKF83959 on neuronal membrane potential and neuronal excitability were investigated in CA1 pyramidal neurons of rat hippocampal slices. SKF83959 (10-100 µM caused a concentration-dependent depolarization, associated with a reduction of input resistance in CA1 pyramidal neurons. The depolarization was blocked neither by antagonists for D₁, D₂, 5-HT(2A/2C receptors and α₁-adrenoceptor, nor by intracellular dialysis of GDP-β-S. However, the specific HCN channel blocker ZD7288 (10 µM antagonized both the depolarization and reduction of input resistance caused by SKF83959. In voltage-clamp experiments, SKF83959 (10-100 µM caused a concentration-dependent increase of Ih current in CA1 pyramidal neurons, which was independent of D₁ receptor activation. Moreover, SKF83959 (50 µM caused a 6 mV positive shift in the activation curve of Ih and significantly accelerated the activation of Ih current. In addition, SKF83959 also reduced the neuronal excitability of CA1 pyramidal neurons, which was manifested by the decrease in the number and amplitude of action potentials evoked by depolarizing currents, and by the increase of firing threshold and rhoebase current. The above results suggest that SKF83959 increased Ih current through a D₁ receptor-independent mechanism, which led to the depolarization of hippocampal CA1 pyramidal neurons. These findings provide a novel mechanism for the drug's neuroprotective effects, which may contributes to its therapeutic benefits in Parkinson's disease.

  1. Cytosolic phospholipase A(2) alpha mediates electrophysiologic responses of hippocampal pyramidal neurons to neurotoxic NMDA treatment.

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    Shen, Ying; Kishimoto, Koji; Linden, David J; Sapirstein, Adam

    2007-04-03

    The arachidonic acid-generating enzyme cytosolic phospholipase A(2) alpha (cPLA(2)alpha) has been implicated in the progression of excitotoxic neuronal injury. However, the mechanisms of cPLA(2)alpha toxicity have yet to be determined. Here, we used a model system exposing mouse hippocampal slices to NMDA as an excitotoxic injury, in combination with simultaneous patch-clamp recording and confocal Ca(2+) imaging of CA1 pyramidal neurons. NMDA treatment caused significantly greater injury in wild-type (WT) than in cPLA(2)alpha null CA1 neurons. Bath application of NMDA evoked a slow inward current in voltage-clamped neurons (composed of both NMDA receptor-mediated and other conductances) that was smaller in cPLA(2)alpha null than in WT slices. This was not due to down-regulation of NMDA receptor function because NMDA receptor-mediated currents were equivalent in each genotype following brief photolysis of caged glutamate. Current-clamp recordings were made during and following NMDA exposure by eliciting a single action potential with a brief current injection. After NMDA exposure, WT CA1 neurons developed a spike-evoked plateau potential and an increased spike-evoked dendritic Ca(2+) transient. These effects were absent in CA1 neurons from cPLA(2)alpha null mice and WT neurons treated with a cPLA(2)alpha inhibitor. The Ca-sensitive K-channel toxins, apamin and paxilline, caused spike broadening and Ca(2+) enhancement in WT and cPLA(2)alpha null slices. NMDA application in WT and arachidonate applied to cPLA(2)alpha null cells occluded the effects of apamin/paxilline. These results indicate that cPLA(2)alpha activity is required for development of aberrant electrophysiologic events triggered by NMDA receptor activation, in part through attenuation of K-channel function.

  2. Simple method for evaluation of planum temporale pyramidal neurons shrinkage in postmortem tissue of Alzheimer disease patients.

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    Kutová, Martina; Mrzílková, Jana; Kirdajová, Denisa; Řípová, Daniela; Zach, Petr

    2014-01-01

    We measured the length of the pyramidal neurons in the cortical layer III in four subregions of the planum temporale (transitions into superior temporal gyrus, Heschl's gyrus, insular cortex, and Sylvian fissure) in control group and Alzheimer disease patients. Our hypothesis was that overall length of the pyramidal neurons would be smaller in the Alzheimer disease group compared to controls and also there would be right-left asymmetry in both the control and Alzheimer disease groups. We found pyramidal neuron length asymmetry only in controls--in the transition into the Sylvian fissure--and the rest of the subregions in the control group and Alzheimer disease patients did not show size difference. However, control-Alzheimer disease group pyramidal neuron length comparison revealed (a) no length difference in superior temporal gyrus transition area, (b) reversal of asymmetry in the insular transition area with left insular transition significantly shorter in the Alzheimer disease group compared to the control group, (c) both right and left Heschl's gyrus transitions significantly shorter in the Alzheimer disease group compared to the control group, and (d) right Sylvian fissure transition significantly shorter in the Alzheimer disease group compared to the control group. This neuronal length measurement method could supplement already existing neuropathological criteria for postmortem Alzheimer disease diagnostics.

  3. Extrasynaptic glutamate receptor activation as cellular bases for dynamic range compression in pyramidal neurons

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    Katerina D Oikonomou

    2012-08-01

    Full Text Available Repetitive synaptic stimulation overcomes the ability of astrocytic processes to clear glutamate from the extracellular space, allowing some dendritic segments to become submerged in a pool of glutamate. This dynamic arrangement activates extrasynaptic NMDA receptors located on dendritic shafts. We used voltage-sensitive and calcium-sensitive dyes to probe dendritic function in this glutamate-rich location. An excess of glutamate in the extrasynaptic space was achieved either by repetitive synaptic stimulation or by glutamate iontophoresis onto the dendrites of pyramidal neurons. Two successive activations of synaptic inputs produced a typical NMDA spike, whereas five successive synaptic inputs produced characteristic plateau potentials, reminiscent of cortical UP states. While NMDA spikes were coupled with brief calcium transients highly restricted to the glutamate input site, the dendritic plateau potentials were accompanied by calcium influx along the entire dendritic branch. Once initiated, the glutamate-mediated dendritic plateau potentials could not be interrupted by negative voltage pulses. Activation of extrasynaptic NMDA receptors in cellular compartments void of spines is sufficient to initiate and support plateau potentials. The only requirement for sustained depolarizing events is a surplus of free glutamate near a group of extrasynaptic receptors. Highly nonlinear dendritic spikes (plateau potentials are summed in a highly sublinear fashion at the soma, revealing the cellular bases of signal compression in cortical circuits. Extrasynaptic NMDA receptors provide pyramidal neurons with a function analogous to a dynamic range compression in audio engineering. They limit or reduce the volume of loud sounds (i.e. strong glut. inputs and amplify quiet sounds (i.e. glutamatergic inputs that barely cross the dendritic threshold for local spike initiation. Our data also explain why consecutive cortical UP states have uniform amplitudes in a

  4. Effects of Calcium Spikes in the Layer 5 Pyramidal Neuron on Coincidence Detection and Activity Propagation.

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    Chua, Yansong; Morrison, Abigail

    2016-01-01

    The role of dendritic spiking mechanisms in neural processing is so far poorly understood. To investigate the role of calcium spikes in the functional properties of the single neuron and recurrent networks, we investigated a three compartment neuron model of the layer 5 pyramidal neuron with calcium dynamics in the distal compartment. By performing single neuron simulations with noisy synaptic input and occasional large coincident input at either just the distal compartment or at both somatic and distal compartments, we show that the presence of calcium spikes confers a substantial advantage for coincidence detection in the former case and a lesser advantage in the latter. We further show that the experimentally observed critical frequency phenomenon, in which action potentials triggered by stimuli near the soma above a certain frequency trigger a calcium spike at distal dendrites, leading to further somatic depolarization, is not exhibited by a neuron receiving realistically noisy synaptic input, and so is unlikely to be a necessary component of coincidence detection. We next investigate the effect of calcium spikes in propagation of spiking activities in a feed-forward network (FFN) embedded in a balanced recurrent network. The excitatory neurons in the network are again connected to either just the distal, or both somatic and distal compartments. With purely distal connectivity, activity propagation is stable and distinguishable for a large range of recurrent synaptic strengths if the feed-forward connections are sufficiently strong, but propagation does not occur in the absence of calcium spikes. When connections are made to both the somatic and the distal compartments, activity propagation is achieved for neurons with active calcium dynamics at a much smaller number of neurons per pool, compared to a network of passive neurons, but quickly becomes unstable as the strength of recurrent synapses increases. Activity propagation at higher scaling factors can be

  5. Activation of Ih and TTX-sensitive sodium current at subthreshold voltages during CA1 pyramidal neuron firing.

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    Yamada-Hanff, Jason; Bean, Bruce P

    2015-10-01

    We used dynamic clamp and action potential clamp techniques to explore how currents carried by tetrodotoxin-sensitive sodium channels and HCN channels (Ih) regulate the behavior of CA1 pyramidal neurons at resting and subthreshold voltages. Recording from rat CA1 pyramidal neurons in hippocampal slices, we found that the apparent input resistance and membrane time constant were strongly affected by both conductances, with Ih acting to decrease apparent input resistance and time constant and sodium current acting to increase both. We found that both Ih and sodium current were active during subthreshold summation of artificial excitatory postsynaptic potentials (EPSPs) generated by dynamic clamp, with Ih dominating at less depolarized voltages and sodium current at more depolarized voltages. Subthreshold sodium current-which amplifies EPSPs-was most effectively recruited by rapid voltage changes, while Ih-which blunts EPSPs-was maximal for slow voltage changes. The combined effect is to selectively amplify rapid EPSPs. We did similar experiments in mouse CA1 pyramidal neurons, doing voltage-clamp experiments using experimental records of action potential firing of CA1 neurons previously recorded in awake, behaving animals as command voltages to quantify flow of Ih and sodium current at subthreshold voltages. Subthreshold sodium current was larger and subthreshold Ih was smaller in mouse neurons than in rat neurons. Overall, the results show opposing effects of subthreshold sodium current and Ih in regulating subthreshold behavior of CA1 neurons, with subthreshold sodium current prominent in both rat and mouse CA1 pyramidal neurons and additional regulation by Ih in rat neurons.

  6. Distinct Physiological Effects of Dopamine D4 Receptors on Prefrontal Cortical Pyramidal Neurons and Fast-Spiking Interneurons.

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    Zhong, Ping; Yan, Zhen

    2016-01-01

    Dopamine D4 receptor (D4R), which is strongly linked to neuropsychiatric disorders, such as attention-deficit hyperactivity disorder and schizophrenia, is highly expressed in pyramidal neurons and GABAergic interneurons in prefrontal cortex (PFC). In this study, we examined the impact of D4R on the excitability of these 2 neuronal populations. We found that D4R activation decreased the frequency of spontaneous action potentials (sAPs) in PFC pyramidal neurons, whereas it induced a transient increase followed by a decrease of sAP frequency in PFC parvalbumin-positive (PV+) interneurons. D4R activation also induced distinct effects in both types of PFC neurons on spontaneous excitatory and inhibitory postsynaptic currents, which drive the generation of sAP. Moreover, dopamine substantially decreased sAP frequency in PFC pyramidal neurons, but markedly increased sAP frequency in PV+ interneurons, and both effects were partially mediated by D4R activation. In the phencyclidine model of schizophrenia, the decreasing effect of D4R on sAP frequency in both types of PFC neurons was attenuated, whereas the increasing effect of D4R on sAP in PV+ interneurons was intact. These results suggest that D4R activation elicits distinct effects on synaptically driven excitability in PFC projection neurons versus fast-spiking interneurons, which are differentially altered in neuropsychiatric disorder-related conditions.

  7. Effect of etomidate on voltage-dependent potassium currents in rat isolated hippocampal pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    TAN Hong-yu; SUN Li-na; WANG Xiao-liang; YE Tie-hu

    2010-01-01

    Background Previous studies demonstrated general anesthetics affect potassium ion channels, which may be one of the mechanisms of general anesthesia. Because the effect of etomidate on potassium channels in rat hippocampus which is involved in memory function has not been studied, we investigated the effects of etomidate on both delayed rectifier potassium current (I_((K(DR))) and transient outward potassium current (I_((K(A))) in acutely dissociated rat hippocampal pyramidal neurons.Methods Single rat hippocampal pyramidal neurons from male Wistar rats of 7-10 days were acutely dissociated by enzymatic digestion and mechanical dispersion according to the methods of Kay and Wong with slight modification. Voltage-clamp recordings were performed in the whole-cell patch clamp configuration. Currents were recorded with a List EPC-10 amplifier and data were stored in a computer using Pulse 8.5. Student's paired two-tail t test was used for data analysis. Results At the concentration of 100 μmol/L, etomidate significantly inhibited I_(K(DR)) by 49.2% at +40 mV when depolarized from -110 mV (P 0.05). The IC_(50) value of etomidate for blocking I_(K(DR)) was calculated as 5.4 μmol/L, with a Hill slope of 2.45. At the presence of 10 μmol/L etomidate, the V_(1/2) of activation curve was shifted from (17.3±1.5) mV to (10.7±9.9) mV (n=8, P <0.05), the V_(1/2) of inactivation curve was shifted from (-18.3±2.2) mV to (-45.3±9.4) mV (n=8, P <0.05). Etomidate 10 μmol/L shifted both the activation curve and inactivation curve of I_(K(DR)) to negative potential, but mainly affected the inactivation kinetics.Conclusions Etomidate potently inhibited I_(K(DR)) but not I_(K(A)) in rat hippocampal pyramidal neurons. I_(K(DR)) was inhibited by etomidate in a concentration-dependent manner, while I_(K(A)) remained unaffected.

  8. Repeated transcranial magnetic stimulation prevents kindling-induced changes in electrophysiological properties of rat hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Shojaei, A; Semnanian, S; Janahmadi, M; Moradi-Chameh, H; Firoozabadi, S M; Mirnajafi-Zadeh, J

    2014-11-01

    The mechanisms underlying antiepileptic or antiepileptogenic effects of repeated transcranial magnetic stimulation (rTMS) are poorly understood. In this study, we investigated the effect of rTMS applied during rapid amygdala kindling on some electrophysiological properties of hippocampal CA1 pyramidal neurons. Male Wistar rats were kindled by daily electrical stimulation of the basolateral amygdala in a semi-rapid manner (12 stimulations/day) until they achieved stage-5 seizure. One group (kindled+rTMS (KrTMS)) of animals received rTMS (1Hz for 4min) 5min after termination of daily kindling stimulations. Twenty four hours following the last kindling stimulation electrophysiological properties of hippocampal CA1 pyramidal neurons were investigated using whole-cell patch-clamp technique. Amygdala kindling significantly depolarized the resting membrane potential and increased the input resistance, spontaneous firing activity, number of evoked spikes and half-width of the first evoked spike. Kindling also decreased the first-spike latency and amplitude significantly. Application of rTMS during kindling somehow prevented the development of seizures and protected CA1 pyramidal neurons of hippocampus against deleterious effect of kindling on both passive and active neuronal electrophysiological properties. Interestingly, application of rTMS alone enhanced the excitability of CA1 pyramidal neurons significantly. Based on the results of our study, it may be suggested that rTMS exerts its anticonvulsant effect, in part, through preventing the amygdala kindling-induced changes in electrophysiological properties of hippocampal CA1 pyramidal neurons. It seems that rTMS exerts protective effects on the neural circuits involved in spreading the seizures from the focus to other parts of the brain.

  9. Effects of lithium chloride on outward potassium currents in acutely isolated hippocampal CA1 pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chaofeng; DU Huizhi; YANG Pin

    2006-01-01

    Although lithium possesses neuroprotective functions, the molecular mechanism underlying its actions has not been fully elucidated. In the present paper, the effects of lithium chloride on voltage-dependent potassium currents in the CA1 pyramidal neurons acutely isolated from rat hippocampus were studied using the whole-cell patch-clamp technique. Depolarizing test pulses activated two components of outward potassium currents: a rapidly activating and inactivating component, IA and a delayed component, IK. Results showed that lithium chloride increased the amplitude of IA in a concentration-dependent manner. Half enhancement concentration (EC50) was 22.80±5.45 μmol·L-1. Lithium chloride of 25 μmol·L-1 shifted the steady-state activation curve and inactivation curve of IA to more negative potentials, but mainly affected the activation kinetics. The amplitude and the activation processes of IK were not affected by lithium chloride. The effects of lithium chloride on potassium channel appear to possess neuroprotective properties by Ca2+-lowing effects modulate neuronal excitability by activating IA in rat hippocampal neurons.

  10. Evidence that dendritic mitochondria negatively regulate dendritic branching in pyramidal neurons in the neocortex.

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    Kimura, Toshiya; Murakami, Fujio

    2014-05-14

    The precise branching patterns of dendritic arbors have a profound impact on information processing in individual neurons and the brain. These patterns are established by positive and negative regulation of the dendritic branching. Although the mechanisms for positive regulation have been extensively investigated, little is known about those for negative regulation. Here, we present evidence that mitochondria located in developing dendrites are involved in the negative regulation of dendritic branching. We visualized mitochondria in pyramidal neurons of the mouse neocortex during dendritic morphogenesis using in utero electroporation of a mitochondria-targeted fluorescent construct. We altered the mitochondrial distribution in vivo by overexpressing Mfn1, a mitochondrial shaping protein, or the Miro-binding domain of TRAK2 (TRAK2-MBD), a truncated form of a motor-adaptor protein. We found that dendritic mitochondria were preferentially targeted to the proximal portion of dendrites only during dendritic morphogenesis. Overexpression of Mfn1 or TRAK2-MBD depleted mitochondria from the dendrites, an effect that was accompanied by increased branching of the proximal portion of the dendrites. This dendritic abnormality cannot be accounted for by changes in the distribution of membrane trafficking organelles since the overexpression of Mfn1 did not alter the distributions of the endoplasmic reticulum, Golgi, or endosomes. Additionally, neither did these constructs impair neuronal viability or mitochondrial function. Therefore, our results suggest that dendritic mitochondria play a critical role in the establishment of the precise branching pattern of dendritic arbors by negatively affecting dendritic branching.

  11. ERK1/2 Activation Is Necessary for BDNF to Increase Dendritic Spine Density in Hippocampal CA1 Pyramidal Neurons

    Science.gov (United States)

    Alonso, Mariana; Medina, Jorge H.; Pozzo-Miller, Lucas

    2004-01-01

    Brain-derived neurotrophic factor (BDNF) is a potent modulator of synaptic transmission and plasticity in the CNS, acting both pre- and postsynaptically. We demonstrated recently that BDNF/TrkB signaling increases dendritic spine density in hippocampal CA1 pyramidal neurons. Here, we tested whether activation of the prominent ERK (MAPK) signaling…

  12. Potential Synaptic Connectivity of Different Neurons onto Pyramidal Cells in a 3D Reconstruction of the Rat Hippocampus

    Directory of Open Access Journals (Sweden)

    Deepak eRopireddy

    2011-07-01

    Full Text Available Most existing connectomic data and ongoing efforts focus either on individual synapses (e.g. with electron microscopy or on regional connectivity (tract tracing. An individual pyramidal cell extends thousands of synapses over macroscopic distances (~cm. The contrasting requirements of high resolution and large field of view make it too challenging to acquire the entire synaptic connectivity for even a single typical cortical neuron. Light microscopy can image whole neuronal arbors and resolve dendritic branches. Analyzing connectivity in terms of close spatial appositions between axons and dendrites could thus bridge the opposite scales, from synaptic level to whole systems. In the mammalian cortex, structural plasticity of spines and boutons makes these ‘potential synapses’ functionally relevant to learning capability and memory capacity. To date, however, potential synapses have only been mapped in the surrounding of a neuron and relative to its local orientation rather than in a system-level anatomical reference. Here we overcome this limitation by estimating the potential connectivity of different neurons embedded into a detailed 3D reconstruction of the rat hippocampus. Axonal and dendritic trees were oriented with respect to hippocampal cytoarchitecture according to longitudinal and transversal curvatures. We report the potential connectivity onto pyramidal cell dendrites from the axons of a dentate granule cell, three CA3 pyramidal cells, one CA2 pyramidal cell, and 13 CA3b interneurons. The numbers, densities, and distributions of potential synapses were analyzed in each sub-region (e.g. CA3 vs. CA1, layer (e.g. oriens vs. radiatum, and septo-temporal location (e.g. dorsal vs. ventral. The overall ratio between the numbers of actual and potential synapses was ~0.20 for the granule and CA3 pyramidal cells. All potential connectivity patterns are strikingly dependent on the anatomical location of both pre-synaptic and post

  13. Dendritic Target Region-Specific Formation of Synapses Between Excitatory Layer 4 Neurons and Layer 6 Pyramidal Cells.

    Science.gov (United States)

    Qi, Guanxiao; Feldmeyer, Dirk

    2016-04-01

    Excitatory connections between neocortical layer 4 (L4) and L6 are part of the corticothalamic feedback microcircuitry. Here we studied the intracortical element of this feedback loop, the L4 spiny neuron-to-L6 pyramidal cell connection. We found that the distribution of synapses onto both putative corticothalamic (CT) and corticocortical (CC) L6 pyramidal cells (PCs) depends on the presynaptic L4 neuron type but is independent of the postsynaptic L6 PC type. L4 spiny stellate cells establish synapses on distal apical tuft dendrites of L6 PCs and elicit slow unitary excitatory postsynaptic potentials (uEPSPs) in L6 somata. In contrast, the majority of L4 star pyramidal neurons target basal and proximal apical oblique dendrites of L6 PCs and show fast uEPSPs. Compartmental modeling suggests that the slow uEPSP time course is primarily the result of dendritic filtering. This suggests that the dendritic target specificity of the 2 L4 spiny neuron types is due to their different axonal projection patterns across cortical layers. The preferential dendritic targeting by different L4 neuron types may facilitate the generation of dendritic Ca(2+) or Na(+) action potentials in L6 PCs; this could play a role in synaptic gain modulation in the corticothalamic pathway.

  14. Dendritic spine density of prefrontal layer 6 pyramidal neurons in relation to apical dendrite sculpting by nicotinic acetylcholine receptors

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    Lily eKang

    2015-10-01

    Full Text Available Prefrontal layer 6 (L6 pyramidal neurons play an important role in the adult control of attention, facilitated by their strong activation by nicotinic acetylcholine receptors. These neurons in mouse association cortex are distinctive morphologically when compared to L6 neurons in primary cortical regions. Roughly equal proportions of the prefrontal L6 neurons have apical dendrites that are long (reaching to the pial surface versus short (terminating in the deep layers, as in primary cortical regions. This distinct prefrontal morphological pattern is established in the post-juvenile period and appears dependent on nicotinic receptors. Here, we examine dendritic spine densities in these two subgroups of prefrontal L6 pyramidal neurons under control conditions as well as after perturbation of nicotinic acetylcholine receptors. In control mice, the long neurons have significantly greater apical and basal dendritic spine density compared to the short neurons. Furthermore, manipulations of nicotinic receptors (chrna5 deletion or chronic developmental nicotine exposure have distinct effects on these two subgroups of L6 neurons: apical spine density is significantly reduced in long neurons, and basal spine density is significantly increased in short neurons. These changes appear dependent on the α5 nicotinic subunit encoded by chrna5. Overall, the two subgroups of prefrontal L6 neurons appear positioned to integrate information either across cortex (long neurons or within the deep layers (short neurons, and nicotinic perturbations differently alter spine density within each subgroup. Such changes have ramifications for adult executive function and possibly also for the morphological vulnerability of prefrontal cortex to subsequent stress exposure.

  15. Synaptic conductances during interictal discharges in pyramidal neurons of rat entorhinal cortex

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    Dmitry V. Amakhin

    2016-10-01

    Full Text Available In epilepsy, the balance of excitation and inhibition underlying the basis of neural network activity shifts, resulting in neuronal network hyperexcitability and recurrent seizure-associated discharges. Mechanisms involved in ictal and interictal events are not fully understood, in particular, because of controversial data regarding the dynamics of excitatory and inhibitory synaptic conductances. In the present study, we estimated AMPAR-, NMDAR-, and GABAAR-mediated conductances during two distinct types of interictal discharge (IID in pyramidal neurons of rat entorhinal cortex in cortico-hippocampal slices. Repetitively emerging seizure-like events and IIDs were recorded in high extracellular potassium, 4-aminopyridine, and reduced magnesium-containing solution. An original procedure for estimating synaptic conductance during IIDs was based on the differences among the current-voltage characteristics of the synaptic components. The synaptic conductance dynamics obtained revealed that the first type of IID is determined by activity of GABAAR channels with depolarized reversal potential. The second type of IID is determined by the interplay between excitation and inhibition, with prominent early AMPAR and prolonged depolarized GABAAR and NMDAR-mediated components. The study then validated the contribution of these components to IIDs by intracellular pharmacological isolation. These data provide new insights into the mechanisms of seizures generation, development, and cessation.

  16. Maternal mobile phone exposure alters intrinsic electrophysiological properties of CA1 pyramidal neurons in rat offspring.

    Science.gov (United States)

    Razavinasab, Moazamehosadat; Moazzami, Kasra; Shabani, Mohammad

    2016-06-01

    Some studies have shown that exposure to electromagnetic field (EMF) may result in structural damage to neurons. In this study, we have elucidated the alteration in the hippocampal function of offspring Wistar rats (n = 8 rats in each group) that were chronically exposed to mobile phones during their gestational period by applying behavioral, histological, and electrophysiological tests. Rats in the EMF group were exposed to 900 MHz pulsed-EMF irradiation for 6 h/day. Whole cell recordings in hippocampal pyramidal cells in the mobile phone groups did show a decrease in neuronal excitability. Mobile phone exposure was mostly associated with a decrease in the number of action potentials fired in spontaneous activity and in response to current injection in both male and female groups. There was an increase in the amplitude of the afterhyperpolarization (AHP) in mobile phone rats compared with the control. The results of the passive avoidance and Morris water maze assessment of learning and memory performance showed that phone exposure significantly altered learning acquisition and memory retention in male and female rats compared with the control rats. Light microscopy study of brain sections of the control and mobile phone-exposed rats showed normal morphology.Our results suggest that exposure to mobile phones adversely affects the cognitive performance of both female and male offspring rats using behavioral and electrophysiological techniques.

  17. Characterization of voltage-gated Ca(2+ conductances in layer 5 neocortical pyramidal neurons from rats.

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    Mara Almog

    Full Text Available Neuronal voltage-gated Ca(2+ channels are involved in electrical signalling and in converting these signals into cytoplasmic calcium changes. One important function of voltage-gated Ca(2+ channels is generating regenerative dendritic Ca(2+ spikes. However, the Ca(2+ dependent mechanisms used to create these spikes are only partially understood. To start investigating this mechanism, we set out to kinetically and pharmacologically identify the sub-types of somatic voltage-gated Ca(2+ channels in pyramidal neurons from layer 5 of rat somatosensory cortex, using the nucleated configuration of the patch-clamp technique. The activation kinetics of the total Ba(2+ current revealed conductance activation only at medium and high voltages suggesting that T-type calcium channels were not present in the patches. Steady-state inactivation protocols in combination with pharmacology revealed the expression of R-type channels. Furthermore, pharmacological experiments identified 5 voltage-gated Ca(2+ channel sub-types - L-, N-, R- and P/Q-type. Finally, the activation of the Ca(2+ conductances was examined using physiologically derived voltage-clamp protocols including a calcium spike protocol and a mock back-propagating action potential (mBPAP protocol. These experiments enable us to suggest the possible contribution of the five Ca(2+ channel sub-types to Ca(2+ current flow during activation under physiological conditions.

  18. Persistent sodium current properties in hippocampal CA1 pyramidal neurons of young and adult rats.

    Science.gov (United States)

    Lunko, Oleksii; Isaev, Dmytro; Maximyuk, Oleksandr; Ivanchick, Gleb; Sydorenko, Vadym; Krishtal, Oleg; Isaeva, Elena

    2014-01-24

    Persistent tetrodotoxin-sensitive sodium current (INaP) plays an important role in cellular and neuronal network excitability in physiological conditions and under different pathological circumstances. However, developmental changes in INaP properties remain largely unclear. In the present study using whole cell patch clamp technique we evaluated INaP properties in CA1 hippocampal pyramidal neurons isolated from young (postnatal day (P) 12-16) and adult (P60-75) rats. We show that the INaP density is substantially larger in the adult group. Although INaP inactivation characteristics were found to be similar in both groups, voltage dependence of INaP activation is shifted to more negative membrane potentials (young: -48.6±0.5mV vs. adult: -52.4±0.2mV, p<0.01). Our data indicates the increase of INaP contribution in the basal membrane sodium conductivity in the mature hippocampus.

  19. Plasticity-dependent, full detonation at hippocampal mossy fiber–CA3 pyramidal neuron synapses

    Science.gov (United States)

    Vyleta, Nicholas P; Borges-Merjane, Carolina; Jonas, Peter

    2016-01-01

    Mossy fiber synapses on CA3 pyramidal cells are 'conditional detonators' that reliably discharge postsynaptic targets. The 'conditional' nature implies that burst activity in dentate gyrus granule cells is required for detonation. Whether single unitary excitatory postsynaptic potentials (EPSPs) trigger spikes in CA3 neurons remains unknown. Mossy fiber synapses exhibit both pronounced short-term facilitation and uniquely large post-tetanic potentiation (PTP). We tested whether PTP could convert mossy fiber synapses from subdetonator into detonator mode, using a recently developed method to selectively and noninvasively stimulate individual presynaptic terminals in rat brain slices. Unitary EPSPs failed to initiate a spike in CA3 neurons under control conditions, but reliably discharged them after induction of presynaptic short-term plasticity. Remarkably, PTP switched mossy fiber synapses into full detonators for tens of seconds. Plasticity-dependent detonation may be critical for efficient coding, storage, and recall of information in the granule cell–CA3 cell network. DOI: http://dx.doi.org/10.7554/eLife.17977.001 PMID:27780032

  20. Regulation of action potential waveforms by axonal GABAA receptors in cortical pyramidal neurons.

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    Yang Xia

    Full Text Available GABAA receptors distributed in somatodendritic compartments play critical roles in regulating neuronal activities, including spike timing and firing pattern; however, the properties and functions of GABAA receptors at the axon are still poorly understood. By recording from the cut end (bleb of the main axon trunk of layer -5 pyramidal neurons in prefrontal cortical slices, we found that currents evoked by GABA iontophoresis could be blocked by picrotoxin, indicating the expression of GABAA receptors in axons. Stationary noise analysis revealed that single-channel properties of axonal GABAA receptors were similar to those of somatic receptors. Perforated patch recording with gramicidin revealed that the reversal potential of the GABA response was more negative than the resting membrane potential at the axon trunk, suggesting that GABA may hyperpolarize the axonal membrane potential. Further experiments demonstrated that the activation of axonal GABAA receptors regulated the amplitude and duration of action potentials (APs and decreased the AP-induced Ca2+ transients at the axon. Together, our results indicate that the waveform of axonal APs and the downstream Ca2+ signals are modulated by axonal GABAA receptors.

  1. Discontinuous Galerkin finite element method for solving population density functions of cortical pyramidal and thalamic neuronal populations.

    Science.gov (United States)

    Huang, Chih-Hsu; Lin, Chou-Ching K; Ju, Ming-Shaung

    2015-02-01

    Compared with the Monte Carlo method, the population density method is efficient for modeling collective dynamics of neuronal populations in human brain. In this method, a population density function describes the probabilistic distribution of states of all neurons in the population and it is governed by a hyperbolic partial differential equation. In the past, the problem was mainly solved by using the finite difference method. In a previous study, a continuous Galerkin finite element method was found better than the finite difference method for solving the hyperbolic partial differential equation; however, the population density function often has discontinuity and both methods suffer from a numerical stability problem. The goal of this study is to improve the numerical stability of the solution using discontinuous Galerkin finite element method. To test the performance of the new approach, interaction of a population of cortical pyramidal neurons and a population of thalamic neurons was simulated. The numerical results showed good agreement between results of discontinuous Galerkin finite element and Monte Carlo methods. The convergence and accuracy of the solutions are excellent. The numerical stability problem could be resolved using the discontinuous Galerkin finite element method which has total-variation-diminishing property. The efficient approach will be employed to simulate the electroencephalogram or dynamics of thalamocortical network which involves three populations, namely, thalamic reticular neurons, thalamocortical neurons and cortical pyramidal neurons.

  2. The influence of phospho-tau on dendritic spines of cortical pyramidal neurons in patients with Alzheimer’s disease

    Science.gov (United States)

    Merino-Serrais, Paula; Benavides-Piccione, Ruth; Blazquez-Llorca, Lidia; Kastanauskaite, Asta; Rábano, Alberto; Avila, Jesús

    2013-01-01

    The dendritic spines on pyramidal cells represent the main postsynaptic elements of cortical excitatory synapses and they are fundamental structures in memory, learning and cognition. In the present study, we used intracellular injections of Lucifer yellow in fixed tissue to analyse over 19 500 dendritic spines that were completely reconstructed in three dimensions along the length of the basal dendrites of pyramidal neurons in the parahippocampal cortex and CA1 of patients with Alzheimer’s disease. Following intracellular injection, sections were immunostained for anti-Lucifer yellow and with tau monoclonal antibodies AT8 and PHF-1, which recognize tau phosphorylated at Ser202/Thr205 and at Ser396/404, respectively. We observed that the diffuse accumulation of phospho-tau in a putative pre-tangle state did not induce changes in the dendrites of pyramidal neurons, whereas the presence of tau aggregates forming intraneuronal neurofibrillary tangles was associated with progressive alteration of dendritic spines (loss of dendritic spines and changes in their morphology) and dendrite atrophy, depending on the degree of tangle development. Thus, the presence of phospho-tau in neurons does not necessarily mean that they suffer severe and irreversible effects as thought previously but rather, the characteristic cognitive impairment in Alzheimer’s disease is likely to depend on the relative number of neurons that have well developed tangles. PMID:23715095

  3. Cdk5 is required for multipolar-to-bipolar transition during radial neuronal migration and proper dendrite development of pyramidal neurons in the cerebral cortex.

    Science.gov (United States)

    Ohshima, Toshio; Hirasawa, Motoyuki; Tabata, Hidenori; Mutoh, Tetsuji; Adachi, Tomoko; Suzuki, Hiromi; Saruta, Keiko; Iwasato, Takuji; Itohara, Shigeyoshi; Hashimoto, Mistuhiro; Nakajima, Kazunori; Ogawa, Masaharu; Kulkarni, Ashok B; Mikoshiba, Katsuhiko

    2007-06-01

    The mammalian cerebral cortex consists of six layers that are generated via coordinated neuronal migration during the embryonic period. Recent studies identified specific phases of radial migration of cortical neurons. After the final division, neurons transform from a multipolar to a bipolar shape within the subventricular zone-intermediate zone (SVZ-IZ) and then migrate along radial glial fibres. Mice lacking Cdk5 exhibit abnormal corticogenesis owing to neuronal migration defects. When we introduced GFP into migrating neurons at E14.5 by in utero electroporation, we observed migrating neurons in wild-type but not in Cdk5(-/-) embryos after 3-4 days. Introduction of the dominant-negative form of Cdk5 into the wild-type migrating neurons confirmed specific impairment of the multipolar-to-bipolar transition within the SVZ-IZ in a cell-autonomous manner. Cortex-specific Cdk5 conditional knockout mice showed inverted layering of the cerebral cortex and the layer V and callosal neurons, but not layer VI neurons, had severely impaired dendritic morphology. The amount of the dendritic protein Map2 was decreased in the cerebral cortex of Cdk5-deficient mice, and the axonal trajectory of cortical neurons within the cortex was also abnormal. These results indicate that Cdk5 is required for proper multipolar-to-bipolar transition, and a deficiency of Cdk5 results in abnormal morphology of pyramidal neurons. In addition, proper radial neuronal migration generates an inside-out pattern of cerebral cortex formation and normal axonal trajectories of cortical pyramidal neurons.

  4. Whole-cell recordings of voltage-gated Calcium, Potassium and Sodium currents in acutely isolated hippocampal pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    Shuyun Huang; Qing Cai; Weitian Liu; Xiaoling Wang; Tao Wang

    2009-01-01

    Objective:To record Calcium, Potassium and Sodium currents in acutely isolated hippocampal pyramidal neurons. Methods:Hip-pocampal CA3 neurons were freshly isolated by 1 mg protease/3 ml SES and mechanical trituration with polished pipettes of progressively smaller tip diameters. Patch clamp technique in whole-cell mode was employed to record voltage-gated channel currents. Results:The procedure dissociated hippocampal neurons, preserving apical dendrites and several basal dendrites, without impairing the electrical characteristics of the neurons. Whole-cell patch clamp configuration was successfully used to record voltage-gated Ca2+ currents, delayed rectifier K+ current and voltage-gated Na+ currents. Conclusion:Protease combined with mechanical trituration may be used for the dissociation of neurons from rat hippocampus. Voltage-gated channels currents could be recorded using a patch clamp technique.

  5. Sulforhodamine 101 induces long-term potentiation of intrinsic excitability and synaptic efficacy in hippocampal CA1 pyramidal neurons

    DEFF Research Database (Denmark)

    Kang, J.; Kang, N.; Yu, Y.;

    2010-01-01

    Sulforhodamine 101 (SR101) has been extensively used for investigation as a specific marker for astroglia in vivo and activity-dependent dye for monitoring regulated exocytosis. Here, we report that SR101 has bioactive effects on neuronal activity. Perfusion of slices with SR101 (1 microM) for 10...... min induced long-term potentiation of intrinsic neuronal excitability (LTP-IE) and a long-lasting increase in evoked EPSCs (eEPSCs) in CA1 pyramidal neurons in hippocampal slices. The increase in intrinsic neuronal excitability was a result of negative shifts in the action potential (AP) threshold...... NMDAR currents, suggesting that SR101 enhances activation of synaptic NMDARs. SR101-induced LTP-IE and potentiation of synaptic transmission triggered spontaneous neuronal firing in slices and in vivo epileptic seizures. Our results suggest that SR101 is an epileptogenic agent that long-lastingly lowers...

  6. Single mechanically-gated cation channel currents can trigger action potentials in neocortical and hippocampal pyramidal neurons.

    Science.gov (United States)

    Nikolaev, Yury A; Dosen, Peter J; Laver, Derek R; van Helden, Dirk F; Hamill, Owen P

    2015-05-22

    The mammalian brain is a mechanosensitive organ that responds to different mechanical forces ranging from intrinsic forces implicated in brain morphogenesis to extrinsic forces that can cause concussion and traumatic brain injury. However, little is known of the mechanosensors that transduce these forces. In this study we use cell-attached patch recording to measure single mechanically-gated (MG) channel currents and their affects on spike activity in identified neurons in neonatal mouse brain slices. We demonstrate that both neocortical and hippocampal pyramidal neurons express stretch-activated MG cation channels that are activated by suctions of ~25mm Hg, have a single channel conductance for inward current of 50-70pS and show weak selectivity for alkali metal cations (i.e., Na(+)pyramidal neurons. Not all neuron types studied here expressed MG channel currents. In particular, locus coeruleus and cerebellar Purkinje neurons showed no detectable MG channel activity. Moreover their robust rhythmic spike activity was resistant to mechanical modulation. Our observation that a single MG channel current can trigger spiking predicates the need for reassessment of the long held view that the impulse output of central neurons depends only upon their intrinsic voltage-gated channels and/or their integrated synaptic input.

  7. Action Potential Modulation in CA1 Pyramidal Neuron Axons Facilitates OLM Interneuron Activation in Recurrent Inhibitory Microcircuits of Rat Hippocampus

    OpenAIRE

    Sooyun Kim

    2014-01-01

    Oriens-lacunosum moleculare (O-LM) interneurons in the CA1 region of the hippocampus play a key role in feedback inhibition and in the control of network activity. However, how these cells are efficiently activated in the network remains unclear. To address this question, I performed recordings from CA1 pyramidal neuron axons, the presynaptic fibers that provide feedback innervation of these interneurons. Two forms of axonal action potential (AP) modulation were identified. First, repetitive ...

  8. LTP is accompanied by an enhanced local excitability of pyramidal neuron dendrites.

    Science.gov (United States)

    Frick, Andreas; Magee, Jeffrey; Johnston, Daniel

    2004-02-01

    The propagation and integration of signals in the dendrites of pyramidal neurons is regulated, in part, by the distribution and biophysical properties of voltage-gated ion channels. It is thus possible that any modification of these channels in a specific part of the dendritic tree might locally alter these signaling processes. Using dendritic and somatic whole-cell recordings, combined with calcium imaging in rat hippocampal slices, we found that the induction of long-term potentiation (LTP) was accompanied by a local increase in dendritic excitability that was dependent on the activation of NMDA receptors. These changes favored the back-propagation of action potentials into this dendritic region with a subsequent boost in the Ca(2+) influx. Dendritic cell-attached patch recordings revealed a hyperpolarized shift in the inactivation curve of transient, A-type K(+) currents that can account for the enhanced excitability. These results suggest an important mechanism associated with LTP for shaping signal processing and controlling dendritic function.

  9. Extracellular calcium modulates persistent sodium current-dependent burst-firing in hippocampal pyramidal neurons.

    Science.gov (United States)

    Su, H; Alroy, G; Kirson, E D; Yaari, Y

    2001-06-15

    The generation of high-frequency spike bursts ("complex spikes"), either spontaneously or in response to depolarizing stimuli applied to the soma, is a notable feature in intracellular recordings from hippocampal CA1 pyramidal cells (PCs) in vivo. There is compelling evidence that the bursts are intrinsically generated by summation of large spike afterdepolarizations (ADPs). Using intracellular recordings in adult rat hippocampal slices, we show that intrinsic burst-firing in CA1 PCs is strongly dependent on the extracellular concentration of Ca(2+) ([Ca(2+)](o)). Thus, lowering [Ca(2+)](o) (by equimolar substitution with Mn(2+) or Mg(2+)) induced intrinsic bursting in nonbursters, whereas raising [Ca(2+)](o) suppressed intrinsic bursting in native bursters. The induction of intrinsic bursting by low [Ca(2+)](o) was associated with enlargement of the spike ADP. Low [Ca(2+)](o)-induced intrinsic bursts and their underlying ADPs were suppressed by drugs that reduce the persistent Na(+) current (I(NaP)), indicating that this current mediates the slow burst depolarization. Blocking Ca(2+)-activated K(+) currents with extracellular Ni(2+) or intracellular chelation of Ca(2+) did not induce intrinsic bursting. This and other evidence suggest that lowering [Ca(2+)](o) may induce intrinsic bursting by augmenting I(NaP). Because repetitive neuronal activity in the hippocampus is associated with marked decreases in [Ca(2+)](o), the regulation of intrinsic bursting by extracellular Ca(2+) may provide a mechanism for preferential recruitment of this firing mode during certain forms of hippocampal activation.

  10. Age-related dysfunctions of the autophagy lysosomal pathway in hippocampal pyramidal neurons under proteasome stress.

    Science.gov (United States)

    Gavilán, Elena; Pintado, Cristina; Gavilan, Maria P; Daza, Paula; Sánchez-Aguayo, Inmaculada; Castaño, Angélica; Ruano, Diego

    2015-05-01

    Autophagy plays a key role in the maintenance of cellular homeostasis, and autophagy deregulation gives rise to severe disorders. Many of the signaling pathways regulating autophagy under stress conditions are still poorly understood. Using a model of proteasome stress in rat hippocampus, we have characterized the functional crosstalk between the ubiquitin proteasome system and the autophagy-lysosome pathway, identifying also age-related modifications in the crosstalk between both proteolytic systems. Under proteasome inhibition, both autophagy activation and resolution were efficiently induced in young but not in aged rats, leading to restoration of protein homeostasis only in young pyramidal neurons. Importantly, proteasome stress inhibited glycogen synthase kinase-3β in young but activated in aged rats. This age-related difference could be because of a dysfunction in the signaling pathway of the insulin growth factor-1 under stress situations. Present data highlight the potential role of glycogen synthase kinase-3β in the coordination of both proteolytic systems under stress situation, representing a key molecular target to sort out this deleterious effect.

  11. THE KINETICS OF MULTIBRANCH INTEGRATION ON THE DENDRITIC ARBOR OF CA1 PYRAMIDAL NEURONS

    Directory of Open Access Journals (Sweden)

    Sunggu eYang

    2014-05-01

    Full Text Available The process by which synaptic inputs separated in time and space are integrated by the dendritic arbor to produce a sequence of action potentials is among the most fundamental signal transformations that takes place within the central nervous system. Some aspects of this complex process, such as integration at the level of individual dendritic branches, have been extensively studied. But other aspects, such as how inputs from multiple branches are combined, and the kinetics of that integration have not been systematically examined. Using a 3D digital holographic photolysis technique to overcome the challenges posed by the complexities of the 3D anatomy of the dendritic arbor of CA1 pyramidal neurons for conventional photolysis, we show that integration on a single dendrite is fundamentally different from that on multiple dendrites. Multibranch integration occurring at oblique and basal dendrites allows somatic action potential firing of the cell to faithfully follow the driving stimuli over a significantly wider frequency range than what is possible with single branch integration. However, multibranch integration requires greater input strength to drive the somatic action potentials. This tradeoff between sensitivity and kinetics may explain the puzzling report of the predominance of multibranch, rather than single branch, integration from in vivo recordings during presentation of visual stimuli.

  12. Acute Modulation of Synaptic Plasticity of Pyramidal Neurons by Activin in Adult Hippocampus

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    Yoshitaka eHasegawa

    2014-06-01

    Full Text Available Activin A is known as a neuroprotective factor produced upon acute excitotoxic injury of the hippocampus (in pathological states. We attempt to reveal the role of activin as a neuromodulator in the adult male hippocampus under physiological conditions (in healthy states, which remains largely unknown. We showed endogenous/basal expression of activin in the hippocampal neurons. Localization of activin receptors in dendritic spines (= postsynapses was demonstrated by immunoelectron microscopy. The incubation of hippocampal acute slices with activin A (10 ng/mL, 0.4 nM for 2 h altered the density and morphology of spines in CA1 pyramidal neurons. The total spine density increased by 1.2-fold upon activin treatments. Activin selectively increased the density of large-head spines, without affecting middle-head and small-head spines. Blocking of Erk/MAPK, PKA or PKC prevented the activin-induced spinogenesis by reducing the density of large-head spines, independent of Smad-induced gene transcription which usually takes more than several hours. Incubation of acute slices with activin for 2 h induced the moderate early long-term potentiation (moderate LTP upon weak theta burst stimuli. This moderate LTP induction was blocked by follistatin, MAPK inhibitor (PD98059 and inhibitor of NR2B subunit of NMDA receptors (Ro25-6981. It should be noted that the weak theta burst stimuli alone cannot induce moderate LTP. These results suggest that MAPK-induced phosphorylation of NMDA receptors (including NR2B may play an important role for activin-induced moderate LTP. Taken together, the current results reveal interesting physiological roles of endogenous activin as a synaptic modulator in the adult hippocampus.

  13. Computational modeling reveals dendritic origins of GABA(A-mediated excitation in CA1 pyramidal neurons.

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    Naomi Lewin

    Full Text Available GABA is the key inhibitory neurotransmitter in the adult central nervous system, but in some circumstances can lead to a paradoxical excitation that has been causally implicated in diverse pathologies from endocrine stress responses to diseases of excitability including neuropathic pain and temporal lobe epilepsy. We undertook a computational modeling approach to determine plausible ionic mechanisms of GABA(A-dependent excitation in isolated post-synaptic CA1 hippocampal neurons because it may constitute a trigger for pathological synchronous epileptiform discharge. In particular, the interplay intracellular chloride accumulation via the GABA(A receptor and extracellular potassium accumulation via the K/Cl co-transporter KCC2 in promoting GABA(A-mediated excitation is complex. Experimentally it is difficult to determine the ionic mechanisms of depolarizing current since potassium transients are challenging to isolate pharmacologically and much GABA signaling occurs in small, difficult to measure, dendritic compartments. To address this problem and determine plausible ionic mechanisms of GABA(A-mediated excitation, we built a detailed biophysically realistic model of the CA1 pyramidal neuron that includes processes critical for ion homeostasis. Our results suggest that in dendritic compartments, but not in the somatic compartments, chloride buildup is sufficient to cause dramatic depolarization of the GABA(A reversal potential and dominating bicarbonate currents that provide a substantial current source to drive whole-cell depolarization. The model simulations predict that extracellular K(+ transients can augment GABA(A-mediated excitation, but not cause it. Our model also suggests the potential for GABA(A-mediated excitation to promote network synchrony depending on interneuron synapse location - excitatory positive-feedback can occur when interneurons synapse onto distal dendritic compartments, while interneurons projecting to the perisomatic

  14. Prenatal morphine exposure reduces pyramidal neurons in CA1, CA2 and CA3 subfields of mice hippocampus

    Directory of Open Access Journals (Sweden)

    Soraya Ghafari

    2014-03-01

    Full Text Available Objective(s:This study was carried out to evaluate the effect of maternal morphine exposure during gestational and lactation period on pyramidal neurons of hippocampus in 18 and 32 day mice offspring. Materials and Methods: Thirty female mice were randomly allocated into cases and controls. In case group, animals received morphinesulfate 10 mg/kg.body weight intraperitoneally during 7 days before mating, gestational period (GD 0-21, 18 and 32 days after delivery in the experimental groups. The control animals received an equivalent volume of normal saline. Cerebrum of six offsprings in each group was removed and stained with cresyl violet and a monoclonal antibody NeuN for immunohistochemical detection of surviving pyramidal neurons. Quantitative computer-assisted morphometric study was done on hippocampus. Results: The number of pyramidal neurons in CA1, CA2 and CA3 in treated groups was significantly reduced in postnatal day 18 and 32 (P18, P32 compared to control groups (P

  15. Blockade of Ca2+-permeable AMPA/kainate channels decreases oxygen-glucose deprivation-induced Zn2+ accumulation and neuronal loss in hippocampal pyramidal neurons.

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    Yin, Hong Z; Sensi, Stefano L; Ogoshi, Fumio; Weiss, John H

    2002-02-15

    Synaptic release of Zn2+ and its translocation into postsynaptic neurons probably contribute to neuronal injury after ischemia or epilepsy. Studies in cultured neurons have revealed that of the three major routes of divalent cation entry, NMDA channels, voltage-sensitive Ca2+ channels (VSCCs), and Ca2+-permeable AMPA/kainate (Ca-A/K) channels, Ca-A/K channels exhibit the highest permeability to exogenously applied Zn2+. However, routes through which synaptically released Zn2+ gains entry to postsynaptic neurons have not been characterized in vivo. To model ischemia-induced Zn2+ movement in a system approximating the in vivo situation, we subjected mouse hippocampal slice preparations to controlled periods of oxygen and glucose deprivation (OGD). Timm's staining revealed little reactive Zn2+ in CA1 and CA3 pyramidal neurons of slices exposed in the presence of O2 and glucose. However, 15 min of OGD resulted in marked labeling in both regions. Whereas strong Zn2+ labeling persisted if both the NMDA antagonist MK-801 and the VSCC blocker Gd3+ were present during OGD, the presence of either the Ca-A/K channel blocker 1-naphthyl acetyl spermine (NAS) or the extracellular Zn2+ chelator Ca2+ EDTA substantially decreased Zn2+ accumulation in pyramidal neurons of both subregions. In parallel experiments, slices were subjected to 5 min OGD exposures as described above, followed 4 hr later by staining with the cell-death marker propidium iodide. As in the Timm's staining experiments, substantial CA1 or CA3 pyramidal neuronal damage occurred despite the presence of MK-801 and Gd3+, whereas injury was decreased by NAS or by Ca2+ EDTA (in CA1).

  16. Layer 5 Pyramidal Neurons' Dendritic Remodeling and Increased Microglial Density in Primary Motor Cortex in a Murine Model of Facial Paralysis.

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    Urrego, Diana; Troncoso, Julieta; Múnera, Alejandro

    2015-01-01

    This work was aimed at characterizing structural changes in primary motor cortex layer 5 pyramidal neurons and their relationship with microglial density induced by facial nerve lesion using a murine facial paralysis model. Adult transgenic mice, expressing green fluorescent protein in microglia and yellow fluorescent protein in projecting neurons, were submitted to either unilateral section of the facial nerve or sham surgery. Injured animals were sacrificed either 1 or 3 weeks after surgery. Two-photon excitation microscopy was then used for evaluating both layer 5 pyramidal neurons and microglia in vibrissal primary motor cortex (vM1). It was found that facial nerve lesion induced long-lasting changes in the dendritic morphology of vM1 layer 5 pyramidal neurons and in their surrounding microglia. Dendritic arborization of the pyramidal cells underwent overall shrinkage. Apical dendrites suffered transient shortening while basal dendrites displayed sustained shortening. Moreover, dendrites suffered transient spine pruning. Significantly higher microglial cell density was found surrounding vM1 layer 5 pyramidal neurons after facial nerve lesion with morphological bias towards the activated phenotype. These results suggest that facial nerve lesions elicit active dendrite remodeling due to pyramidal neuron and microglia interaction, which could be the pathophysiological underpinning of some neuropathic motor sequelae in humans.

  17. Hippocampal pyramidal neurons switch from a multipolar migration mode to a novel "climbing" migration mode during development.

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    Kitazawa, Ayako; Kubo, Ken-ichiro; Hayashi, Kanehiro; Matsunaga, Yuki; Ishii, Kazuhiro; Nakajima, Kazunori

    2014-01-22

    The hippocampus plays important roles in brain functions. Despite the importance of hippocampal functions, recent analyses of neuronal migration have mainly been performed on the cerebral neocortex, and the cellular mechanisms responsible for the formation of the hippocampus are not yet completely understood. Moreover, why a prolonged time is required for hippocampal neurons to complete their migration has been unexplainable for several decades. We analyzed the migratory profile of neurons in the developing mouse hippocampal CA1 region and found that the hippocampal pyramidal neurons generated near the ventricle became postmitotic multipolar cells and accumulated in the multipolar cell accumulation zone (MAZ) in the late stage of development. The hippocampal neurons passed through the pyramidal layer by a unique mode of migration. Their leading processes were highly branched and made contact with many radial fibers. Time-lapse imaging revealed that the migrating cells changed their scaffolds from the original radial fibers to other radial fibers, and as a result they proceed in a zigzag manner, with long intervals. The migrating cells in the hippocampus reminded us of "rock climbers" that instead of using their hands to pull up their bodies were using their leading processes to pull up their cell bodies. Because this mode of migration had never been described, we called it the "climbing" mode. The change from the "climbing" mode in the hippocampus to the "locomotion" mode in the neocortex may have contributed to the brain expansion during evolution.

  18. Tonic GABAA conductance decreases membrane time constant and increases EPSP-spike precision in hippocampal pyramidal neurons

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    Agnieszka I Wlodarczyk

    2013-12-01

    Full Text Available Because of a complex dendritic structure, pyramidal neurons have a large membrane surface relative to other cells and so a large electrical capacitance and a large membrane time constant (τm. This results in slow depolarizations in response to excitatory synaptic inputs, and consequently increased and variable action potential latencies, which may be computationally undesirable. Tonic activation of GABAA receptors increases membrane conductance and thus regulates neuronal excitability by shunting inhibition. In addition, tonic increases in membrane conductance decrease the membrane time constant (τm, and improve the temporal fidelity of neuronal firing. Here we performed whole-cell current clamp recordings from hippocampal CA1 pyramidal neurons and found that bath application of 10 µM GABA indeed decreases τm in these cells. GABA also decreased first spike latency and jitter (standard deviation of the latency produced by current injection of 2 rheobases (500 ms. However, when larger current injections (3-6 rheobases were used, GABA produced no significant effect on spike jitter, which was low. Using mathematical modelling we demonstrate that the tonic GABAA conductance decreases rise time, decay time and half-width of EPSPs in pyramidal neurons. A similar effect was observed on EPSP/IPSP pairs produced by stimulation of Schaffer collaterals: the EPSP part of the response became shorter after application of GABA. Consistent with the current injection data, a significant decrease in spike latency and jitter was obtained in cell attached recordings only at near-threshold stimulation (50% success rate, S50. When stimulation was increased to 2- or 3- times S50, GABA significantly affected neither spike latency nor spike jitter. Our results suggest that a decrease in τm associated with elevations in ambient GABA can improve EPSP-spike precision at near-threshold synaptic inputs.

  19. Tonic GABAA conductance decreases membrane time constant and increases EPSP-spike precision in hippocampal pyramidal neurons.

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    Wlodarczyk, Agnieszka I; Xu, Chun; Song, Inseon; Doronin, Maxim; Wu, Yu-Wei; Walker, Matthew C; Semyanov, Alexey

    2013-01-01

    Because of a complex dendritic structure, pyramidal neurons have a large membrane surface relative to other cells and so a large electrical capacitance and a large membrane time constant (τm). This results in slow depolarizations in response to excitatory synaptic inputs, and consequently increased and variable action potential latencies, which may be computationally undesirable. Tonic activation of GABAA receptors increases membrane conductance and thus regulates neuronal excitability by shunting inhibition. In addition, tonic increases in membrane conductance decrease the membrane time constant (τm), and improve the temporal fidelity of neuronal firing. Here we performed whole-cell current clamp recordings from hippocampal CA1 pyramidal neurons and found that bath application of 10μM GABA indeed decreases τm in these cells. GABA also decreased first spike latency and jitter (standard deviation of the latency) produced by current injection of 2 rheobases (500 ms). However, when larger current injections (3-6 rheobases) were used, GABA produced no significant effect on spike jitter, which was low. Using mathematical modeling we demonstrate that the tonic GABAA conductance decreases rise time, decay time and half-width of EPSPs in pyramidal neurons. A similar effect was observed on EPSP/IPSP pairs produced by stimulation of Schaffer collaterals: the EPSP part of the response became shorter after application of GABA. Consistent with the current injection data, a significant decrease in spike latency and jitter was obtained in cell attached recordings only at near-threshold stimulation (50% success rate, S50). When stimulation was increased to 2- or 3- times S50, GABA significantly affected neither spike latency nor spike jitter. Our results suggest that a decrease in τm associated with elevations in ambient GABA can improve EPSP-spike precision at near-threshold synaptic inputs.

  20. Activation of functional α7-containing nAChRs in hippocampal CA1 pyramidal neurons by physiological levels of choline in the presence of PNU-120596.

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    Bopanna I Kalappa

    Full Text Available BACKGROUND: The level of expression of functional α7-containing nicotinic acetylcholine receptors (nAChRs in hippocampal CA1 pyramidal neurons is believed to be very low compared to hippocampal CA1 interneurons, and for many years this expression was largely overlooked. However, high densities of expression of functional α7-containing nAChRs in CA1 pyramidal neurons may not be necessary for triggering important cellular and network functions, especially if activation of α7-containing nAChRs occurs in the presence of positive allosteric modulators such as PNU-120596. METHODOLOGY/PRINCIPAL FINDINGS: An approach previously developed for α7-containing nAChRs expressed in tuberomammillary neurons was applied to investigate functional CA1 pyramidal α7-containing nAChRs using rat coronal hippocampal slices and patch-clamp electrophysiology. The majority (∼71% of tested CA1 pyramidal neurons expressed low densities of functional α7-containing nAChRs as evidenced by small whole-cell responses to choline, a selective endogenous agonist of α7 nAChRs. These responses were potentiated by PNU-120596, a novel positive allosteric modulator of α7 nAChRs. The density of functional α7-containing nAChRs expressed in CA1 pyramidal neurons (and thus, the normalized net effect of activation, i.e., response net charge per unit of membrane capacitance per unit of time was estimated to be ∼5% of the density observed in CA1 interneurons. The results of this study demonstrate that despite low levels of expression of functional pyramidal α7-containing nAChRs, physiological levels of choline (∼10 µM are sufficient to activate these receptors and transiently depolarize and even excite CA1 pyramidal neurons in the presence of PNU-120596. The observed effects are possible because in the presence of 10 µM choline and 1-5 µM PNU-120596, a single opening of an individual pyramidal α7-containing nAChR ion channel appears to transiently depolarize (∼4 mV the

  1. Changes in Neuronal Excitability by Activated Microglia: Differential Na(+) Current Upregulation in Pyramid-Shaped and Bipolar Neurons by TNF-α and IL-18.

    Science.gov (United States)

    Klapal, Lars; Igelhorst, Birte A; Dietzel-Meyer, Irmgard D

    2016-01-01

    Microglia are activated during pathological events in the brain and are capable of releasing various types of inflammatory cytokines. Here, we demonstrate that the addition of 5% microglia activated by 1 μg/ml lipopolysaccharides (LPS) to hippocampal cultures upregulates Na(+) current densities (INavD) of bipolar as well as pyramid-shaped neurons, thereby increasing their excitability. Deactivation of microglia by the addition of 10 ng/ml transforming growth factor-β (TGF-β) decreases INavD below control levels suggesting that the residual activated microglial cells influence neuronal excitability in control cultures. Preincubation of hippocampal cultures with 10 ng/ml tumor necrosis factor-α (TNF-α), a major cytokine released by activated microglia, upregulated INavD significantly by ~30% in bipolar cells, whereas in pyramid-shaped cells, the upregulation only reached an increase of ~14%. Incubation of the cultures with antibodies against either TNF-receptor 1 or 2 blocked the upregulation of INavD in bipolar cells, whereas in pyramid-shaped cells, increases in INavD were exclusively blocked by antibodies against TNF-receptor 2, suggesting that both cell types respond differently to TNF-α exposure. Since additional cytokines, such as interleukin-18 (IL-18), are released from activated microglia, we tested potential effects of IL-18 on INavD in both cell types. Exposure to 5-10 ng/ml IL-18 for 4 days increased INavD in both pyramid-shaped as well as bipolar neurons, albeit the dose-response curves were shifted to lower concentrations in bipolar cells. Our results suggest that by secretion of cytokines, microglial cells upregulate Na(+) current densities in bipolar and pyramid-shaped neurons to some extent differentially. Depending on the exact cytokine composition and concentration released, this could change the balance between the activity of inhibitory bipolar and excitatory pyramid-shaped cells. Since bipolar cells show a larger upregulation of

  2. Changes in neuronal excitability by activated microglia: Differential Na+ current up-regulation in pyramid-shaped and bipolar neurons by TNF-α and IL-18

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    Lars eKlapal

    2016-03-01

    Full Text Available Microglia are activated during pathological events in the brain and are capable of releasing various types of inflammatory cytokines. Here we demonstrate that the addition of 5% microglia activated by 1 µg/ml lipopolysaccharides (LPS to hippocampal cultures up-regulates Na+ current densities (INavD of bipolar as well as pyramid-shaped neurons, thereby increasing their excitability. Deactivation of microglia by the addition of 10 ng/ml transforming growth factor-β (TGF-β decreases INavD below control levels suggesting that the residual activated microglial cells influence neuronal excitability in control cultures. Preincubation of hippocampal cultures with 10 ng/ml tumor necrosis factor-α (TNF-α, a major cytokine released by activated microglia, up-regulated INavD significantly by ~30% in bipolar cells, whereas in pyramid-shaped cells the up-regulation only reached an increase of ~14%. Incubation of the cultures with antibodies against either TNF-receptor 1 or 2 blocked the up-regulation of INavD in bipolar cells, whereas in pyramid-shaped cells increases in INavD were exclusively blocked by antibodies against TNF-receptor 2, suggesting that both cell types respond differently to TNF-α exposure. Since additional cytokines, such as interleukin-18 (IL-18, are released from activated microglia we tested potential effects of IL-18 on INavD in both cell types. Exposure to 5-10 ng/ml IL-18 for 4 days increased INavD in both pyramid-shaped as well as bipolar neurons, albeit the dose-response curves were shifted to lower concentrations in bipolar cells. Our results suggest that by secretion of cytokines microglial cells up-regulate Na+ current densities in bipolar and pyramid-shaped neurons to some extent differentially. Depending on the exact cytokine composition and concentration released this could change the balance between the activity of inhibitory bipolar and excitatory pyramid-shaped cells. Since bipolar cells show a larger up-regulation of

  3. The electrical activity of hippocampal pyramidal neuron is subjected to descending control by the brain orexin/hypocretin system.

    Science.gov (United States)

    Riahi, Esmail; Arezoomandan, Reza; Fatahi, Zahra; Haghparast, Abbas

    2015-03-01

    The hippocampus receives sparse orexinergic innervation from the lateral hypothalamus and expresses a high level of orexin receptor. The function of orexin receptor in the regulation of hippocampal neural activity has never been investigated. In this study, in vivo single unit recording was performed in urethane-anesthetized rats. After 15 min of baseline recording from pyramidal neuron within the CA1 region of the dorsal hippocampus, i.c.v. injection of orexin-A 0.5 nmol, SB334867 400 nmol, a selective orexin receptor 1 antagonist, saline, or DMSO, or microinjection of carbachol 250 nmol or saline into the ipsilateral lateral hypothalamus were performed using a Hamilton microsyringe, and the spontaneous firing activity continued to be recorded for 25 min. Results showed that orexin administration into the lateral cerebral ventricle excited 6 out of 8 neurons and inhibited 1 neuron. Chemical stimulation of the lateral hypothalamus by carbachol excited 9 out of 13 hippocampal neurons and inhibited 3 neurons. On the other hand, i.c.v. injection of the SB334867, caused reductions in the firing activity of 6 out of 10 neurons and increases in 4 additional neurons. It seems that orexin neurotransmission in the hippocampus mostly elicits an excitatory response, whereas blockade of orexin receptor has an inhibitory effect. Further studies need to be done to elucidate the underlying mechanism of orexin action on hippocampal neurons.

  4. Convergence of entorhinal and CA3 inputs onto pyramidal neurons and interneurons in hippocampal area CA1--an anatomical study in the rat.

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    Kajiwara, Riichi; Wouterlood, Floris G; Sah, Anupam; Boekel, Amber J; Baks-te Bulte, Luciënne T G; Witter, Menno P

    2008-01-01

    The entorhinal cortex (EC) conveys information to hippocampal field CA1 either directly by way of projections from principal neurons in layer III, or indirectly by axons from layer II via the dentate gyrus, CA3, and Schaffer collaterals. These two pathways differentially influence activity in CA1, yet conclusive evidence is lacking whether and to what extent they converge onto single CA1 neurons. Presently we studied such convergence. Different neuroanatomical tracers injected into layer III of EC and into CA3, respectively, tagged simultaneously the direct entorhino-hippocampal fibers and the indirect innervation of CA1 neurons by Schaffer collaterals. In slices of fixed brains we intracellularly filled CA1 pyramidal cells and interneurons in stratum lacunosum-moleculare (LM) and stratum radiatum (SR). Sections of these slices were scanned in a confocal laser scanning microscope. 3D-reconstruction was used to determine whether boutons of the labeled input fibers were in contact with the intracellularly filled neurons. We analyzed 12 pyramidal neurons and 21 interneurons. Perforant path innervation to pyramidal neurons in our material was observed to be denser than that from CA3. All pyramidal neurons and 17 of the interneurons received contacts of both perforant pathway and Schaffer input on their dendrites and cell bodies. Four interneurons, which were completely embedded in LM, received only labeled perforant pathway input. Thus, we found convergence of both projection systems on single CA1 pyramidal and interneurons with dendrites that access the layers where perforant pathway fibers and Schaffer collaterals end.

  5. Adenosine actions on CA1 pyramidal neurones in rat hippocampal slices.

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    Greene, R W; Haas, H L

    1985-09-01

    Intracellular recordings with a bridge amplifier of CA1 pyramidal neurones in vitro were employed to study the mechanisms of action of exogenously applied adenosine in the hippocampal slice preparation of the rat. Adenosine enhanced the calcium-dependent, long-duration after-hyperpolarization (a.h.p.) at least in part by a reduction in the rate of decay of the a.h.p. Both the reduced rate of decay and that of the control can be described with a single exponential. Antagonism of the calcium-dependent potassium current (and as a result, the a.h.p.) by bath application of CdCl2 or intracellular injection of EGTA (ethyleneglycolbis-(beta-aminoethyl ether)N,N'-tetraacetic acid) did not reduce the adenosine-evoked hyperpolarization or decrease in input resistance. Similarly, TEA (tetraethylammonium), which antagonizes both the voltage- and calcium-sensitive, delayed, outward rectification, had no effect on the adenosine-evoked changes in resting membrane properties. Adenosine did not affect the early, transient, outward rectification. During exposure to 4-aminopyridine (4-AP) in concentrations sufficient to antagonize this early rectification, the changes in resting membrane properties evoked by adenosine were unaffected. We conclude that the enhancement of the a.h.p. and accommodation by adenosine may be mediated by a change in the regulation of intracellular calcium. However, the mechanism responsible for the hyperpolarization and decrease in input resistance evoked by adenosine is both calcium and voltage insensitive. Thus, it appears distinct from that mediating the enhancement of the a.h.p. and accommodation.

  6. The establishment of GABAergic and glutamatergic synapses on CA1 pyramidal neurons is sequential and correlates with the development of the apical dendrite.

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    Tyzio, R; Represa, A; Jorquera, I; Ben-Ari, Y; Gozlan, H; Aniksztejn, L

    1999-12-01

    We have performed a morphofunctional analysis of CA1 pyramidal neurons at birth to examine the sequence of formation of GABAergic and glutamatergic postsynaptic currents (PSCs) and to determine their relation to the dendritic arborization of pyramidal neurons. We report that at birth pyramidal neurons are heterogeneous. Three stages of development can be identified: (1) the majority of the neurons (80%) have small somata, an anlage of apical dendrite, and neither spontaneous nor evoked PSCs; (2) 10% of the neurons have a small apical dendrite restricted to the stratum radiatum and PSCs mediated only by GABA(A) receptors; and (3) 10% of the neurons have an apical dendrite that reaches the stratum lacunosum moleculare and PSCs mediated both by GABA(A) and glutamate receptors. These three groups of pyramidal neurons can be differentiated by their capacitance (C(m) = 17.9 +/- 0.8; 30.2 +/- 1.6; 43.2 +/- 3.0 pF, respectively). At birth, the synaptic markers synapsin-1 and synaptophysin labeling are present in dendritic layers but not in the stratum pyramidale, suggesting that GABAergic peridendritic synapses are established before perisomatic ones. The present observations demonstrate that GABAergic and glutamatergic synapses are established sequentially with GABAergic synapses being established first most likely on the apical dendrites of the principal neurons. We propose that different sets of conditions are required for the establishment of functional GABA and glutamate synapses, the latter necessitating more developed neurons that have apical dendrites that reach the lacunosum moleculare region.

  7. Loss of sensory input increases the intrinsic excitability of layer 5 pyramidal neurons in rat barrel cortex.

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    Breton, Jean-Didier; Stuart, Greg J

    2009-11-01

    Development of the cortical map is experience dependent, with different critical periods in different cortical layers. Previous work in rodent barrel cortex indicates that sensory deprivation leads to changes in synaptic transmission and plasticity in layer 2/3 and 4. Here, we studied the impact of sensory deprivation on the intrinsic properties of layer 5 pyramidal neurons located in rat barrel cortex using simultaneous somatic and dendritic recording. Sensory deprivation was achieved by clipping all the whiskers on one side of the snout. Loss of sensory input did not change somatic active and resting membrane properties, and did not influence dendritic action potential (AP) backpropagation. In contrast, sensory deprivation led to an increase in the percentage of layer 5 pyramidal neurons showing burst firing. This was associated with a reduction in the threshold for generation of dendritic calcium spikes during high-frequency AP trains. Cell-attached recordings were used to assess changes in the properties and expression of dendritic HCN channels. These experiments indicated that sensory deprivation caused a decrease in HCN channel density in distal regions of the apical dendrite. To assess the contribution of HCN down-regulation on the observed increase in dendritic excitability following sensory deprivation, we investigated the impact of blocking HCN channels. Block of HCN channels removed differences in dendritic calcium electrogenesis between control and deprived neurons. In conclusion, these observations indicate that sensory loss leads to increased dendritic excitability of cortical layer 5 pyramidal neurons. Furthermore, they suggest that increased dendritic calcium electrogenesis following sensory deprivation is mediated in part via down-regulation of dendritic HCN channels.

  8. Neuronal Dystroglycan Is Necessary for Formation and Maintenance of Functional CCK-Positive Basket Cell Terminals on Pyramidal Cells.

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    Früh, Simon; Romanos, Jennifer; Panzanelli, Patrizia; Bürgisser, Daniela; Tyagarajan, Shiva K; Campbell, Kevin P; Santello, Mirko; Fritschy, Jean-Marc

    2016-10-05

    Distinct types of GABAergic interneurons target different subcellular domains of pyramidal cells, thereby shaping pyramidal cell activity patterns. Whether the presynaptic heterogeneity of GABAergic innervation is mirrored by specific postsynaptic factors is largely unexplored. Here we show that dystroglycan, a protein responsible for the majority of congenital muscular dystrophies when dysfunctional, has a function at postsynaptic sites restricted to a subset of GABAergic interneurons. Conditional deletion of Dag1, encoding dystroglycan, in pyramidal cells caused loss of CCK-positive basket cell terminals in hippocampus and neocortex. PV-positive basket cell terminals were unaffected in mutant mice, demonstrating interneuron subtype-specific function of dystroglycan. Loss of dystroglycan in pyramidal cells had little influence on clustering of other GABAergic postsynaptic proteins and of glutamatergic synaptic proteins. CCK-positive terminals were not established at P21 in the absence of dystroglycan and were markedly reduced when dystroglycan was ablated in adult mice, suggesting a role for dystroglycan in both formation and maintenance of CCK-positive terminals. The necessity of neuronal dystroglycan for functional innervation by CCK-positive basket cell axon terminals was confirmed by reduced frequency of inhibitory events in pyramidal cells of dystroglycan-deficient mice and further corroborated by the inefficiency of carbachol to increase IPSC frequency in these cells. Finally, neurexin binding seems dispensable for dystroglycan function because knock-in mice expressing binding-deficient T190M dystroglycan displayed normal CCK-positive terminals. Together, we describe a novel function of dystroglycan in interneuron subtype-specific trans-synaptic signaling, revealing correlation of presynaptic and postsynaptic molecular diversity.

  9. Dendritic Na(+) spikes enable cortical input to drive action potential output from hippocampal CA2 pyramidal neurons.

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    Sun, Qian; Srinivas, Kalyan V; Sotayo, Alaba; Siegelbaum, Steven A

    2014-01-01

    Synaptic inputs from different brain areas are often targeted to distinct regions of neuronal dendritic arbors. Inputs to proximal dendrites usually produce large somatic EPSPs that efficiently trigger action potential (AP) output, whereas inputs to distal dendrites are greatly attenuated and may largely modulate AP output. In contrast to most other cortical and hippocampal neurons, hippocampal CA2 pyramidal neurons show unusually strong excitation by their distal dendritic inputs from entorhinal cortex (EC). In this study, we demonstrate that the ability of these EC inputs to drive CA2 AP output requires the firing of local dendritic Na(+) spikes. Furthermore, we find that CA2 dendritic geometry contributes to the efficient coupling of dendritic Na(+) spikes to AP output. These results provide a striking example of how dendritic spikes enable direct cortical inputs to overcome unfavorable distal synaptic locale to trigger axonal AP output and thereby enable efficient cortico-hippocampal information flow.

  10. The rostral migratory stream generates hippocampal CA1 pyramidal-like neurons in a novel organotypic slice co-culture model

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    Ilyas Singec

    2015-10-01

    Full Text Available The mouse subventricular zone (SVZ generates large numbers of neuroblasts, which migrate in a distinct pathway, the rostral migratory stream (RMS, and replace specific interneurons in the olfactory bulb (OB. Here, we introduce an organotypic slice culture model that directly connects the RMS to the hippocampus as a new destination. RMS neuroblasts widely populate the hippocampus and undergo cellular differentiation. We demonstrate that RMS cells give rise to various neuronal subtypes and, surprisingly, to CA1 pyramidal neurons. Pyramidal neurons are typically generated before birth and are lost in various neurological disorders. Hence, this unique slice culture model enables us to investigate their postnatal genesis under defined in vitro conditions from the RMS, an unanticipated source for hippocampal pyramidal neurons.

  11. Kv2 channel regulation of action potential repolarization and firing patterns in superior cervical ganglion neurons and hippocampal CA1 pyramidal neurons.

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    Liu, Pin W; Bean, Bruce P

    2014-04-02

    Kv2 family "delayed-rectifier" potassium channels are widely expressed in mammalian neurons. Kv2 channels activate relatively slowly and their contribution to action potential repolarization under physiological conditions has been unclear. We explored the function of Kv2 channels using a Kv2-selective blocker, Guangxitoxin-1E (GxTX-1E). Using acutely isolated neurons, mixed voltage-clamp and current-clamp experiments were done at 37°C to study the physiological kinetics of channel gating and action potentials. In both rat superior cervical ganglion (SCG) neurons and mouse hippocampal CA1 pyramidal neurons, 100 nm GxTX-1E produced near-saturating block of a component of current typically constituting ∼60-80% of the total delayed-rectifier current. GxTX-1E also reduced A-type potassium current (IA), but much more weakly. In SCG neurons, 100 nm GxTX-1E broadened spikes and voltage clamp experiments using action potential waveforms showed that Kv2 channels carry ∼55% of the total outward current during action potential repolarization despite activating relatively late in the spike. In CA1 neurons, 100 nm GxTX-1E broadened spikes evoked from -70 mV, but not -80 mV, likely reflecting a greater role of Kv2 when other potassium channels were partially inactivated at -70 mV. In both CA1 and SCG neurons, inhibition of Kv2 channels produced dramatic depolarization of interspike voltages during repetitive firing. In CA1 neurons and some SCG neurons, this was associated with increased initial firing frequency. In all neurons, inhibition of Kv2 channels depressed maintained firing because neurons entered depolarization block more readily. Therefore, Kv2 channels can either decrease or increase neuronal excitability depending on the time scale of excitation.

  12. Prolonged enhancement and depression of synaptic transmission in CA1 pyramidal neurons induced by transient forebrain ischemia in vivo.

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    Gao, T M; Pulsinelli, W A; Xu, Z C

    1998-11-01

    Evoked postsynaptic potentials of CA1 pyramidal neurons in rat hippocampus were studied during 48 h after severe ischemic insult using in vivo intracellular recording and staining techniques. Postischemic CA1 neurons displayed one of three distinct response patterns following contralateral commissural stimulation. At early recirculation times (0-12 h) approximately 50% of neurons exhibited, in addition to the initial excitatory postsynaptic potential, a late depolarizing postsynaptic potential lasting for more than 100 ms. Application of dizocilpine maleate reduced the amplitude of late depolarizing postsynaptic potential by 60%. Other CA1 neurons recorded in this interval failed to develop late depolarizing postsynaptic potentials but showed a modest blunting of initial excitatory postsynaptic potentials (non-late depolarizing postsynaptic potential neuron). The proportion of recorded neurons with late depolarizing postsynaptic potential characteristics increased to more than 70% during 13-24 h after reperfusion. Beyond 24 h reperfusion, approximately 20% of CA neurons exhibited very small excitatory postsynaptic potentials even with maximal stimulus intensity. The slope of the initial excitatory postsynaptic potentials in late depolarizing postsynaptic potential neurons increased to approximately 150% of control values up to 12 h after reperfusion indicating a prolonged enhancement of synaptic transmission. In contrast, the slope of the initial excitatory postsynaptic potentials in non-late depolarizing postsynaptic potential neurons decreased to less than 50% of preischemic values up to 24 h after reperfusion indicating a prolonged depression of synaptic transmission. More late depolarizing postsynaptic potential neurons were located in the medial portion of CA1 zone where neurons are more vulnerable to ischemia whereas more non-late depolarizing postsynaptic potential neurons were located in the lateral portion of CA1 zone where neurons are more resistant to

  13. Layer- and column-specific knockout of NMDA receptors in pyramidal neurons of the mouse barrel cortex.

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    Rachel Aronoff

    2007-11-01

    Full Text Available Viral vectors injected into the mouse brain offer the possibility for localized genetic modifications in a highly controlled manner. Lentivector injection into mouse neocortex transduces cells within a diameter of approximately 200µm, which closely matches the lateral scale of a column in barrel cortex. The depth and volume of the injection determines which cortical layer is transduced. Furthermore, transduced gene expression from the lentivector can be limited to predominantly pyramidal neurons by using a 1.3kb fragment of the αCaMKII promoter. This technique therefore allows genetic manipulation of a specific cell type in defined columns and layers of the neocortex. By expressing Cre recombinase from such a lentivector in gene-targeted mice carrying a floxed gene, highly specific genetic lesions can be induced. Here, we demonstrate the utility of this approach by specifically knocking out NMDA receptors (NMDARs in pyramidal neurons in the somatosensory barrel cortex of gene-targeted mice carrying floxed NMDAR 1 genes. Neurons transduced with lentivector encoding GFP and Cre recombinase exhibit not only reductions in NMDAR 1 mRNA levels, but reduced NMDAR-dependent currents and pairing-induced synaptic potentiation. This technique for knockout of NMDARs in a cell type, column- and layer-specific manner in the mouse somatosensory cortex may help further our understanding of the functional roles of NMDARs in vivo during sensory perception and learning.

  14. The protective role of ascorbic acid on hippocampal CA1 pyramidal neurons in a rat model of maternal lead exposure.

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    Sepehri, Hamid; Ganji, Farzaneh

    2016-07-01

    Oxidative stress is a major pathogenic mechanism of lead neurotoxicity. The antioxidant ascorbic acid protects hippocampal pyramidal neurons against cell death during congenital lead exposure; however, critical functions like synaptic transmission, integration, and plasticity depend on preservation of dendritic and somal morphology. This study was designed to examine if ascorbic acid also protects neuronal morphology during developmental lead exposure. Timed pregnant rats were divided into four treatment groups: (1) control, (2) 100mg/kg ascorbic acid once a day via gavage, (3) 0.05% lead acetate in drinking water, and (4) 0.05% lead+100mg/kg oral ascorbic acid. Brains of eight male pups (P25) per treatment group were processed for Golgi staining. Changes in hippocampal CA1 pyramidal neurons' somal size were estimated by cross-sectional area and changes in dendritic arborization by Sholl's analysis. One-way ANOVA was used to compare results among treatment groups. Lead-exposed pups exhibited a significant decrease in somal size compared to controls (Pascorbic acid. Sholl's analysis revealed a significant increase in apical dendritic branch points near cell body (PAscorbic acid significantly but only partially reversed the somal and dendritic damage caused by developmental lead exposure. Oxidative stress thus contributes to lead neurotoxicity but other pathogenic mechanisms are also involved.

  15. Activation of CRH receptor type 1 expressed on glutamatergic neurons increases excitability of CA1 pyramidal neurons by the modulation of voltage-gated ion channels

    Directory of Open Access Journals (Sweden)

    Stephan eKratzer

    2013-07-01

    Full Text Available Corticotropin-releasing hormone (CRH plays an important role in a substantial number of patients with stress-related mental disorders, such as anxiety disorders and depression. CRH has been shown to increase neuronal excitability in the hippocampus, but the underlying mechanisms are poorly understood. The effects of CRH on neuronal excitability were investigated in acute hippocampal brain slices. Population spikes (PS and field excitatory postsynaptic potentials (fEPSP were evoked by stimulating Schaffer-collaterals and recorded simultaneously from the somatic and dendritic region of CA1 pyramidal neurons. CRH was found to increase PS amplitudes (mean  Standard error of the mean; 231.8  31.2% of control; n=10 while neither affecting fEPSPs (104.3 ± 4.2%; n=10 nor long-term potentiation (LTP. However, when Schaffer-collaterals were excited via action potentials (APs generated by stimulation of CA3 pyramidal neurons, CRH increased fEPSP amplitudes (119.8 ± 3.6%; n=8 and the magnitude of LTP in the CA1 region. Experiments in slices from transgenic mice revealed that the effect on PS amplitude is mediated exclusively by CRH receptor 1 (CRHR1 expressed on glutamatergic neurons. The effects of CRH on PS were dependent on phosphatase-2B, L- and T-type calcium channels and voltage-gated potassium channels but independent on intracellular Ca2+-elevation. In patch-clamp experiments, CRH increased the frequency and decay times of APs and decreased currents through A-type and delayed-rectifier potassium channels. These results suggest that CRH does not affect synaptic transmission per se, but modulates voltage-gated ion currents important for the generation of APs and hence elevates by this route overall neuronal activity.

  16. Responses of CA1 pyramidal neurons in rat hippocampus to transient forebrain ischemia: an in vivo intracellular recording study.

    Science.gov (United States)

    Xu, Z C; Pulsinelli, W A

    1994-04-25

    The electrophysiological responses of CA1 pyramidal neurons to 5 min forebrain ischemia were studied with intracellular recording and staining techniques in vivo. The baseline membrane potential rapidly depolarized to approximately -20 mV about 3 min after the onset of ischemia and began to repolarize 1-3 min after recirculation. The amplitude of this ischemic depolarization (ID) was related directly to the severity of ischemia and its latency of onset was inversely related to brain temperature. Spontaneous synaptic activity ceased shortly after ischemia onset while the evoke synaptic potentials lasted until shortly before the onset of ID. Inhibitory postsynaptic potentials (IPSPs) disappeared earlier than excitatory postsynaptic potentials (EPSPs) and the membrane input resistance of CA1 neurons increased after the onset of ischemia.

  17. Age- and location-dependent differences in store depletion-induced h-channel plasticity in hippocampal pyramidal neurons.

    Science.gov (United States)

    Clemens, Ann M; Johnston, Daniel

    2014-03-01

    Disruptions of endoplasmic reticulum (ER) Ca(2+) homeostasis are heavily linked to neuronal pathology. Depletion of ER Ca(2+) stores can result in cellular dysfunction and potentially cell death, although adaptive processes exist to aid in survival. We examined the age and region dependence of one postulated, adaptive response to ER store-depletion (SD), hyperpolarization-activated cation-nonspecific (h)-channel plasticity in neurons of the dorsal and ventral hippocampus (DHC and VHC, respectively) from adolescent and adult rats. With the use of whole-cell patch-clamp recordings from the soma and dendrites of CA1 pyramidal neurons, we observed a change in h-sensitive measurements in response to SD, induced by treatment with cyclopiazonic acid, a sarcoplasmic reticulum/ER Ca(2+)-ATPase blocker. We found that whereas DHC and VHC neurons in adolescent animals respond to SD with a perisomatic expression of SD h plasticity, adult animals express SD h plasticity with a dendritic and somatodendritic locus of plasticity in DHC and VHC neurons, respectively. Furthermore, SD h plasticity in adults was dependent on membrane potential and on the activation of L-type voltage-gated Ca(2+) channels. These results suggest that cellular responses to the impairment of ER function, or ER stress, are dependent on brain region and age and that the differential expression of SD h plasticity could provide a neural basis for region- and age-dependent disease vulnerabilities.

  18. Occurrence of complement protein C3 in dying pyramidal neurons in rat hippocampus after systemic administration of kainic acid.

    Science.gov (United States)

    Morita, Hiroyuki; Suzuki, Katsuaki; Mori, Norio; Yasuhara, Osamu

    2006-11-27

    To evaluate the roles of complement in kainic acid (KA)-induced neuronal damages, the immunohistochemical localization of the complement protein C3 was examined in rat hippocampus after systemic KA injection. The immunoreactivity for C3 was found in glial cells in control rats, and such glial cells were increased in number after KA injection. Our confocal study showed that C3-positive glial cells were microglia. Three to seven days after KA, C3 immunoreactivity appeared in CA1 and CA3 pyramidal neurons. Double staining for C3 combined with the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling showed that occurrence of C3 immunoreactivity in neurons coincided well with that of DNA fragmentation. Western blot analysis and RT-PCR experiments suggested local synthesis of C3 by brain cells. Our results suggest that C3 contributes greatly to neuronal death after systemic KA administration, and that microglia and neurons are the local source of C3 in KA-induced brain injury.

  19. Three-dimensional Quantification of Dendritic Spines from Pyramidal Neurons Derived from Human Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Gouder, Laura; Tinevez, Jean-Yves; Goubran-Botros, Hany; Benchoua, Alexandra; Bourgeron, Thomas; Cloëz-Tayarani, Isabelle

    2015-10-10

    Dendritic spines are small protrusions that correspond to the post-synaptic compartments of excitatory synapses in the central nervous system. They are distributed along the dendrites. Their morphology is largely dependent on neuronal activity, and they are dynamic. Dendritic spines express glutamatergic receptors (AMPA and NMDA receptors) on their surface and at the levels of postsynaptic densities. Each spine allows the neuron to control its state and local activity independently. Spine morphologies have been extensively studied in glutamatergic pyramidal cells of the brain cortex, using both in vivo approaches and neuronal cultures obtained from rodent tissues. Neuropathological conditions can be associated to altered spine induction and maturation, as shown in rodent cultured neurons and one-dimensional quantitative analysis (1). The present study describes a protocol for the 3D quantitative analysis of spine morphologies using human cortical neurons derived from neural stem cells (late cortical progenitors). These cells were initially obtained from induced pluripotent stem cells. This protocol allows the analysis of spine morphologies at different culture periods, and with possible comparison between induced pluripotent stem cells obtained from control individuals with those obtained from patients with psychiatric diseases.

  20. Downregulation of transient K+ channels in dendrites of hippocampal CA1 pyramidal neurons by activation of PKA and PKC.

    Science.gov (United States)

    Hoffman, D A; Johnston, D

    1998-05-15

    We have reported recently a high density of transient A-type K+ channels located in the distal dendrites of CA1 hippocampal pyramidal neurons and shown that these channels shape EPSPs, limit the back-propagation of action potentials, and prevent dendritic action potential initiation (). Because of the importance of these channels in dendritic signal propagation, their modulation by protein kinases would be of significant interest. We investigated the effects of activators of cAMP-dependent protein kinase (PKA) and the Ca2+-dependent phospholipid-sensitive protein kinase (PKC) on K+ channels in cell-attached patches from the distal dendrites of hippocampal CA1 pyramidal neurons. Inclusion of the membrane-permeant PKA activators 8-bromo-cAMP (8-br-cAMP) or forskolin in the dendritic patch pipette resulted in a depolarizing shift in the activation curve for the transient channels of approximately 15 mV. Activation of PKC by either of two phorbol esters also resulted in a 15 mV depolarizing shift of the activation curve. Neither PKA nor PKC activation affected the sustained or slowly inactivating component of the total outward current. This downregulation of transient K+ channels in the distal dendrites may be responsible for some of the frequently reported increases in cell excitability found after PKA and PKC activation. In support of this hypothesis, we found that activation of either PKA or PKC significantly increased the amplitude of back-propagating action potentials in distal dendrites.

  1. Hyperforin modulates dendritic spine morphology in hippocampal pyramidal neurons by activating Ca(2+) -permeable TRPC6 channels.

    Science.gov (United States)

    Leuner, Kristina; Li, Wei; Amaral, Michelle D; Rudolph, Stephanie; Calfa, Gaston; Schuwald, Anita M; Harteneck, Christian; Inoue, Takafumi; Pozzo-Miller, Lucas

    2013-01-01

    The standardized extract of the St. John's wort plant (Hypericum perforatum) is commonly used to treat mild to moderate depression. Its active constituent is hyperforin, a phloroglucinol derivative that reduces the reuptake of serotonin and norepinephrine by increasing intracellular Na(+) concentration through the activation of nonselective cationic TRPC6 channels. TRPC6 channels are also Ca(2+) -permeable, resulting in intracellular Ca(2+) elevations. Indeed, hyperforin activates TRPC6-mediated currents and Ca(2+) transients in rat PC12 cells, which induce their differentiation, mimicking the neurotrophic effect of nerve growth factor. Here, we show that hyperforin modulates dendritic spine morphology in CA1 and CA3 pyramidal neurons of hippocampal slice cultures through the activation of TRPC6 channels. Hyperforin also evoked intracellular Ca(2+) transients and depolarizing inward currents sensitive to the TRPC channel blocker La(3+) , thus resembling the actions of the neurotrophin brain-derived neurotrophic factor (BDNF) in hippocampal pyramidal neurons. These results suggest that the antidepressant actions of St. John's wort are mediated by a mechanism similar to that engaged by BDNF.

  2. β-Adrenergic receptor agonist increases voltage-gated Na(+) currents in medial prefrontal cortex pyramidal neurons.

    Science.gov (United States)

    Szulczyk, Bartlomiej

    2015-05-19

    The prefrontal cortex does not function properly in neuropsychiatric diseases and during chronic stress. The aim of this study was to test the effects of isoproterenol, a β-adrenergic receptor agonist, on the voltage-dependent fast-inactivating Na(+) currents in medial prefrontal cortex (mPFC) pyramidal neurons obtained from young rats. The recordings were performed in the cell-attached configuration. Isoproterenol (2μM) did not change the peak Na(+) current amplitude but shifted the IV curve of the Na(+) currents toward hyperpolarization. Pretreatment of the cells with the β-adrenergic antagonists propranolol and metoprolol abolished the effect of isoproterenol on the Na(+) currents, suggesting the involvement of β1-adrenergic receptors. The effect of β-adrenergic receptor stimulation on the sodium currents was dependent on kinase A and kinase C; the effect was diminished in the presence of the kinase A antagonist H-89 and the kinase C antagonist chelerythrine and abolished when the antagonists were coapplied. Moreover, isoproterenol depolarized the membrane potential recorded using the perforated-patch method, and this depolarization was abolished by cesium ions. Thus, in mPFC pyramidal neurons, stimulation of β-adrenergic receptors up-regulates the fast-inactivating voltage-gated Na(+) currents evoked by suprathreshold depolarizations.

  3. Delayed effects of corticosterone on slow after-hyperpolarization potentials in mouse hippocampal versus prefrontal cortical pyramidal neurons.

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    Anup G Pillai

    Full Text Available The rodent stress hormone corticosterone changes neuronal activity in a slow and persistent manner through transcriptional regulation. In the rat dorsal hippocampus, corticosterone enhances the amplitude of calcium-dependent potassium currents that cause a lingering slow after-hyperpolarization (sAHP at the end of depolarizing events. In this study we compared the putative region-dependency of the delayed effects of corticosterone (approximately 5 hrs after treatment on sAHP as well as other active and passive properties of layer 2/3 pyramidal neurons from three prefrontal areas, i.e. the lateral orbitofrontal, prelimbic and infralimbic cortex, with the hippocampus of adult mice. In agreement with previous studies, corticosterone increased sAHP amplitude in the dorsal hippocampus with depolarizing steps of increasing amplitude. However, in the lateral orbitofrontal, prelimbic and infralimbic cortices we did not observe any modifications of sAHP amplitude after corticosterone treatment. Properties of single action potentials or % ratio of the last spike interval with respect to the first spike interval, an indicator of accommodation in an action potential train, were not significantly affected by corticosterone in all brain regions examined. Lastly, corticosterone treatment did not induce any lasting changes in passive membrane properties of hippocampal or cortical neurons. Overall, the data indicate that corticosterone slowly and very persistently increases the sAHP amplitude in hippocampal pyramidal neurons, while this is not the case in the cortical regions examined. This implies that changes in excitability across brain regions reached by corticosterone may vary over a prolonged period of time after stress.

  4. Increased Synaptic Excitation and Abnormal Dendritic Structure of Prefrontal Cortex Layer V Pyramidal Neurons following Prolonged Binge-Like Consumption of Ethanol

    Science.gov (United States)

    Klenowski, Paul M.; Fogarty, Matthew J.; Shariff, Masroor; Belmer, Arnauld

    2016-01-01

    Abstract Long-term alcohol use causes a multitude of neurochemical changes in cortical regions that facilitate the transition to dependence. Therefore, we used a model of long-term, binge-like ethanol consumption in rats to determine the effects on morphology and synaptic physiology of medial prefrontal cortex (mPFC) layer V pyramidal neurons. Following 10 weeks of ethanol consumption, we recorded synaptic currents from mPFC neurons and used neurobiotin filling to analyze their morphology. We then compared these data to measurements obtained from age-matched, water-drinking control rats. We found that long-term ethanol consumption caused a significant increase in total dendrite arbor length of mPFC layer V pyramidal neurons. Dendritic restructuring was primarily observed in basal dendrite arbors, with mPFC neurons from animals engaged in long-term ethanol drinking having significantly larger and more complex basal arbors compared with controls. These changes were accompanied by significantly increased total spine densities and spontaneous postsynaptic excitatory current frequency, suggesting that long-term binge-like ethanol consumption enhances basal excitatory synaptic transmission in mPFC layer V pyramidal neurons. Our results provide insights into the morphological and functional changes in mPFC layer V pyramidal neuronal physiology following prolonged exposure to ethanol and support changes in mPFC activity during the development of alcohol dependence. PMID:28032119

  5. The anterior cingulate cortex

    Directory of Open Access Journals (Sweden)

    Pavlović D.M.

    2009-01-01

    Full Text Available The anterior cingulate cortex (ACC has a role in attention, analysis of sensory information, error recognition, problem solving, detection of novelty, behavior, emotions, social relations, cognitive control, and regulation of visceral functions. This area is active whenever the individual feels some emotions, solves a problem, or analyzes the pros and cons of an action (if it is a right decision. Analogous areas are also found in higher mammals, especially whales, and they contain spindle neurons that enable complex social interactions. Disturbance of ACC activity is found in dementias, schizophrenia, depression, the obsessive-compulsive syndrome, and other neuropsychiatric diseases.

  6. How cesium dialysis affects the passive properties of pyramidal neurons: implications for voltage clamp studies of persistent sodium current

    Energy Technology Data Exchange (ETDEWEB)

    Fleidervish, Ilya A; Libman, Lior [Koret School of Veterinary Medicine, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100 (Israel)], E-mail: fleider@agri.huji.ac.il

    2008-03-15

    In order to accurately understand and model neuronal integration in the brain, we must know the biophysical properties of channels that are located far from the soma, in the axonal and dendritic membranes of central nerve cells. Reliable electrophysiological measurements in these regions are difficult to obtain, because the processes are too tiny to directly study with an electrode. One common strategy is to record with a somatic electrode that contains Cs{sup +}, to dialyze the intracellular space with this K{sup +} channel blocker, and thereby to render the neuron electrotonically compact. Does this work? Here, we combine the experimental and modeling techniques to determine the extent to which a whole-cell voltage clamp, established with a Cs{sup +}-containing pipette in the soma of a cortical pyramidal cell, attains adequate voltage control of distal neuronal processes. We focus on the low-voltage-activated, slowly inactivating 'persistent' Na{sup +} current (I{sub NaP}), that plays a crucial role in determining neuronal excitability and synaptic integration.

  7. How cesium dialysis affects the passive properties of pyramidal neurons: implications for voltage clamp studies of persistent sodium current

    Science.gov (United States)

    Fleidervish, Ilya A.; Libman, Lior

    2008-03-01

    In order to accurately understand and model neuronal integration in the brain, we must know the biophysical properties of channels that are located far from the soma, in the axonal and dendritic membranes of central nerve cells. Reliable electrophysiological measurements in these regions are difficult to obtain, because the processes are too tiny to directly study with an electrode. One common strategy is to record with a somatic electrode that contains Cs+, to dialyze the intracellular space with this K+ channel blocker, and thereby to render the neuron electrotonically compact. Does this work? Here, we combine the experimental and modeling techniques to determine the extent to which a whole-cell voltage clamp, established with a Cs+-containing pipette in the soma of a cortical pyramidal cell, attains adequate voltage control of distal neuronal processes. We focus on the low-voltage-activated, slowly inactivating 'persistent' Na+ current (INaP), that plays a crucial role in determining neuronal excitability and synaptic integration.

  8. Automated evolutionary optimization of ion channel conductances and kinetics in models of young and aged rhesus monkey pyramidal neurons.

    Science.gov (United States)

    Rumbell, Timothy H; Draguljić, Danel; Yadav, Aniruddha; Hof, Patrick R; Luebke, Jennifer I; Weaver, Christina M

    2016-08-01

    Conductance-based compartment modeling requires tuning of many parameters to fit the neuron model to target electrophysiological data. Automated parameter optimization via evolutionary algorithms (EAs) is a common approach to accomplish this task, using error functions to quantify differences between model and target. We present a three-stage EA optimization protocol for tuning ion channel conductances and kinetics in a generic neuron model with minimal manual intervention. We use the technique of Latin hypercube sampling in a new way, to choose weights for error functions automatically so that each function influences the parameter search to a similar degree. This protocol requires no specialized physiological data collection and is applicable to commonly-collected current clamp data and either single- or multi-objective optimization. We applied the protocol to two representative pyramidal neurons from layer 3 of the prefrontal cortex of rhesus monkeys, in which action potential firing rates are significantly higher in aged compared to young animals. Using an idealized dendritic topology and models with either 4 or 8 ion channels (10 or 23 free parameters respectively), we produced populations of parameter combinations fitting the target datasets in less than 80 hours of optimization each. Passive parameter differences between young and aged models were consistent with our prior results using simpler models and hand tuning. We analyzed parameter values among fits to a single neuron to facilitate refinement of the underlying model, and across fits to multiple neurons to show how our protocol will lead to predictions of parameter differences with aging in these neurons.

  9. Dynamic FoxG1 expression coordinates the integration of multipolar pyramidal neuron precursors into the cortical plate.

    Science.gov (United States)

    Miyoshi, Goichi; Fishell, Gord

    2012-06-21

    Pyramidal cells of the cerebral cortex are born in the ventricular zone and migrate through the intermediate zone to enter into the cortical plate. In the intermediate zone, these migrating precursors move tangentially and initiate the extension of their axons by transiently adopting a characteristic multipolar morphology. We observe that expression of the forkhead transcription factor FoxG1 is dynamically regulated during this transitional period. By utilizing conditional genetic strategies, we show that the downregulation of FoxG1 at the beginning of the multipolar cell phase induces Unc5D expression, the timing of which ultimately determines the laminar identity of pyramidal neurons. In addition, we demonstrate that the re-expression of FoxG1 is required for cells to transit out of the multipolar cell phase and to enter into the cortical plate. Thus, the dynamic expression of FoxG1 during migration within the intermediate zone is essential for the proper assembly of the cerebral cortex.

  10. Loss of Functional A-Type Potassium Channels in the Dendrites of CA1 Pyramidal Neurons from a Mouse Model of Fragile X Syndrome

    OpenAIRE

    Routh, Brandy N.; Johnston, Daniel; Brager, Darrin H.

    2013-01-01

    Despite the critical importance of voltage-gated ion channels in neurons, very little is known about their functional properties in Fragile X syndrome: the most common form of inherited cognitive impairment. Using three complementary approaches, we investigated the physiological role of A-type K+ currents (IKA) in hippocampal CA1 pyramidal neurons from fmr1-/y mice. Direct measurement of IKA using cell-attached patch-clamp recordings revealed that there was significantly less IKA in the dendr...

  11. Activity-Dependent Release of Endogenous BDNF From Mossy Fibers Evokes a TRPC3 Current and Ca2+ Elevations in CA3 Pyramidal Neurons

    OpenAIRE

    Yong LI; Calfa, Gaston; Inoue, Takafumi; Amaral, Michelle D.; Pozzo-Miller, Lucas

    2010-01-01

    Multiple studies have demonstrated that brain-derived neurotrophic factor (BDNF) is a potent modulator of neuronal structure and function in the hippocampus. However, the majority of studies to date have relied on the application of recombinant BDNF. We herein report that endogenous BDNF, released via theta burst stimulation of mossy fibers (MF), elicits a slowly developing cationic current and intracellular Ca2+ elevations in CA3 pyramidal neurons with the same pharmacological profile of the...

  12. Selective shunting of the NMDA EPSP component by the slow afterhyperpolarization in rat CA1 pyramidal neurons.

    Science.gov (United States)

    Fernández de Sevilla, David; Fuenzalida, Marco; Porto Pazos, Ana B; Buño, Washington

    2007-05-01

    Pyramidal neuron dendrites express voltage-gated conductances that control synaptic integration and plasticity, but the contribution of the Ca(2+)-activated K(+)-mediated currents to dendritic function is not well understood. Using dendritic and somatic recordings in rat hippocampal CA1 pyramidal neurons in vitro, we analyzed the changes induced by the slow Ca(2+)-activated K(+)-mediated afterhyperpolarization (sAHP) generated by bursts of action potentials on excitatory postsynaptic potentials (EPSPs) evoked at the apical dendrites by perforant path-Schaffer collateral stimulation. Both the amplitude and decay time constants of EPSPs (tau(EPSP)) were reduced by the sAHP in somatic recordings. In contrast, the dendritic EPSP amplitude remained unchanged, whereas tau(EPSP) was reduced. Temporal summation was reduced and spatial summation linearized by the sAHP. The amplitude of the isolated N-methyl-D-aspartate component of EPSPs (EPSP(NMDA)) was reduced, whereas tau(NMDA) was unaffected by the sAHP. In contrast, the sAHP did not modify the amplitude of the isolated EPSP(AMPA) but reduced tau(AMPA) both in dendritic and somatic recordings. These changes are attributable to a conductance increase that acted mainly via a selective "shunt" of EPSP(NMDA) because they were absent under voltage clamp, not present with imposed hyperpolarization simulating the sAHP, missing when the sAHP was inhibited with isoproterenol, and reduced under block of EPSP(NMDA). EPSPs generated at the basal dendrites were similarly modified by the sAHP, suggesting both a somatic and apical dendritic location of the sAHP channels. Therefore the sAHP may play a decisive role in the dendrites by regulating synaptic efficacy and temporal and spatial summation.

  13. Calcium-activated potassium conductances contribute to action potential repolarization at the soma but not the dendrites of hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Poolos, N P; Johnston, D

    1999-07-01

    Evidence is accumulating that voltage-gated channels are distributed nonuniformly throughout neurons and that this nonuniformity underlies regional differences in excitability within the single neuron. Previous reports have shown that Ca2+, Na+, A-type K+, and hyperpolarization-activated, mixed cation conductances have varying distributions in hippocampal CA1 pyramidal neurons, with significantly different densities in the apical dendrites compared with the soma. Another important channel mediates the large-conductance Ca2+-activated K+ current (IC), which is responsible in part for repolarization of the action potential (AP) and generation of the afterhyperpolarization that follows the AP recorded at the soma. We have investigated whether this current is activated by APs retrogradely propagating in the dendrites of hippocampal pyramidal neurons using whole-cell dendritic patch-clamp recording techniques. We found no IC activation by back-propagating APs in distal dendritic recordings. Dendritic APs activated IC only in the proximal dendrites, and this activation decayed within the first 100-150 micrometer of distance from the soma. The decay of IC in the proximal dendrites occurred despite AP amplitude, plus presumably AP-induced Ca2+ influx, that was comparable with that at the soma. Thus we conclude that IC activation by action potentials is nonuniform in the hippocampal pyramidal neuron, which may represent a further example of regional differences in neuronal excitability that are determined by the nonuniform distribution of voltage-gated channels in dendrites.

  14. Activation of pyramidal neurons in mouse medial prefrontal cortex enhances food seeking behavior while reducing impulsivity in the absence of an effect on food intake

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    Daniel McAllister Warthen

    2016-03-01

    Full Text Available The medial prefrontal cortex (mPFC is involved in a wide range of executive cognitive functions, including reward evaluation, decision-making, memory extinction, mood, and task switching. Manipulation of the mPFC has been shown to alter food intake and food reward valuation, but whether exclusive stimulation of mPFC pyramidal neurons, which form the principle output of the mPFC, is sufficient to mediate food rewarded instrumental behavior is unknown. We sought to determine the behavioral consequences of manipulating mPFC output by exciting pyramidal neurons in mouse mPFC during performance of a panel of behavioral assays, focusing on food reward. We found that increasing mPFC pyramidal cell output using Designer Receptors Exclusively Activated by Designer Drugs (DREADD enhanced performance in instrumental food reward assays that assess food seeking behavior, while sparing effects in affect and food intake. Specifically, activation of mPFC pyramidal neurons enhanced operant responding for food reward, reinstatement of palatable food seeking, and suppression of impulsive responding for food reward. Conversely, activation of mPFC pyramidal neurons had no effect on unconditioned food intake, social interaction, or behavior in an open field. Furthermore, we found that behavioral outcome is influenced by the degree of mPFC activation, with a low drive sufficient to enhance operant responding and a higher drive required to alter impulsivity. Additionally, we provide data demonstrating that DREADD stimulation involves a nitric oxide synthase dependent pathway, similar to endogenous muscarinic M3 receptor stimulation, a finding that provides novel mechanistic insight into an increasingly widespread method of remote neuronal control.

  15. Immediate Effects of Repetitive Magnetic Stimulation on Single Cortical Pyramidal Neurons

    Science.gov (United States)

    Banerjee, Jineta; Sorrell, Mary E.; Celnik, Pablo A.; Pelled, Galit

    2017-01-01

    Repetitive Transcranial Magnetic Stimulation (rTMS) has been successfully used as a non-invasive therapeutic intervention for several neurological disorders in the clinic as well as an investigative tool for basic neuroscience. rTMS has been shown to induce long-term changes in neuronal circuits in vivo. Such long-term effects of rTMS have been investigated using behavioral, imaging, electrophysiological, and molecular approaches, but there is limited understanding of the immediate effects of TMS on neurons. We investigated the immediate effects of high frequency (20 Hz) rTMS on the activity of cortical neurons in an effort to understand the underlying cellular mechanisms activated by rTMS. We used whole-cell patch-clamp recordings in acute rat brain slices and calcium imaging of cultured primary neurons to examine changes in neuronal activity and intracellular calcium respectively. Our results indicate that each TMS pulse caused an immediate and transient activation of voltage gated sodium channels (9.6 ± 1.8 nA at -45 mV, p value rTMS stimulation induced action potentials in a subpopulation of neurons, and significantly increased the steady state current of the neurons at near threshold voltages (at -45 mV: before TMS: I = 130 ± 17 pA, during TMS: I = 215 ± 23 pA, p value = 0.001). rTMS stimulation also led to a delayed increase in intracellular calcium (153.88 ± 61.94% increase from baseline). These results show that rTMS has an immediate and cumulative effect on neuronal activity and intracellular calcium levels, and suggest that rTMS may enhance neuronal responses when combined with an additional motor, sensory or cognitive stimulus. Thus, these results could be translated to optimize rTMS protocols for clinical as well as basic science applications. PMID:28114421

  16. The role of extracellular conductivity profiles in compartmental models for neurons: particulars for layer 5 pyramidal cells.

    Science.gov (United States)

    Wang, Kai; Riera, Jorge; Enjieu-Kadji, Herve; Kawashima, Ryuta

    2013-07-01

    With the rapid increase in the number of technologies aimed at observing electric activity inside the brain, scientists have felt the urge to create proper links between intracellular- and extracellular-based experimental approaches. Biophysical models at both physical scales have been formalized under assumptions that impede the creation of such links. In this work, we address this issue by proposing a multicompartment model that allows the introduction of complex extracellular and intracellular resistivity profiles. This model accounts for the geometrical and electrotonic properties of any type of neuron through the combination of four devices: the integrator, the propagator, the 3D connector, and the collector. In particular, we applied this framework to model the tufted pyramidal cells of layer 5 (PCL5) in the neocortex. Our model was able to reproduce the decay and delay curves of backpropagating action potentials (APs) in this type of cell with better agreement with experimental data. We used the voltage drops of the extracellular resistances at each compartment to approximate the local field potentials generated by a PCL5 located in close proximity to linear microelectrode arrays. Based on the voltage drops produced by backpropagating APs, we were able to estimate the current multipolar moments generated by a PCL5. By adding external current sources in parallel to the extracellular resistances, we were able to create a sensitivity profile of PCL5 to electric current injections from nearby microelectrodes. In our model for PCL5, the kinetics and spatial profile of each ionic current were determined based on a literature survey, and the geometrical properties of these cells were evaluated experimentally. We concluded that the inclusion of the extracellular space in the compartmental models of neurons as an extra electrotonic medium is crucial for the accurate simulation of both the propagation of the electric potentials along the neuronal dendrites and the

  17. Loss of functional A-type potassium channels in the dendrites of CA1 pyramidal neurons from a mouse model of fragile X syndrome.

    Science.gov (United States)

    Routh, Brandy N; Johnston, Daniel; Brager, Darrin H

    2013-12-11

    Despite the critical importance of voltage-gated ion channels in neurons, very little is known about their functional properties in Fragile X syndrome: the most common form of inherited cognitive impairment. Using three complementary approaches, we investigated the physiological role of A-type K(+) currents (I(KA)) in hippocampal CA1 pyramidal neurons from fmr1-/y mice. Direct measurement of I(KA) using cell-attached patch-clamp recordings revealed that there was significantly less I(KA) in the dendrites of CA1 neurons from fmr1-/y mice. Interestingly, the midpoint of activation for A-type K(+) channels was hyperpolarized for fmr1-/y neurons compared with wild-type, which might partially compensate for the lower current density. Because of the rapid time course for recovery from steady-state inactivation, the dendritic A-type K(+) current in CA1 neurons from both wild-type and fmr1-/y mice is likely mediated by K(V)4 containing channels. The net effect of the differences in I(KA) was that back-propagating action potentials had larger amplitudes producing greater calcium influx in the distal dendrites of fmr1-/y neurons. Furthermore, CA1 pyramidal neurons from fmr1-/y mice had a lower threshold for LTP induction. These data suggest that loss of I(KA) in hippocampal neurons may contribute to dendritic pathophysiology in Fragile X syndrome.

  18. Axonal action-potential initiation and Na+ channel densities in the soma and axon initial segment of subicular pyramidal neurons.

    Science.gov (United States)

    Colbert, C M; Johnston, D

    1996-11-01

    A long-standing hypothesis is that action potentials initiate first in the axon hillock/initial segment (AH-IS) region because of a locally high density of Na+ channels. We tested this idea in subicular pyramidal neurons by using patch-clamp recordings in hippocampal slices. Simultaneous recordings from the soma and IS confirmed that orthodromic action potentials initiated in the axon and then invaded the soma. However, blocking Na+ channels in the AH-IS with locally applied tetrodotoxin (TTX) did not raise the somatic threshold membrane potential for orthodromic spikes. TTX applied to the axon beyond the AH-IS (30-60 microm from the soma) raised the apparent somatic threshold by approximately 8 mV. We estimated the Na+ current density in the AH-IS and somatic membranes by using cell-attached patch-clamp recordings and found similar magnitudes (3-4 pA/microm2). Thus, the present results suggest that orthodromic action potentials initiate in the axon beyond the AH-IS and that the minimum threshold for spike initiation of the neuron is not determined by a high density of Na+ channels in the AH-IS region.

  19. Biphasic somatic A-type K channel downregulation mediates intrinsic plasticity in hippocampal CA1 pyramidal neurons.

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    Sung-Cherl Jung

    Full Text Available Since its original description, the induction of synaptic long-term potentiation (LTP has been known to be accompanied by a lasting increase in the intrinsic excitability (intrinsic plasticity of hippocampal neurons. Recent evidence shows that dendritic excitability can be enhanced by an activity-dependent decrease in the activity of A-type K(+ channels. In the present manuscript, we examined the role of A-type K(+ channels in regulating intrinsic excitability of CA1 pyramidal neurons of the hippocampus after synapse-specific LTP induction. In electrophysiological recordings we found that LTP induced a potentiation of excitability which was accompanied by a two-phased change in A-type K(+ channel activity recorded in nucleated patches from organotypic slices of rat hippocampus. Induction of LTP resulted in an immediate but short lasting hyperpolarization of the voltage-dependence of steady-state A-type K(+ channel inactivation along with a progressive, long-lasting decrease in peak A-current density. Blocking clathrin-mediated endocytosis prevented the A-current decrease and most measures of intrinsic plasticity. These results suggest that two temporally distinct but overlapping mechanisms of A-channel downregulation together contribute to the plasticity of intrinsic excitability. Finally we show that intrinsic plasticity resulted in a global enhancement of EPSP-spike coupling.

  20. The spatio-temporal characteristics of action potential initiation in layer 5 pyramidal neurons: a voltage imaging study.

    Science.gov (United States)

    Popovic, Marko A; Foust, Amanda J; McCormick, David A; Zecevic, Dejan

    2011-09-01

    The spatial pattern of Na(+) channel clustering in the axon initial segment (AIS) plays a critical role in tuning neuronal computations, and changes in Na(+) channel distribution have been shown to mediate novel forms of neuronal plasticity in the axon. However, immunocytochemical data on channel distribution may not directly predict spatio-temporal characteristics of action potential initiation, and prior electrophysiological measures are either indirect (extracellular) or lack sufficient spatial resolution (intracellular) to directly characterize the spike trigger zone (TZ). We took advantage of a critical methodological improvement in the high sensitivity membrane potential imaging (V(m) imaging) technique to directly determine the location and length of the spike TZ as defined in functional terms. The results show that in mature axons of mouse cortical layer 5 pyramidal cells, action potentials initiate in a region ∼20 μm in length centred between 20 and 40 μm from the soma. From this region, the AP depolarizing wave invades initial nodes of Ranvier within a fraction of a millisecond and propagates in a saltatory fashion into axonal collaterals without failure at all physiologically relevant frequencies. We further demonstrate that, in contrast to the saltatory conduction in mature axons, AP propagation is non-saltatory (monotonic) in immature axons prior to myelination.

  1. Repetitive magnetic stimulation induces plasticity of excitatory postsynapses on proximal dendrites of cultured mouse CA1 pyramidal neurons.

    Science.gov (United States)

    Lenz, Maximilian; Platschek, Steffen; Priesemann, Viola; Becker, Denise; Willems, Laurent M; Ziemann, Ulf; Deller, Thomas; Müller-Dahlhaus, Florian; Jedlicka, Peter; Vlachos, Andreas

    2015-11-01

    Repetitive transcranial magnetic stimulation (rTMS) of the human brain can lead to long-lasting changes in cortical excitability. However, the cellular and molecular mechanisms which underlie rTMS-induced plasticity remain incompletely understood. Here, we used repetitive magnetic stimulation (rMS) of mouse entorhino-hippocampal slice cultures to study rMS-induced plasticity of excitatory postsynapses. By employing whole-cell patch-clamp recordings of CA1 pyramidal neurons, local electrical stimulations, immunostainings for the glutamate receptor subunit GluA1 and compartmental modeling, we found evidence for a preferential potentiation of excitatory synapses on proximal dendrites of CA1 neurons (2-4 h after stimulation). This rMS-induced synaptic potentiation required the activation of voltage-gated sodium channels, L-type voltage-gated calcium channels and N-methyl-D-aspartate-receptors. In view of these findings we propose a cellular model for the preferential strengthening of excitatory synapses on proximal dendrites following rMS in vitro, which is based on a cooperative effect of synaptic glutamatergic transmission and postsynaptic depolarization.

  2. Activity-dependent structural plasticity after aversive experiences in amygdala and auditory cortex pyramidal neurons.

    Science.gov (United States)

    Gruene, Tina; Flick, Katelyn; Rendall, Sam; Cho, Jin Hyung; Gray, Jesse; Shansky, Rebecca

    2016-07-22

    The brain is highly plastic and undergoes changes in response to many experiences. Learning especially can induce structural remodeling of dendritic spines, which is thought to relate to memory formation. Classical Pavlovian fear conditioning (FC) traditionally pairs an auditory cue with an aversive footshock, and has been widely used to study neural processes underlying associative learning and memory. Past research has found dendritic spine changes after FC in several structures. But, due to heterogeneity of cells within brain structures and limitations of traditional neuroanatomical techniques, it is unclear if all cells included in analyses were actually active during learning processes, even if known circuits are isolated. In this study, we employed a novel approach to analyze structural plasticity explicitly in neurons activated by exposure to either cued or uncued footshocks. We used male and female Arc-dVenus transgenic mice, which express the Venus fluorophore driven by the activity-related Arc promoter, to identify neurons that were active during either scenario. We then targeted fluorescent microinjections to Arc+ and neighboring Arc- neurons in the basolateral area of the amygdala (BLA) and auditory association cortex (TeA). In both BLA and TeA, Arc+ neurons had reduced thin and mushroom spine densities compared to Arc- neurons. This effect was present in males and females alike and also in both cued and uncued shock groups. Overall, this study adds to our understanding of how neuronal activity affects structural plasticity, and represents a methodological advance in the ways we can directly relate structural changes to experience-related neural activity.

  3. Steady-state dynamics and experience-dependent plasticity of dendritic spines of layer 4/5a pyramidal neurons in somatosensory cortex

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    Amaya Miquelajauregui

    2014-04-01

    Full Text Available The steady state dynamics and experience-dependent plasticity of dendritic spines of layer (L 2/3 and L5B cortical pyramidal neurons have recently been assessed using in vivo two-photon microscopy (Trachtenberg et al., 2002; Zuo et al., 2005; Holtmaat et al., 2006. In contrast, not much is known about spine dynamics in L4/5a neurons, regarded as direct recipients of thalamocortical input (Constantinople and Bruno, 2013. In the adult mouse somatosensory cortex (SCx, the transcription factor Ebf2 is enriched in excitatory neurons of L4/5a, including pyramidal neurons. We assessed the molecular and electrophysiological properties of these neurons as well as the morphology of their apical tufts (Scholl analysis and cortical outputs (optogenetics within the SCx. To test the hypothesis that L4/5a pyramidal neurons play an important role in sensory processing (given their key laminar position; soma depth ~450-480 µm, we successfully labeled them in Ebf2-Cre mice with EGFP by expressing recombinant rAAV vectors in utero. Using longitudinal in vivo two-photon microscopy through a craniotomy (Mostany and Portera-Cailliau, 2008, we repeatedly imaged spines in apical dendritic tufts of L4/5a neurons under basal conditions and after sensory deprivation. Under steady-state conditions in adults, the morphology of the apical tufts and the mean spine density were stable at 0.39 ± 0.05 spines/μm (comparable to L5B, Mostany et al., 2011. Interestingly, spine elimination increases 4-8 days after sensory deprivation, probably due to input loss. This suggests that Ebf2+ L4/5a neurons could be involved in early steps of processing of thalamocortical information.

  4. Homeostatic maintenance in excitability of tree shrew hippocampal CA3 pyramidal neurons after chronic stress

    NARCIS (Netherlands)

    Kole, MHP; Czeh, B; Fuchs, E

    2004-01-01

    The experience of chronic stress induces a reversible regression of hippocampal CA3 apical neuron dendrites. Although such postsynaptic membrane reduction will obviously diminish the possibility of synaptic input, the consequences for the functional membrane properties of these cells are not well un

  5. Beyond laminar fate: toward a molecular classification of cortical projection/pyramidal neurons.

    NARCIS (Netherlands)

    Hevner, R.F.; Daza, R.A.; Rubenstein, J.L.; Stunnenberg, H.G.; Olavarria, J.F.; Englund, C.

    2003-01-01

    Cortical projection neurons exhibit diverse morphological, physiological, and molecular phenotypes, but it is unknown how many distinct types exist. Many projection cell phenotypes are associated with laminar fate (radial position), but each layer may also contain multiple types of projection cells.

  6. Effect of low frequency repetitive transcranial magnetic stimulation on kindling-induced changes in electrophysiological properties of rat CA1 pyramidal neurons.

    Science.gov (United States)

    Moradi Chameh, Homeira; Janahmadi, Mahyar; Semnanian, Saeed; Shojaei, Amir; Mirnajafi-Zadeh, Javad

    2015-05-01

    In this study, the effect of repetitive transcranial magnetic stimulation (rTMS) on the kindling induced changes in electrophysiological firing properties of hippocampal CA1 pyramidal neurons was investigated. Male Wistar rats were kindled by daily electrical stimulation of the basolateral amygdala in a semi-rapid manner (12 stimulations/day) until they achieved stage-5 seizure. One group (kindled+rTMS (KrTMS)) of animals received rTMS (240 pulses at 1 Hz) at 5 min after termination of daily kindling stimulations. Twenty-four hours following the last kindling stimulation electrophysiological properties of hippocampal CA1 pyramidal neurons were investigated using a whole-cell patch clamp technique, under current clamp condition. Amygdala kindling significantly decreased the adaptation index, post-afterhyperpolarization, rheobase current, utilization time, and delay to the first rebound spike. It also caused an increase in the voltage sag, number of rebound spikes and number of evoked action potential. Results of the present study revealed that application of rTMS following kindling stimulations had antiepileptogenic effects. In addition, application of rTMS prevented hyperexcitability of CA1 pyramidal neurons induced by kindling and conserved the normal neuronal firing.

  7. Dopamine Inhibits High-Frequency Stimulation-Induced Long-Term Potentiation of Intrinsic Excitability in CA1 Hippocampal Pyramidal Neurons

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    Chun-ling Wei

    2012-09-01

    Full Text Available The efficiency of neural circuits is modified by changes not only in synaptic strength, but also in intrinsic excitability of neurons. In CA1 hippocampal pyramidal neurons, bidirectional changes in the intrinsic excitability are often presented after induction of synaptic long-term potentiation or depression. This plasticity of intrinsic excitability has been identified as a cellular correlate of learning. Besides, behavioral learning often involves action of reinforcement or rewarding mediated by dopamine (DA. Here, we examined how DA influences the intrinsic plasticity of CA1 hippocampal pyramidal neurons when high-frequency stimulation (HFS was applied to Schaffer collaterals. The results showed that DA inhibits the decrease in rheobase and increase in mean firing rate of pyramidal neurons induced by HFS, and that this inhibition was abolished by the D1-like receptor antagonist SCH23390 but not by the D2-like receptor antagonist sulpiride. The results suggest that DA inhibits the potentiation of excitability induced by presynaptic HFS, and that this inhibition depends on the activation of D1-like receptors.

  8. [The effect of enzymatic treatment using proteases on properties of persistent sodium current in CA1 pyramidal neurons of rat hippocampus].

    Science.gov (United States)

    Lun'ko, O O; Isaiev, D S; Maxymiuk, O P; Kryshtal', O O; Isaieva, O V

    2014-01-01

    We investigated the effect of proteases, widely used for neuron isolation in electrophysiological studies, on the amplitude and kinetic characteristics of persistent sodium current (I(NaP)) in hippocampal CA1 pyramidal neurons. Properties of I(NaP) were studied on neurons isolated by mechanical treatment (control group) and by mechanical and enzymatic treatment using pronase E (from Streptomyces griseus) or protease type XXIII (from Aspergillus oryzae). We show that in neurons isolated with pronase E kinetic of activation and density of I(NaP) was unaltered. Enzymatic treatment with protease type XXIII did not alter I(NaP) activation but result in significant decrease in I(NaP) density. Our data indicates that enzymatic treatment using pronase E for neuron isolation is preferable for investigation of I(NaP).

  9. Translational profiling of stress-induced neuroplasticity in the CA3 pyramidal neurons of BDNF Val66Met mice.

    Science.gov (United States)

    Gray, J D; Rubin, T G; Kogan, J F; Marrocco, J; Weidmann, J; Lindkvist, S; Lee, F S; Schmidt, E F; McEwen, B S

    2016-12-13

    Genetic susceptibility and environmental factors (such as stress) can interact to affect the likelihood of developing a mood disorder. Stress-induced changes in the hippocampus have been implicated in mood disorders, and mutations in several genes have now been associated with increased risk, such as brain-derived neurotrophic factor (BDNF). The hippocampus has important anatomical subdivisions, and pyramidal neurons of the vulnerable CA3 region show significant remodeling after chronic stress, but the mechanisms underlying their unique plasticity remain unknown. This study characterizes stress-induced changes in the in vivo translating mRNA of this cell population using a CA3-specific enhanced green fluorescent protein (EGFP) reporter fused to the L10a large ribosomal subunit (EGFPL10a). RNA-sequencing after isolation of polysome-bound mRNAs allows for cell-type-specific, genome-wide characterization of translational changes after stress. The data demonstrate that acute and chronic stress produce unique translational profiles and that the stress history of the animal can alter future reactivity of CA3 neurons. CA3-specific EGFPL10a mice were then crossed to the stress-susceptible BDNF Val66Met mouse line to characterize how a known genetic susceptibility alters both baseline translational profiles and the reactivity of CA3 neurons to stress. Not only do Met allele carriers exhibit distinct levels of baseline translation in genes implicated in ion channel function and cytoskeletal regulation, but they also activate a stress response profile that is highly dissimilar from wild-type mice. Closer examination of genes implicated in the mechanisms of neuroplasticity, such as the NMDA and AMPA subunits and the BDNF pathway, reveal how wild-type mice upregulate many of these genes in response to stress, but Met allele carriers fail to do so. These profiles provide a roadmap of stress-induced changes in a genetically homogenous population of hippocampal neurons and

  10. Muscarinic Long-Term Enhancement of Tonic and Phasic GABAA Inhibition in Rat CA1 Pyramidal Neurons

    Science.gov (United States)

    Domínguez, Soledad; Fernández de Sevilla, David; Buño, Washington

    2016-01-01

    Acetylcholine (ACh) regulates network operation in the hippocampus by controlling excitation and inhibition in rat CA1 pyramidal neurons (PCs), the latter through gamma-aminobutyric acid type-A receptors (GABAARs). Although, the enhancing effects of ACh on GABAARs have been reported (Dominguez et al., 2014, 2015), its role in regulating tonic GABAA inhibition has not been explored in depth. Therefore, we aimed at determining the effects of the activation of ACh receptors on responses mediated by synaptic and extrasynaptic GABAARs. Here, we show that under blockade of ionotropic glutamate receptors ACh, acting through muscarinic type 1 receptors, paired with post-synaptic depolarization induced a long-term enhancement of tonic GABAA currents (tGABAA) and puff-evoked GABAA currents (pGABAA). ACh combined with depolarization also potentiated IPSCs (i.e., phasic inhibition) in the same PCs, without signs of interactions of synaptic responses with pGABAA and tGABAA, suggesting the contribution of two different GABAA receptor pools. The long-term enhancement of GABAA currents and IPSCs reduced the excitability of PCs, possibly regulating plasticity and learning in behaving animals. PMID:27833531

  11. Bidirectional Hebbian Plasticity Induced by Low-Frequency Stimulation in Basal Dendrites of Rat Barrel Cortex Layer 5 Pyramidal Neurons

    Science.gov (United States)

    Díez-García, Andrea; Barros-Zulaica, Natali; Núñez, Ángel; Buño, Washington; Fernández de Sevilla, David

    2017-01-01

    According to Hebb's original hypothesis (Hebb, 1949), synapses are reinforced when presynaptic activity triggers postsynaptic firing, resulting in long-term potentiation (LTP) of synaptic efficacy. Long-term depression (LTD) is a use-dependent decrease in synaptic strength that is thought to be due to synaptic input causing a weak postsynaptic effect. Although the mechanisms that mediate long-term synaptic plasticity have been investigated for at least three decades not all question have as yet been answered. Therefore, we aimed at determining the mechanisms that generate LTP or LTD with the simplest possible protocol. Low-frequency stimulation of basal dendrite inputs in Layer 5 pyramidal neurons of the rat barrel cortex induces LTP. This stimulation triggered an EPSP, an action potential (AP) burst, and a Ca2+ spike. The same stimulation induced LTD following manipulations that reduced the Ca2+ spike and Ca2+ signal or the AP burst. Low-frequency whisker deflections induced similar bidirectional plasticity of action potential evoked responses in anesthetized rats. These results suggest that both in vitro and in vivo similar mechanisms regulate the balance between LTP and LTD. This simple induction form of bidirectional hebbian plasticity could be present in the natural conditions to regulate the detection, flow, and storage of sensorimotor information. PMID:28203145

  12. Ablation of SNX6 leads to defects in synaptic function of CA1 pyramidal neurons and spatial memory

    Science.gov (United States)

    Niu, Yang; Dai, Zhonghua; Liu, Wenxue; Zhang, Cheng; Yang, Yanrui; Guo, Zhenzhen; Li, Xiaoyu; Xu, Chenchang; Huang, Xiahe; Wang, Yingchun; Shi, Yun S; Liu, Jia-Jia

    2017-01-01

    SNX6 is a ubiquitously expressed PX-BAR protein that plays important roles in retromer-mediated retrograde vesicular transport from endosomes. Here we report that CNS-specific Snx6 knockout mice exhibit deficits in spatial learning and memory, accompanied with loss of spines from distal dendrites of hippocampal CA1 pyramidal cells. SNX6 interacts with Homer1b/c, a postsynaptic scaffold protein crucial for the synaptic distribution of other postsynaptic density (PSD) proteins and structural integrity of dendritic spines. We show that SNX6 functions independently of retromer to regulate distribution of Homer1b/c in the dendritic shaft. We also find that Homer1b/c translocates from shaft to spines by protein diffusion, which does not require SNX6. Ablation of SNX6 causes reduced distribution of Homer1b/c in distal dendrites, decrease in surface levels of AMPAR and impaired AMPAR-mediated synaptic transmission. These findings reveal a physiological role of SNX6 in CNS excitatory neurons. DOI: http://dx.doi.org/10.7554/eLife.20991.001 PMID:28134614

  13. Neonatal Propofol and Etomidate Exposure Enhance Inhibitory Synaptic Transmission in Hippocampal Cornus Ammonis 1 Pyramidal Neurons

    Institute of Scientific and Technical Information of China (English)

    Jia-Qiang Zhang; Wan-Ying Xu; Chang-Qing Xu

    2016-01-01

    Background:Propofol and etomidate are the most important intravenous general anesthetics in the current clinical use and that mediate gamma-aminobutyric acid's (GABAergic) synaptic transmission.However,their long-term effects on GABAergic synaptic transmission induced by neonatal propofol or etomidate exposure remain unclear.We investigated the long-term GABAergic neurotransmission alterations,following neonatal propofol and etomidate administration.Methods:Sprague-Dawley rat pups at postnatal days 4 6 were underwent 6-h-long propofol-induced or 5-h-long etomidate-induced anesthesia.We performed whole-cell patch-clamp recording from pyramidal cells in the cornus ammonis 1 area of acute hippocampal slices of postnatal 80-90 days.Spontaneous and miniature inhibitory GABAergic currents (spontaneous inhibitory postsynaptic currents [sIPSCs] and miniature inhibitory postsynaptic currents [mIPSCs]) and their kinetic characters were measured.The glutamatergic tonic effect on inhibitory transmission and the effect of bumetanide on neonatal propofol exposure were also examined.Results:Neonatal propofol exposure significantly increased the frequency of mIPSCs (from 1.87 ± 0.35 Hz to 3.43 ± 0.51 Hz,P < 0.05) and did not affect the amplitude of mIPSCs and sIPSCs.Both propofol and etomidate slowed the decay time of mIPSCs kinetics (168.39 ± 27.91 ms and 267.02 ± 100.08 ms vs.68.18 ± 12.43 ms;P < 0.05).Bumetanide significantly blocked the frequency increase and reversed the kinetic alteration of mIPSCs induced by neonatal propofol exposure (3.01 ± 0.45 Hz and 94.30 ± 32.56 ms).Conclusions:Neonatal propofol and etomidate exposure has long-term effects on inhibitory GABAergic transmission.Propofol might act at pre-and post-synaptic GABA receptor A (GABAA) receptors within GABAergic synapses and impairs the glutamatergic tonic input to GABAergic synapses;etomidate might act at the postsynaptic site.

  14. Dysregulated Expression of Neuregulin-1 by Cortical Pyramidal Neurons Disrupts Synaptic Plasticity

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    Amit Agarwal

    2014-08-01

    Full Text Available Neuregulin-1 (NRG1 gene variants are associated with increased genetic risk for schizophrenia. It is unclear whether risk haplotypes cause elevated or decreased expression of NRG1 in the brains of schizophrenia patients, given that both findings have been reported from autopsy studies. To study NRG1 functions in vivo, we generated mouse mutants with reduced and elevated NRG1 levels and analyzed the impact on cortical functions. Loss of NRG1 from cortical projection neurons resulted in increased inhibitory neurotransmission, reduced synaptic plasticity, and hypoactivity. Neuronal overexpression of cysteine-rich domain (CRD-NRG1, the major brain isoform, caused unbalanced excitatory-inhibitory neurotransmission, reduced synaptic plasticity, abnormal spine growth, altered steady-state levels of synaptic plasticity-related proteins, and impaired sensorimotor gating. We conclude that an “optimal” level of NRG1 signaling balances excitatory and inhibitory neurotransmission in the cortex. Our data provide a potential pathomechanism for impaired synaptic plasticity and suggest that human NRG1 risk haplotypes exert a gain-of-function effect.

  15. The GLP-1 Receptor Agonist Exendin-4 and Diazepam Differentially Regulate GABAA Receptor-Mediated Tonic Currents in Rat Hippocampal CA3 Pyramidal Neurons.

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    Sergiy V Korol

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a metabolic hormone that is secreted in a glucose-dependent manner and enhances insulin secretion. GLP-1 receptors are also found in the brain where their signalling affects neuronal activity. We have previously shown that the GLP-1 receptor agonists, GLP-1 and exendin-4 enhanced GABA-activated synaptic and tonic currents in rat hippocampal CA3 pyramidal neurons. The hippocampus is the centre for memory and learning and is important for cognition. Here we examined if exendin-4 similarly enhanced the GABA-activated currents in the presence of the benzodiazepine diazepam. In whole-cell recordings in rat brain slices, diazepam (1 μM, an allosteric positive modulator of GABAA receptors, alone enhanced the spontaneous inhibitory postsynaptic current (sIPSC amplitude and frequency by a factor of 1.3 and 1.6, respectively, and doubled the tonic GABAA current normally recorded in the CA3 pyramidal cells. Importantly, in the presence of exendin-4 (10 nM plus diazepam (1 μM, only the tonic but not the sIPSC currents transiently increased as compared to currents recorded in the presence of diazepam alone. The results suggest that exendin-4 potentiates a subpopulation of extrasynaptic GABAA receptors in the CA3 pyramidal neurons.

  16. Ongoing epileptiform activity in the post-ischemic hippocampus is associated with a permanent shift of the excitatory-inhibitory synaptic balance in CA3 pyramidal neurons.

    Science.gov (United States)

    Epsztein, Jérôme; Milh, Mathieu; Bihi, Rachid Id; Jorquera, Isabel; Ben-Ari, Yehezkel; Represa, Alfonso; Crépel, Valérie

    2006-06-28

    Ischemic strokes are often associated with late-onset epilepsy, but the underlying mechanisms are poorly understood. In the hippocampus, which is one of the regions most sensitive to ischemic challenge, global ischemia induces a complete loss of CA1 pyramidal neurons, whereas the resistant CA3 pyramidal neurons display a long-term hyperexcitability several months after the insult. The mechanisms of this long-term hyperexcitability remain unknown despite its clinical implication. Using chronic in vivo EEG recordings and in vitro field recordings in slices, we now report spontaneous interictal epileptiform discharges in the CA3 area of the hippocampus from post-ischemic rats several months after the insult. Whole-cell recordings from CA3 pyramidal neurons, revealed a permanent reduction in the frequency of spontaneous and miniature GABAergic IPSCs and a parallel increase in the frequency of spontaneous and miniature glutamatergic postsynaptic currents. Global ischemia also induced a dramatic loss of GABAergic interneurons and terminals together with an increase in glutamatergic terminals in the CA3 area of the hippocampus. Altogether, our results show a morpho-functional reorganization in the CA3 network several months after global ischemia, resulting in a net shift in the excitatory-inhibitory balance toward excitation that may constitute a substrate for the generation of epileptiform discharges in the post-ischemic hippocampus.

  17. Bidirectional modulation of hyperalgesia via the specific control of excitatory and inhibitory neuronal activity in the ACC

    OpenAIRE

    Kang, SukJae Joshua; Kwak, Chuljung; Lee, Jaejyun; Sim, Su-Eon; Shim, Jaehoon; Choi, Taehyuk; Graham L. Collingridge; Zhou, Min; Kaang, B-K

    2015-01-01

    Neurons in the anterior cingulate cortex (ACC) are assumed to play important roles in the perception of nociceptive signals and the associated emotional responses. However, the neuronal types within the ACC that mediate these functions are poorly understood. In the present study, we used optogenetic techniques to selectively modulate excitatory pyramidal neurons and inhibitory interneurons in the ACC and to assess their ability to modulate peripheral mechanical hypersensitivity in freely movi...

  18. Kv4 potassium channel subunits control action potential repolarization and frequency-dependent broadening in rat hippocampal CA1 pyramidal neurones.

    Science.gov (United States)

    Kim, Jinhyun; Wei, Dong-Sheng; Hoffman, Dax A

    2005-11-15

    A-type potassium channels regulate neuronal firing frequency and the back-propagation of action potentials (APs) into dendrites of hippocampal CA1 pyramidal neurones. Recent molecular cloning studies have found several families of voltage-gated K(+) channel genes expressed in the mammalian brain. At present, information regarding the relationship between the protein products of these genes and the various neuronal functions performed by voltage-gated K(+) channels is lacking. Here we used a combination of molecular, electrophysiological and imaging techniques to show that one such gene, Kv4.2, controls AP half-width, frequency-dependent AP broadening and dendritic action potential propagation. Using a modified Sindbis virus, we expressed either the enhanced green fluorescence protein (EGFP)-tagged Kv4.2 or an EGFP-tagged dominant negative mutant of Kv4.2 (Kv4.2g(W362F)) in CA1 pyramidal neurones of organotypic slice cultures. Neurones expressing Kv4.2g(W362F) displayed broader action potentials with an increase in frequency-dependent AP broadening during a train compared with control neurones. In addition, Ca(2)(+) imaging of Kv4.2g(W362F) expressing dendrites revealed enhanced AP back-propagation compared to control neurones. Conversely, neurones expressing an increased A-type current through overexpression of Kv4.2 displayed narrower APs with less frequency dependent broadening and decreased dendritic propagation. These results point to Kv4.2 as the major contributor to the A-current in hippocampal CA1 neurones and suggest a prominent role for Kv4.2 in regulating AP shape and dendritic signalling. As Ca(2)(+) influx occurs primarily during AP repolarization, Kv4.2 activity can regulate cellular processes involving Ca(2)(+)-dependent second messenger cascades such as gene expression and synaptic plasticity.

  19. Inhibitory control of linear and supralinear dendritic excitation in CA1 pyramidal neurons.

    Science.gov (United States)

    Müller, Christina; Beck, Heinz; Coulter, Douglas; Remy, Stefan

    2012-09-01

    The transformation of dendritic excitatory synaptic inputs to axonal action potential output is the fundamental computation performed by all principal neurons. We show that in the hippocampus this transformation is potently controlled by recurrent inhibitory microcircuits. However, excitatory input on highly excitable dendritic branches could resist inhibitory control by generating strong dendritic spikes and trigger precisely timed action potential output. Furthermore, we show that inhibition-sensitive branches can be transformed into inhibition-resistant, strongly spiking branches by intrinsic plasticity of branch excitability. In addition, we demonstrate that the inhibitory control of spatially defined dendritic excitation is strongly regulated by network activity patterns. Our findings suggest that dendritic spikes may serve to transform correlated branch input into reliable and temporally precise output even in the presence of inhibition.

  20. Selective neurofilament (SMI-32, FNP-7 and N200) expression in subpopulations of layer V pyramidal neurons in vivo and in vitro.

    Science.gov (United States)

    Voelker, Courtney C J; Garin, Nathalie; Taylor, Jeremy S H; Gähwiler, Beat H; Hornung, Jean-Pierre; Molnár, Zoltán

    2004-11-01

    There are two main types of layer V pyramidal neurons in rat cortex. Type I neurons have tufted apical dendrites extending into layer I, produce bursts of action potentials and project to subcortical targets (spinal cord, superior colliculus and pontine nuclei). Type II neurons have apical dendrites, which arborize in layers II-IV, do not produce bursts of action potentials and project to ipsilateral and contralateral cortex. The specific expression of different genes and proteins in these two distinct layer V neurons is unknown. To distinguish between distinct subpopulations, fluorescent microspheres were injected into subcortical targets (labeling type I neurons) or primary somatosensory cortex (labeling type II neurons) of adult rats. After transport, cortical sections were processed for immunohistochemistry using various antibodies. This study demonstrated that antigens recognized by SMI-32, N200 and FNP-7 antibodies were only expressed in subcortical (type I)--but not in contralateral (type II)--projecting neurons. NR1, NR2a/b, PLCbeta1, BDNF, NGF and TrkB antigens were highly expressed in all neuronal subpopulations examined. Organotypic culture experiments demonstrated that the development of neurofilament expression and laminar specificity does not depend on the presence of the subcortical targets. This study suggests specific markers for the subcortical projecting layer V neuron subpopulations.

  1. 17beta-estradiol benzoate decreases the AHP amplitude in CA1 pyramidal neurons.

    Science.gov (United States)

    Kumar, Ashok; Foster, Thomas C

    2002-08-01

    Disruption of Ca(2+) homeostasis is hypothesized to mediate several electrophysiological markers of brain aging. Recent evidence indicates that estradiol can rapidly alter Ca(2+)-dependent processes in neurons through nongenomic mechanisms. In the current study, electrophysiological effects of 17beta-estradiol benzoate (EB) on the Ca(2+)-activated afterhyperpolarization (AHP) were investigated using intracellular sharp electrode recording in hippocampal slices from ovariectomized Fischer 344 female rats. The AHP amplitude was enhanced in aged (22-24 mo) compared with young (5-8 mo) rats and direct application of EB (100 pM) reduced the AHP in aged rats. The age-related difference was due, in part, to the increased AHP amplitude of aged animals, since an EB-mediated decrease in the AHP could be observed in young rats when the extracellular Ca(2+) was elevated to increase the AHP amplitude. In aged rats, bath application of EB occluded the ability of the L-channel blocker, nifedipine (10 microM), to attenuate the AHP. The results support a role for EB in modifying hippocampal Ca(2+)-dependent processes in a manner diametrically opposite that observed during aging, possibly through L-channel inhibition.

  2. Pituitary adenylate cyclase-activating polypeptide (PACAP) inhibits the slow afterhyperpolarizing current sIAHP in CA1 pyramidal neurons by activating multiple signaling pathways.

    Science.gov (United States)

    Taylor, Ruth D T; Madsen, Marita Grønning; Krause, Michael; Sampedro-Castañeda, Marisol; Stocker, Martin; Pedarzani, Paola

    2014-01-01

    The slow afterhyperpolarizing current (sIAHP ) is a calcium-dependent potassium current that underlies the late phase of spike frequency adaptation in hippocampal and neocortical neurons. sIAHP is a well-known target of modulation by several neurotransmitters acting via the cyclic AMP (cAMP) and protein kinase A (PKA)-dependent pathway. The neuropeptide pituitary adenylate cyclase activating peptide (PACAP) and its receptors are present in the hippocampal formation. In this study we have investigated the effect of PACAP on the sIAHP and the signal transduction pathway used to modulate intrinsic excitability of hippocampal pyramidal neurons. We show that PACAP inhibits the sIAHP , resulting in a decrease of spike frequency adaptation, in rat CA1 pyramidal cells. The suppression of sIAHP by PACAP is mediated by PAC1 and VPAC1 receptors. Inhibition of PKA reduced the effect of PACAP on sIAHP, suggesting that PACAP exerts part of its inhibitory effect on sIAHP by increasing cAMP and activating PKA. The suppression of sIAHP by PACAP was also strongly hindered by the inhibition of p38 MAP kinase (p38 MAPK). Concomitant inhibition of PKA and p38 MAPK indicates that these two kinases act in a sequential manner in the same pathway leading to the suppression of sIAHP. Conversely, protein kinase C is not part of the signal transduction pathway used by PACAP to inhibit sIAHP in CA1 neurons. Our results show that PACAP enhances the excitability of CA1 pyramidal neurons by inhibiting the sIAHP through the activation of multiple signaling pathways, most prominently cAMP/PKA and p38 MAPK. Our findings disclose a novel modulatory action of p38 MAPK on intrinsic excitability and the sIAHP, underscoring the role of this current as a neuromodulatory hub regulated by multiple protein kinases in cortical neurons.

  3. Electrophysiological changes of CA1 pyramidal neurons following transient forebrain ischemia: an in vivo intracellular recording and staining study.

    Science.gov (United States)

    Xu, Z C; Pulsinelli, W A

    1996-09-01

    1. Electrophysiological changes of CA1 pyramidal neurons in rat hippocampus were studied before, during 5 min forebrain ischemia, and after reperfusion using in vivo intracellular recording and staining techniques. 2. membrane input resistance of CA1 neurons decreased from 25.98 +/- 7.24 M omega (mean +/- SD, n = 42) before ischemia to 16.33 +/- 6.50 M omega shortly after the onset of ischemia (n = 6, P < 0.01). The input resistance fell to zero during ischemic depolarization and quickly returned to 24.42 +/- 10.36 M omega (n = 11) within 2 h after reperfusion. 3. The time constant of CA1 neurons decreased from 11.49 +/- 5.45 ms (n = 36) to 3.09 +/- 1.66 ms (n = 6, P < 0.01) during ischemia. The time constant remained significantly less than preischemic levels within 2 h after reperfusion (5.40 +/- 2.60 ms, n = 13, P < 0.01) and gradually returned to preischemic levels 4-5 h after reperfusion. 4. The spike height decreased from 91 +/- 10.35 mV (n = 45) before ischemia to 82 +/- 8.00 mV (n = 9, P < 0.05) within 2 h after reperfusion and fully returned to preischemic level 2-5 h after reperfusion. The spike width increased from 1.14 +/- 0.22 ms (n = 45) before ischemia to 1.36 +/- 0.22 ms (n = 9, P < 0.05) within 2 h after reperfusion and remained at this level 4-5 h after reperfusion. 5. The spike threshold significantly increased from -54 +/- 3.93 mV (n = 45) before ischemia to -49 +/- 5.04 mV (n = 8, P < 0.01) within 2 h after reperfusion. The rheobase increased accordingly from 0.34 +/- 0.16 nA (n = 41) to 0.73 +/- 0.26 nA (n = 6, P < 0.01). The spike threshold returned to control levels 4-5 h after reperfusion, while the rheobase was still significantly higher than control levels (0.50 +/- 0.21 nA, n = 16, P < 0.01). 6. The frequency of repetitive firing evoked by depolarizing current pulses was suppressed within 2 h after reperfusion (n = 6, P < 0.01). The spike frequency increased slightly 2-5 h after reperfusion but was still significantly below the control

  4. Effects of deprivation of oxygen or glucose on the neural activity in the guinea pig hippocampal slice--intracellular recording study of pyramidal neurons.

    Science.gov (United States)

    Takata, T; Okada, Y

    1995-06-12

    The block of synaptic transmission and neural activity during deprivation of oxygen or glucose has been simply attributed to the lack of energy due to the disorder of energy production. To clarify the interrelation between neural activity and energy metabolism during hypoxia or glucose deprivation, we studied the changes in ATP levels and electrical events of pyramidal neurons in the CA3 region and [Ca2+]i mobilization of the dendritic and cellular region of CA3 area, using guinea pig hippocampal slices. The studies of field potentials and intracellular recording from the pyramidal cell of CA3 area during hypoxia or glucose deprivation revealed that the cessation of synaptic activity and the depolarization of resting potential occurred earlier than during glucose deprivation while the increase of [Ca2+]i was slow during hypoxia but rapid during glucose deprivation although the ATP level of CA3 area was maintained at its original level for 20 min during both conditions. When glucose was replaced by lactate, ATP concentration was not reduced but the electrical activity decayed and [Ca2+]i increased with the similar time course as observed during lack of glucose, only. These results suggest that different mechanisms underlie the block of synaptic transmission in the CA3 pyramidal neurons during hypoxia and glucose deprivation and that lactate cannot substitute for glucose in the maintenance of neural activity.

  5. Functional and molecular differences between voltage-gated K+ channels of fast-spiking interneurons and pyramidal neurons of rat hippocampus.

    Science.gov (United States)

    Martina, M; Schultz, J H; Ehmke, H; Monyer, H; Jonas, P

    1998-10-15

    We have examined gating and pharmacological characteristics of somatic K+ channels in fast-spiking interneurons and regularly spiking principal neurons of hippocampal slices. In nucleated patches isolated from basket cells of the dentate gyrus, a fast delayed rectifier K+ current component that was highly sensitive to tetraethylammonium (TEA) and 4-aminopyridine (4-AP) (half-maximal inhibitory concentrations Kv3 (Kv3.1, Kv3.2) subunit transcripts were expressed in almost all (89%) of the interneurons but only in 17% of the pyramidal neurons. In contrast, Kv4 (Kv4.2, Kv4.3) subunit mRNAs were present in 87% of pyramidal neurons but only in 55% of interneurons. Selective block of fast delayed rectifier K+ channels, presumably assembled from Kv3 subunits, by 4-AP reduced substantially the action potential frequency in interneurons. These results indicate that the differential expression of Kv3 and Kv4 subunits shapes the action potential phenotypes of principal neurons and interneurons in the cortex.

  6. High- and low-conductance NMDA receptors are present in layer 4 spiny stellate and layer 2/3 pyramidal neurons of mouse barrel cortex.

    Science.gov (United States)

    Scheppach, Christian

    2016-12-01

    N-Methyl-D-aspartate (NMDA) receptors are ion channels activated by the neurotransmitter glutamate in the mammalian brain and are important in synaptic function and plasticity, but are also found in extrasynaptic locations and influence neuronal excitability. There are different NMDA receptor subtypes which differ in their single-channel conductance. Recently, synaptic plasticity has been studied in the mouse barrel cortex, the primary sensory cortex for input from the animal's whiskers. Pharmacological data imply the presence of low-conductance NMDA receptors in spiny stellate neurons of cortical layer 4, but of high-conductance NMDA receptors in pyramidal neurons of layer 2/3. Here, to obtain complementary electrophysiological information on the functional NMDA receptors expressed in layer 4 and layer 2/3 neurons, single NMDA receptor currents were recorded with the patch-clamp method. Both cell types were found to contain high-conductance as well as low-conductance NMDA receptors. The results are consistent with the reported pharmacological data on synaptic plasticity, and with previous claims of a prominent role of low-conductance NMDA receptors in layer 4 spiny stellate neurons, including broad integration, amplification and distribution of excitation within the barrel in response to whisker stimulation, as well as modulation of excitability by ambient glutamate. However, layer 4 cells also expressed high-conductance NMDA receptors. The presence of low-conductance NMDA receptors in layer 2/3 pyramidal neurons suggests that some of these functions may be shared with layer 4 spiny stellate neurons.

  7. Sub-millisecond firing synchrony of closely neighboring pyramidal neurons in hippocampal CA1 of rats during delayed non-matching to sample task

    Directory of Open Access Journals (Sweden)

    Susumu Takahashi

    2009-09-01

    Full Text Available Firing synchrony among neurons is thought to play functional roles in several brain regions. In theoretical analyses, firing synchrony among neurons within sub-millisecond precision is feasible to convey information. However, little is known about the occurrence and the functional significance of the sub-millisecond synchrony among closely neighboring neurons in the brain of behaving animals because of a technical issue: spikes simultaneously generated from closely neighboring neurons are overlapped in the extracellular space and are not easily separated. As described herein, using a unique spike sorting technique based on independent component analysis together with extracellular 12-channel multi-electrodes (dodecatrodes, we separated such overlapping spikes and investigated the firing synchrony among closely neighboring pyramidal neurons in the hippocampal CA1 of rats during a delayed non-matching to sample task. Results showed that closely neighboring pyramidal neurons in the hippocampal CA1 can co-fire with sub-millisecond precision. The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison and external (stimulus input and motor output events during the task. However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently. We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information—as represented by the firing rate modulations—to downstream neurons.

  8. Combined chronic blockade of hyper-active L-type calcium channels and NMDA receptors ameliorates HIV-1 associated hyper-excitability of mPFC pyramidal neurons.

    Science.gov (United States)

    Khodr, Christina E; Chen, Lihua; Dave, Sonya; Al-Harthi, Lena; Hu, Xiu-Ti

    2016-10-01

    Human Immunodeficiency Virus type 1 (HIV-1) infection induces neurological and neuropsychological deficits, which are associated with dysregulation of the medial prefrontal cortex (mPFC) and other vulnerable brain regions. We evaluated the impact of HIV infection in the mPFC and the therapeutic potential of targeting over-active voltage-gated L-type Ca(2+) channels (L-channel) and NMDA receptors (NMDAR), as modeled in HIV-1 transgenic (Tg) rats. Whole-cell patch-clamp recording was used to assess the membrane properties and voltage-sensitive Ca(2+) potentials (Ca(2+) influx) in mPFC pyramidal neurons. Neurons from HIV-1 Tg rats displayed reduced rheobase, spike amplitude and inwardly-rectifying K(+) influx, increased numbers of action potentials, and a trend of aberrant firing compared to those from non-Tg control rats. Neuronal hyper-excitation was associated with abnormally-enhanced Ca(2+) influx (independent of NMDAR), which was eliminated by acute L-channel blockade. Combined chronic blockade of over-active L-channels and NMDARs with open-channel blockers abolished HIV effects on spiking, aberrant firing and Ca(2+) potential half-amplitude duration, though not the reduced inward rectification. In contrast, individual chronic blockade of over-active L-channels or NMDARs did not alleviate HIV-induced mPFC hyper-excitability. These studies demonstrate that HIV alters mPFC neuronal activity by dysregulating membrane excitability and Ca(2+) influx through the L-channels. This renders these neurons more susceptible and vulnerable to excitatory stimuli, and could contribute to HIV-associated neuropathogenesis. Combined targeting of over-active L-channels/NMDARs alleviates HIV-induced dysfunction of mPFC pyramidal neurons, emphasizing a potential novel therapeutic strategy that may effectively decrease HIV-induced Ca(2+) dysregulation in the mPFC.

  9. A comparison of 15 Hz sine on-line and off-line magnetic stimulation affecting the voltage-gated sodium channel currents of prefrontal cortex pyramidal neurons

    Science.gov (United States)

    Zheng, Yu; Dong, Lei; Gao, Yang; Dou, Jun-Rong; Li, Ze-yan

    2016-10-01

    Combined with the use of patch-clamp techniques, repetitive transcranial magnetic stimulation (rTMS) has proven to be a noninvasive neuromodulation tool that can inhibit or facilitate excitability of neurons after extensive research. The studies generally focused on the method: the neurons are first stimulated in an external standard magnetic exposure device, and then moved to the patch-clamp to record electrophysiological characteristics (off-line magnetic exposure). Despite its universality, real-time observation of the effects of magnetic stimulation on the neurons is more effective (on-line magnetic stimulation). In this study, we selected a standard exposure device for magnetic fields acting on mouse prefrontal cortex pyramidal neurons, and described a new method that a patch-clamp setup was modified to allow on-line magnetic stimulation. By comparing the off-line exposure and on-line stimulation of the same magnetic field intensity and frequency affecting the voltage-gated sodium channel currents, we succeeded in proving the feasibility of the new on-line stimulation device. We also demonstrated that the sodium channel currents of prefrontal cortex pyramidal neurons increased significantly under the 15 Hz sine 1 mT, and 2 mT off-line magnetic field exposure and under the 1 mT and 2 mT on-line magnetic stimulation, and the rate of acceleration was most significant on 2 mT on-line magnetic stimulation. This study described the development of a new on-line magnetic stimulator and successfully demonstrated its practicability for scientific stimulation of neurons.

  10. Elevated potassium elicits recurrent surges of large GABAA-receptor-mediated post-synaptic currents in hippocampal CA3 pyramidal neurons.

    Science.gov (United States)

    Shin, Damian Seung-Ho; Yu, Wilson; Sutton, Alex; Calos, Megan; Carlen, Peter Louis

    2011-03-01

    Previously, we found that rat hippocampal CA3 interneurons become hyperactive with increasing concentrations of extracellular K(+) up to 10 mM. However, it is unclear how this enhanced interneuronal activity affects pyramidal neurons. Here we voltage-clamped rat hippocampal CA3 pyramidal neurons in vitro at 0 mV to isolate γ-aminobutyric acid (GABA)-activated inhibitory post-synaptic currents (IPSCs) and measured these in artificial cerebrospinal fluid (aCSF) and with 10 mM K(+) bath perfusion. In aCSF, small IPSCs were present with amplitudes of 0.053 ± 0.007 nA and a frequency of 0.27 ± 0.14 Hz. With 10 mM K(+) perfusion, IPSCs increased greatly in frequency and amplitude, culminating in surge events with peak amplitudes of 0.56 ± 0.08 nA, that appeared and disappeared cyclically with durations lasting 2.02 ± 0.37 min repeatedly, up to 10 times over a 30-min bath perfusion of elevated K(+). These large IPSCs were GABA(A)-receptor mediated and did not involve significant desensitization of this receptor. Perfusion of a GABA transporter inhibitor (NO-711), glutamate receptor inhibitors CNQX and APV, or a gap junctional blocker (carbenoxolone) prevented the resurgence of large IPSCs. Pressure ejected sucrose resulted in the abolishment of subsequent surges. No elevated K(+)-mediated surges were observed in CA3 interneurons from the stratum oriens layer. In conclusion, these cyclic large IPSC events observable in CA3 pyramidal neurons in 10 mM KCl may be due to transient GABA depletion from continuously active interneuronal afferents.

  11. Low Concentrations of Alcohol Inhibit BDNF-Dependent GABAergic Plasticity via L-type Ca2+ channel Inhibition in Developing CA3 Hippocampal Pyramidal Neurons

    OpenAIRE

    Zucca, Stefano; Valenzuela, C. Fernando

    2010-01-01

    Fetal Alcohol Spectrum Disorder (FASD) is associated with learning and memory alterations that could be, in part, a consequence of hippocampal damage. The CA3 hippocampal subfield is one of the regions affected by ethanol (EtOH), including exposure during the 3rd trimester-equivalent (i.e. neonatal period in rats). However, the mechanism of action of EtOH is poorly understood. In CA3 pyramidal neurons from neonatal rats, dendritic BDNF release causes long-term potentiation of the frequency of...

  12. Enhanced intrinsic excitability and EPSP-spike coupling accompany enriched environment-induced facilitation of LTP in hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Malik, Ruchi; Chattarji, Sumantra

    2012-03-01

    Environmental enrichment (EE) is a well-established paradigm for studying naturally occurring changes in synaptic efficacy in the hippocampus that underlie experience-induced modulation of learning and memory in rodents. Earlier research on the effects of EE on hippocampal plasticity focused on long-term potentiation (LTP). Whereas many of these studies investigated changes in synaptic weight, little is known about potential contributions of neuronal excitability to EE-induced plasticity. Here, using whole-cell recordings in hippocampal slices, we address this gap by analyzing the impact of EE on both synaptic plasticity and intrinsic excitability of hippocampal CA1 pyramidal neurons. Consistent with earlier reports, EE increased contextual fear memory and dendritic spine density on CA1 cells. Furthermore, EE facilitated LTP at Schaffer collateral inputs to CA1 pyramidal neurons. Analysis of the underlying causes for enhanced LTP shows EE to increase the frequency but not amplitude of miniature excitatory postsynaptic currents. However, presynaptic release probability, assayed using paired-pulse ratios and use-dependent block of N-methyl-d-aspartate receptor currents, was not affected. Furthermore, CA1 neurons fired more action potentials (APs) in response to somatic depolarization, as well as during the induction of LTP. EE also reduced spiking threshold and after-hyperpolarization amplitude. Strikingly, this EE-induced increase in excitability caused the same-sized excitatory postsynaptic potential to fire more APs. Together, these findings suggest that EE may enhance the capacity for plasticity in CA1 neurons, not only by strengthening synapses but also by enhancing their efficacy to fire spikes-and the two combine to act as an effective substrate for amplifying LTP.

  13. Pituitary adenylate cyclase-activating polypeptide (PACAP) inhibits the slow afterhyperpolarizing current sIAHP in CA1 pyramidal neurons by activating multiple signaling pathways

    Science.gov (United States)

    Taylor, Ruth DT; Madsen, Marita Grønning; Krause, Michael; Sampedro-Castañeda, Marisol; Stocker, Martin; Pedarzani, Paola

    2014-01-01

    The slow afterhyperpolarizing current (sIAHP) is a calcium-dependent potassium current that underlies the late phase of spike frequency adaptation in hippocampal and neocortical neurons. sIAHP is a well-known target of modulation by several neurotransmitters acting via the cyclic AMP (cAMP) and protein kinase A (PKA)-dependent pathway. The neuropeptide pituitary adenylate cyclase activating peptide (PACAP) and its receptors are present in the hippocampal formation. In this study we have investigated the effect of PACAP on the sIAHP and the signal transduction pathway used to modulate intrinsic excitability of hippocampal pyramidal neurons. We show that PACAP inhibits the sIAHP, resulting in a decrease of spike frequency adaptation, in rat CA1 pyramidal cells. The suppression of sIAHP by PACAP is mediated by PAC1 and VPAC1 receptors. Inhibition of PKA reduced the effect of PACAP on sIAHP, suggesting that PACAP exerts part of its inhibitory effect on sIAHP by increasing cAMP and activating PKA. The suppression of sIAHP by PACAP was also strongly hindered by the inhibition of p38 MAP kinase (p38 MAPK). Concomitant inhibition of PKA and p38 MAPK indicates that these two kinases act in a sequential manner in the same pathway leading to the suppression of sIAHP. Conversely, protein kinase C is not part of the signal transduction pathway used by PACAP to inhibit sIAHP in CA1 neurons. Our results show that PACAP enhances the excitability of CA1 pyramidal neurons by inhibiting the sIAHP through the activation of multiple signaling pathways, most prominently cAMP/PKA and p38 MAPK. Our findings disclose a novel modulatory action of p38 MAPK on intrinsic excitability and the sIAHP, underscoring the role of this current as a neuromodulatory hub regulated by multiple protein kinases in cortical neurons. © 2013 The Authors. Hippocampus Published by Wiley Periodicals, Inc. PMID:23996525

  14. Resurgent Na+ current in pyramidal neurones of rat perirhinal cortex: axonal location of channels and contribution to depolarizing drive during repetitive firing

    Science.gov (United States)

    Castelli, Loretta; Biella, Gerardo; Toselli, Mauro; Magistretti, Jacopo

    2007-01-01

    The perirhinal cortex (PRC) is a supra-modal cortical area that collects and integrates information originating from uni- and multi-modal neocortical regions and directed to the hippocampus. The mechanisms that underlie the specific excitable properties of the different PRC neuronal types are still largely unknown, and their elucidation may be important in understanding the integrative functions of PRC. In this study we investigated the expression and properties of resurgent Na+ current (INaR) in pyramidal neurones of rat PRC area 35 (layer II). Patch-clamp experiments in acute PRC slices were first carried out. A measurable INaR was expressed by a large majority of neurones (31 out of 35 cells). INaR appeared as an inward, slowly decaying current elicited upon step repolarization after depolarizations sufficient to induce nearly complete inactivation of the transient Na+ current (INaT). INaR had a peak amplitude of ∼2.5% that of INaT, and showed the typical biophysical properties also observed in other neuronal types (i.e. cerebellar Purkinje and granule cells), including a bell-shaped current–voltage relationship with a peak at approximately −40 mV, and a characteristic acceleration of activation and decay speed at potentials negative to −45 mV. Current-clamp experiments were then carried out in which repetitive action-potential discharge at various frequencies was induced with depolarizing current injection. The voltage signals thus obtained were then used as command waveforms for voltage-clamp recordings. These experiments showed that a Na+ current identifiable as INaR activates in the early interspike phase even at relatively high firing frequencies (20 Hz), thereby contributing to the depolarizing drive and possibly enhancing repetitive discharge. In acutely dissociated area 35 layer II neurones, as well as in nucleated patches from the same neurones, INaR was never observed, despite the presence of typical INaTs. Since in both preparations neuronal

  15. Slow recovery from inactivation of Na+ channels underlies the activity-dependent attenuation of dendritic action potentials in hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Colbert, C M; Magee, J C; Hoffman, D A; Johnston, D

    1997-09-01

    Na+ action potentials propagate into the dendrites of pyramidal neurons driving an influx of Ca2+ that seems to be important for associative synaptic plasticity. During repetitive (10-50 Hz) firing, dendritic action potentials display a marked and prolonged voltage-dependent decrease in amplitude. Such a decrease is not apparent in somatic action potentials. We investigated the mechanisms of the different activity dependence of somatic and dendritic action potentials in CA1 pyramidal neurons of adult rats using whole-cell and cell-attached patch-clamp methods. There were three main findings. First, dendritic Na+ currents decreased in amplitude when repeatedly activated by brief (2 msec) depolarizations. Recovery was slow and voltage-dependent. Second, Na+ currents decreased much less in somatic than in dendritic patches. Third, although K+ currents remained constant during trains, K+ currents were necessary for dendritic action potential amplitude to decrease in whole-cell experiments. These results suggest that regional differences in Na+ and K+ channels determine the differences in the activity dependence of somatic and dendritic action potential amplitudes.

  16. Brain-derived neurotrophic factor-mediated retrograde signaling required for the induction of long-term potentiation at inhibitory synapses of visual cortical pyramidal neurons.

    Science.gov (United States)

    Inagaki, Tsuyoshi; Begum, Tahamina; Reza, Faruque; Horibe, Shoko; Inaba, Mie; Yoshimura, Yumiko; Komatsu, Yukio

    2008-06-01

    High-frequency stimulation (HFS) induces long-term potentiation (LTP) at inhibitory synapses of layer 5 pyramidal neurons in developing rat visual cortex. This LTP requires postsynaptic Ca2+ rise for induction, while the maintenance mechanism is present at the presynaptic site, suggesting presynaptic LTP expression and the necessity of retrograde signaling. We investigated whether the supposed signal is mediated by brain-derived neurotrophic factor (BDNF), which is expressed in pyramidal neurons but not inhibitory interneurons. LTP did not occur when HFS was applied in the presence of the Trk receptor tyrosine kinase inhibitor K252a in the perfusion medium. HFS produced LTP when bath application of K252a was started after HFS or when K252a was loaded into postsynaptic cells. LTP did not occur in the presence of TrkB-IgG scavenging BDNF or function-blocking anti-BDNF antibody in the medium. In cells loaded with the Ca2+ chelator BAPTA, the addition of BDNF to the medium enabled HFS to induce LTP without affecting baseline synaptic transmission. These results suggest that BDNF released from postsynaptic cells activates presynaptic TrkB, leading to LTP. Because BDNF, expressed activity dependently, regulates the maturation of cortical inhibition, inhibitory LTP may contribute to this developmental process, and hence experience-dependent functional maturation of visual cortex.

  17. Aβ induces acute depression of excitatory glutamatergic synaptic transmission through distinct phosphatase-dependent mechanisms in rat CA1 pyramidal neurons.

    Science.gov (United States)

    Yao, Wen; Zou, Hao-Jun; Sun, Da; Ren, Si-Qiang

    2013-06-17

    Beta-amyloid peptide (Aβ) has a causal role in the pathophysiology of Alzheimer's disease (AD). Recent studies indicate that Aβ can disrupt excitatory glutamatergic synaptic function at synaptic level. However, the underlying mechanisms remain obscure. In this study, we recorded evoked and spontaneous EPSCs in hippocampal CA1 pyramidal neurons via whole-cell voltage-clamping methods and found that 1 μM Aβ can induce acute depression of basal glutamatergic synaptic transmission through both presynaptic and postsynaptic dysfunction. Moreover, we also found that Aβ-induced both presynaptic and postsynaptic dysfunction can be reversed by the inhibitor of protein phosphatase 2B (PP2B), FK506, whereas only postsynaptic disruption can be ameliorated by the inhibitor of PP1/PP2A, Okadaic acid (OA). These results indicate that PP1/PP2A and PP2B have overlapping but not identical functions in Aβ-induced acute depression of excitatory glutamatergic synaptic transmission of hippocampal CA1 pyramidal neurons.

  18. Conditional ablation of neuroligin-1 in CA1 pyramidal neurons blocks LTP by a cell-autonomous NMDA receptor-independent mechanism

    Science.gov (United States)

    Jiang, Man; Polepalli, Jai; Chen, Lulu Y.; Zhang, Bo; Südhof, Thomas C.; Malenka, Robert C.

    2016-01-01

    Neuroligins are postsynaptic cell-adhesion molecules implicated in autism and other neuropsychiatric disorders. Despite extensive work, the role of neuroligins in synapse function and plasticity, especially NMDA receptor (NMDAR)-dependent LTP, remains unclear. To establish which synaptic functions unequivocally require neuroligins, we analyzed single and triple conditional knockout (cKO) mice for all three major neuroligin isoforms (NL1-NL3). We inactivated neuroligins by stereotactic viral expression of Cre-recombinase in hippocampal CA1 region pyramidal neurons at postnatal day 0 (P0) or day 21 (P21), and measured synaptic function, synaptic plasticity, and spine numbers in acute hippocampal slices 2–3 weeks later. Surprisingly, we find that ablation of neuroligins in newborn or juvenile mice only modestly impaired basal synaptic function in hippocampus, and caused no alteration in postsynaptic spine numbers. However, triple cKO of NL1-NL3 or single cKO of NL1 impaired NMDAR-mediated excitatory postsynaptic currents (NMDAR EPSCs), and abolished NMDAR-dependent LTP. Strikingly, the NL1 cKO also abolished LTP elicited by activation of L-type Ca2+-channels during blockade of NMDARs. These findings demonstrate that neuroligins are generally not essential for synapse formation in CA1 pyramidal neurons but shape synaptic properties and that NL1 specifically is required for LTP induced by postsynaptic Ca2+-elevations, a function which may contribute to the pathophysiological role of neuroligins in brain disorders. PMID:27217145

  19. Latent N-methyl-D-aspartate receptors in the recurrent excitatory pathway between hippocampal CA1 pyramidal neurons: Ca(2+)-dependent activation by blocking A1 adenosine receptors.

    Science.gov (United States)

    Klishin, A; Tsintsadze, T; Lozovaya, N; Krishtal, O

    1995-01-01

    When performed at increased external [Ca2+]/[Mg2+] ratio (2.5 mM/0.5 mM), temporary block of A1 adenosine receptors in hippocampus [by 8-cyclopentyltheophylline (CPT)] leads to a dramatic and irreversible change in the excitatory postsynaptic current (EPSC) evoked by Schaffer collateral/commissural (SCC) stimulation and recorded by in situ patch clamp in CA1 pyramidal neurons. The duration of the EPSC becomes stimulus dependent, increasing with increase in stimulus strength. The later occurring component of the EPSC is carried through N-methyl-D-aspartate (NMDA) receptor-operated channels but disappears under either the NMDA antagonist 2-amino-5-phosphonovaleric acid (APV) or the non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). These findings indicate that the late component of the SCC-evoked EPSC is polysynaptic: predominantly non-NMDA receptor-mediated SCC inputs excite CA1 neurons that recurrently excite each other by predominantly NDMA receptor-mediated synapses. These recurrent connections are normally silent but become active after CPT treatment, leading to enhancement of the late component of the EPSC. The activity of these connections is maintained for at least 2 hr after CPT removal. When all functional NMDA receptors are blocked by dizocilpine maleate (MK-801), subsequent application of CPT leads to a partial reappearance of NMDA receptor-mediated EPSCs evoked by SCC stimulation, indicating that latent NMDA receptors are recruited. Altogether, these findings indicate the existence of a powerful system of NMDA receptor-mediated synaptic contacts in SCC input to hippocampal CA1 pyramidal neurons and probably also in reciprocal connections between these neurons, which in the usual preparation are kept latent by activity of A1 receptors. PMID:8618915

  20. Characterization of single voltage-gated Na+ and Ca2+ channels in apical dendrites of rat CA1 pyramidal neurons.

    Science.gov (United States)

    Magee, J C; Johnston, D

    1995-08-15

    1. We have used dendrite-attached patch-clamp techniques to record single Na+ and Ca2+ channel activity from the apical dendrites (up to 350 microns away from soma) of CA1 pyramidal neurons in rat hippocampal slices (ages: 2-8 weeks). 2. Na+ channels were found in every patch examined (range: 2 to > 20 channels per patch). Channel openings, which had a slope conductance of 15 +/- 0.3 pS (mean +/- S.E.M.), began with test commands to around -50 mV and consisted of both early transient channel activity and also later occurring prolonged openings of 5-15 ms. All Na+ channel activity was suppressed by inclusion of TTX (1 microM) in the recording pipette. 3. Ca2+ channel activity was recorded in about 80% of the patches examined (range: 1 to > 10 channels per patch). Several types of channel behaviour were observed in these patches. Single channel recordings in 110 mM BaCl2, revealed an approximately 10 pS channel of small unitary current amplitude (-0.5 pA at -20 mV). These channels began activating at relatively hyperpolarized potentials (-50 mV) and ensemble averages of this low voltage-activated (LVA) channel activity showed rapid inactivation. 4. A somewhat heterogeneous population of high voltage-activated, moderate conductance (HVAm; approximately 17 pS), Ca2+ channel activity was also encountered. These channels exhibited a relatively large unitary amplitude (-0.8 pA at 0 mV) and ensemble averages demonstrated moderate inactivation. The HVAm population of channels could be tentatively subdivided into two separate groups based upon mean channel open times. 5. Less frequently, HVA, large conductance (27 pS) Ca2+ channel activity (HVA1) was also observed. This large unitary amplitude (-1.5 pA at 0 mV) channel activity began with steps to approximately 0 mV and ensemble averages did not show any time-dependent inactivation. The dihydropyridine Ca2+ channel agonist Bay K 8644 (0.5 or 1 microM) was found to characteristically prolong these channel openings. 6. omega

  1. The effects of realistic synaptic distribution and 3D geometry on signal integration and extracellular field generation of hippocampal pyramidal cells and inhibitory neurons

    Directory of Open Access Journals (Sweden)

    Attila I Gulyas

    2016-11-01

    Full Text Available In vivo and in vitro multichannel field and somatic intracellular recordings are frequently used to study mechanisms of network pattern generation. When interpreting these data, neurons are often implicitly considered as electrotonically compact cylinders with a homogeneous distribution of excitatory and inhibitory inputs. However, the actual distributions of dendritic length, diameter, and the densities of excitatory and inhibitory input are non-uniform and cell type-specific. We first review quantitative data on the dendritic structure and synaptic input and output distribution of pyramidal cells and interneurons in the hippocampal CA1 area. Second, using multicompartmental passive models of four different types of neurons, we quantitatively explore the effect of differences in dendritic structure and synaptic distribution on the errors and biases of voltage clamp measurements of inhibitory and excitatory postsynaptic currents. Finally, using the 3-dimensional distribution of dendrites and synaptic inputs we calculate how different inhibitory and excitatory inputs contribute to the generation of local field potential in the hippocampus. We analyze these effects at different realistic background activity levels as synaptic bombardment influences neuronal conductance and thus the propagation of signals in the dendritic tree.We conclude that, since dendrites are electrotonically long and entangled in 3D, somatic intracellular and field potential recordings miss the majority of dendritic events in some cell types, and thus overemphasize the importance of perisomatic inhibitory inputs and belittle the importance of complex dendritic processing. Modeling results also suggest that pyramidal cells and inhibitory neurons probably use different input integration strategies. In pyramidal cells, second- and higher-order thin dendrites are relatively well-isolated from each other, which may support branch-specific local processing as suggested by studies

  2. Genotype-specific effects of Mecp2 loss-of-function on morphology of Layer V pyramidal neurons in heterozygous female Rett Syndrome model mice

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    Leslie eRietveld

    2015-04-01

    Full Text Available Rett Syndrome (RTT is a progressive neurological disorder primarily caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2. The heterozygous female brain consists of mosaic of neurons containing both wildtype MeCP2 (MeCP2+ and mutant MeCP2 (MeCP2-. 3-dimensional morphological analysis was performed on individually genotyped layer V pyramidal neurons in the primary motor cortex of heterozygous (Mecp2+/- and wild-type (Mecp2+/+ female mice (>6 mo. from the Mecp2tm1.1Jae line. Comparing basal dendrite morphology, soma and nuclear size of MeCP2+ to MeCP2- neurons reveals a significant cell autonomous, genotype specific effect of Mecp2. MeCP2- neurons have 15% less total basal dendritic length, predominantly in the region 70-130 μm from the cell body and on average 3 fewer branch points, specifically loss in the 2nd and 3rd branch orders. Soma and nuclear areas of neurons of mice were analyzed across a range of ages (5-21 mo. and X-chromosome inactivation (XCI ratios (12-56%. On average, MeCP2- somata and nuclei were 15% and 13% smaller than MeCP2+ neurons respectively. In most respects branching morphology of neurons in wild-type brains (MeCP2 WT was not distinguishable from MeCP2+ but somata and nuclei of MeCP2 WT neurons were larger than those of MeCP2+ neurons. These data reveal cell autonomous effects of Mecp2 mutation on dendritic morphology, but also suggest non-cell autonomous effects with respect to cell size. MeCP2+ and MeCP2- neuron sizes were not correlated with age, but were correlated with XCI ratio. Unexpectedly the MeCP2- neurons were smallest in brains where the XCI ratio was highly skewed towards MeCP2+, i.e. wild-type. This raises the possibility of cell non-autonomous effects that act through mechanisms other than globally secreted factors; perhaps competition for synaptic connections influences cell size and morphology in the genotypically mosaic brain of RTT model mice.

  3. Genotype-specific effects of Mecp2 loss-of-function on morphology of Layer V pyramidal neurons in heterozygous female Rett syndrome model mice.

    Science.gov (United States)

    Rietveld, Leslie; Stuss, David P; McPhee, David; Delaney, Kerry R

    2015-01-01

    Rett syndrome (RTT) is a progressive neurological disorder primarily caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). The heterozygous female brain consists of mosaic of neurons containing both wild-type MeCP2 (MeCP2+) and mutant MeCP2 (MeCP2-). Three-dimensional morphological analysis was performed on individually genotyped layer V pyramidal neurons in the primary motor cortex of heterozygous (Mecp2(+/-) ) and wild-type (Mecp2(+/+) ) female mice ( > 6 mo.) from the Mecp2(tm1.1Jae) line. Comparing basal dendrite morphology, soma and nuclear size of MeCP2+ to MeCP2- neurons reveals a significant cell autonomous, genotype specific effect of Mecp2. MeCP2- neurons have 15% less total basal dendritic length, predominantly in the region 70-130 μm from the cell body and on average three fewer branch points, specifically loss in the second and third branch orders. Soma and nuclear areas of neurons of mice were analyzed across a range of ages (5-21 mo.) and X-chromosome inactivation (XCI) ratios (12-56%). On average, MeCP2- somata and nuclei were 15 and 13% smaller than MeCP2+ neurons respectively. In most respects branching morphology of neurons in wild-type brains (MeCP2 WT) was not distinguishable from MeCP2+ but somata and nuclei of MeCP2 WT neurons were larger than those of MeCP2+ neurons. These data reveal cell autonomous effects of Mecp2 mutation on dendritic morphology, but also suggest non-cell autonomous effects with respect to cell size. MeCP2+ and MeCP2- neuron sizes were not correlated with age, but were correlated with XCI ratio. Unexpectedly the MeCP2- neurons were smallest in brains where the XCI ratio was highly skewed toward MeCP2+, i.e., wild-type. This raises the possibility of cell non-autonomous effects that act through mechanisms other than globally secreted factors; perhaps competition for synaptic connections influences cell size and morphology in the genotypically mosaic brain of RTT model mice.

  4. Phasic and tonic type A γ-Aminobutryic acid receptor mediated effect of Withania somnifera on mice hippocampal CA1 pyramidal Neurons

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    Janardhan Prasad Bhattarai

    2014-01-01

    Full Text Available Background: In Nepali and Indian system of traditional medicine, Withania somnifera (WS is considered as a rejuvenative medicine to maintain physical and mental health and has also been shown to improve memory consolidation. Objective: In this study, a methanolic extract of WS (mWS was applied on mice hippocampal CA1 neurons to identify the receptors activated by the WS. Materials and Methods: The whole cell patch clamp recordings were performed on CA1 pyramidal neurons from immature mice (7-20 postnatal days. The cells were voltage clamped at -60 mV. Extract of WS root were applied to identify the effect of mWS. Results: The application of mWS (400 ng/μl induced remarkable inward currents (-158.1 ± 28.08 pA, n = 26 on the CA1 pyramidal neurons. These inward currents were not only reproducible but also concentration dependent. mWS-induced inward currents remained persistent in the presence of amino acid receptor blocking cocktail (AARBC containing blockers for the ionotropic glutamate receptors, glycine receptors and voltage-gated Na + channel (Control: -200.3 ± 55.42 pA, AARBC: -151.5 ± 40.58 pA, P > 0.05 suggesting that most of the responses by mWS are postsynaptic events. Interestingly, these inward currents were almost completely blocked by broad GABA A receptor antagonist, bicuculline- 20 μM (BIC (BIC: -1.46 ± 1.4 pA, P < 0.001, but only partially by synaptic GABA A receptor blocker gabazine (1 μM (GBZ: -18.26 ± 4.70 pA, P < 0.01. Conclusion: These results suggest that WS acts on synaptic/extrasynaptic GABA A receptors and may play an important role in the process of memory and neuroprotection via activation of synaptic and extrasynaptic GABA A receptors.

  5. Dopaminergic Modulation of Excitatory Transmission in the Anterior Cingulate Cortex of Adult Mice

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    Darvish-Ghane, Soroush; Yamanaka, Manabu

    2016-01-01

    Dopamine (DA) possesses potent neuromodulatory properties in the central nervous system. In the anterior cingulate cortex, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPAR) are key ion channels in mediating nerve injury induced long-term potentiation (LTP) and chronic pain phenotype. In the present study, we reported the effects of DA on glutamate mediated excitatory post-synaptic currents (EPSCs) in pyramidal neurons of layer II/III of the ACC in adult mice. Bath application of DA (50 μM) caused a significant, rapid and reversible inhibition of evoked EPSCs (eEPSC). This inhibitory effect is dose-related and was absent in lower concentration of DA (5 μM). Furthermore, selective postsynaptic application of GDP-β-S (1.6 mM) in the internal solution completely abolished the inhibitory effects of DA (50 μM). We also investigated modulation of spontaneous EPSCs (sEPSCs) and TTX sensitive, miniature EPSCs (mEPSCs) by DA. Our results indicated mixed effects of potentiation and inhibition of frequency and amplitude for sEPSCs and mEPSCs. Furthermore, high doses of SCH23390 (100 μM) and sulpiride (100 μM) revealed that, inhibition of eEPSCs is mediated by postsynaptic D2-receptors (D2R). Our finding posits a pre- and postsynaptic mode of pyramidal neuron EPSC modulation in mice ACC by DA. PMID:27317578

  6. Low concentrations of alcohol inhibit BDNF-dependent GABAergic plasticity via L-type Ca2+ channel inhibition in developing CA3 hippocampal pyramidal neurons.

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    Zucca, Stefano; Valenzuela, C Fernando

    2010-05-12

    Fetal alcohol spectrum disorder (FASD) is associated with learning and memory alterations that could be, in part, a consequence of hippocampal damage. The CA3 hippocampal subfield is one of the regions affected by ethanol (EtOH), including exposure during the third trimester-equivalent (i.e., neonatal period in rats). However, the mechanism of action of EtOH is poorly understood. In CA3 pyramidal neurons from neonatal rats, dendritic BDNF release causes long-term potentiation of the frequency of GABAA receptor-mediated spontaneous postsynaptic currents (LTP-GABAA) and this mechanism is thought to play a role in GABAergic synapse maturation. Here, we show that short- and long-term exposure of neonatal male rats to low EtOH concentrations abolishes LTP-GABAA by inhibiting L-type voltage-gated Ca2+ channels. These findings support the recommendation that even light drinking should be avoided during pregnancy.

  7. Glutamic acid decarboxylase-67-positive hippocampal interneurons undergo a permanent reduction in number following kainic acid-induced degeneration of ca3 pyramidal neurons.

    Science.gov (United States)

    Shetty, A K; Turner, D A

    2001-06-01

    Kainic acid (KA)-induced degeneration of CA3 pyramidal neurons leads to synaptic reorganization and hyperexcitability in both dentate gyrus and CA1 region of the hippocampus. We hypothesize that the substrate for hippocampal inhibitory circuitry incurs significant and permanent alterations following degeneration of CA3 pyramidal neurons. We quantified changes in interneuron density (N(v)) in all strata of the dentate gyrus and the CA1 and CA3 subfields of adult rats at 1, 4, and 6 months following intracerebroventricular (icv) KA administration, using glutamic acid decarboxylase-67 (GAD-67) immunocytochemistry. At 1 month postlesion, GAD-67-positive interneuron density was significantly reduced in all strata of every hippocampal region except stratum pyramidale of CA1. The reduction in GAD-67-positive interneuron density either persisted or exacerbated at 4 and 6 months postlesion in every stratum of all hippocampal regions. Further, the soma of remaining GAD-67-positive interneurons in dentate gyrus and CA3 subfield showed significant hypertrophy. Thus, both permanent reductions in the density of GAD-67-positive interneurons in all hippocampal regions and somatic hypertrophy of remaining GAD-67-positive interneurons in dentate gyrus and CA3 subfield occur following icv KA. In contrast, the density of interneurons visualized with Nissl in CA1 and CA3 regions was nearly equivalent to that in the intact hippocampus at all postlesion time points. Collectively, these results suggest that persistent reductions in GAD-67-positive interneuron density observed throughout the hippocampus following CA3 lesion are largely due to a permanent loss of GAD-67 expression in a significant fraction of interneurons, rather than widespread degeneration of interneurons. Nevertheless, a persistent decrease in interneuron activity, as evidenced by permanent down-regulation of GAD-67 in a major fraction of interneurons, would likely enhance the degree of hyperexcitability in the CA3

  8. Activation of Pyramidal Neurons in Mouse Medial Prefrontal Cortex Enhances Food-Seeking Behavior While Reducing Impulsivity in the Absence of an Effect on Food Intake.

    Science.gov (United States)

    Warthen, Daniel M; Lambeth, Philip S; Ottolini, Matteo; Shi, Yingtang; Barker, Bryan Scot; Gaykema, Ronald P; Newmyer, Brandon A; Joy-Gaba, Jonathan; Ohmura, Yu; Perez-Reyes, Edward; Güler, Ali D; Patel, Manoj K; Scott, Michael M

    2016-01-01

    The medial prefrontal cortex (mPFC) is involved in a wide range of executive cognitive functions, including reward evaluation, decision-making, memory extinction, mood, and task switching. Manipulation of the mPFC has been shown to alter food intake and food reward valuation, but whether exclusive stimulation of mPFC pyramidal neurons (PN), which form the principle output of the mPFC, is sufficient to mediate food rewarded instrumental behavior is unknown. We sought to determine the behavioral consequences of manipulating mPFC output by exciting PN in mouse mPFC during performance of a panel of behavioral assays, focusing on food reward. We found that increasing mPFC pyramidal cell output using designer receptors exclusively activated by designer drugs (DREADD) enhanced performance in instrumental food reward assays that assess food seeking behavior, while sparing effects on affect and food intake. Specifically, activation of mPFC PN enhanced operant responding for food reward, reinstatement of palatable food seeking, and suppression of impulsive responding for food reward. Conversely, activation of mPFC PN had no effect on unconditioned food intake, social interaction, or behavior in an open field. Furthermore, we found that behavioral outcome is influenced by the degree of mPFC activation, with a low drive sufficient to enhance operant responding and a higher drive required to alter impulsivity. Additionally, we provide data demonstrating that DREADD stimulation involves a nitric oxide (NO) synthase dependent pathway, similar to endogenous muscarinic M3 receptor stimulation, a finding that provides novel mechanistic insight into an increasingly widespread method of remote neuronal control.

  9. Roles of HIF-1α, VEGF, and NF-κB in Ischemic Preconditioning-Mediated Neuroprotection of Hippocampal CA1 Pyramidal Neurons Against a Subsequent Transient Cerebral Ischemia.

    Science.gov (United States)

    Lee, Jae-Chul; Tae, Hyun-Jin; Kim, In Hye; Cho, Jeong Hwi; Lee, Tae-Kyeong; Park, Joon Ha; Ahn, Ji Hyeon; Choi, Soo Young; Bai, Hui Chen; Shin, Bich-Na; Cho, Geum-Sil; Kim, Dae Won; Kang, Il Jun; Kwon, Young-Guen; Kim, Young-Myeong; Won, Moo-Ho; Bae, Eun Joo

    2016-10-26

    Ischemic preconditioning (IPC) provides neuroprotection against subsequent severe ischemic insults by specific mechanisms. We tested the hypothesis that IPC attenuates post-ischemic neuronal death in the gerbil hippocampal CA1 region (CA1) throughout hypoxia inducible factor-1α (HIF-1α) and its associated factors such as vascular endothelial growth factor (VEGF) and nuclear factor-kappa B (NF-κB). Lethal ischemia (LI) without IPC increased expressions of HIF-1α, VEGF, and p-IκB-α (/and translocation of NF-κB p65 into nucleus) in CA1 pyramidal neurons at 12 h and/or 1-day post-LI; thereafter, their expressions were decreased in the CA1 pyramidal neurons with time and newly expressed in non-pyramidal cells (pericytes), and the CA1 pyramidal neurons were dead at 5-day post-LI, and, at this point in time, their immunoreactivities were newly expressed in pericytes. In animals with IPC subjected to LI (IPC/LI)-group), CA1 pyramidal neurons were well protected, and expressions of HIF-1α, VEGF, and p-IκB-α (/and translocation of NF-κB p65 into nucleus) were significantly increased compared to the sham-group and maintained after LI. Whereas, treatment with 2ME2 (a HIF-1α inhibitor) into the IPC/LI-group did not preserve the IPC-mediated increases of HIF-1α, VEGF, and p-IκB-α (/and translocation of NF-κB p65 into nucleus) expressions and did not show IPC-mediated neuroprotection. In brief, IPC protected CA1 pyramidal neurons from LI by upregulation of HIF-1α, VEGF, and p-IκB-α expressions. This study suggests that IPC increases HIF-1α expression in CA1 pyramidal neurons, which enhances VEGF expression and NF-κB activation and that IPC may be a strategy for a therapeutic intervention of cerebral ischemic injury.

  10. Activity-dependent release of endogenous BDNF from mossy fibers evokes a TRPC3 current and Ca2+ elevations in CA3 pyramidal neurons.

    Science.gov (United States)

    Li, Yong; Calfa, Gaston; Inoue, Takafumi; Amaral, Michelle D; Pozzo-Miller, Lucas

    2010-05-01

    Multiple studies have demonstrated that brain-derived neurotrophic factor (BDNF) is a potent modulator of neuronal structure and function in the hippocampus. However, the majority of studies to date have relied on the application of recombinant BDNF. We herein report that endogenous BDNF, released via theta burst stimulation of mossy fibers (MF), elicits a slowly developing cationic current and intracellular Ca(2+) elevations in CA3 pyramidal neurons with the same pharmacological profile of the transient receptor potential canonical 3 (TRPC3)-mediated I(BDNF) activated in CA1 neurons by brief localized applications of recombinant BDNF. Indeed, sensitivity to both the extracellular BDNF scavenger tropomyosin-related kinase B (TrkB)-IgG and small hairpin interference RNA-mediated TRPC3 channel knockdown confirms the identity of this conductance as such, henceforth-denoted MF-I(BDNF). Consistent with such activity-dependent release of BDNF, these MF-I(BDNF) responses were insensitive to manipulations of extracellular Zn(2+) concentration. Brief theta burst stimulation of MFs induced a long-lasting depression in the amplitude of excitatory postsynaptic currents (EPSCs) mediated by both AMPA and N-methyl-d-aspartate (NMDA) receptors without changes in the NMDA receptor/AMPA receptor ratio, suggesting a reduction in neurotransmitter release. This depression of NMDAR-mediated EPSCs required activity-dependent release of endogenous BDNF from MFs and activation of Trk receptors, as it was sensitive to the extracellular BDNF scavenger TrkB-IgG and the tyrosine kinase inhibitor k-252b. These results uncovered the most immediate response to endogenously released--native--BDNF in hippocampal neurons and lend further credence to the relevance of BDNF signaling for synaptic function in the hippocampus.

  11. Age- and location-dependent differences in store depletion-induced h-channel plasticity in hippocampal pyramidal neurons

    OpenAIRE

    Clemens, Ann M.; Johnston, Daniel

    2013-01-01

    Disruptions of endoplasmic reticulum (ER) Ca2+ homeostasis are heavily linked to neuronal pathology. Depletion of ER Ca2+ stores can result in cellular dysfunction and potentially cell death, although adaptive processes exist to aid in survival. We examined the age and region dependence of one postulated, adaptive response to ER store-depletion (SD), hyperpolarization-activated cation-nonspecific (h)-channel plasticity in neurons of the dorsal and ventral hippocampus (DHC and VHC, respectivel...

  12. Fast oscillatory activity in the anterior cingulate cortex: dopaminergic modulation and efect of perineuronal net loss

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    Pascal eSteullet

    2014-08-01

    Full Text Available Dopamine release in the prefrontal cortex plays a critical role in cognitive function such as working memory, attention and planning. Dopamine exerts complex modulation on excitability of pyramidal neurons and interneurons, and regulates excitatory and inhibitory synaptic transmission. Because of the complexity of this modulation, it is difficult to fully comprehend the effect of dopamine on neuronal network activity. In this study, we investigated the effect of dopamine on local high-frequency oscillatory neuronal activity (in  band in slices of the mouse anterior cingulate cortex (ACC. We found that dopamine enhanced the power of these oscillations induced by kainate and carbachol, but did not affect their peak frequency. Activation of D2R and in a lesser degree D1R increased the oscillation power, while activation of D4R had no effect. These high-frequency oscillations in the ACC relied on both phasic inhibitory and excitatory transmission and functional gap junctions. Thus, dopamine released in the ACC promotes high-frequency synchronized local cortical activity which is known to favor information transfer, fast selection and binding of distributed neuronal responses. Finally, the power of these oscillations was significantly enhanced after degradation of the perineuronal nets enwrapping most parvalbumin interneurons. This study provides new insights for a better understanding of the abnormal prefrontal gamma activity in schizophrenia patients who display prefrontal anomalies of both the dopaminergic system and the perineuronal nets.

  13. Enlargement of Axo-Somatic Contacts Formed by GAD-Immunoreactive Axon Terminals onto Layer V Pyramidal Neurons in the Medial Prefrontal Cortex of Adolescent Female Mice Is Associated with Suppression of Food Restriction-Evoked Hyperactivity and Resilience to Activity-Based Anorexia.

    Science.gov (United States)

    Chen, Yi-Wen; Wable, Gauri Satish; Chowdhury, Tara Gunkali; Aoki, Chiye

    2016-06-01

    Many, but not all, adolescent female mice that are exposed to a running wheel while food restricted (FR) become excessive wheel runners, choosing to run even during the hours of food availability, to the point of death. This phenomenon is called activity-based anorexia (ABA). We used electron microscopic immunocytochemistry to ask whether individual differences in ABA resilience may correlate with the lengths of axo-somatic contacts made by GABAergic axon terminals onto layer 5 pyramidal neurons (L5P) in the prefrontal cortex. Contact lengths were, on average, 40% greater for the ABA-induced mice, relative to controls. Correspondingly, the proportion of L5P perikaryal plasma membrane contacted by GABAergic terminals was 45% greater for the ABA mice. Contact lengths in the anterior cingulate cortex correlated negatively and strongly with the overall wheel activity after FR (R = -0.87, P < 0.01), whereas those in the prelimbic cortex correlated negatively with wheel running specifically during the hours of food availability of the FR days (R = -0.84, P < 0.05). These negative correlations support the idea that increases in the glutamic acid decarboxylase (GAD) terminal contact lengths onto L5P contribute toward ABA resilience through suppression of wheel running, a behavior that is intrinsically rewarding and helpful for foraging but maladaptive within a cage.

  14. The role of dendritic action potentials and Ca2+ influx in the induction of homosynaptic long-term depression in hippocampal CA1 pyramidal neurons.

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    Christie, B R; Magee, J C; Johnston, D

    1996-01-01

    Long-term depression (LTD) of synaptic efficacy at CA1 synapses is believed to be a Ca(2+)-dependent process. We used high-speed fluorescence imaging and patch-clamp techniques to quantify the spatial distribution of changes in intracellular Ca2+ accompanying the induction of LTD at Schaffer collateral synapses in CA1 pyramidal neurons. Low-frequency stimulation (3 Hz), which was subthreshold for action potentials, produced small changes in [Ca2+]i and failed to elicit LTD. Increasing the stimulus strength so that action potentials were generated produced both robust LTD and increases in [Ca2+]i. Back-propagating action potentials at 3 Hz in the absence of synaptic stimulation also produced increases in [Ca2+]i, but failed to induce LTD. When subthreshold synaptic stimulation was paired with back-propagating action potentials, however, large increases in [Ca2+]i were observed and robust LTD was induced. The LTD was blocked by the N-methyl-D-aspartate receptor (NMDAr) antagonist APV, and stimulus-induced increases in [Ca2+]i were reduced throughout the neuron under these conditions. The LTD was also dependent on Ca2+ influx via voltage-gated Ca2+ channels (VGCCs), because LTD was severely attenuated or blocked by both nimodipine and Ni2+. These findings suggest that back-propagating action potentials can exert a powerful control over the induction of LTD and that both VGCCs and NMDArs are involved in the induction of this form of plasticity.

  15. Diverse levels of an inwardly rectifying potassium conductance generate heterogeneous neuronal behavior in a population of dorsal cochlear nucleus pyramidal neurons.

    Science.gov (United States)

    Leao, Ricardo M; Li, Shuang; Doiron, Brent; Tzounopoulos, Thanos

    2012-06-01

    Homeostatic mechanisms maintain homogeneous neuronal behavior among neurons that exhibit substantial variability in the expression levels of their ionic conductances. In contrast, the mechanisms, which generate heterogeneous neuronal behavior across a neuronal population, remain poorly understood. We addressed this problem in the dorsal cochlear nucleus, where principal neurons exist in two qualitatively distinct states: spontaneously active or not spontaneously active. Our studies reveal that distinct activity states are generated by the differential levels of a Ba(2+)-sensitive, inwardly rectifying potassium conductance (K(ir)). Variability in K(ir) maximal conductance causes variations in the resting membrane potential (RMP). Low K(ir) conductance depolarizes RMP to voltages above the threshold for activating subthreshold-persistent sodium channels (Na(p)). Once Na(p) channels are activated, the RMP becomes unstable, and spontaneous firing is triggered. Our results provide a biophysical mechanism for generating neural heterogeneity, which may play a role in the encoding of sensory information.

  16. Short-term desensitization of G-protein-activated, inwardly rectifying K+ (GIRK) currents in pyramidal neurons of rat neocortex.

    Science.gov (United States)

    Sickmann, Thomas; Alzheimer, Christian

    2003-10-01

    Whole cell recordings from acutely isolated rat neocortical pyramidal cells were performed to study the kinetics and the mechanisms of short-term desensitization of G-protein-activated, inwardly rectifying K+ (GIRK) currents during prolonged application (5 min) of baclofen, adenosine, or serotonin. Most commonly, desensitization of GIRK currents was characterized by a biphasic time course with average time constants for fast and slow desensitization in the range of 8 and 120 s, respectively. The time constants were independent of the agonist used to evoke the current. The biphasic time course was preserved in perforated-patch recordings, indicating that neither component of desensitization is attributable to cell dialysis. Desensitization of GIRK currents displayed a strong heterologous component in that application of a second agonist substantially reduced the responsiveness to a test agonist. Fast desensitization, but not slow desensitization, was lost in cells loaded with GDP, suggesting that the hydrolysis cycle of G proteins might underlie the initial, rapid current decline. Hydrolysis of phosphatidylinositol biphosphate is an unlikely candidate underlying short-term desensitization, because both components of desensitization were preserved in the presence of the phospholipase C inhibitor U73122. We conclude that short-term desensitization does neither result from receptor downregulation nor from altered channel gating but might involve modifications of the G-protein-dependent pathway that serves to translate receptor activation into channel opening.

  17. Streptozotocin Inhibits Electrophysiological Determinants of Excitatory and Inhibitory Synaptic Transmission in CA1 Pyramidal Neurons of Rat Hippocampal Slices: Reduction of These Effects by Edaravone

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    Ting Ju

    2016-12-01

    Full Text Available Background: Streptozotocin (STZ has served as an agent to generate an Alzheimer's disease (AD model in rats, while edaravone (EDA, a novel free radical scavenger, has recently emerged as an effective treatment for use in vivo and vitro AD models. However, to date, these beneficial effects of EDA have only been clearly demonstrated within STZ-induced animal models of AD and in cell models of AD. A better understanding of the mechanisms of EDA may provide the opportunity for their clinical application in the treatment of AD. Therefore, the purpose of this study was to investigate the underlying mechanisms of STZ and EDA as assessed upon electrophysiological alterations in CA1 pyramidal neurons of rat hippocampal slices. Methods: Through measures of evoked excitatory postsynaptic currents (eEPSCs, AMPAR-mediated eEPSCs (eEPSCsAMPA, evoked inhibitory postsynaptic currents (eIPSCs, evoked excitatory postsynaptic current paired pulse ratio (eEPSC PPR and evoked inhibitory postsynaptic current paired pulse ratio (eIPSC PPR, it was possible to investigate mechanisms as related to the neurotoxicity of STZ and reductions in these effects by EDA. Results: Our results showed that STZ (1000 µM significantly inhibited peak amplitudes of eEPSCs, eEPSCsAMPA and eIPSCs, while EDA (1000 µM attenuated these STZ-induced changes at holding potentials ranging from -60mV to +40 mV for EPSCs and -60mV to +20 mV for IPSCs. Our work also indicated that mean eEPSC PPR were substantially altered by STZ, effects which were partially restored by EDA. In contrast, no significant effects upon eIPSC PPR were obtained in response to STZ and EDA. Conclusion: Our data suggest that STZ inhibits glutamatergic transmission involving pre-synaptic mechanisms and AMPAR, and that STZ inhibits GABAergic transmission by post-synaptic mechanisms within CA1 pyramidal neurons. These effects are attenuated by EDA.

  18. Modulation of Hyperpolarization-Activated Cation Currents (Ih) by Ethanol in Rat Hippocampal CA3 Pyramidal Neurons

    OpenAIRE

    Licheri, Valentina

    2015-01-01

    It is well established that ethanol (EtOH), through the interaction with several membrane proteins, as well as intracellular pathways, is capable to modulate many neuronal function. Recent reports show that EtOH increases the firing rate of hippocampal GABAergic interneurons through the positive modulation of the hyperpolarization-activated cyclic nucleotide-gated (HCN) cation channels. This effect might be consistent with the increase of GABA release from presynaptic terminals...

  19. Progressive effect of beta amyloid peptides accumulation on CA1 pyramidal neurons: a model study suggesting possible treatments

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    Viviana eCulmone

    2012-07-01

    Full Text Available Several independent studies show that accumulation of β-amyloid (Aβ peptides , one of the characteristic hallmark of Alzheimer’s Disease (AD, can affect normal neuronal activity in different ways. However, in spite of intense experimental work to explain the possible underlying mechanisms of action, a comprehensive and congruent understanding is still lacking. Part of the problem might be the opposite ways in which Aβ have been experimentally found to affect the normal activity of a neuron; for example, making a neuron more excitable (by reducing the A- or DR-type K+ currents or less excitable (by reducing synaptic transmission and Na+ current. The overall picture is therefore confusing, since the interplay of many mechanisms makes it difficult to link individual experimental findings with the more general problem of understanding the progression of the disease. This is an important issue, especially for the development of new drugs trying to ameliorate the effects of the disease. We addressed these paradoxes through computational models. We first modeled the different stages of AD by progressively modifying the intrinsic membrane and synaptic properties of a realistic model neuron, while accounting for multiple and different experimental findings and by evaluating the contribution of each mechanism to the overall modulation of the cell’s excitability. We then tested a number of manipulations of channel and synaptic activation properties that could compensate for the effects of Aβ. The model predicts possible therapeutic treatments in terms of pharmacological manipulations of channels’ kinetic and activation properties. The results also suggest how and which mechanisms can be targeted by a drug to restore the original firing conditions.

  20. Kv2 Channel Regulation of Action Potential Repolarization and Firing Patterns in Superior Cervical Ganglion Neurons and Hippocampal CA1 Pyramidal Neurons

    OpenAIRE

    Liu, Pin W.; Bean, Bruce P.

    2014-01-01

    Kv2 family “delayed-rectifier” potassium channels are widely expressed in mammalian neurons. Kv2 channels activate relatively slowly and their contribution to action potential repolarization under physiological conditions has been unclear. We explored the function of Kv2 channels using a Kv2-selective blocker, Guangxitoxin-1E (GxTX-1E). Using acutely isolated neurons, mixed voltage-clamp and current-clamp experiments were done at 37°C to study the physiological kinetics of channel gating and ...

  1. Spatial distributions of GABA receptors and local inhibition of Ca2+ transients studied with GABA uncaging in the dendrites of CA1 pyramidal neurons.

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    Yuya Kanemoto

    Full Text Available GABA (γ-amino-butylic acid-mediated inhibition in the dendrites of CA1 pyramidal neurons was characterized by two-photon uncaging of a caged-GABA compound, BCMACM-GABA, and one-photon uncaging of RuBi-GABA in rat hippocampal slice preparations. Although we found that GABA(A-mediated currents were diffusely distributed along the dendrites, currents elicited at the branch points of the apical dendritic trunk were approximately two times larger than those elsewhere in the dendrite. We examined the inhibitory action of the GABA-induced currents on Ca(2+ transients evoked with a single back-propagating action potential (bAP in oblique dendrites. We found that GABA uncaging selectively inhibited the Ca(2+ transients in the region adjacent (20 µm. Our data indicate that GABA inhibition results in spatially confined inhibition of Ca(2+ transients shortly after bAP, and suggest that this effect is particularly potent at the dendritic branch points where GABA receptors cluster.

  2. A protein phosphatase is involved in the cholinergic suppression of the Ca(2+)-activated K(+) current sI(AHP) in hippocampal pyramidal neurons.

    Science.gov (United States)

    Krause, M; Pedarzani, P

    2000-04-27

    The slow calcium-activated potassium current sI(AHP) underlies spike-frequency adaptation and has a substantial impact on the excitability of hippocampal CA1 pyramidal neurons. Among other neuromodulatory substances, sI(AHP) is modulated by acetylcholine acting via muscarinic receptors. The second-messenger systems mediating the suppression of sI(AHP) by muscarinic agonists are largely unknown. Both protein kinase C and A do not seem to be involved, whereas calcium calmodulin kinase II has been shown to take part in the muscarinic action on sI(AHP). We re-examined the mechanism of action of muscarinic agonists on sI(AHP) combining whole-cell recordings with the use of specific inhibitors or activators of putative constituents of the muscarinic pathway. Our results suggest that activation of muscarinic receptors reduces sI(AHP) in a G-protein-mediated and phospholipase C-independent manner. Furthermore, we obtained evidence for the involvement of the cGMP-cGK pathway and of a protein phosphatase in the cholinergic suppression of sI(AHP), whereas release of Ca(2+) from IP(3)-sensitive stores seems to be relevant neither for maintenance nor for modulation of sI(AHP).

  3. Cell-attached single-channel recordings in intact prefrontal cortex pyramidal neurons reveal compartmentalized D1/D5 receptor modulation of the persistent sodium current.

    Directory of Open Access Journals (Sweden)

    Natalia eGorelova

    2015-02-01

    Full Text Available The persistent Na current (INap is believed to be an important target of dopamine modulation in prefrontal cortex (PFC neurons. While past studies have tested the effects of dopamine on INap, the results have been contradictory largely because of difficulties in measuring INap using somatic whole-cell recordings. To circumvent these confounds we used the cell-attached patch-clamp technique to record single Na channels from the soma, proximal dendrite or proximal axon of intact prefrontal layer V pyramidal neurons. Under baseline conditions, numerous well resolved Na channel openings were recorded that exhibited an extrapolated reversal potential of 73 mV, a slope conductance of 14-19pS and were blocked by TTX. While similar in most respects, the propensity to exhibit prolonged bursts lasting >40ms was many fold greater in the axon than the soma or dendrite. Bath application of the D1 agonist SKF81297 shifted the ensemble current activation curve leftward and increased the number of late events recorded from the proximal dendrite but not the soma or axon. However, the greatest effect was on prolonged bursting where the D1 agonist increased their occurrence 3 fold in the proximal dendrite and nearly 7 fold in the soma, but not at all in the axon. As a result, D1 activation equalized the probability of prolonged burst occurrence across the proximal axosomatodendritic region. Therefore, D1 modulation appears to be targeted mainly to Na channels in the proximal dendrite/soma and not the proximal axon. By circumventing the pitfalls of previous attempts to study the D1R modulation of INap, we demonstrate conclusively that D1R can increase the INap generated proximally, however questions still remain as to how D1R modulates Na currents in the more distal initial segment where most of the INap is normally generated.

  4. Antagomirs targeting microRNA-134 increase hippocampal pyramidal neuron spine volume in vivo and protect against pilocarpine-induced status epilepticus.

    Science.gov (United States)

    Jimenez-Mateos, Eva M; Engel, Tobias; Merino-Serrais, Paula; Fernaud-Espinosa, Isabel; Rodriguez-Alvarez, Natalia; Reynolds, James; Reschke, Cristina R; Conroy, Ronan M; McKiernan, Ross C; deFelipe, Javier; Henshall, David C

    2015-07-01

    Emerging data support roles for microRNA (miRNA) in the pathogenesis of various neurologic disorders including epilepsy. MicroRNA-134 (miR-134) is enriched in dendrites of hippocampal neurons, where it negatively regulates spine volume. Recent work identified upregulation of miR-134 in experimental and human epilepsy. Targeting miR-134 in vivo using antagomirs had potent anticonvulsant effects against kainic acid-induced seizures and was associated with a reduction in dendritic spine number. In the present study, we measured dendritic spine volume in mice injected with miR-134-targeting antagomirs and tested effects of the antagomirs on status epilepticus triggered by the cholinergic agonist pilocarpine. Morphometric analysis of over 6,400 dendritic spines in Lucifer yellow-injected CA3 pyramidal neurons revealed increased spine volume in mice given antagomirs compared to controls that received a scrambled sequence. Treatment of mice with miR-134 antagomirs did not alter performance in a behavioral test (novel object location). Status epilepticus induced by pilocarpine was associated with upregulation of miR-134 within the hippocampus of mice. Pretreatment of mice with miR-134 antagomirs reduced the proportion of animals that developed status epilepticus following pilocarpine and increased animal survival. In antagomir-treated mice that did develop status epilepticus, seizure onset was delayed and total seizure power was reduced. These studies provide in vivo evidence that miR-134 regulates spine volume in the hippocampus and validation of the seizure-suppressive effects of miR-134 antagomirs in a model with a different triggering mechanism, indicating broad conservation of anticonvulsant effects.

  5. Enhanced sensitivity to ethanol-induced inhibition of LTP in CA1 pyramidal neurons of socially isolated C57BL/6J mice: role of neurosteroids

    Directory of Open Access Journals (Sweden)

    Giuseppe eTalani

    2011-10-01

    Full Text Available Ethanol (EtOH–induced impairment of long-term potentiation (LTP in the rat hippocampus is prevented by the 5α-reductase inhibitor finasteride, suggesting that this effect of EtOH is dependent on the increased local release of neurosteroids such as 3α,5α-THP that promote GABA–mediated transmission. Given that social isolation (SI in rodents is associated with altered plasma and brain levels of such neurosteroids as well as with an enhanced neurosteroidogenic action of EtOH, we examined whether the inhibitory effect of EtOH on LTP at CA3-CA1 hippocampal excitatory synapses is altered in C57BL/6J mice subjected to SI for 6 weeks in comparison with group-housed (GH animals. Extracellular recording of fEPSPs as well as patch-clamp analysis were performed in hippocampal slices prepared from both SI and GH mice. Consistent with previous observations, recording of fEPSPs revealed that the extent of LTP induced in the CA1 region of SI mice was significantly reduced compared with that in GH animals. EtOH (40 mM inhibited LTP in slices from SI mice but not in those from GH mice, and this effect of EtOH was abolished by co-application of 1 µM finasteride. Current-clamp analysis of CA1 pyramidal neurons revealed a decrease in action potential frequency and an increase in the intensity of injected current required to evoke the first action potential in SI mice compared with GH mice, indicative of a decrease in neuronal excitability associated with SI. Together, our data suggest that SI results in reduced levels of neuronal excitability and synaptic plasticity in the hippocampus. Furthermore, the increased sensitivity to the neurosteroidogenic effect of EtOH associated with SI likely accounts for the greater inhibitory effect of EtOH on LTP in SI mice. The increase in EtOH sensitivity induced by SI may be important for the changes in the effects of EtOH on anxiety and on learning and memory associated with the prolonged stress attributable to social

  6. Dampening of hyperexcitability in CA1 pyramidal neurons by polyunsaturated fatty acids acting on voltage-gated ion channels.

    Directory of Open Access Journals (Sweden)

    Jenny Tigerholm

    Full Text Available A ketogenic diet is an alternative treatment of epilepsy in infants. The diet, rich in fat and low in carbohydrates, elevates the level of polyunsaturated fatty acids (PUFAs in plasma. These substances have therefore been suggested to contribute to the anticonvulsive effect of the diet. PUFAs modulate the properties of a range of ion channels, including K and Na channels, and it has been hypothesized that these changes may be part of a mechanistic explanation of the ketogenic diet. Using computational modelling, we here study how experimentally observed PUFA-induced changes of ion channel activity affect neuronal excitability in CA1, in particular responses to synaptic input of high synchronicity. The PUFA effects were studied in two pathological models of cellular hyperexcitability associated with epileptogenesis. We found that experimentally derived PUFA modulation of the A-type K (K(A channel, but not the delayed-rectifier K channel, restored healthy excitability by selectively reducing the response to inputs of high synchronicity. We also found that PUFA modulation of the transient Na channel was effective in this respect if the channel's steady-state inactivation was selectively affected. Furthermore, PUFA-induced hyperpolarization of the resting membrane potential was an effective approach to prevent hyperexcitability. When the combined effect of PUFA on the K(A channel, the Na channel, and the resting membrane potential, was simulated, a lower concentration of PUFA was needed to restore healthy excitability. We therefore propose that one explanation of the beneficial effect of PUFAs lies in its simultaneous action on a range of ion-channel targets. Furthermore, this work suggests that a pharmacological cocktail acting on the voltage dependence of the Na-channel inactivation, the voltage dependences of K(A channels, and the resting potential can be an effective treatment of epilepsy.

  7. Nerve injury-induced neuropathic pain causes disinhibition of the anterior cingulate cortex.

    Science.gov (United States)

    Blom, Sigrid Marie; Pfister, Jean-Pascal; Santello, Mirko; Senn, Walter; Nevian, Thomas

    2014-04-23

    Neuropathic pain caused by peripheral nerve injury is a debilitating neurological condition of high clinical relevance. On the cellular level, the elevated pain sensitivity is induced by plasticity of neuronal function along the pain pathway. Changes in cortical areas involved in pain processing contribute to the development of neuropathic pain. Yet, it remains elusive which plasticity mechanisms occur in cortical circuits. We investigated the properties of neural networks in the anterior cingulate cortex (ACC), a brain region mediating affective responses to noxious stimuli. We performed multiple whole-cell recordings from neurons in layer 5 (L5) of the ACC of adult mice after chronic constriction injury of the sciatic nerve of the left hindpaw and observed a striking loss of connections between excitatory and inhibitory neurons in both directions. In contrast, no significant changes in synaptic efficacy in the remaining connected pairs were found. These changes were reflected on the network level by a decrease in the mEPSC and mIPSC frequency. Additionally, nerve injury resulted in a potentiation of the intrinsic excitability of pyramidal neurons, whereas the cellular properties of interneurons were unchanged. Our set of experimental parameters allowed constructing a neuronal network model of L5 in the ACC, revealing that the modification of inhibitory connectivity had the most profound effect on increased network activity. Thus, our combined experimental and modeling approach suggests that cortical disinhibition is a fundamental pathological modification associated with peripheral nerve damage. These changes at the cortical network level might therefore contribute to the neuropathic pain condition.

  8. Differential Vulnerability of CA1 versus CA3 Pyramidal Neurons After Ischemia: Possible Relationship to Sources of Zn2+ Accumulation and Its Entry into and Prolonged Effects on Mitochondria.

    Science.gov (United States)

    Medvedeva, Yuliya V; Ji, Sung G; Yin, Hong Z; Weiss, John H

    2017-01-18

    Excitotoxic mechanisms contribute to the degeneration of hippocampal pyramidal neurons after recurrent seizures and brain ischemia. However, susceptibility differs, with CA1 neurons degenerating preferentially after global ischemia and CA3 neurons after limbic seizures. Whereas most studies address contributions of excitotoxic Ca(2+) entry, it is apparent that Zn(2+) also contributes, reflecting accumulation in neurons either after synaptic release and entry through postsynaptic channels or upon mobilization from intracellular Zn(2+)-binding proteins such as metallothionein-III (MT-III). Using mouse hippocampal slices to study acute oxygen glucose deprivation (OGD)-triggered neurodegeneration, we found evidence for early contributions of excitotoxic Ca(2+) and Zn(2+) accumulation in both CA1 and CA3, as indicated by the ability of Zn(2+) chelators or Ca(2+) entry blockers to delay pyramidal neuronal death in both regions. However, using knock-out animals (of MT-III and vesicular Zn(2+) transporter, ZnT3) and channel blockers revealed substantial differences in relevant Zn(2+) sources, with critical contributions of presynaptic release and its permeation through Ca(2+)- (and Zn(2+))-permeable AMPA channels in CA3 and Zn(2+) mobilization from MT-III predominating in CA1. To assess the consequences of the intracellular Zn(2+) accumulation, we used OGD exposures slightly shorter than those causing acute neuronal death; under these conditions, cytosolic Zn(2+) rises persisted for 10-30 min after OGD, followed by recovery over ∼40-60 min. Furthermore, the recovery appeared to be accompanied by mitochondrial Zn(2+) accumulation (via the mitochondrial Ca(2+) uniporter MCU) in CA1 but not in CA3 neurons and was markedly diminished in MT-III knock-outs, suggesting that it depended upon Zn(2+) mobilization from this protein.

  9. Cognitive Control Signals in Posterior Cingulate Cortex

    Directory of Open Access Journals (Sweden)

    Benjamin eHayden

    2010-12-01

    Full Text Available Efficiently shifting between tasks is a central function of cognitive control. The role of the default network—a constellation of areas with high baseline activity that declines during task performance—in cognitive control remains poorly understood. We hypothesized that task switching demands cognitive control to shift the balance of processing towards the external world, and therefore predicted that switching between the two tasks would require suppression of activity of neurons within the CGp. To test this idea, we recorded the activity of single neurons in posterior cingulate cortex (CGp, a central node in the default network, in monkeys performing two interleaved tasks. As predicted, we found that basal levels of neuronal activity were reduced following a switch from one task to another and gradually returned to pre-switch baseline on subsequent trials. We failed to observe these effects in lateral intraparietal cortex (LIP, part of the dorsal fronto-parietal cortical attention network directly connected to CGp. These findings indicate that suppression of neuronal activity in CGp facilitates cognitive control, and suggest that activity in the default network reflects processes that directly compete with control processes elsewhere in the brain..

  10. Novel bio-spectroscopic imaging reveals disturbed protein homeostasis and thiol redox with protein aggregation prior to hippocampal CA1 pyramidal neuron death induced by global brain ischemia in the rat.

    Science.gov (United States)

    Hackett, Mark J; Smith, Shari E; Caine, Sally; Nichol, Helen; George, Graham N; Pickering, Ingrid J; Paterson, Phyllis G

    2015-12-01

    occur in the same CA1 pyramidal neurons 1 day after global ischemia. Further, analysis of serial tissue sections using X-ray absorption spectroscopy at the sulfur K-edge has revealed that CA1 pyramidal neurons have increased disulfide levels, a direct indicator of oxidative stress, at this time point. These changes at 1 day after ischemia precede a massive increase in aggregated protein and disulfide levels concomitant with loss of neuron integrity 2 days after ischemia. Therefore, this study has provided direct support for a correlative mechanistic link in both spatial and temporal domains between oxidative stress, protein aggregation and altered protein homeostasis prior to irreparable neuron damage following global ischemia.

  11. Growth of dendritic spines and its synapses in pyramidal neurons of visual cortex in mice%小鼠视皮质锥体神经元树突棘和突触的发育

    Institute of Scientific and Technical Information of China (English)

    赵凯冰; 崔占军; 陈文静; 牛艳丽

    2012-01-01

    目的:通过观察小鼠视皮质锥体神经元正常发育过程中树突棘的形态变化,研究树突棘与突触的发生及其可塑性的关系.方法:利用DiI散射方法标记小鼠视皮质锥体神经元树突棘,使用共聚焦显微镜对其进行观察分析;同时利用透射电子显微镜技术,对树突棘的超微结构进行分析.结果:树突棘的形态大小及其密度随发育而变化;成熟树突棘内部存在滑面内质网与棘器;树突棘参与了大部分突触后成分的构成.结论:树突棘的发育过程与突触的形成以及突触可塑性密切相关.%Objective:To explore the relationship among the synaptogenesis, synaptic plasticity and dendritic spines by observing the morphological changes of dendritic spines of pyramidal neurons in the visual cortex of mice during development Methods: The dendritic spines of the pyramidal neurons of mouse visual cortex were labeled with Dil and observed under a confocal microscope. The ultrastructures of dendritic spines were observed by means of transmission electron microscopy. Results:The morphology and density of dendritic spines were changing with mouse growth in response to neuronal activity. The smooth endoplasmic reticulum and spine apparatus were detectable in matured dendritic spines. And, dendritic spines offered most parts of the postsynaptic element. Conclusion :These findings suggest that dendritic spines be close related synaptogenesis and synaptic plasticity.

  12. Expression of 5-HT2A receptors in prefrontal cortex pyramidal neurons projecting to nucleus accumbens. Potential relevance for atypical antipsychotic action

    OpenAIRE

    Mocci, Giuseppe; Jiménez-Sánchez, Laura; Adell, Albert; Cortés, Roser; Artigas, Francesc

    2013-01-01

    The prefrontal cortex (PFC) is involved in higher brain functions altered in schizophrenia. Classical antipsychotic drugs modulate information processing in cortico-limbic circuits via dopamine D2 receptor blockade in nucleus accumbens (NAc) whereas atypical antipsychotic drugs preferentially target cortical serotonin (5-HT) receptors. The brain networks involved in the therapeutic action of atypical drugs are not fully understood. Previous work indicated that medial PFC (mPFC) pyramidal neur...

  13. Pyramid Comet Sampler Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Based on the sampling requirements, we propose an Inverted Pyramid sampling system. Each face of the pyramid includes a cutting blade which is independently actuated...

  14. 小鼠海马CA1区锥体神经元树突棘的发育%Dendritic spine development of mouse hippocampal CA1 pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    刘畅; 范文娟; 程维杰; 左曙光; 邓锦波

    2012-01-01

    Objective To investigate the developmental characteristics of dendritic spines in mouse hippocampal CA1 pyramidal neurons by analysing the spine density and morphological changes. Methods Fifty mice were collected at postnatal days ( P ) 0, 5, 10, 20 and 30, 10 mice for each age. Dil diolistic labeling with gene gun was performed to observe dendritic spines development in mouse hippocampal CA1 pyramidal neurons. High quality labeled neurons were examined and photographed under a confocal microscope, whereas the ultrastructure of spines was observed under a transmission electron microscope. Results Dendritic spines changed their morphology and density with mouse development in response to neuronal activity. The smooth endoplasmic reticulum and spine apparatus in dendritic spines of hippocampal CA1 were observed with electron microscopy analysis, which might be involved in the regulation of plasticity at individual synapses. Conclusion The development of dendritic spines may be closely related to synaptogenesis and the formation of synaptic plasticity.%目的 对小鼠海马CA1区锥体神经元正常发育中树突棘密度及各种形态变化进行分析测定,为深入研究突触发生及突触可塑性提供直接的形态学依据.方法 分别取出生后0、5、10、20及30d 5个年龄段的C57BL/6小鼠各10只,采用基因枪对小鼠海马CA1区锥体神经元树突棘进行亲脂性荧光染料DiI标记,通过激光共焦显微镜对其进行观察分析;同时利用透射电镜技术对树突棘的超微结构进行分析.结果 树突棘的形态、大小及其密度随小鼠发育而变化,成熟树突棘内部存在滑面内质网与棘器,可能参与了突触后膜结合蛋白及其转运体的合成.结论 树突棘的发育过程与突触连接的形成以及突触可塑性密切相关.

  15. 人体海马CA1区锥体细胞胞体的发育%The Development of the Cell Body of Human Fetal CA1 Pyramidal Neurons

    Institute of Scientific and Technical Information of China (English)

    贺立新; 卢大华; 蔡海荣

    2011-01-01

    Objective: To explore the process of cell body morphogenesis of human fetal CA1 pyramidal neurons. Methods: 19 gestational weeks (GW), 20GW, 26GW, 35GW, 38GW fetuses (Cystic induction of labor) and one 8-year-old (8Y) child {Killed in traffic accidents) were collected. All specimens were in line with the relevant laws and the ethical requirements. The Golgi staining technology and the confocal microscope equipped with "Neurolucida" software were used to observe the cell body of human fetal CA1 pyramidal neurons and analyze the length and area of the cell body. Results: The morphology of CA1 pyramidal neurons is not clear at 19GW and 20GW. The cell body length at 26GW, 35GW, 38GW, 8Y was 56.5 ± 2.5 (μ m), 80.8 ± 8.5 (μm),85.9± 12.2 (μm),91.3± 9.6 (μ m) respectively, and the cell body area was 254.5 ± 13.7 (μ m2). 362.5 ± 15.5 (μ m2), 380.5 ± 22.8 (μ m2), 460.8 ± 25.7 (μ m2) respectively. There were significant differences (P <0.05) in the length and area at 26GW compared to those at 35GW, 38 GW and 8Y. Compared with 38GW, the length and area at 8Y had a slight increase. Cell morphology: The plane sections of CA1 pyramidal cells showed oval or triangle shapes at 26W, 35W and 38W. With the growing of gestational age, the length and area of cell body were gradually increased, especially the basal parts of the cell body widened. The oval cell bodies were transformed into triangle cell bodies. Meanwhile, the number of base dendrites was increased gradually, which could be reached 4-7 at 38GW. At 8Y, almost all sections of CA1 neurons showed pyramidal shapes. The length and area at 8Y were slightly increased and relatively stable compared with those at 38GW. Conclusions: During body development, the CA1 pyramidal cells showed a gradual increase in length and area. The difference between 26GW and 35GW was most significant, while the difference of cell area between 38GW and 8Y was not significant. Such increase trends gradually slowed down and tended to

  16. Pyramid beam splitter

    Science.gov (United States)

    McKeown, Mark H.; Beason, Steven C.; Fairer, George

    1992-01-01

    The apparatus of the present invention provides means for obtaining accurate, dependable, measurement of bearings and directions for geologic mapping in subterranean shafts, such as, for example, nuclear waste storage investigations. In operation, a laser beam is projected along a reference bearing. A pyramid is mounted such that the laser beam is parallel to the pyramid axis and can impinge on the apex of the pyramid thus splitting the beam several ways into several beams at right angles to each other and at right angles to the reference beam. The pyramid is also translatable and rotatable in a plane perpendicular to the reference beam.

  17. Thermoluminescence of pyramid stones

    Energy Technology Data Exchange (ETDEWEB)

    Gomaa, M.A.; Eid, A.M. (Atomic Energy Establishment, Cairo (Egypt))

    1982-01-01

    It is the aim of the present study to investigate some thermoluminescence properties of pyramid stones. Using a few grammes of pyramid stones from Pyramids I and II, the TL glow peaks were observed at 250 and 310/sup 0/C, respectively. The TL glow peaks of samples annealed at 600/sup 0/C, then exposed to /sup 60/Co ..gamma..-rays were observed at 120, 190 and 310/sup 0/C, respectively. The accumulated dose of natural samples is estimated to be around 310 Gray (31 krad). By assuming an annual dose is 1 mGy, the estimated age of pyramid stones is 0.31 M year.

  18. 电针改变CFA炎症痛大鼠前扣带回脑区神经元放电活动%ELECTRO-ACUPUNCTURE MODULATES THE NEURONAL FIRINGS OF ANTERIOR CINGULATE CORTEX IN RATS WITH INFLAMMATORY PAIN

    Institute of Scientific and Technical Information of China (English)

    周萌萌; 刘风雨; 岳路鹏; 蔡捷; 廖斐斐; 朱兵; 景向红; 万有; 伊鸣

    2016-01-01

    目的:研究电针对炎症痛大鼠前扣带回(anterior cingulate cortex,ACC)神经元放电的影响.方法:实验大鼠分为4组:CFA炎症痛模型组加电针,CFA炎症痛模型组加假电针,对照组加电针,对照组加假电针.应用多通道在体记录技术,记录在电针前、后1h内以及给予激光痛刺激前、后ACC神经元的放电,处理记录到的神经信号并进行统计分析.结果:电针后,CFA炎症痛组和对照组大鼠ACC神经元的平均放电率均增高,CFA炎症痛组大鼠ACC脑区内对激光痛刺激有反应的兴奋性神经元反应性降低.结论:电针激活炎症痛大鼠ACC脑区的神经元,但抑制ACC脑区内对痛刺激起兴奋性反应的神经元.推测电针通过调节ACC脑区神经元活动而镇痛.

  19. Rebuilding the Food Pyramid.

    Science.gov (United States)

    Willet, Walter C.; Stampfer, Meir J.

    2003-01-01

    Discusses the old food guide pyramid released in 1992 by the U.S. Department of Agriculture. Contradicts the message that fat is bad, which was presented to the public by nutritionists, and the effects of plant oils on cholesterol. Introduces a new food pyramid. (YDS)

  20. The Healthy Eating Pyramid

    Institute of Scientific and Technical Information of China (English)

    Jimmy; Lin

    2007-01-01

    Experts from the Harvard School of Public Health created the Healthy Eating Pyramid.The pyramid is about the links between diet and health and offers useable information to help people make better choices about what to eat. Remember:its base is daily exercise and weight control.

  1. Submillisecond precision of the input-output transformation function mediated by fast sodium dendritic spikes in basal dendrites of CA1 pyramidal neurons.

    Science.gov (United States)

    Ariav, Gal; Polsky, Alon; Schiller, Jackie

    2003-08-27

    The ability of cortical neurons to perform temporally accurate computations has been shown to be important for encoding of information in the cortex; however, cortical neurons are expected to be imprecise temporal encoders because of the stochastic nature of synaptic transmission and ion channel gating, dendritic filtering, and background synaptic noise. Here we show for the first time that fast local spikes in basal dendrites can serve to improve the temporal precision of neuronal output. Integration of coactivated, spatially distributed synaptic inputs produces temporally imprecise output action potentials within a time window of several milliseconds. In contrast, integration of closely spaced basal inputs initiates local dendritic spikes that amplify and sharpen the summed somatic potential. In turn, these fast basal spikes allow precise timing of output action potentials with submillisecond temporal jitter over a wide range of activation intensities and background synaptic noise. Our findings indicate that fast spikes initiated in individual basal dendrites can serve as precise "timers" of output action potentials in various network activity states and thus may contribute to temporal coding in the cortex.

  2. Posterior cingulate cortex: adapting behavior to a changing world.

    Science.gov (United States)

    Pearson, John M; Heilbronner, Sarah R; Barack, David L; Hayden, Benjamin Y; Platt, Michael L

    2011-04-01

    When has the world changed enough to warrant a new approach? The answer depends on current needs, behavioral flexibility and prior knowledge about the environment. Formal approaches solve the problem by integrating the recent history of rewards, errors, uncertainty and context via Bayesian inference to detect changes in the world and alter behavioral policy. Neuronal activity in posterior cingulate cortex - a key node in the default network - is known to vary with learning, memory, reward and task engagement. We propose that these modulations reflect the underlying process of change detection and motivate subsequent shifts in behavior.

  3. The schizophrenia- and autism-associated gene, transcription factor 4 regulates the columnar distribution of layer 2/3 prefrontal pyramidal neurons in an activity-dependent manner.

    Science.gov (United States)

    Page, S C; Hamersky, G R; Gallo, R A; Rannals, M D; Calcaterra, N E; Campbell, M N; Mayfield, B; Briley, A; Phan, B N; Jaffe, A E; Maher, B J

    2017-03-14

    Disruption of the laminar and columnar organization of the brain is implicated in several psychiatric disorders. Here, we show in utero gain-of-function of the psychiatric risk gene transcription factor 4 (TCF4) severely disrupts the columnar organization of medial prefrontal cortex (mPFC) in a transcription- and activity-dependent manner. This morphological phenotype was rescued by co-expression of TCF4 plus calmodulin in a calcium-dependent manner and by dampening neuronal excitability through co-expression of an inwardly rectifying potassium channel (Kir2.1). For we believe the first time, we show that N-methyl-d-aspartate (NMDA) receptor-dependent Ca(2+) transients are instructive to minicolumn organization because Crispr/Cas9-mediated mutation of NMDA receptors rescued TCF4-dependent morphological phenotypes. Furthermore, we demonstrate that the transcriptional regulation by the psychiatric risk gene TCF4 enhances NMDA receptor-dependent early network oscillations. Our novel findings indicate that TCF4-dependent transcription directs the proper formation of prefrontal cortical minicolumns by regulating the expression of genes involved in early spontaneous neuronal activity, and thus our results provides insights into potential pathophysiological mechanisms of TCF4-associated psychiatric disorders.Molecular Psychiatry advance online publication, 14 March 2017; doi:10.1038/mp.2017.37.

  4. Anterior cingulate integrity: executive and neuropsychiatric features in Parkinson's disease.

    Science.gov (United States)

    Lewis, Simon J G; Shine, James M; Duffy, Shantel; Halliday, Glenda; Naismith, Sharon L

    2012-09-01

    Patients with advanced Parkinson's disease (PD) commonly suffer with significant executive dysfunction and concomitant visual hallucinations. Although the underlying pathophysiology remains poorly understood, numerous studies have highlighted the strong association between these neuropsychiatric features, suggesting common neural pathways. Although previous neuroimaging studies have identified widespread volume loss across a number of cortical regions, to date, no studies have utilized proton magnetic resonance spectroscopy to provide insights into how neurometabolic changes may relate to such symptoms. Twenty patients with PD and 20 healthy controls underwent spectroscopy to determine the N-acetyl aspartate/creatine (NAA/Cr) ratio, which reflects the degree of neuronal integrity in neurodegenerative diseases. Voxels were obtained from the anterior cingulate cortex (ACC), an area critical for a wide range of executive mechanisms as well as from a control volume in the posterior cingulate cortex (PCC). Compared to controls, patients with PD had lower NAA/Cr ratios in the ACC. In turn, lower NAA/Cr ratios significantly correlated with poorer executive function on tasks of attentional set-shifting and response inhibition, as well as more-severe psychotic symptoms and poorer performance on the Bistable Percept Paradigm, a neuropsychological probe of visual hallucinations. NAA/Cr ratios were significantly lower in hallucinators, compared to nonhallucinators, within the ACC, but did not differ in the PCC. These results suggest that loss of neuronal integrity within the ACC plays an important role in the pathophysiology underlying executive functioning and visual hallucinations in PD. © 2012 Movement Disorder Society.

  5. Effect of 5-HT7 receptor agonist on pyramidal neurons in the medial frontal cortex in a rat model of Parkinson's disease%5-羟色胺-7受体激动剂对帕金森病模型大鼠内侧前额叶皮层锥体神经元兴奋性的影响

    Institute of Scientific and Technical Information of China (English)

    范玲玲; 邓博; 闫君宝; 胡志红; 任爱红; 胡咏梅; 杨东伟

    2016-01-01

    Objective To investigate the activity of pyramidal neurons in the medial prefrontal cortex (mPFC) of normal and 6-OHDA-lesioned rats and the responses of the neurons to 5-hydroxytryptamine-7 (5-HT7) receptor stimulation. Methods The changes in spontaneous firing of the pyramidal neurons in the mPFC in response to 5-HT7 receptor stimulation were observed by extracellular recording in normal and 6-OHDA-lesioned rats. Results Both systemic and local administration of 5-HT7 receptor agonist AS 19 resulted in 3 response patterns (excitation, inhibition and no change) of the pyramidal neurons in the mPFC of normal and 6-OHDA-lesioned rats. In normal rats, the predominant response of the pyramidal neurons to AS 19 stimulation was excitatory, and the inhibitory effect of systemically administered AS 19 was reversed by GABAA receptor antagonist picrotoxinin. In the lesioned rats, systemic administration of AS 19 also increased the mean firing rate of the pyramidal neurons, but the cumulative dose for producing excitation was higher than that in normal rats. Systemic administration of AS 19 produced an inhibitory effect in the lesioned rats, which was partially reversed by picrotoxinin. Local administration of AS 19 at the same dose did not change the fi ring rate of the neurons in the lesioned rats. Conclusion The activity of mPFC pyramidal neurons is directly or indirectly regulated by 5-HT7 receptor, and degeneration of the nigrostriatal pathway leads to decreased response of these neurons to AS 19.%目的:探讨5-羟色胺(5-hydroxytryptamine,5-HT)-7受体对帕金森病(Parkinson's disease, PD)模型大鼠内侧前额叶皮层(medial prefrontal cortex, mPFC)中锥体神经元兴奋性的影响。方法以正常大鼠和6-羟多巴胺单侧损毁黑质致密部建立的PD模型大鼠为研究对象,采用在体细胞外生物电记录的方法,观察5-HT7受体激动剂AS 19对mPFC中锥体神经元电活动的影响。结果无论是

  6. Climbing the Needs Pyramids

    Directory of Open Access Journals (Sweden)

    J. C. Lomas

    2013-08-01

    Full Text Available Abraham Maslow’s theory of human adult motivation is often represented by a pyramid image showing two proposals: First, the five needs stages in emergent order of hierarchical ascension and second, a percentage of the adult population suggested to occupy each needs tier. Specifically, Maslow proposed that adults would be motivated to satisfy their unfilled needs until they reached the hierarchy’s apex and achieved self-transcendence. Yet how adults can purposefully ascend Maslow’s pyramid through satisfying unfilled needs remains elusive. This brief article challenges this on the theory’s 70th anniversary by presenting a new image of the needs hierarchy, based on ecological design principles to support adults’ purposeful endeavors to climb the needs pyramid.

  7. The Anterior Cingulate Cortex and Pain Processing

    Directory of Open Access Journals (Sweden)

    Perry Neil Fuchs

    2014-05-01

    Full Text Available The neural network that contributes to the suffering which accompanies persistent pain states involves a number of brain regions. Of primary interest is the contribution of the cingulate cortex in processing the affective component of pain. The purpose of this review is to summarize recent data obtained using novel behavioral paradigms in animals based on measuring escape and/or avoidance of a noxious stimulus. These paradigms have successfully been used to study the nature of the neuroanatomical and neurochemical contributions of the anterior cingulate cortex to higher order pain processing in rodents.

  8. Effect of coriaria lactone on adenosine triphosphate-sensitive potassium channels in pyramidal neurons%马桑内酯对锥体神经元三磷酸腺苷敏感钾通道的作用

    Institute of Scientific and Technical Information of China (English)

    邹晓毅; 周华; 周树舜

    2005-01-01

    BACKGROUND: Abnormal neuronal discharge arose from the activation of cell membrane ion channels and transmembrane ion transport. The electric activity of the cells is associated with cell metabolism fundamentally through adenosine triphosphate (ATP)-sensitive potassium(KATP) channels.Currently the involvement of KATP channels in the pathogenesis of epilepsy and the regulation of KATP channels by coriaria lacton (EL) remain unknown.OBJETCIVE: To investigate the changes of cell membrane KATP channels in rat hippocampal neurons in response to CL as an epilepsy-inducing agent, and explore the role of KATP channels in the pathogenesis of epilepsy.DESIGN: Randomized controlled experiment.SETTING: Department of Neurology, West China Hospital Affiliated to Sichuan University, and Teaching and Research Section of Physiology,West China College of Preclinical Medicine and Forensic Medicine of Sichuan University.MATERIALS: This experiment was carried out at Luzhou Medical College between May and December 2000. Hippocampus pyramidal neurons were obtained from neonatal Wistar rats and randomized into normal control group, tetraethylammonium chloride (TEA) group, DNP group, CL group, and electric conductance and dynamics group.METHODS: The hippocampus of newborn Wistar rats was separated under aseptic condition and cultured for 24 hours prior to treatment with 10 μmol/L cytarabine for selective cell culture for 7-10 days. The cells in good growth exhibiting typical morphology of pyramidal neurons were then selected for patch-clamp experiment. The cells in the normal control group were treated with normal saline, which was replaced by 5 mmol/L TEA in TEA group, by 30 μmol/L DNP then 0.5 mol/L ATP in DNP group, and by 1.0 mL/L CL then 1 μmol/L glibenclamide in CL group. In electric conductance and dynamics group, the clamp voltage was firstly adjusted to investigate the channel opening before CL was added to the cells.MAIN OUTCOME MEASURES: ① Activity and curve of neuronal

  9. Hippocampal CA3 pyramidal cells selectively innervate aspiny interneurons.

    Science.gov (United States)

    Wittner, Lucia; Henze, Darrell A; Záborszky, László; Buzsáki, György

    2006-09-01

    The specific connectivity among principal cells and interneurons determines the flow of activity in neuronal networks. To elucidate the connections between hippocampal principal cells and various classes of interneurons, CA3 pyramidal cells were intracellularly labelled with biocytin in anaesthetized rats and the three-dimensional distribution of their axon collaterals was reconstructed. The sections were double-stained for substance P receptor (SPR)- or metabotropic glutamate receptor 1alpha (mGluR-1alpha)-immunoreactivity to investigate interneuron targets of the CA3 pyramidal cells. SPR-containing interneurons represent a large portion of the GABAergic population, including spiny and aspiny classes. Axon terminals of CA3 pyramidal cells contacted SPR-positive interneuron dendrites in the hilus and in all hippocampal strata in both CA3 and CA1 regions (7.16% of all boutons). The majority of axons formed single contacts (87.5%), but multiple contacts (up to six) on single target neurons were also found. CA3 pyramidal cell axon collaterals innervated several types of morphologically different aspiny SPR-positive interneurons. In contrast, spiny SPR-interneurons or mGluR-1alpha-positive interneurons in the hilus, CA3 and CA1 regions were rarely contacted by the filled pyramidal cells. These findings indicate a strong target selection of CA3 pyramidal cells favouring the activation of aspiny classes of interneurons.

  10. 5-羟色胺-7受体激动剂对大鼠内侧前额叶皮层锥体神经元电活动的影响%Effect of 5-HT7 receptor agonist on pyramidal neurons in medial frontal cortex of rats

    Institute of Scientific and Technical Information of China (English)

    范玲玲; 王红伟; 胡志红; 任爱红; 胡咏梅; 杨东伟

    2013-01-01

    Objective:To investigate the activity of medial prefrontal cortex (mPFC) pyramidal neurons in rats and their response to 5-hydroxytryptamine-7 (5-HT7) receptor stimulation.Methods:The change of the spontaneous firing of pyramidal neurons in mPFC was observed by extracellular recording in viva.Results:In this study,we reported that systemic and local administration of 5-HT7 receptor agonist AS19 produced excitation,inhibition and no change in the firing rate of pyramidal neurons in mPFC of rats.The mean response of the pyramidal neurons to AS19 (0.08 μg/100 nl) by systemic and local administration in mPFC was excitatory.The inhibitory effect by systemic administration of AS 19 was reversed by γ-aminobntyricacid A receptor antagonist picrotoxinin (2 mg/kg).Systemic administration of picrotoxinin excited all the neurons examined in rats.After treatment with picrotoxinin,the local administration of AS19 increased the firing rate of the neurons.Conclusion:These results indicate that the activity of mPFC pyramidal neurons is regulated through activation of 5-HT7 receptor by direct or indirect action.%目的:探讨5-羟色胺-7 (5-hydroxytryptamine-7,5-HT7)受体对内侧前额叶皮层(medial prefrontal cortex,mPFC)中锥体神经元电活动的影响.方法:以大鼠为研究对象,采用在体细胞外生物电记录的方法,观察mPFC锥体神经元电活动的变化.结果:静脉给予累积剂量的(40~640 μg/kg)5-HT7受体激动剂AS19后,对大鼠mPFC中锥体神经元的电活动产生兴奋、抑制和不变3种不同的影响.无论是体循环,还是mPFC局部微量注射AS19(0.08 μg/100 nl),锥体神经元的总体反应都是兴奋的,而体循环给予AS19所引起的抑制效应能够被γ-氨基丁酸A型受体拮抗剂picrotoxinin(2 mg/kg)反转.静脉给予picrotoxinin能兴奋所有记录到的锥体神经元;静脉注射picrotoxinin后,再局部给予AS19能够进一步增加所记录到的神经元的放电频率.结论:mPFC锥体神经元

  11. PYRAMID ROADLESS AREA, CALIFORNIA.

    Science.gov (United States)

    Armstrong, Augustus K.; Scott, Douglas F.

    1984-01-01

    A geologic and mineral survey was conducted in the Pyramid Roadless Area, California. The area contains mineral showings, but no mineral-resource potential was identified during our studies. Three granodiorite samples on the west side of the roadless area contained weakly anomalous concentrations of uranium. Two samples of roof-pendant rocks, one metasedimentary rock and one metavolcanic rock, contain low concentrations of copper, and of copper and molybdenum, respectively. Although none was identified, the geologic terrane is permissive for mineral occurrences and large-scale, detailed geologic mapping of the areas of metasedimentary and metavolcanic roof pendants in the Pyramid Roadless Area could define a mineral-resource potential for tungsten and precious metals.

  12. Building the next pyramid

    CERN Document Server

    West, Joseph; Waters, Kevin; Ward, Stephen; Ward, Tia

    2015-01-01

    The results of experimental tests of a novel method for moving large (pyramid construction size) stone blocks by rolling them are presented. The method is implemented by tying 12 identical rods of appropriately chosen radius to the faces of the block forming a rough dodecagon prism. Experiments using a 1,000 kg block show that it can be moved across level open ground with a dynamic coefficient of friction of less than 0.06. This value is a factor of five lower than that obtained for dragging the block, and the best values reported for dragging by others, at 0.3. the results are more dramatic than those obtained on smaller scale experiments on a 29.6 kg block, also reported here. For full scale pyramid blocks, the wooden "rods" woudl need to be posts of order 30 cm in diameter, similar in size to those used as masts on ships in the Nile.

  13. Migration abnormality in the left cingulate gyrus presenting with autistic disorder.

    Science.gov (United States)

    Korkmaz, Bariş; Benbir, Gülçin; Demirbilek, Veysi

    2006-07-01

    Autism, characterized by an impairment in communication, including language, narrowly focused interests, and poor sociability, is a neurodevelopmental disorder of still largely unknown pathogenesis. In children with autistic symptomatology, the most consistent functional or anatomic abnormalities are found in the cingulate gyrus, particularly in the anterior regions. Neuronal migration malformations caused by incomplete neuronal migration and characterized by loss of the normal gyral patterns in the cerebral hemispheres and prominent disorganization of the cerebral cortical cytoarchitecture are generally associated with profound neurologic deficits, epilepsy, and autism. In this report, we present a case with an isolated migration abnormality located in the anterior part of the left cingulate gyrus who was admitted with the complaints of epileptic seizures and autism. In addition, the role of the localization of the migration abnormality in the appearance of autistic symptomatology is discussed.

  14. Climbing the Needs Pyramids

    OpenAIRE

    J. C. Lomas

    2013-01-01

    Abraham Maslow’s theory of human adult motivation is often represented by a pyramid image showing two proposals: First, the five needs stages in emergent order of hierarchical ascension and second, a percentage of the adult population suggested to occupy each needs tier. Specifically, Maslow proposed that adults would be motivated to satisfy their unfilled needs until they reached the hierarchy’s apex and achieved self...

  15. Imaging the Cheops Pyramid

    CERN Document Server

    Bui, H D

    2012-01-01

    In this book Egyptian Archeology  and Mathematics meet. The author is an expert in theories and applications in Solid Mechanics and Inverse Problems, a former professor at Ecole Polytechnique and now works with Electricité de France on maintenance operations on nuclear power plants. In the Autumn of 1986, after the end of the operation on the King’s chamber conducted under the Technological and Scientific Sponsorship of EDF, to locate a cavity, he was called to solve a mathematical inverse problem, to find the unknown tomb of the King and the density structure of the whole pyramid based on measurements of microgravity made inside and outside of the pyramid. This book recounts the various search operations on the pyramid of Cheops made at the request of the Egyptian and French authorities in 1986-1987. After the premature end of the Cheops operation in the Autumn of 1986, following the fiasco of unsuccessful drillings in the area suspected by both architects G. Dormion and J.P. Goidin and microgravity aus...

  16. Event Detection by Velocity Pyramid

    OpenAIRE

    2014-01-01

    In this paper, we propose velocity pyramid for multimediaevent detection. Recently, spatial pyramid matching is proposed to in-troduce coarse geometric information into Bag of Features framework,and is eective for static image recognition and detection. In video, notonly spatial information but also temporal information, which repre-sents its dynamic nature, is important. In order to fully utilize it, wepropose velocity pyramid where video frames are divided into motionalsub-regions. Our meth...

  17. Activation of mu opioid receptor inhibits the excitatory glutamatergic transmission in the anterior cingulate cortex of the rats with peripheral inflammation.

    Science.gov (United States)

    Zheng, Weihong

    2010-02-25

    Emerging evidence recently indicates that the anterior cingulate cortex is critically involved in the central processing and modulation of noxious stimulus, although the neuroadaptation in the anterior cingulate cortex has not been well documented in the conditions of chronic pain. Meanwhile, the cellular mechanism underlying opiate analgesia in the anterior cingulate cortex remains unclear. To address these issues, the present study was undertaken to explore the adaptation of excitatory glutamatergic transmission and mu opioid receptor-mediated modulation of glutamatergic transmission in the anterior cingulate cortex slices from the complete Freund's adjuvant (CFA)-inflamed rats. The results demonstrated that glutamatergic paired-pulse facilitation was decreased in the anterior cingulate cortex neurons from the CFA-inflamed rats, indicating an enhanced presynaptic glutamate release. In addition, activation of mu opioid receptor significantly inhibited the glutamatergic excitatory postsynaptic currents (EPSCs) in the anterior cingulate cortex neurons, which was attained through the suppression of presynaptic glutamate release. Taken together, these findings provided the evidence for the functional adaptation of central glutamatergic transmission induced by peripheral inflammation, and elucidated the cellular mechanism underlying opiate analgesia in the anterior cingulate cortex.

  18. Dendritic development of hippocampal CA1 pyramidal cells in a neonatal hypoxia-ischemia injury model.

    Science.gov (United States)

    Zhao, Yan Dong; Ou, Shan; Cheng, Sai Yu; Xiao, Zhi; He, Wen Juan; Zhang, Jin Hai; Ruan, Huai Zhen

    2013-09-01

    It is believed that neonatal hypoxia-ischemia (HI) brain injury causes neuron loss and brain functional defects. However, the effect of HI brain injury on dendritic development of the remaining pyramidal cells of the hippocampus and the reaction of contralateral hippocampal neurons require further studies. The Morris water maze and Golgi-Cox staining were used to evaluate the learning and memory and dendritic morphology of pyramidal cells. The results of Golgi-Cox staining showed CA1 pyramidal neurons of HI injury models with fewer bifurcations and shorter dendrite length than the naive control group. The density of dendritic spines of hippocampal CA1 pyramidal neurons was significantly lower in the HI brain injury group than in controls. With respect to hippocampal function, the HI brain injury group presented cognitive deficits in the reference memory task and probe trail. In the HI group, the pyramidal cells of left hippocampus that did not experienced ischemia but did experience hypoxia had more complex dendrites and higher density of spine than the HI injury side and control. The functional implementation of injured hippocampus might depend mainly on the hypertrophy of contralateral hippocampus after HI brain injury. Corticosterone can partially prevent the hippocampal pyramidal cells from HI injury and reduce the difference of the bilateral hippocampus pyramidal cells, but there was no improvement in learning and memory.

  19. Temporal prediction errors modulate cingulate-insular coupling.

    Science.gov (United States)

    Limongi, Roberto; Sutherland, Steven C; Zhu, Jian; Young, Michael E; Habib, Reza

    2013-05-01

    Prediction error (i.e., the difference between the expected and the actual event's outcome) mediates adaptive behavior. Activity in the anterior mid-cingulate cortex (aMCC) and in the anterior insula (aINS) is associated with the commission of prediction errors under uncertainty. We propose a dynamic causal model of effective connectivity (i.e., neuronal coupling) between the aMCC, the aINS, and the striatum in which the task context drives activity in the aINS and the temporal prediction errors modulate extrinsic cingulate-insular connections. With functional magnetic resonance imaging, we scanned 15 participants when they performed a temporal prediction task. They observed visual animations and predicted when a stationary ball began moving after being contacted by another moving ball. To induced uncertainty-driven prediction errors, we introduced spatial gaps and temporal delays between the balls. Classical and Bayesian fMRI analyses provided evidence to support that the aMCC-aINS system along with the striatum not only responds when humans predict whether a dynamic event occurs but also when it occurs. Our results reveal that the insula is the entry port of a three-region pathway involved in the processing of temporal predictions. Moreover, prediction errors rather than attentional demands, task difficulty, or task duration exert an influence in the aMCC-aINS system. Prediction errors debilitate the effect of the aMCC on the aINS. Finally, our computational model provides a way forward to characterize the physiological parallel of temporal prediction errors elicited in dynamic tasks.

  20. PYRAMID LAKE RENEWEABLE ENERGY PLAN

    Energy Technology Data Exchange (ETDEWEB)

    HIGH DESERT GEOCULTURE, LLC

    2009-06-06

    The Pyramid Lake Renewable Energy Plan covers these areas: energy potential (primarily focusing on geothermal resource potential, but also more generally addressing wind energy potential); renewable energy market potential; transmission system development; geothermal direct use potential; and business structures to accomplish the development objectives of the Pyramid Lake Paiute Tribe.

  1. Contrasting reward signals in the orbitofrontal cortex and anterior cingulate cortex.

    Science.gov (United States)

    Wallis, Jonathan D; Kennerley, Steven W

    2011-12-01

    Damage to the orbitofrontal cortex (OFC) and anterior cingulate cortex (ACC) impairs decision making, but the underlying value computations that cause such impairments remain unclear. Both the OFC and ACC encode a wide variety of signals correlated with decision making. The current challenge is to determine how these two different areas support decision-making processes. Here, we review a series of experiments that have helped define these roles. A special population of neurons in the ACC, but not the OFC, multiplex value information across decision parameters using a unified encoding scheme, and encode reward prediction errors. In contrast, neurons in the OFC, but not the ACC, encode the value of a choice relative to the recent history of choice values. Together, these results suggest complementary valuation processes: OFC neurons dynamically evaluate current choices relative to the value contexts recently experienced, while ACC neurons encode choice predictions and prediction errors using a common valuation currency reflecting the integration of multiple decision parameters.

  2. Effects of Glycine on Trains of Action Potentials in Pyramidal Neurone of Rat Prefrontal Cortex%甘氨酸对大鼠前额叶皮质锥体神经元串连动作电位影响的研究

    Institute of Scientific and Technical Information of China (English)

    刘宇炜; 黄丹; 陈晓青; 许晓利; 艾永循

    2012-01-01

    Objective: To study the effect of glycine on trains of action potentials in pyramidal neurone of rat prefrontal cortex. Methods : Rat prefrontal cortex slices were prepared. Trains of action potentials were investigated using whole-cell patch-clamp recording in pyramidal neurone. Results : The frequency of trains of action potentials in pyramidal neurone was decreased significantly by 300 μmol/L glycine, this effect could be blocked by 1 μmol/L strychnine, demonstrating that it acts on strychnine-dependent glycine receptors. The glycine can cause membrane hyperpolariza- tion, prolong the latent period of action potential, accelerate the repolarization process. Conclusion : The glycine receptors in prefrontal cortex may involve in important function in regulation of VTA-NAcc-PFC neural circuit.%目的:研究甘氨酸对大鼠前额叶皮质锥体神经元串连动作电位的影响。方法:大鼠前额叶皮质切片,全细胞膜片钳记录锥体神经元串连动作电位。结果:甘氨酸(300μmol/L)可显著降低大鼠前额叶皮质锥体神经元串连动作电位的发放频率,其作用可被番木鳖碱(1μmol/L)所阻断,表明其作用部位为番木鳖碱依赖性甘氨酸受体。甘氨酸还引起膜超极化,延长动作电位的潜伏期,加快复极化进程。结论:前额叶皮质的甘氨酸受体可能在VTA—NAcc—PFC神经环路的调控中发挥重要作用。

  3. Practice explains abolished behavioural adaptation after human dorsal anterior cingulate cortex lesions.

    Science.gov (United States)

    van Steenbergen, H; Haasnoot, E; Bocanegra, B R; Berretty, E W; Hommel, B

    2015-04-08

    The role of mid-cingulate cortex (MCC), also referred to as dorsal anterior cingulate cortex, in regulating cognitive control is a topic of primary importance in cognitive neuroscience. Although many studies have shown that MCC responds to cognitive demands, lesion studies in humans are inconclusive concerning the causal role of the MCC in the adaptation to these demands. By elegantly combining single-cell recordings with behavioural methods, Sheth et al. [Sheth, S. et al. Human dorsal anterior cingulate cortex neurons mediate ongoing behavioural adaptation. Nature 488, 218-22 (2012).] recently were able to show that neurons in MCC encode cognitive demand. Importantly, this study also claimed that focal lesions of the MCC abolished behavioural adaptation to cognitive demands. Here we show that the absence of post-cingulotomy behavioural adaptation reported in this study may have been due to practice effects. We run a control condition where we tested subjects before and after a dummy treatment, which substituted cingulotomy with a filler task (presentation of a documentary). The results revealed abolished behavioural adaptation following the dummy treatment. Our findings suggest that future work using proper experimental designs is needed to advance the understanding of the causal role of the MCC in behavioural adaptation.

  4. The changes of brain-derived neurotrophic factor positive neurons and the morphology of pyramidal cells in hippocampal in sodium valproate induced autism rats%丙戊酸钠孤独症模型鼠海马脑源性神经营养因子阳性神经元表达及锥体细胞形态学的变化

    Institute of Scientific and Technical Information of China (English)

    衣明纪; 马小旭; 李音

    2013-01-01

    目的 观察丙戊酸钠(VPA)孤独症模型鼠海马脑源性神经营养因子(BDNF)阳性神经元表达及锥体细胞形态学改变.方法 按Schneider方法制作VPA孤独症动物模型,采用免疫组化和图像分析技术检测模型鼠海马CA1区BDNF阳性神经元表达水平及海马CA1区锥体细胞形态学的改变.结果 孤独症模型组与正常对照组比较,海马CA1区锥体细胞BDNF阳性神经元表达水平增强,孤独症模型组与正常对照组阳性细胞数分别为(5.00±1.60)/视野和(3.00±1.04)/视野,差异有统计学意义(t=3.63,P=0.0015);海马CA1区锥体细胞形态学显示,孤独症模型鼠海马CA1区锥体神经元发生凋亡增加.结论 孤独症的发病可能与海马CA1区锥体细胞BDNF表达水平以及锥体神经细胞的凋亡有关.%Objective To explore the pathogenesis of autism by observation of changes of brain-derived neurotrophic factor(BDNF) positive neurons and the morphology of pyramidal cells in hippocampal CA1 region,and provide theoretical evidence for the therapeutic schedule.Methods Animal model of autism was obtained by Schneider method.Using the immunohistochemistry methods and image analysis,the number of BDNF positive neurons was examined in hippocampal CA1 region of the autism model rats and the normal rats,and the changes of pyramidal cell were observed in hippocampal CA1 region after HE staining.Results The numbers of BDNF positive neurons in the hippocampal CA1 region of the autism model rats were more than those of the normal rats (5.00 ±1.60 vs 3.00 ± 1.04,t =3.63,P =0.0015).The morphology of pyramidal cells showed that the pyramidal cells of the autism model rats in hippocampal CA1 region had apoptosis.Conclusion The occurrence of autism may be related to the changes of BDNF and the morphology of pyramidal cells in hippocampal CA1 region.

  5. Pyramidal cell-interneuron interactions underlie hippocampal ripple oscillations.

    Science.gov (United States)

    Stark, Eran; Roux, Lisa; Eichler, Ronny; Senzai, Yuta; Royer, Sebastien; Buzsáki, György

    2014-07-16

    High-frequency ripple oscillations, observed most prominently in the hippocampal CA1 pyramidal layer, are associated with memory consolidation. The cellular and network mechanisms underlying the generation, frequency control, and spatial coherence of the rhythm are poorly understood. Using multisite optogenetic manipulations in freely behaving rodents, we found that depolarization of a small group of nearby pyramidal cells was sufficient to induce high-frequency oscillations, whereas closed-loop silencing of pyramidal cells or activation of parvalbumin- (PV) or somatostatin-immunoreactive interneurons aborted spontaneously occurring ripples. Focal pharmacological blockade of GABAA receptors abolished ripples. Localized PV interneuron activation paced ensemble spiking, and simultaneous induction of high-frequency oscillations at multiple locations resulted in a temporally coherent pattern mediated by phase-locked interneuron spiking. These results constrain competing models of ripple generation and indicate that temporally precise local interactions between excitatory and inhibitory neurons support ripple generation in the intact hippocampus.

  6. Pain and Emotion Interactions in Subregions of the Cingulate Gyrus

    OpenAIRE

    Vogt, Brent A.

    2005-01-01

    Acute pain and emotion are processed in two forebrain networks and cingulate cortex is in both. Although Brodmann’s cingulate gyrus had two divisions and was not based on any functional criteria, functional imaging reports the location of activity by this model. Recent cingulate cytoarchitectural studies support a four-region model with subregions based on connections and qualitatively unique functions. Although pain and emotion activity have been widely reported, some view these as emergent ...

  7. An analysis of von Economo neurons in the cerebral cortex of cetaceans, artiodactyls, and perissodactyls.

    Science.gov (United States)

    Raghanti, Mary Ann; Spurlock, Linda B; Treichler, F Robert; Weigel, Sara E; Stimmelmayr, Raphaela; Butti, Camilla; Thewissen, J G M Hans; Hof, Patrick R

    2015-07-01

    Von Economo neurons (VENs) are specialized projection neurons with a characteristic spindle-shaped soma and thick basal and apical dendrites. VENs have been described in restricted cortical regions, with their most frequent appearance in layers III and V of the anterior cingulate cortex, anterior insula, and frontopolar cortex of humans, great apes, macaque monkeys, elephants, and some cetaceans. Recently, a ubiquitous distribution of VENs was reported in various cortical areas in the pygmy hippopotamus, one of the closest living relatives of cetaceans. That finding suggested that VENs might not be unique to only a few species that possess enlarged brains. In the present analysis, we assessed the phylogenetic distribution of VENs within species representative of the superordinal clade that includes cetartiodactyls and perissodactyls, as well as afrotherians. In addition, the distribution of fork cells that are often found in close proximity to VENs was also assessed. Nissl-stained sections from the frontal pole, anterior cingulate cortex, anterior insula, and occipital pole of bowhead whale, cow, sheep, deer, horse, pig, rock hyrax, and human were examined using stereologic methods to quantify VENs and fork cells within layer V of all four cortical regions. VENs and fork cells were found in each of the species examined here with species-specific differences in distributions and densities. The present results demonstrated that VENs and fork cells were not restricted to highly encephalized or socially complex species, and their repeated emergence among distantly related species seems to represent convergent evolution of specialized pyramidal neurons. The widespread phylogenetic presence of VENs and fork cells indicates that these neuron morphologies readily emerged in response to selective forces,whose variety and nature are yet to be identified.

  8. The pyramidal capacitated vehicle routing problem

    DEFF Research Database (Denmark)

    Lysgaard, Jens

    2010-01-01

    This paper introduces the pyramidal capacitated vehicle routing problem (PCVRP) as a restricted version of the capacitated vehicle routing problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the pyramidal traveling salesman problem (PTSP). A pyramidal...

  9. Overcomplete steerable pyramid filters and rotation invariance

    OpenAIRE

    1994-01-01

    A given (overcomplete) discrete oriented pyramid may be converted into a steerable pyramid by interpolation. We present a technique for deriving the optimal interpolation functions (otherwise called 'steering coefficients'). The proposed scheme is demonstrated on a computationally efficient oriented pyramid, which is a variation on the Burt and Adelson (1983) pyramid. We apply the generated steerable pyramid to orientation-invariant texture analysis in order to demonstrate its excellent rotat...

  10. Expression of Kv3.1b potassium channel is widespread in macaque motor cortex pyramidal cells: A histological comparison between rat and macaque.

    Science.gov (United States)

    Soares, David; Goldrick, Isabelle; Lemon, Roger N; Kraskov, Alexander; Greensmith, Linda; Kalmar, Bernadett

    2017-02-18

    There are substantial differences across species in the organisation and function of the motor pathways. These differences extend to basic electrophysiological properties. Thus, in rat motor cortex, pyramidal cells have long duration action potentials, while in the macaque, some pyramidal neurons exhibit short duration 'thin' spikes. These differences may be related to the expression of the fast potassium channel Kv3.1b, which in rat interneurons is associated with generation of thin spikes. Rat pyramidal cells typically lack these channels, while there are reports that they are present in macaque pyramids. Here we made a systematic, quantitative comparison of the expression of Kv3.1b in sections from macaque and rat motor cortex, using two different antibodies (NeuroMab, Millipore). As our standard reference, we examined, in the same sections, Kv3.1b staining in parvalbumin-positive interneurons, which show strong Kv3.1b immunoreactivity. In macaque motor cortex, a large sample of pyramidal neurons were nearly all found to express Kv3.1b in their soma membranes. These labelled neurons were identified as pyramidal based either by expression of SMI32 (a pyramidal marker), or by their shape and size, lack of expression of parvalbumin (a marker for some classes of interneuron). Large (Betz cells), medium and small pyramidal neurons all expressed Kv3.1b. In rat motor cortex, SMI32-postive pyramidal neurons expressing Kv3.1b were very rare and weakly stained. Thus, there is a marked species difference in the immunoreactivity of Kv3.1b in pyramidal neurons, and this may be one of the factors explaining the pronounced electrophysiological differences between rat and macaque pyramidal neurons. This article is protected by copyright. All rights reserved.

  11. 钾通道阻断剂4-氨基吡啶诱导海马CA1锥体神经元钙瞬变%Calcium transient of CA1 pyramidal neurons induced by potassium blocker 4-aminopyridine in acute hippocampal slices

    Institute of Scientific and Technical Information of China (English)

    苏涛; 丛文东; 廖卫平

    2011-01-01

    Objective To investigate the calcium transient of CA1 pyramidal neurons induced by potassium blocker 4-aminopyridine (4-AP) in acute hippocampal slices to explore the relation between potassium channel function and calcium transient, and their mechanism. Methods Fluorescent probe was employed to mark the hippocampai neurons in acute brain slices of rats; confocal microscopy was used to perform calcium imaging to observe the influences of different concentrations of 4-AP and perfusate with/without calcium on calcium transient of CA1 pyramidal neurons. Results The response of [Ca2+]I to lower concentration of 4-AP (<15 mmol/L) was in a dose-dependent manner (r2=0.910, P=0.000); the higher the concentration of 4-AP (20-80 mmol/L), the lower the peak level of calcium transient. The latency and amplitude of calcium transient induced by 4-AP were obviously reduced when the extracellular condition was switched to an absence of calcium, which was significantly different as compared with that with calcium (P<0.05). Conclusion Blockade of potassium channels with 4-AP can increase [Ca2+]I in the hippocampal pyramidal neurons of acute slices. The increase of [Ca2+]1 to 4-AP could be ascribe to calcium release from intracellular stores and calcium influx from extracellular matrix.%目的 研究4-氨基吡啶(4-AP)诱导的急性脑片海马CA1锥体神经元钙瞬变现象,探讨钾通道功能与钙瞬变的关系及可能机制.方法 荧光探针标记正常大鼠急性脑片海马神经元.共聚焦显微镜技术进行钙成像,观察不同浓度4-AP及细胞灌流液条件对神经元钙瞬变的影响.结果 低浓度(<15 mmol/L)4-AP诱导的钙瞬变峰值与剂量呈线性相关(r2=0.910,P=0.000),高浓度(20~80 mmol/L)4-AP诱导的钙瞬变峰值随浓度增高而下降.在无钙灌流液条件下,4-AP诱导的钙瞬变峰值水平下降,达峰时间延长,与含钙灌流液比较差异有统计学意义(P<0.05).结论 4-AP可诱导急性脑片海马CA1锥体神经

  12. High temperatures alter physiological properties of pyramidal cells and inhibitory interneurons in hippocampus

    OpenAIRE

    Kim, Jennifer A; Barry W Connors

    2012-01-01

    Temperature has multiple effects on neurons, yet little is known about the effects of high temperature on the physiology of mammalian central neurons. Hyperthermia can influence behavior and cause febrile seizures. We studied the effects of acute hyperthermia on the immature hippocampus in vitro by recording from pyramidal neurons and inhibitory oriens-lacunosum moleculare (O-LM) interneurons (identified by green fluorescent protein (GFP) expression in the GIN mouse line). Warming to 41°C cau...

  13. Widespread heterogeneous neuronal loss across the cerebral cortex in Huntington's disease.

    Science.gov (United States)

    Nana, Alissa L; Kim, Eric H; Thu, Doris C V; Oorschot, Dorothy E; Tippett, Lynette J; Hogg, Virginia M; Synek, Beth J; Roxburgh, Richard; Waldvogel, Henry J; Faull, Richard L M

    2014-01-01

    Huntington's disease is an autosomal dominant neurodegenerative disease characterized by neuronal degeneration in the basal ganglia and cerebral cortex, and a variable symptom profile. Although progressive striatal degeneration is known to occur and is related to symptom profile, little is known about the cellular basis of symptom heterogeneity across the entire cerebral cortex. To investigate this, we have undertaken a double blind study using unbiased stereological cell counting techniques to determine the pattern of cell loss in six representative cortical regions from the frontal, parietal, temporal, and occipital lobes in the brains of 14 Huntington's disease cases and 15 controls. The results clearly demonstrate a widespread loss of total neurons and pyramidal cells across all cortical regions studied, except for the primary visual cortex. Importantly, the results show that cell loss is remarkably variable both within and between Huntington's disease cases. The results also show that neuronal loss in the primary sensory and secondary visual cortices relate to Huntington's disease motor symptom profiles, and neuronal loss across the associational cortices in the frontal, parietal and temporal lobes is related to both Huntington's disease motor and to mood symptom profiles. This finding considerably extends a previous study (Thu et al., Brain, 2010; 133:1094-1110) which showed that neuronal loss in the primary motor cortex was related specifically to the motor symptom profiles while neuronal loss in the anterior cingulate cortex was related specifically to mood symptom profiles. The extent of cortical cell loss in the current study was generally related to the striatal neuropathological grade, but not to CAG repeat length on the HTT gene. Overall our findings show that Huntington's disease is characterized by a heterogeneous pattern of neuronal cell loss across the entire cerebrum which varies with symptom profile.

  14. Neurons of human nucleus accumbens

    Directory of Open Access Journals (Sweden)

    Sazdanović Maja

    2011-01-01

    Full Text Available Background/Aim. Nucleus accumbens is a part of the ventral striatum also known as a drug active brain region, especially related with drug addiction. The aim of the study was to investigate the Golgi morphology of the nucleus accumbens neurons. Methods. The study was performed on the frontal and sagittal sections of 15 human brains by the Golgi Kopsch method. We classified neurons in the human nucleus accumbens according to their morphology and size into four types: type I - fusiform neurons; type II - fusiform neurons with lateral dendrite, arising from a part of the cell body; type III - pyramidal-like neuron; type IV - multipolar neuron. The medium spiny neurons, which are mostly noted regarding to the drug addictive conditions of the brain, correspond to the type IV - multipolar neurons. Results. Two regions of human nucleus accumbens could be clearly recognized on Nissl and Golgi preparations each containing different predominant neuronal types. Central part of nucleus accumbens, core region, has a low density of impregnated neurons with predominant type III, pyramidal-like neurons, with spines on secondary branches and rare type IV, multipolar neurons. Contrary to the core, peripheral region, shell of nucleus, has a high density of impregnated neurons predominantly contained of type I and type IV - multipolar neurons, which all are rich in spines on secondary and tertiary dendritic branches. Conclusion. Our results indicate great morphological variability of human nucleus accumbens neurons. This requires further investigations and clarifying clinical significance of this important brain region.

  15. Rule activity related to spatial and numerical magnitudes: comparison of prefrontal, premotor, and cingulate motor cortices.

    Science.gov (United States)

    Eiselt, Anne-Kathrin; Nieder, Andreas

    2014-05-01

    In everyday situations, quantitative rules, such as "greater than/less than," need to be applied to a multitude of magnitude comparisons, be they sensory, spatial, temporal, or numerical. We have previously shown that rules applied to different magnitudes are encoded in the lateral PFC. To investigate if and how other frontal lobe areas also contribute to the encoding of quantitative rules applied to multiple magnitudes, we trained monkeys to switch between "greater than/less than" rules applied to either line lengths (spatial magnitudes) or dot numerosities (discrete numerical magnitudes). We recorded single-cell activity from the dorsal premotor cortex (dPMC) and cingulate motor cortex (CMA) and compared it with PFC activity. We found the largest proportion of quantitative rule-selective cells in PFC (24% of randomly selected cells), whereas neurons in dPMC and CMA rarely encoded the rule (6% of the cells). In addition, rule selectivity of individual cells was highest in PFC neurons compared with dPMC and CMA neurons. Rule-selective neurons that simultaneously represented the "greater than/less than" rules applied to line lengths and numerosities ("rule generalists") were exclusively present in PFC. In dPMC and CMA, however, neurons primarily encoded rules applied to only one of the two magnitude types ("rule specialists"). Our data suggest a special involvement of PFC in representing quantitative rules at an abstract level, both in terms of the proportion of neurons engaged and the coding capacities.

  16. Pyramid Lake Task Force : Final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Pyramid Lake Task Force was created to address Pyramid Lake’s recession and recommend possible solutions that would consider both the needs for preserving the...

  17. One Kind of Network Complexity Pyramid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Pyramid architecture can be widely found in nature and most social fields. For example, Zoltvai and Barabasi firstly proposed the life’s complexity pyramid in biology science, and it was found that the

  18. A Rebuttal of NTL Institute's Learning Pyramid

    Science.gov (United States)

    Letrud, Kare

    2012-01-01

    This article discusses the learning pyramid corroborated by National Training Laboratories Institute. It present and compliment historical and methodological critique against the learning pyramid, and call upon NTL Institute ought to retract their model.

  19. Impaired cognitive control and reduced cingulate activity during mental fatigue

    NARCIS (Netherlands)

    Lorist, MM; Boksem, MAS; Ridderinkhof, KR

    2005-01-01

    Neurocognitive mechanisms underlying the effects of mental fatigue are poorly understood. Here, we examined whether error-related brain activity, indexing performance monitoring by the anterior cingulate cortex (ACC), and strategic behavioural adjustments were modulated by mental fatigue, as induced

  20. Urban Public Health: Is There a Pyramid?

    OpenAIRE

    Meirong Su; Bin Chen; Zhifeng Yang; Yanpeng Cai; Jiao Wang

    2013-01-01

    Early ecologists identified a pyramidal trophic structure in terms of number, biomass and energy transfer. In 1943, the psychologist Maslow put forward a pyramid model to describe layers of human needs. It is indicated that the pyramid principle is universally applicable in natural, humanistic and social disciplines. Here, we report that a pyramid structure also exists in urban public health (UPH). Based on 18 indicators, the UPH states of four cities (Beijing, Tokyo, New York, and London) ar...

  1. [Morphology of neurons of human subiculum proper].

    Science.gov (United States)

    Stanković-Vulović, Maja; Zivanović-Macuzić, Ivana; Sazdanović, Predrag; Jeremić, Dejan; Tosevski, Jovo

    2010-01-01

    Subiculum proper is an archicortical structure of the subicular complex and presents the place of origin of great majority of axons of the whole hippocampal formation. In contrast to the hippocampus which has been intensively studied, the data about human subiculum proper are quite scarce. The aim of our study was to identify morphological characteristics of neurons of the human subiculum proper. The study was performed on 10 brains of both genders by using Golgi impregnation and Nissl staining. The subiculum has three layers: molecular, pyramidal and polymorphic layer. The dominant cell type in the pyramidal layer was the pyramidal neurons, which had pyramidal shaped soma, multiple basal dendrites and one apical dendrite. The nonpyramidal cells were scattered among the pyramidal cells of the pyramidal layer. The nonpyramidal cells were classified on: multipolar, bipolar and neurons with triangular-shaped soma. The neurons of the molecular layer of the human subiculum were divided into groups: bipolar and multipolar neurons. The most numerous cells of the polymorphic layer were bipolar and multipolar neurons.

  2. Homeostatic responses by surviving cortical pyramidal cells in neurodegenerative tauopathy.

    Science.gov (United States)

    Crimins, Johanna L; Rocher, Anne B; Peters, Alan; Shultz, Penny; Lewis, Jada; Luebke, Jennifer I

    2011-11-01

    Cortical neuron death is prevalent by 9 months in rTg(tau(P301L))4510 tau mutant mice (TG) and surviving pyramidal cells exhibit dendritic regression and spine loss. We used whole-cell patch-clamp recordings to investigate the impact of these marked structural changes on spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) of layer 3 pyramidal cells in frontal cortical slices from behaviorally characterized TG and non-transgenic (NT) mice at this age. Frontal lobe function of TG mice was intact following a short delay interval but impaired following a long delay interval in an object recognition test, and cortical atrophy and cell loss were pronounced. Surviving TG cells had significantly reduced dendritic diameters, total spine density, and mushroom spines, yet sEPSCs were increased and sIPSCs were unchanged in frequency. Thus, despite significant regressive structural changes, synaptic responses were not reduced in TG cells, indicating that homeostatic compensatory mechanisms occur during progressive tauopathy. Consistent with this idea, surviving TG cells were more intrinsically excitable than NT cells, and exhibited sprouting of filopodia and axonal boutons. Moreover, the neuropil in TG mice showed an increased density of asymmetric synapses, although their mean size was reduced. Taken together, these data indicate that during progressive tauopathy, cortical pyramidal cells compensate for loss of afferent input by increased excitability and establishment of new synapses. These compensatory homeostatic mechanisms may play an important role in slowing the progression of neuronal network dysfunction during neurodegenerative tauopathies.

  3. A magic pyramid of supergravities

    Energy Technology Data Exchange (ETDEWEB)

    Anastasiou, A.; Borsten, L.; Duff, M.J.; Hughes, L.J.; Nagy, S. [Theoretical Physics, Blackett Laboratory, Imperial College London,London SW7 2AZ (United Kingdom)

    2014-04-29

    By formulating N=1,2,4,8, D=3, Yang-Mills with a single Lagrangian and single set of transformation rules, but with fields valued respectively in ℝ,ℂ,ℍ,O, it was recently shown that tensoring left and right multiplets yields a Freudenthal-Rosenfeld-Tits magic square of D=3 supergravities. This was subsequently tied in with the more familiar ℝ,ℂ,ℍ,O description of spacetime to give a unified division-algebraic description of extended super Yang-Mills in D=3,4,6,10. Here, these constructions are brought together resulting in a magic pyramid of supergravities. The base of the pyramid in D=3 is the known 4×4 magic square, while the higher levels are comprised of a 3×3 square in D=4, a 2×2 square in D=6 and Type II supergravity at the apex in D=10. The corresponding U-duality groups are given by a new algebraic structure, the magic pyramid formula, which may be regarded as being defined over three division algebras, one for spacetime and each of the left/right Yang-Mills multiplets. We also construct a conformal magic pyramid by tensoring conformal supermultiplets in D=3,4,6. The missing entry in D=10 is suggestive of an exotic theory with G/H duality structure F{sub 4(4)}/Sp(3)×Sp(1)

  4. A magic pyramid of supergravities

    Science.gov (United States)

    Anastasiou, A.; Borsten, L.; Duff, M. J.; Hughes, L. J.; Nagy, S.

    2014-04-01

    By formulating = 1, 2, 4, 8, D = 3, Yang-Mills with a single Lagrangian and single set of transformation rules, but with fields valued respectively in , it was recently shown that tensoring left and right multiplets yields a Freudenthal-Rosenfeld-Tits magic square of D = 3 supergravities. This was subsequently tied in with the more familiar description of spacetime to give a unified division-algebraic description of extended super Yang-Mills in D = 3, 4, 6, 10. Here, these constructions are brought together resulting in a magic pyramid of supergravities. The base of the pyramid in D = 3 is the known 4 × 4 magic square, while the higher levels are comprised of a 3 × 3 square in D = 4, a 2 × 2 square in D = 6 and Type II supergravity at the apex in D = 10. The corresponding U-duality groups are given by a new algebraic structure, the magic pyramid formula, which may be regarded as being defined over three division algebras, one for spacetime and each of the left/right Yang-Mills multiplets. We also construct a conformal magic pyramid by tensoring conformal supermultiplets in D = 3, 4, 6. The missing entry in D = 10 is suggestive of anexotic theory with G/ H duality structure F 4(4)/Sp(3) × Sp(1).

  5. The Chinese Pyramids and the Sun

    CERN Document Server

    Sparavigna, Amelia Carolina

    2012-01-01

    The Chinese Pyramids are huge ancient burial mounds. In the satellite images we can see some complexes where the main buildings are the pyramidal mounds of an emperor and his empress. Here we discuss a possible sunrise/sunset orientation of these two pyramids on the solstices and equinoxes.

  6. Three Types of Network Complexity Pyramid

    Institute of Scientific and Technical Information of China (English)

    FANG; Jin-qing; LI; Yong; LIU; Qiang

    2012-01-01

    <正>Exploring the complexity and diversity of complex networks have been very challenging issues in network science and engineering. Among them exploring the network complexity pyramids (NCP) are one of important expressions in network complexity. So far as we have proposed the three types of the network complexity pyramid (NCP). The first type of NCP is the network model complexity pyramid with

  7. Functions of the orbitofrontal and pregenual cingulate cortex in taste, olfaction, appetite and emotion.

    Science.gov (United States)

    Rolls, E T

    2008-06-01

    Complementary neurophysiological recordings in macaques and functional neuroimaging in humans show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature, and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. The representation of taste and other food-related stimuli in the orbitofrontal cortex of macaques is found from its lateral border throughout area 13 to within 7 mm of the midline, and in humans the representation of food-related and other pleasant stimuli is found particularly in the medial orbitofrontal cortex. In the orbitofrontal cortex, feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour, and the activation produced by the odour in the orbitofrontal cortex. Food intake is thus controlled by building a multimodal representation of the sensory properties of food in the orbitofrontal cortex, and gating this representation by satiety signals to produce a representation of the pleasantness or reward value of food which drives food intake. A neuronal representation of taste is also found in the pregenual cingulate cortex, which receives inputs from the orbitofrontal cortex, and in humans many pleasant

  8. Homeostatic plasticity: single hippocampal neurons see the light.

    Science.gov (United States)

    Sutton, Michael A

    2010-11-04

    Neurons adapt to altered network activity through homeostatic changes in synaptic function. In this issue of Neuron, Goold and Nicoll report that chronic hyperactivation of individual CA1 pyramidal neurons drives cell-autonomous, compensatory synapse elimination via CaMKIV-dependent transcription. These findings suggest that neurons gauge their intrinsic activity to instruct homeostatic regulation of synaptic inputs.

  9. High temperatures alter physiological properties of pyramidal cells and inhibitory interneurons in hippocampus

    Directory of Open Access Journals (Sweden)

    Jennifer eKim

    2012-07-01

    Full Text Available Temperature has multiple effects on neurons, yet little is known about the effects of high temperature on the physiology of mammalian central neurons. Hyperthermia can influence behavior and cause febrile seizures. We studied the effects of acute hyperthermia on the immature hippocampus in vitro by recording from pyramidal neurons and inhibitory oriens-lacunosum moleculare (O-LM interneurons (identified by green fluorescent protein expression in the GIN mouse line. Warming to 41°C caused depolarization, spontaneous action potentials, reduced input resistance and membrane time constant, and increased spontaneous synaptic activity of most pyramidal cells and O-LM interneurons. Pyramidal neurons of area CA3 were more strongly excited by hyperthermia than those of area CA1. About 90% of O-LM interneurons in both CA1 and CA3 increased their firing rates at hyperthermic temperatures; interneurons in CA3 fired faster than those in CA1 on average. Blockade of fast synaptic transmission did not abolish the effect of hyperthermia on neuronal excitability. Our results suggest that hyperthermia increases hippocampal excitability, particularly in seizure-prone area CA3, by altering the intrinsic membrane properties of pyramidal cells and interneurons.

  10. High temperatures alter physiological properties of pyramidal cells and inhibitory interneurons in hippocampus.

    Science.gov (United States)

    Kim, Jennifer A; Connors, Barry W

    2012-01-01

    Temperature has multiple effects on neurons, yet little is known about the effects of high temperature on the physiology of mammalian central neurons. Hyperthermia can influence behavior and cause febrile seizures. We studied the effects of acute hyperthermia on the immature hippocampus in vitro by recording from pyramidal neurons and inhibitory oriens-lacunosum moleculare (O-LM) interneurons (identified by green fluorescent protein (GFP) expression in the GIN mouse line). Warming to 41°C caused depolarization, spontaneous action potentials, reduced input resistance and membrane time constant, and increased spontaneous synaptic activity of most pyramidal cells and O-LM interneurons. Pyramidal neurons of area CA3 were more strongly excited by hyperthermia than those of area CA1. About 90% of O-LM interneurons in both CA1 and CA3 increased their firing rates at hyperthermic temperatures; interneurons in CA3 fired faster than those in CA1 on average. Blockade of fast synaptic transmission did not abolish the effect of hyperthermia on neuronal excitability. Our results suggest that hyperthermia increases hippocampal excitability, particularly in seizure-prone area CA3, by altering the intrinsic membrane properties of pyramidal cells and interneurons.

  11. The mammalian neocortical pyramidal cell: a new theory on prenatal development

    Directory of Open Access Journals (Sweden)

    Miguel eMarín-Padilla

    2014-01-01

    Full Text Available Mammals’ new cerebral cortex (neocortex and the new type of pyramidal neuron are mammalian innovations that have evolved for operating their increasing motor capabilities using essentially analogous anatomical and neural makeups. The human neocortex starts to develop in the 6-week-old embryo with the establishment of a primordial cortical organization that resembles the primitive cortices of amphibian and reptiles that operated his early motor activities. From the 8th to the 15th week of age, the new pyramidal neurons, of ependymal origin, are progressively incorporated within this primordial cortex forming a cellular plate that divide its components into those above it (neocortex first lamina and those below it (neocortex subplate elements. From the 16th week of age to birth and postnatally, the new pyramidal neurons continue to elongate functionally their apical dendrite by adding synaptic membrane to incorporate the needed sensory information for operating the animal muscular activities. The new pyramidal neuron’ distinguishing feature is the capacity of elongating anatomically and functionally its apical dendrite (its main receptive surface without losing its original attachment to first lamina or the location of its soma retaining its essential nature. The number of pyramidal cell functional strata established in the motor cortex increases and reflects each mammalian species motor capabilities: the hedgehog needs 2 pyramidal cell functional strata to carry out all its motor activities, the mouse three, cat four, primates 5 and humans 6. The presence of six pyramidal cell functional strata distinguish the human motor cortex from that of others primates. Homo sapiens represent a new evolutionary stage that have transformed his primate brain for operating his unique motor capabilities, such as speaking, writing, painting, sculpturing including thinking as a premotor activity.

  12. Single-cell coding of sensory, spatial and numerical magnitudes in primate prefrontal, premotor and cingulate motor cortices.

    Science.gov (United States)

    Eiselt, Anne-Kathrin; Nieder, Andreas

    2016-01-01

    The representation of magnitude information enables humans and animal species alike to successfully interact with the external environment. However, how various types of magnitudes are processed by single neurons to guide goal-directed behavior remains elusive. Here, we recorded single-cell activity from the dorsolateral prefrontal (PFC), dorsal premotor (PMd) and cingulate motor (CMA) cortices in monkeys discriminating discrete numerical (numerosity), continuous spatial (line length) and basic sensory (spatial frequency) stimuli. We found that almost exclusively PFC neurons represented the different magnitude types during sample presentation and working memory periods. The frequency of magnitude-selective cells in PMd and CMA did not exceed chance level. The proportion of PFC neurons selectively tuned to each of the three magnitude types were comparable. Magnitude coding was mainly dissociated at the single-neuron level, with individual neurons representing only one of the three tested magnitude types. Neuronal magnitude discriminability, coding strength and temporal evolution were comparable between magnitude types encoded by PFC neuron populations. Our data highlight the importance of PFC neurons in representing various magnitude categories. Such magnitude representations are based on largely distributed coding by single neurons that are anatomically intermingled within the same cortical area.

  13. A magic pyramid of supergravities

    CERN Document Server

    Anastasiou, A; Duff, M J; Hughes, L J; Nagy, S

    2013-01-01

    By formulating N = 1, 2, 4, 8, D = 3, Yang-Mills with a single Lagrangian and single set of transformation rules, but with fields valued respectively in R,C,H,O, it was recently shown that tensoring left and right multiplets yields a Freudenthal-Rosenfeld-Tits magic square of D = 3 supergravities. This was subsequently tied in with the more familiar R,C,H,O description of spacetime to give a unified division-algebraic description of extended super Yang-Mills in D = 3, 4, 6, 10. Here, these constructions are brought together resulting in a magic pyramid of supergravities. The base of the pyramid in D = 3 is the known 4x4 magic square, while the higher levels are comprised of a 3x3 square in D = 4, a 2x2 square in D = 6 and Type II supergravity at the apex in D = 10. The corresponding U-duality groups are given by a new algebraic structure, the magic pyramid formula, which may be regarded as being defined over three division algebras, one for spacetime and each of the left/right Yang-Mills multiplets. We also c...

  14. A simulation study on the effects of dendritic morphology on layer V PFC pyramidal cell firing behavior

    Directory of Open Access Journals (Sweden)

    Maria Psarrou

    2014-03-01

    Full Text Available The majority of neuronal cells found in the cerebral cortex are pyramidal neurons. Their function has been associated with higher cognitive and emotional functions. Pyramidal neurons have a characteristic structure, consisting of a triangular shaped soma whereon descend two extended and complex dendritic trees, and a long bifurcated axon. All the morphological components of the pyramidal neurons exhibit significant variability across different brain areas and layers. Pyramidal cells receive numerous synaptic inputs along their structure, integration of which in space and in time generates local dendritic spikes that shape their firing pattern. In addition, synaptic integration is influenced by voltage-gated and ion channels, which are expressed in a large repertoire by pyramidal neurons. Electrophysiological categories of pyramidal cells can be established, based on the action potential frequency, generated from a fixed somatic stimulus: (1 cells that fire repetitive action potentials (Regular Spiking – RS, (2 cells that fire clusters of 2 – 5 action potentials with short ISIs (Intrinsic Bursting – IB, and (3 cells that fire in repetitive clusters of 2 – 5 action potentials with short ISIs (Repetitive Oscillatory Bursts – ROB. In vitro and in silico scientific studies, correlate the firing patterns of the pyramidal neurons to their morphological features. This study provides a quantitatively analysis via compartmental neuronal modelling of the effects of dendritic morphology and distribution and concentration of ionic mechanisms, along the basal and/or apical dendrites on the firing behavior of a 112-set of layer V rat PFC pyramidal cells. We focus on how particular morphological and passive features of the dendritic trees shape the neuronal firing patterns. Our results suggest that specific morphological parameters (such as total length, volume and branch number can discriminate the cells as RS or IB, regardless of what is the

  15. Bidirectional shift in the cornu ammonis 3 pyramidal dendritic organization following brief stress

    NARCIS (Netherlands)

    Kole, MHP; Costoli, T; Koolhaas, JM; Fuchs, E

    2004-01-01

    The negative impact of chronic stress at the structure of apical dendrite branches of cornu ammonis 3 (CA3) pyramidal neurons is well established. However, there is no information available on the CA3 dendritic organization related to short-lasting stress, which suffices to produce longterm habituat

  16. A threshold sodium current in pyramidal cells in rat hippocampus.

    Science.gov (United States)

    French, C R; Gage, P W

    1985-05-23

    Maintained, inward currents were activated by small depolarizations from the resting membrane potential (-50 to -60 mV) in voltage-clamped, pyramidal neurons in rat hippocampal slices. The currents were apparently Na currents as they were blocked by tetrodotoxin or removal of extracellular Na and were not affected by Cd. They showed little decrease in amplitude during prolonged depolarizations. The increase in Na conductance with depolarization was sigmoidal, with half-maximum conductance at about -50 mV, and saturated at -20 to -30 mV. This 'threshold' Na current may be involved in setting patterns of repetitive firing of action potentials.

  17. FPGA implementation of a pyramidal Weightless Neural Networks learning system.

    Science.gov (United States)

    Al-Alawi, Raida

    2003-08-01

    A hardware architecture of a Probabilistic Logic Neuron (PLN) is presented. The suggested model facilitates the on-chip learning of pyramidal Weightless Neural Networks using a modified probabilistic search reward/penalty training algorithm. The penalization strategy of the training algorithm depends on a predefined parameter called the probabilistic search interval. A complete Weightless Neural Network (WNN) learning system is modeled and implemented on Xilinx XC4005E Field Programmable Gate Array (FPGA), allowing its architecture to be configurable. Various experiments have been conducted to examine the feasibility and performance of the WNN learning system. Results show that the system has a fast convergence rate and good generalization ability.

  18. Tourette's syndrome: a disorder of cingulate and orbitofrontal function?

    Science.gov (United States)

    Weeks, R A; Turjanski, N; Brooks, D J

    1996-06-01

    We discuss the clinical characteristics of tics and Tourette's syndrome (TS) and also possible treatment options. Based upon an overview of published pathophysiological and PET data, and the results of a recent PET study of changes in opioid receptor binding in TS, we hypothesize that the disease arises due to dysfunction within the cingulate and orbitofrontal cortex. The beneficial effects of dopamine receptor antagonists and dopamine-depleting agents in TS are suggested to be mediated via basal ganglia-thalamofrontal circuits, while opioid agents may act directly on the cingulate.

  19. Layer 5 Pyramidal Neurons’ Dendritic Remodeling and Increased Microglial Density in Primary Motor Cortex in a Murine Model of Facial Paralysis

    Directory of Open Access Journals (Sweden)

    Diana Urrego

    2015-01-01

    Full Text Available This work was aimed at characterizing structural changes in primary motor cortex layer 5 pyramidal neurons and their relationship with microglial density induced by facial nerve lesion using a murine facial paralysis model. Adult transgenic mice, expressing green fluorescent protein in microglia and yellow fluorescent protein in projecting neurons, were submitted to either unilateral section of the facial nerve or sham surgery. Injured animals were sacrificed either 1 or 3weeks after surgery. Two-photon excitation microscopy was then used for evaluating both layer 5 pyramidal neurons and microglia in vibrissal primary motor cortex (vM1. It was found that facial nerve lesion induced long-lasting changes in the dendritic morphology of vM1 layer 5 pyramidal neurons and in their surrounding microglia. Dendritic arborization of the pyramidal cells underwent overall shrinkage. Apical dendrites suffered transient shortening while basal dendrites displayed sustained shortening. Moreover, dendrites suffered transient spine pruning. Significantly higher microglial cell density was found surrounding vM1 layer 5 pyramidal neurons after facial nerve lesion with morphological bias towards the activated phenotype. These results suggest that facial nerve lesions elicit active dendrite remodeling due to pyramidal neuron and microglia interaction, which could be the pathophysiological underpinning of some neuropathic motor sequelae in humans.

  20. AMPA receptor modulators have different impact on hippocampal pyramidal cells and interneurons.

    Science.gov (United States)

    Xia, Y-F; Arai, A C

    2005-01-01

    Positive modulators of AMPA receptors enhance synaptic plasticity and memory encoding. Facilitation of AMPA receptor currents not only results in enhanced activation of excitatory neurons but also increases the activity of inhibitory interneurons by up-modulating their excitatory input. However, little is known about the effects of these modulators on cells other than pyramidal neurons and about their impact on local microcircuits. This study examined the effects of members from three subfamilies of modulators (mainly CX516, CX546 and cyclothiazide) on excitatory synaptic responses in four classes of hippocampal CA1 neurons and on excitatory and disynaptically induced inhibitory field potentials in hippocampal slices. Effects on excitatory postsynaptic currents (EPSCs) were examined in pyramidal cells, in two types of inhibitory interneurons located in stratum radiatum and oriens, and in stratum radiatum giant cells, a novel type of excitatory neuron. With CX516, increases in EPSC amplitude in pyramidal cells were two to three times larger than in interneurons and six times larger than in radiatum giant cells. The effects of CX546 on response duration similarly were largest in pyramidal cells. However, this drug also strongly differentiated between stratum oriens and radiatum interneurons with increases being four times larger in the latter. In contrast, cyclothiazide had similar effects on response duration in all cell types. In field recordings, CX516 was several times more potent in enhancing excitatory postsynaptic potentials (EPSPs) than feedback or feedforward circuits, as expected from its larger influence on pyramidal cells. In contrast, BDP-20, a CX546 analog, was more potent in enhancing feedforward inhibition than either EPSPs or feedback inhibition. This preference for feedforward over feedback circuits is probably related to its higher potency in stratum radiatum versus oriens interneurons. Taken together, AMPA receptor modulators differ substantially

  1. Morphological and electrophysiological properties of atypically oriented layer 2 pyramidal cells of the juvenile rat neocortex.

    Science.gov (United States)

    van Brederode, J F; Foehring, R C; Spain, W J

    2000-01-01

    We used whole-cell patch clamp recordings combined with intracellular dye-filling to examine the morphological and electrophysiological properties of atypically oriented pyramidal cells located at the layer 1/2 border of the juvenile rat neocortex. Orientation of the apical dendrite varied from oblique (>20 degrees from vertical) to truly horizontal (90 degrees from vertical). The length of the apical dendrite ranged from 150 to 400 microm. The total horizontal domain of the dendritic tree (including basal dendrites) of the longest horizontal pyramids exceeded 500 microm, but we also found short horizontal cells with horizontal dendritic domains of less than 300 microm. In addition, atypically oriented pyramids had long horizontal axon collaterals in layer 1/2. Electrophysiologically, atypically oriented pyramidal cells had intrinsic membrane properties similar to regularly oriented pyramids that have been described in the superficial layers at this age in the rat. Cells that fired repetitively were all regular spiking. In addition, we identified a subgroup of neurons (20%) in this sample, which were unable to fire more than a few spikes at the beginning of the current pulse. We suggest that the unique orientation and size of their dendritic trees and the length and arrangement of their local axons collaterals make atypically oriented pyramids in layer 2 ideally suited to perform horizontal integration of synaptic inputs in the neocortex.

  2. The pyramids of Greece: Ancient meridian observatories?

    Science.gov (United States)

    Theodossiou, Efstratios; Manimanis, Vassilios N.; Dimitrijević, Milan S.; Katsiotis, Marco

    Pyramids, "Dragon Houses" ("Drakospita") and megalithic structures in general create always a special interest. We postulate that, as happens with the Drakospita of Euboea, the pyramid-like structures of Argolis (Eastern Peloponnese) were constructed by the Dryops. It is known that, in addition to Euboea and some Cyclades islands, this prehellenic people had also settled in Argolis, where they founded the city of Asine. We also propose that the pyramids of Argolis and in particular the pyramid of Hellinikon village were very likely, besides being a burial monument or guard house, might be served also for astronomical observations.

  3. Urban public health: is there a pyramid?

    Science.gov (United States)

    Su, Meirong; Chen, Bin; Yang, Zhifeng; Cai, Yanpeng; Wang, Jiao

    2013-01-28

    Early ecologists identified a pyramidal trophic structure in terms of number, biomass and energy transfer. In 1943, the psychologist Maslow put forward a pyramid model to describe layers of human needs. It is indicated that the pyramid principle is universally applicable in natural, humanistic and social disciplines. Here, we report that a pyramid structure also exists in urban public health (UPH). Based on 18 indicators, the UPH states of four cities (Beijing, Tokyo, New York, and London) are compared from the point of view of five aspects, namely physical health, living conditions, social security, environmental quality, and education and culture. A pyramid structure was found in each city when focusing on 2000-2009 data. The pyramid of Beijing is relatively similar to that of Tokyo, and the pyramids of New York and London are similar to each other. A general development trend in UPH is proposed and represented by different pyramid modes. As a basic conjecture, the UPH pyramid model can be verified and developed with data of more cities over a longer period, and be used to promote healthy urban development.

  4. Urban Public Health: Is There a Pyramid?

    Directory of Open Access Journals (Sweden)

    Meirong Su

    2013-01-01

    Full Text Available Early ecologists identified a pyramidal trophic structure in terms of number, biomass and energy transfer. In 1943, the psychologist Maslow put forward a pyramid model to describe layers of human needs. It is indicated that the pyramid principle is universally applicable in natural, humanistic and social disciplines. Here, we report that a pyramid structure also exists in urban public health (UPH. Based on 18 indicators, the UPH states of four cities (Beijing, Tokyo, New York, and London are compared from the point of view of five aspects, namely physical health, living conditions, social security, environmental quality, and education and culture. A pyramid structure was found in each city when focusing on 2000–2009 data. The pyramid of Beijing is relatively similar to that of Tokyo, and the pyramids of New York and London are similar to each other. A general development trend in UPH is proposed and represented by different pyramid modes. As a basic conjecture, the UPH pyramid model can be verified and developed with data of more cities over a longer period, and be used to promote healthy urban development.

  5. Selective serotonergic excitation of callosal projection neurons

    Directory of Open Access Journals (Sweden)

    Daniel eAvesar

    2012-03-01

    Full Text Available Serotonin (5-HT acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs of the mouse medial prefrontal cortex (mPFC, and found 3 distinct response types: long-lasting 5-HT1A (1A receptor-dependent inhibitory responses (84% of L5PNs, 5-HT2A (2A receptor-dependent excitatory responses (9%, and biphasic responses in which 2A-dependent excitation followed brief inhibition (5%. Relative to 5-HT-inhibited neurons, those excited by 5-HT had physiological properties characteristic of callosal/commissural (COM neurons that project to the contralateral cortex. We tested whether serotonergic responses in cortical pyramidal neurons are correlated with their axonal projection pattern using retrograde fluorescent labeling of COM and corticopontine-projecting (CPn neurons. 5-HT generated excitatory or biphasic responses in all 5-HT-responsive layer 5 COM neurons. Conversely, CPn neurons were universally inhibited by 5-HT. Serotonergic excitation of COM neurons was blocked by the 2A antagonist MDL 11939, while serotonergic inhibition of CPn neurons was blocked by the 1A antagonist WAY 100635, confirming a role for these two receptor subtypes in regulating pyramidal neuron activity. Selective serotonergic excitation of COM neurons was not layer-specific, as COM neurons in layer 2/3 were also selectively excited by 5-HT relative to their non-labeled pyramidal neuron neighbors. Because neocortical 2A receptors are implicated in the etiology and pathophysiology of schizophrenia, we propose that COM neurons may represent a novel cellular target for intervention in psychiatric disease.

  6. Puusepp's sign--clinical significance of a forgotten pyramidal sign.

    Science.gov (United States)

    Tacik, Pawel; Krasnianski, M; Zierz, S

    2009-12-01

    The pyramidal signs in the lower extremity can be divided into three groups: (1) Babinski's group characterised by dorsoflexion of the great toe, (2) pyramidal signs marked by plantar flexion of the toes (e.g. Rossolimo's sign), and (3) synkinetic movements such as Strümpell's phenomenon. Puusepp's sign described by the Estonian neurologist and neurosurgeon Ludvig Puusepp belongs to none of these three groups. Its eliciting does not differ from that of Babinski's sign. The response, however, is different and consists of a tonic slow abduction of the little toe. We showed its relevance on the basis of clinical examination of six patients: four females aged 29, 50, 43 and 57 years and two males aged 42 and 49 years. The diagnoses were as follows: a new relapse of multiple sclerosis, a secondary progressive multiple sclerosis, a left middle cerebral artery stroke, a lumbago resulting in L3-L4 fusion surgery, an amyotrophic lateral sclerosis and a left intracerebral haemorrhage respectively. Puusepp's sign was the only elicitable pyramidal sign in all the patients but two. The 50-year-old female patient revealed on neurological examination Babinski's sign on the left side and Puusepp's sign on the right side. The testing of pyramidal signs in the 57-year-old woman displayed a bilateral Strümpell's sign and a left Puusepp's sign. These six cases showed that although rarely recognized in the clinical practice Puusepp's sign contributed to establishing the diagnosis of a central motor neuron involvement in the case of an absent Babinski's sign. Thus, its testing does not differ from that of Babinski's sign which requires only a little attention from the examiner, but provides an important piece of clinical information.

  7. Anterior Cingulate Cortex in Schema Assimilation and Expression

    Science.gov (United States)

    Wang, Szu-Han; Tse, Dorothy; Morris, Richard G. M.

    2012-01-01

    In humans and in animals, mental schemas can store information within an associative framework that enables rapid and efficient assimilation of new information. Using a hippocampal-dependent paired-associate task, we now report that the anterior cingulate cortex is part of a neocortical network of schema storage with NMDA receptor-mediated…

  8. Anterior cingulate cortex involvement in subclinical social anxiety.

    Science.gov (United States)

    Duval, Elizabeth R; Hale, Lisa R; Liberzon, Israel; Lepping, Rebecca; N Powell, Joshua; Filion, Diane L; Savage, Cary R

    2013-12-30

    We demonstrated differential activation in the anterior cingulate cortex (ACC) between subjects with high and low social anxiety in response to angry versus neutral faces. Activation in the ACC distinguished between facial expressions in the low, but not the high, anxious group. The ACC's role in threat processing is discussed.

  9. Mining the posterior cingulate: Segregation between memory and pain components

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup; Balslev, Daniela; Hansen, Lars Kai

    2005-01-01

    We present a general method for automatic meta-analyses in neuroscience and apply it on text data from published functional imaging studies to extract main functions associated with a brain area --- the posterior cingulate cortex. Abstracts from PubMed are downloaded, words extracted and converted...

  10. Value, search, persistence and model updating in anterior cingulate cortex

    NARCIS (Netherlands)

    Kolling, N.; Wittmann, M.K.; Behrens, T.E.J.; Boorman, E.D.; Mars, R.B.; Rushworth, M.F.S.

    2016-01-01

    Dorsal anterior cingulate cortex (dACC) carries a wealth of value-related information necessary for regulating behavioral flexibility and persistence. It signals error and reward events informing decisions about switching or staying with current behavior. During decision-making, it encodes the avera

  11. Effects of 0.5mT power frequency electromagnetic fields on delayed rectifier potassium channels in hippocampus CA3 pyramidal neurons%0.5 mT工频磁场对小鼠海马CA3区锥体神经元延迟整流钾离子通道和动作电位的影响

    Institute of Scientific and Technical Information of China (English)

    沈佩同; 毕平; 李刚; 林凌

    2010-01-01

    Objective To study the effects of 0.5mT power frequency electromagnetic fields on hippocampus CA3 pyramidal neurons. Methods Hippocampus CA3 pyramidal neurons of rats were prepared by acute isolation and then exposed to an electromagnetic fields, with frequency of 50 Hz and the intensity of 0.5 mT,for 30 minutes. The delayed rectifier potassium channel currents were recorded by whole-cell patch-clamp technique. Results The results showed that after 30 minutes exposure to the electromagnetic fields, the delayedrectifier potassium channel current density of the rats' hippocampus CA3 area pyramidal neurons decreased, with the maximum value of control group was(171.05±1.32) pA/pF, and that of the exposure group was(139.65±2.37)pA/pE(n=12, P<0.05). The half-activation potential of control group and that of exposure group were (7.44±0.64)mV and (34.09±6.48) mV(n=12, P<0.05), respectively and the slope factor were 11.36±0.57 and 19.97 ±3.45(n=12, P<0.05), respectively. APD90 extended from (14.63±0.34) ms to (21.74±1.47) ms (n=12, P<0.05). Conclusion It can be speculated that the electromagnetic fields can reduce the currents of delayed rectifier potassium,change the process of activation and increase the half activation potential. After exposure, the activation speed decreased, while the APD increases.%目的 研究与日常生活密切相关的0.5 mT工频磁场对小鼠海马CA3区锥体神经元的影响.方法 采用急性分离的方法制备小鼠海马CA3区锥体神经元,用0.5 mT、50 Hz磁场对小鼠海马CA3区锥体神经元刺激30 min后,运用全细胞膜片钳技术研究其延迟整流钾通道电流,Ik和动作电位特性.结果 0.5 mT工频磁场照射小鼠海马CA3区锥体神经元30 min后,其电流密度减小,对照组和曝磁组最大电流密度分别为(171.05+1.32)pA/pF、(139.65±2.37)pA/pF(n=12,P<0.05);对照组和曝磁组半数激活电压分别为(7.44±0.64)mV、(34.09+6.48)mV(n=12,P<0.05);斜率因子分别为11.36±0.57

  12. Active browsing using similarity pyramids

    Science.gov (United States)

    Chen, Jau-Yuen; Bouman, Charles A.; Dalton, John C.

    1998-12-01

    In this paper, we describe a new approach to managing large image databases, which we call active browsing. Active browsing integrates relevance feedback into the browsing environment, so that users can modify the database's organization to suit the desired task. Our method is based on a similarity pyramid data structure, which hierarchically organizes the database, so that it can be efficiently browsed. At coarse levels, the similarity pyramid allows users to view the database as large clusters of similar images. Alternatively, users can 'zoom into' finer levels to view individual images. We discuss relevance feedback for the browsing process, and argue that it is fundamentally different from relevance feedback for more traditional search-by-query tasks. We propose two fundamental operations for active browsing: pruning and reorganization. Both of these operations depend on a user-defined relevance set, which represents the image or set of images desired by the user. We present statistical methods for accurately pruning the database, and we propose a new 'worm hole' distance metric for reorganizing the database, so that members of the relevance set are grouped together.

  13. Upregulation of glutamatergic transmission in anterior cingulate cortex in the diabetic rats with neuropathic pain.

    Science.gov (United States)

    Li, Weifang; Wang, Peng; Li, Hua

    2014-05-07

    Peripheral neuropathic pain is a common complication in the diabetic patients, and the underlying central mechanism remains unclear. Forebrain anterior cingulate cortex (ACC) is critically involved in the supraspinal perception of physical and affective components of noxious stimulus and pain modulation. Excitatory glutamatergic transmission in the ACC extensively contributed to the maintenance of negative affective component of chronic pain. The present study examined the adaptation of glutamatergic transmission in the ACC in rats with diabetic neuropathic pain. Injection with streptozotocin (STZ) induced hyperglycemia, thermal hyperalgesia and mechanical allodynia in the rats. In these rats, significant enhanced basal glutamatergic transmission was observed in the ACC neurons. The increased presynaptic glutamate release and enhanced conductance of postsynaptic glutamate receptors were also observed in the ACC neurons of these modeled rats. Increased phosphorylation of PKMζ, but not the expression of total PKMζ, was also observed in the ACC. Microinjection of PKMζ inhibitor ZIP into ACC attenuated the upregulation of glutamate transmission and painful behaviors in STZ-injected rats. These results revealed a substantial central sensitization in the ACC neurons in the rodents with diabetic neuropathic pain, which may partially underlie the negative affective components of patients with diabetic neuropathic pain.

  14. A computational study on plasticity during theta cycles at Schaffer collateral synapses on CA1 pyramidal cells in the hippocampus.

    Science.gov (United States)

    Saudargiene, Ausra; Cobb, Stuart; Graham, Bruce P

    2015-02-01

    Cellular activity in the CA1 area of the hippocampus waxes and wanes at theta frequency (4-8 Hz) during exploratory behavior of rats. Perisomatic inhibition onto pyramidal cells tends to be strongest out of phase with pyramidal cell activity, whereas dendritic inhibition is strongest in phase with pyramidal cell activity. Synaptic plasticity also varies across the theta cycle, from strong long-term potentiation (LTP) to long-term depression (LTD), putatively corresponding to encoding and retrieval phases for information patterns encoded by pyramidal cell activity (Hasselmo et al. (2002a) Neural Comput 14:793-817). The mechanisms underpinning the phasic changes in plasticity are not clear, but it is likely that inhibition plays a role by affecting levels of electrical activity and calcium concentration at synapses. We explore the properties of synaptic plasticity during theta at Schaffer collateral synapses on CA1 pyramidal neurons and the influence of spatially and temporally targeted inhibition using a detailed multicompartmental model of the CA1 pyramidal neuron microcircuit and a phenomenological model of synaptic plasticity. The results suggest CA3-CA1 synapses are potentiated on one phase of theta due to high calcium levels provided by paired weak CA3 and layer III entorhinal cortex (EC) inputs even when somatic spiking is inhibited by perisomatic interneuron activity. Weak CA3 inputs alone induce lower calcium transients and result in depression of the CA3-CA1 synapses. These synapses are depressed if activated in phase with dendritic inhibition as strong CA3 inputs alone are not able to cause high calcium in this theta phase even though the CA1 pyramidal neuron shows somatic spiking. Dendritic inhibition acts as a switch that prevents LTP and promotes LTD during the retrieval phases of the theta rhythm in CA1 pyramidal cell. This may be important for not overly reinforcing recalled memories and in forgetting no longer relevant memories.

  15. Neuronal morphology in the African elephant (Loxodonta africana) neocortex.

    Science.gov (United States)

    Jacobs, Bob; Lubs, Jessica; Hannan, Markus; Anderson, Kaeley; Butti, Camilla; Sherwood, Chet C; Hof, Patrick R; Manger, Paul R

    2011-01-01

    Virtually nothing is known about the morphology of cortical neurons in the elephant. To this end, the current study provides the first documentation of neuronal morphology in frontal and occipital regions of the African elephant (Loxodonta africana). Cortical tissue from the perfusion-fixed brains of two free-ranging African elephants was stained with a modified Golgi technique. Neurons of different types (N=75), with a focus on superficial (i.e., layers II-III) pyramidal neurons, were quantified on a computer-assisted microscopy system using Neurolucida software. Qualitatively, elephant neocortex exhibited large, complex spiny neurons, many of which differed in morphology/orientation from typical primate and rodent pyramidal neurons. Elephant cortex exhibited a V-shaped arrangement of bifurcating apical dendritic bundles. Quantitatively, the dendrites of superficial pyramidal neurons in elephant frontal cortex were more complex than in occipital cortex. In comparison to human supragranular pyramidal neurons, elephant superficial pyramidal neurons exhibited similar overall basilar dendritic length, but the dendritic segments tended to be longer in the elephant with less intricate branching. Finally, elephant aspiny interneurons appeared to be morphologically consistent with other eutherian mammals. The current results thus elaborate on the evolutionary roots of Afrotherian brain organization and highlight unique aspects of neural architecture in elephants.

  16. Accelerated dendritic development of rat cortical pyramidal cells and interneurons after biolistic transfection with BDNF and NT4/5.

    Science.gov (United States)

    Wirth, Marcus J; Brun, Annika; Grabert, Jochen; Patz, Silke; Wahle, Petra

    2003-12-01

    Neurotrophins are candidate molecules for regulating dendritogenesis. We report here on dendritic growth of rat visual cortex pyramidal and interneurons overexpressing 'brain-derived neurotrophic factor' BDNF and 'neurotrophin 4/5' NT4/5. Neurons in organotypic cultures were transfected with plasmids encoding either 'enhanced green fluorescent protein' EGFP, BDNF/EGFP or NT4/5/EGFP either at the day of birth with analysis at 5 days in vitro, or at 5 days in vitro with analysis at 10 days in vitro. In pyramidal neurons, both TrkB ligands increased dendritic length and number of segments without affecting maximum branch order and number of primary dendrites. In the early time window, only infragranular neurons were responsive. Neurons in layers II/III became responsive to NT4/5, but not BDNF, during the later time window. BDNF and NT4/5 transfectants at 10 days in vitro had still significantly shorter dendrites than adult pyramidal neurons, suggesting a massive growth spurt after 10 days in vitro. However, segment numbers were already in the range of adult neurons. Although this suggested a role for BDNF, long-term activity-deprived, and thus BDNF-deprived, pyramidal cells developed a dendritic complexity not different from neurons in active cultures except for higher spine densities on neurons of layers II/III and VI. Neutralization of endogenous NT4/5 causes shorter and less branched dendrites at 10 days in vitro suggesting an essential role for NT4/5. Neutralization of BDNF had no effect. Transfected multipolar interneurons became identifiable during the second time window. Both TrkB ligands significantly increased number of segments and branch order towards the adult state with little effects on dendritic length. The results suggested that early in development BDNF and NT4/5 probably accelerate dendritogenesis in an autocrine fashion. In particular, branch formation was advanced towards the adult pattern in pyramidal cells and interneurons.

  17. The Pyramidal Capacitated Vehicle Routing Problem

    DEFF Research Database (Denmark)

    Lysgaard, Jens

    This paper introduces the Pyramidal Capacitated Vehicle Routing Problem (PCVRP) as a restricted version of the Capacitated Vehicle Routing Problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the Pyramidal Traveling Salesman Problem (PTSP). A pyramidal...... found in many optimal solutions to CVRP instances. An optimal solution to the PCVRP may therefore be useful in itself as a heuristic solution to the CVRP. Further, an attempt can be made to find an even better CVRP solution by solving a TSP, possibly leading to a non-pyramidal route, for each...... of the routes in the PCVRP solution. This paper develops an exact branch-and-cut-and-price (BCP) algorithm for the PCVRP. At the pricing stage, elementary routes can be computed in pseudo-polynomial time in the PCVRP, unlike in the CVRP. We have therefore implemented pricing algorithms that generate only...

  18. 猫扣带回前部内脏与躯体伤害感受神经元膜电学特性的对比研究%A Comparative Study of Membrane Electrical Properties of Visceral and Somatic Nociceptive Neurons of Anterior Cingulate Gyrus in Cats

    Institute of Scientific and Technical Information of China (English)

    吴敏范; 张勇; 杨宇; 姚阳; 马积昊; 商丽宏

    2015-01-01

    Objective To perform a comparative study on membrane electrical properties of visceral and somatic nociceptive neurons of anterior cin⁃gulate gyrus(ACG)in cats,so as to provide the experimental basis for elucidating the mechanism of differences in perceptual qualities between vis⁃ceral pain and somatic pain from the membrane electrical aspects. Methods A total of 77 adult cats,female or male,weighting 2.0 to 3.5 kg were selected for the study. According to the properties of the greater splanchnic nerve(GSN)or saphenous nerve(SN)evoked responses of neurons in ACG and effect of morphine on the evoked responses,visceral nociceptive neurons(VNNs)having the long latency(≥50 ms)GSN evoked re⁃sponses or somatic nociceptive neurons(SNNs)having the long latency(≥50 ms)SN evoked responses were detected. With a glass microelectrode in vivo,a series of polarizing current of different intensity from-5 nA to+5 nA with a 50 ms duration were injected to these neurons in ACG,and the membrane electrical responses of these neurons were recorded. Finally,the membrane electrical parameters of these neurons were calculated. Re⁃sults Totally 254 VNNs and 172 SNNs were recorded in ACG. GSN evoked response threshold of VNNs were higher than SN evoked response threshold of SNNs. Compared with SNNs,the membrane resistance,the membrane capacity and the time constant of VNNs were larger. Conclusion Our data proved that there are some differences in the membrane electrical properties between VNNs and SNNs in ACG,which might be the mem⁃brane electrical basis for differences in perceptual qualities between visceral pain and somatic pain.%目的:对比研究猫扣带回前部内脏伤害感受神经元与躯体伤害感受神经元膜电学特性,从膜电学方面为阐明内脏痛与躯体痛具有不同感受特性的机制提供实验依据。方法选择成龄猫77只,体质量2.0~3.5 kg,雄雌不限。根据在体微电极记录的扣带回前部神经元对电刺激

  19. 内源性大麻素对海马神经元 AMPA 受体GluR2的作用%Effect of endocannabinoids pretreatment on the expression of AMPA receptor GluR2 subunit in the hippocampal pyramidal neurons of mouse

    Institute of Scientific and Technical Information of China (English)

    刘曌宇; 高杨; 孙思斯; 陈绍洋; 王强

    2015-01-01

    ) (the solvent of 2-AG or AM251) was injected intraperitoneally in vehicle group mice. Global cerebral I/R was induced at 30 min after preconditioning by occlusion of bilateral common carotid artery for 20 min and then followed by reperfusion.Immunofluorescence and Western blot were employed to detect the expression of GluR2 in the hippocampus.Results The AMPA receptor GluR2 subunit was highly expressed in the pyramidal cell layers of hippocampal CA1.Two hours after reperfusion, global cerebral ischemia induced a marked reduction in GluR2 expression in the pyramidal neurons (P<0.05).In 2-AG group, hippocampal neuronal GluR2 expression was significantly up-regulated compared with that of I/R group (P<0.05).The GluR2 expression decreased in the AM251 +2-AG group compared with that in 2-AG group ( P <0.05 ).Conclusion Endocannabinoids preconditioning increases the expression of hippocampal neuronal AMPA receptor GluR2 via CB1R after global cerebral ischemia.

  20. Corticospinal mirror neurons.

    Science.gov (United States)

    Kraskov, A; Philipp, R; Waldert, S; Vigneswaran, G; Quallo, M M; Lemon, R N

    2014-01-01

    Here, we report the properties of neurons with mirror-like characteristics that were identified as pyramidal tract neurons (PTNs) and recorded in the ventral premotor cortex (area F5) and primary motor cortex (M1) of three macaque monkeys. We analysed the neurons' discharge while the monkeys performed active grasp of either food or an object, and also while they observed an experimenter carrying out a similar range of grasps. A considerable proportion of tested PTNs showed clear mirror-like properties (52% F5 and 58% M1). Some PTNs exhibited 'classical' mirror neuron properties, increasing activity for both execution and observation, while others decreased their discharge during observation ('suppression mirror-neurons'). These experiments not only demonstrate the existence of PTNs as mirror neurons in M1, but also reveal some interesting differences between M1 and F5 mirror PTNs. Although observation-related changes in the discharge of PTNs must reach the spinal cord and will include some direct projections to motoneurons supplying grasping muscles, there was no EMG activity in these muscles during action observation. We suggest that the mirror neuron system is involved in the withholding of unwanted movement during action observation. Mirror neurons are differentially recruited in the behaviour that switches rapidly between making your own movements and observing those of others.

  1. Phase precession in hippocampal interneurons showing strong functional coupling to individual pyramidal cells.

    Science.gov (United States)

    Maurer, Andrew P; Cowen, Stephen L; Burke, Sara N; Barnes, Carol A; McNaughton, Bruce L

    2006-12-27

    Although hippocampal interneurons typically do not show discrete regions of elevated firing in an environment, such as seen in pyramidal cell place fields, they do exhibit significant spatial modulation (McNaughton et al., 1983a). Strong monosynaptic coupling between pyramidal neurons and nearby interneurons in the CA1 stratum pyramidale has been strongly implicated on the basis of significant, short-latency peaks in cross-correlogram plots (Csicsvari et al., 1998). Furthermore, interneurons receiving a putative monosynaptic connection from a simultaneously recorded pyramidal cell appear to inherit the spatial modulation of the latter (Marshall et al., 2002). Buzsaki and colleagues hypothesize that interneurons may also adopt the firing phase dynamics of their afferent place cells, which show a phase shift relative to the hippocampal theta rhythm as a rat passes through the place field ("phase precession"). This study confirms and extends the previous reports by showing that interneurons in the dorsal and middle hippocampus with putative monosynaptic connections with place cells recorded on the same tetrode share other properties with their pyramidal cell afferents, including the spatial scale of the place field of pyramidal cell, a characteristic of the septotemporal level of the hippocampus from which the cells are recorded, and the rate of phase precession, which is slower in middle regions. Furthermore, variations in pyramidal cell place field scale within each septotemporal level attributable to task variations are similarly associated with variations in interneuron place field scale. The available data strongly suggest that spatial selectivity of CA1 stratum pyramidale interneurons is inherited from a small cluster of local pyramidal cells and is not a consequence of spatially selective synaptic input from CA3 or other sources.

  2. Maskless inverted pyramid texturization of silicon.

    Science.gov (United States)

    Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du

    2015-06-02

    We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists.

  3. Development of anterior cingulate functional connectivity from late childhood to early adulthood.

    Science.gov (United States)

    Kelly, A M Clare; Di Martino, Adriana; Uddin, Lucina Q; Shehzad, Zarrar; Gee, Dylan G; Reiss, Philip T; Margulies, Daniel S; Castellanos, F Xavier; Milham, Michael P

    2009-03-01

    Human cerebral development is remarkably protracted. Although microstructural processes of neuronal maturation remain accessible only to morphometric post-mortem studies, neuroimaging tools permit the examination of macrostructural aspects of brain development. The analysis of resting-state functional connectivity (FC) offers novel possibilities for the investigation of cerebral development. Using seed-based FC methods, we examined the development of 5 functionally distinct cingulate-based intrinsic connectivity networks (ICNs) in children (n = 14, 10.6 +/- 1.5 years), adolescents (n = 12, 15.4 +/- 1.2) and young adults (n=14, 22.4 +/- 1.2). Children demonstrated a more diffuse pattern of correlation with voxels proximal to the seed region of interest (ROI) ("local FC"), whereas adults exhibited more focal patterns of FC, as well as a greater number of significantly correlated voxels at long distances from the seed ROI. Adolescents exhibited intermediate patterns of FC. Consistent with evidence for different maturational time courses, ICNs associated with social and emotional functions exhibited the greatest developmental effects. Our findings demonstrate the utility of FC for the study of developing functional organization. Moreover, given that ICNs are thought to have an anatomical basis in neuronal connectivity, measures of FC may provide a quantitative index of brain maturation in healthy subjects and those with neurodevelopmental disorders.

  4. The beneficial effects of meditation: contribution of the anterior cingulate and locus coeruleus.

    Science.gov (United States)

    Craigmyle, Nancy A

    2013-01-01

    During functional magnetic resonance imaging studies of meditation the cortical salience detecting and executive networks become active during "awareness of mind wandering," "shifting," and "sustained attention." The anterior cingulate (AC) is activated during "awareness of mind wandering." The AC modulates both the peripheral sympathetic nervous system (SNS) and the central locus coeruleus (LC) norepinephrine systems, which form the principal neuromodulatory system, regulating in multiple ways both neuronal and non-neuronal cells to maximize adaptation in changing environments. The LC is the primary source of central norepinephrine (C-NE) and nearly the exclusive source of cortical norepinephrine. Normally activated by novel or salient stimuli, the AC initially inhibits the SNS reflexively, lowering peripheral norepinephrine and activates the LC, increasing C-NE. Moderate levels of C-NE enhance working memory through alpha 2 adrenergic receptors, while higher levels of C-NE, acting on alpha 1 and beta receptors, enhance other executive network functions such as the stopping of ongoing behavior, attentional set-shifting, and sustained attention. The actions of the AC on both the central and peripheral noradrenergic systems are implicated in the beneficial effects of meditation. This paper will explore some of the known functions and interrelationships of the AC, SNS, and LC with respect to their possible relevance to meditation.

  5. The beneficial effects of meditation: contribution of the anterior cingulate and locus coeruleus

    Directory of Open Access Journals (Sweden)

    Nancy Alker Craigmyle

    2013-10-01

    Full Text Available Abstract During fMRI studies of meditation the cortical salience detecting and executive networks become active during awareness of mind wandering, shifting and sustained attention. The anterior cingulate (AC is activated during awareness of mind wandering.The AC modulates both the peripheral sympathetic nervous system (SNS and the central locus coeruleus (LC norepinephrine systems, which form the principal neuromodulatory system, regulating in multiple ways both neuronal and non-neuronal cells to maximize adaptation in changing environments. The LC is the primary source of central norepinephrine (C-NE and nearly the exclusive source of cortical norepinephrine. Normally activated by novel or salient stimuli, the AC initially inhibits the SNS reflexively, lowering peripheral norepinephrine (P-NE and activates the LC, increasing C-NE.Moderate levels of C-NE enhance working memory through alpha 2 adrenergic receptors, while higher levels of C-NE, acting on alpha 1 and beta receptors, enhance other executive network functions such as the stopping of ongoing behavior, attentional set shifting and sustained attention. The actions of the AC on both the central and peripheral noradrenergic systems are implicated in the beneficial effects of meditation. This paper will explore some of the known functions and interrelationships of the AC, SNS and LC with respect to their possible relevance to meditation.

  6. Cingulate metabolites during pain and morphine treatment as assessed by magnetic resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Hansen TM

    2014-05-01

    Full Text Available Tine Maria Hansen,1 Anne Estrup Olesen,2 Carsten Wiberg Simonsen,1 Asbjørn Mohr Drewes,2,3 Jens Brøndum Frøkjær11Mech-Sense, Department of Radiology, 2Mech-Sense, Department of Gastroenterology, 3Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, DenmarkBackground: Experimental investigation of cerebral mechanisms underlying pain and analgesia are important in the development of methods for diagnosis and treatment of pain. The aim of the current study was to explore brain metabolites in response to pain and treatment with morphine.Methods: Proton magnetic resonance spectroscopy of the anterior cingulate cortex was performed in 20 healthy volunteers (13 males and seven females, aged 24.9±2.6 years during rest and acute pain before and during treatment with 30 mg of oral morphine or placebo in a randomized, double-blinded, cross-over study design. Pain was evoked by skin stimulation applied to the right upper leg using a contact heat-evoked potential stimulator.Results: Data from 12 subjects were valid for analysis. Painful stimulation induced an increase in N-acetylaspartate/creatine compared with rest (F=5.5, P=0.04. During treatment with morphine, painful stimulation induced decreased glutamate/creatine (F=7.3, P=0.02, myo-inositol/creatine (F=8.38, P=0.02, and N-acetylaspartate/creatine (F=13.8, P=0.004 concentrations, whereas an increase in the pain-evoked N-acetylaspartate/creatine concentration (F=6.1, P=0.04 was seen during treatment with placebo.Conclusion: This explorative study indicates that neuronal metabolites in the anterior cingulate cortex, such as N-acetylaspartate, glutamate, and myo-inositol, could be related to the physiology of pain and treatment with morphine. This experimental method has the potential to enable the study of brain metabolites involved in pain and its treatment, and may in the future be used to provide further insight into these mechanisms

  7. Simulation of gene pyramiding in Drosophila melanogaster

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Gene pyramiding has been successfully practiced in plant breeding for developing new breeds or lines in which favorable genes from several different lines were integrated.But it has not been used in animal breeding,and some theoretical investigation and simulation analysis with respect to its strategies,feasibility and efficiency are needed before it can be implemented in animals.In this study,we used four different pure fines of Drosophila melanogaster,each of which is homozygous at a specific mutant gene with a visible effect on phenotype,to simulate the gene pyramiding process and analyze the duration and population size required in different pyramiding strategies.We finally got the ideal individuals,which are homozygous at the four target genes simultaneously.This study demonstrates that gene pyramiding is feasible in animal breeding and the interaction between genes may affect the final results.

  8. Waring’s Problem for Pyramidal Numbers

    Institute of Scientific and Technical Information of China (English)

    邓越凡; 杨振宁

    1994-01-01

    It has been proved that every positive integer is expressible as a sum of no more than eight pyramidal numbers P(m)=(m-1)m(m+1)/6.This paper reports on a computer calculation of the partition of integers from n=1 to 109 into pyramidal numbers.We find that no integer≤10°needs more than five pyramidal numbers for its partition,and only 241 of them do need five.We define J(n) as the least number of pyramidal numbers to partition n,and Nk(n) as the number of positive integers l less than or equal to n for which J(l)=k.Based on our numerical results we make conjectures about the asymptotic form of Nk(n) for n→∞

  9. FABRIC DEFECT DETECTION USING STEERABLE PYRAMID

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    S. Mythili

    2011-05-01

    Full Text Available In this paper, a novel idea is proposed for fabric defect detection. De- fects are detected in the fabric using steerable pyramid along with a defect detection algorithm. Various steerable pyramid of four size 256*256, 128*128, 64*64, 32*32 and with four orientation bands 00,450, 900, 1350 are used. Utilizing a Steerable pyramid proved ade- quate in the representation of fabric images in multi-scale and multi- orientations; thus allowing defect detection algorithms to run more effectively. Defect detection algorithm identifies and locates the im- perfection in the defective sample using the statistics mean and stan- dard deviation. This statistics represents the relative amount of inten- sity in the texture and is sufficient to measure defects in the current model .The obtained result are compared with the existing methods wavelet based system and with Gaussian and Laplacian pyramid.

  10. Evaluation of the Green Egyptian Pyramid

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    Mohamed Gamal Ammar

    2012-12-01

    The research concluded to the need of developing the Egyptian pyramid system through studying more global systems, in addition to the need to benefit from the Egyptian experience stock of solutions and environmental treatments in ancient architecture.

  11. Structured Dendritic Inhibition Supports Branch-Selective Integration in CA1 Pyramidal Cells.

    Science.gov (United States)

    Bloss, Erik B; Cembrowski, Mark S; Karsh, Bill; Colonell, Jennifer; Fetter, Richard D; Spruston, Nelson

    2016-03-02

    Neuronal circuit function is governed by precise patterns of connectivity between specialized groups of neurons. The diversity of GABAergic interneurons is a hallmark of cortical circuits, yet little is known about their targeting to individual postsynaptic dendrites. We examined synaptic connectivity between molecularly defined inhibitory interneurons and CA1 pyramidal cell dendrites using correlative light-electron microscopy and large-volume array tomography. We show that interneurons can be highly selective in their connectivity to specific dendritic branch types and, furthermore, exhibit precisely targeted connectivity to the origin or end of individual branches. Computational simulations indicate that the observed subcellular targeting enables control over the nonlinear integration of synaptic input or the initiation and backpropagation of action potentials in a branch-selective manner. Our results demonstrate that connectivity between interneurons and pyramidal cell dendrites is more precise and spatially segregated than previously appreciated, which may be a critical determinant of how inhibition shapes dendritic computation.

  12. An Improved Pyramid for Spatially Scalable Video Coding

    OpenAIRE

    2005-01-01

    This paper discusses an improved pyramid for spatially scalable video coding. We introduce additional update steps in the analysis and the synthesis of the Laplacian pyramid. Our pyramid is able to control efficiently the quantization noise energy in the reconstruction. Hence, it provides improved coding performance when compared to the standard Laplacian pyramid. Moreover, our pyramid does not require biorthogonal filters as they should be used for the frame reconstruction of the Laplacian p...

  13. The trajectory of sensory pathways from the lamina terminalis to the insular and cingulate cortex: a neuroanatomical framework for the generation of thirst.

    Science.gov (United States)

    Hollis, Jacob H; McKinley, Michael J; D'Souza, Moyra; Kampe, Juliane; Oldfield, Brian J

    2008-04-01

    The pathways involved in the emotional aspects of thirst, the arousal and affect associated with the generation of thirst and the motivation to obtain satiation, have been studied but remain poorly understood. Rats were therefore injected with the neurotropic virus pseudorabies in either the insular or cingulate cortex. After 2 days of infection, pseudorabies-positive neurons were identified within the thalamus and lamina terminalis. In a separate group of rats, the retrograde tracer cholera toxin subunit b (CTb) was used in combination with either isotonic (0.15 M NaCl) or hypertonic (0.8 M NaCl) saline (1 ml/100 g body wt ip). Rats injected with CTb in the insular cortex and stimulated with hypertonic saline had increased numbers of Fos/CTb double-positive neurons in the paraventricular, rhomboid, and reuniens thalamic nuclei, whereas those rats injected with CTb in the cingulate cortex and challenged with hypertonic saline had increased numbers of Fos/CTb double-positive neurons in the medial part of the mediodorsal, interanteromedial, anteromedial, and ventrolateral part of the laterodorsal thalamic nuclei. Rats injected with CTb in the dorsal midline of the thalamus and challenged with hypertonic saline had increased numbers of Fos/CTb double-positive neurons within the organum vasculosum of the lamina terminalis (OVLT), median preoptic nucleus, and insular cortex but not the subfornical organ. A small proportion of the CTb-positive neurons in the OVLT were immunopositive for transient receptor potential vanilloid 1, a putative osmoresponsive membrane protein. These results identify functional thalamocortical pathways involved in relaying osmotic signals to the insular and cingulate cortex and may provide a neuroanatomical framework for the emotional aspects of thirst.

  14. Morphometric characteristics of Neuropeptide Y immunoreactive neurons of human cortical amygdaloid nucleus

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    Mališ Miloš

    2008-01-01

    Full Text Available Introduction Cortical amygdaloid nucleus belongs to the corticomedial part of the amygdaloid complex. In this nucleus there are neurons that produce neuropetide Y. This peptide has important roles in sleeping, learning, memory, gastrointestinal regulation, anxiety, epilepsy, alcoholism and depression. Material and methods We investigated morphometric characteristics (numbers of primary dendrites, longer and shorter diameters of cell bodies and maximal radius of dendritic arborization of NPY immunoreactive neurons of human cortical amygdaloid nucleus on 6 male adult human brains, aged 46 to 77 years, by immunohistochemical avidin-biotin technique. Results Our investigation has shown that in this nucleus there is a moderate number of NPY immunoreactive neurons. 67% of found neurons were nonpyramidal, while 33% were pyramidal. Among the nonpyramidal neurons the dominant groups were multipolar neurons (41% - of which 25% were multipolar irregular, and 16% multipolar oval. Among the pyramidal neurons the dominant groups were the neurons with triangular shape of cell body (21%. All found NPY immunoreactive neurons (pyramidal and nonpyramidal altogether had intervals of values of numbers of primary dendrites 2 to 6, longer diameters of cell bodies 13 to 38 µm, shorter diameters of cell bodies 9 to 20 µm and maximal radius of dendritic arborization 50 to 340 µm. More than a half of investigated neurons (57% had 3 primary dendrites. Discussion and conclusion The other researchers did not find such percentage of pyramidal immunoreactive neurons in this amygdaloid nucleus. If we compare our results with the results of the ather researchers we can conclude that all pyramidal NPY immunoreactive neurons found in this human amygdaloid nucleus belong to the class I of neurons, and that all nonpyramidal NPY immunoreactive neurons belong to the class II of neurons described by other researchers. We suppose that all found pyramidal neurons were projectional.

  15. Neurotoxicity and reactive astrogliosis in the anterior cingulate cortex in acute ciguatera poisoning.

    Science.gov (United States)

    Zhang, Xu; Cao, Bing; Wang, Jun; Liu, Jin; Tung, Vivian Oi Vian; Lam, Paul Kwan Sing; Chan, Leo Lai; Li, Ying

    2013-06-01

    Ciguatoxins (CTXs) cause long-term disturbance of cerebral functions. The primary mechanism of neurotoxicity is related to their interaction with voltage-gated sodium channels. However, until now, the neurological targets for CTXs in the brain of intact animals have not been described. In our study, 1 day following oral exposure to 0.26 ng/g of Pacific ciguatoxin 1 (P-CTX-1), we performed in vivo electrophysiological recordings in the rat anterior cingulate cortex (ACC) and identified the increase in spontaneous firings and enhanced responses to visceral noxious stimulation. Local field recordings characterized the P-CTX-1-induced synaptic potentiation and blockage of the induction of electrical stimulation-induced long-term potentiation in the medial thalamus (MT)-ACC pathway. Furthermore, intracerebroventricular administration of P-CTX-1 at doses of 1.0, 5.0, and 10 nM produced a dose-dependent increase in ACC neuronal firings and MT-ACC synaptic transmission. Further studies showed upregulated Na(+) channel expression in astrocytes under pathological conditions. We hypothesized that the astrocytes might have been activated in the ciguatera poisoning in vivo. Increases in glial fibrillary acid protein expression were detected in reactive astrocytes in the rat ACC. The activation of astroglia was further indicated by activation of the gap junction protein connexin 43 and upregulation of excitatory amino acid transporter 2 expression suggesting that glutamate was normally rapidly cleared from the synaptic cleft during acute ciguatera poisoning. However, neurotoxicity and reactive astrogliosis were not detected in the ACC after 7 days of P-CTX-1 exposure. The present results are the first characterization of P-CTX-1-invoked brain cortex neuronal excitotoxicity in vivo and supported the theme that neuron and astroglia signals might play roles in acute ciguatera poisoning.

  16. Somatosensory stimulation suppresses the excitability of pyramidal cells in the hippocampal CA1 region in rats

    Institute of Scientific and Technical Information of China (English)

    Yang Wang; Zhouyan Feng; Jing Wang; Xiaojing Zheng

    2014-01-01

    The hippocampal region of the brain is important for encoding environment inputs and memory formation. However, the underlying mechanisms are unclear. To investigate the behavior of indi-vidual neurons in response to somatosensory inputs in the hippocampal CA1 region, we recorded and analyzed changes in local ifeld potentials and the ifring rates of individual pyramidal cells and interneurons during tail clamping in urethane-anesthetized rats. We also explored the mechanisms underlying the neuronal responses. Somatosensory stimulation, in the form of tail clamping, chan-ged local ifeld potentials into theta rhythm-dominated waveforms, decreased the spike ifring of py-ramidal cells, and increased interneuron ifring. In addition, somatosensory stimulation attenuated orthodromic-evoked population spikes. These results suggest that somatosensory stimulation sup-presses the excitability of pyramidal cells in the hippocampal CA1 region. Increased inhibition by local interneurons might underlie this effect. These ifndings provide insight into the mechanisms of signal processing in the hippocampus and suggest that sensory stimulation might have thera-peutic potential for brain disorders associated with neuronal hyperexcitability.

  17. Proton magnetic resonance spectroscopy of the frontal, cingulate and perirolandic cortices and its relationship to skin conductance in patients with schizophrenia

    Energy Technology Data Exchange (ETDEWEB)

    Sanches, R.F.; Crippa, J.A.S.; Hallak, J.E.C.; Sousa, J.P.M. de; Zuardi, A.W. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP, (Brazil). Faculdade de Medicina. Dept. de Neurociencias e Ciencias do Comportamento]. E-mail: awzuardi@fmrp.usp.br; Araujo, D.; Santos, A.C. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP, (Brazil). Faculdade de Medicina. Div. de Radiologia

    2008-07-01

    The aim of the present study was to determine whether specific subgroups of schizophrenic patients, grouped according to electrodermal characteristics, show differences in the N-acetylaspartate/creatine plus choline (NAA / (Cr + Cho)) ratios in the frontal, cingulate and perirolandic cortices. Skin conductance levels (SCL) and skin conductance responses to auditory stimulation were measured in 38 patients with schizophrenia and in the same number of matched healthy volunteers (control). All subjects were submitted to multivoxel proton magnetic resonance spectroscopic imaging. When compared to the control group, patients presented significantly lower NAA / (Cr + Cho) ratios in the right dorsolateral prefrontal cortex (schizophrenia 0.95 {+-} 0.03; control = 1.12 {+-} 0.04) and in the right (schizophrenia 0.88 {+-} 0.02; control = 0.94 {+-} 0.03) and left (schizophrenia 0.84 {+-} 0.03; control = 0.94 {+-} 0.03) cingulates. These ratios did not differ between electrodermally responsive and non-responsive patients. When patients were divided into two groups: lower SCL (less than the mean SCL of the control group minus two standard deviations) and normal SCL (similar to the control group), the subgroup with a lower level of SCL showed a lower NAA / (Cr + Cho) ratio in the left cingulate (0.78 {+-} 0.05) than the controls (0.95 {+-} 0.02, P < 0.05) and the subgroup with normal SCL (0.88 {+-} 0.03, P < 0.05). There was a negative correlation between the NAA / (Cr + Cho) ratio in the left cingulate of patients with schizophrenia and the duration of the disease and years under medication. These data suggest the existence of a schizophrenic subgroup characterized by low SCL that could be a consequence of the lower neuronal viability observed in the left cingulate of these patients. (author)

  18. Housing in Pyramid Counteracts Neuroendocrine and Oxidative Stress Caused by Chronic Restraint in Rats

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    M. Surekha Bhat

    2007-01-01

    Full Text Available The space within the great pyramid and its smaller replicas is believed to have an antistress effect. Research has shown that the energy field within the pyramid can protect the hippocampal neurons of mice from stress-induced atrophy and also reduce neuroendocrine stress, oxidative stress and increase antioxidant defence in rats. In this study, we have, for the first time, attempted to study the antistress effects of pyramid exposure on the status of cortisol level, oxidative damage and antioxidant status in rats during chronic restraint stress. Adult female Wistar rats were divided into four groups as follows: normal controls (NC housed in home cage and left in the laboratory; restrained rats (with three subgroups subject to chronic restraint stress by placing in a wire mesh restrainer for 6 h per day for 14 days, the restrained controls (RC having their restrainers kept in the laboratory; restrained pyramid rats (RP being kept in the pyramid; and restrained square box rats (RS in the square box during the period of restraint stress everyday. Erythrocyte malondialdehyde (MDA and plasma cortisol levels were significantly increased and erythrocyte-reduced glutathione (GSH levels, erythrocyte glutathione peroxidase (GSH-Px and superoxide dismutase (SOD activities were significantly decreased in RC and RS rats as compared to NC. However, these parameters were maintained to near normal levels in RP rats which showed significantly decreased erythrocyte MDA and plasma cortisol and significantly increased erythrocyte GSH levels, erythrocyte GSH-Px and SOD activities when compared with RS rats. The results showed that housing in pyramid counteracts neuroendocrine and oxidative stress caused by chronic restraint in rats.

  19. Housing in pyramid counteracts neuroendocrine and oxidative stress caused by chronic restraint in rats.

    Science.gov (United States)

    Bhat, M Surekha; Rao, Guruprasad; Murthy, K Dilip; Bhat, P Gopalakrishna

    2007-03-01

    The space within the great pyramid and its smaller replicas is believed to have an antistress effect. Research has shown that the energy field within the pyramid can protect the hippocampal neurons of mice from stress-induced atrophy and also reduce neuroendocrine stress, oxidative stress and increase antioxidant defence in rats. In this study, we have, for the first time, attempted to study the antistress effects of pyramid exposure on the status of cortisol level, oxidative damage and antioxidant status in rats during chronic restraint stress. Adult female Wistar rats were divided into four groups as follows: normal controls (NC) housed in home cage and left in the laboratory; restrained rats (with three subgroups) subject to chronic restraint stress by placing in a wire mesh restrainer for 6 h per day for 14 days, the restrained controls (RC) having their restrainers kept in the laboratory; restrained pyramid rats (RP) being kept in the pyramid; and restrained square box rats (RS) in the square box during the period of restraint stress everyday. Erythrocyte malondialdehyde (MDA) and plasma cortisol levels were significantly increased and erythrocyte-reduced glutathione (GSH) levels, erythrocyte glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were significantly decreased in RC and RS rats as compared to NC. However, these parameters were maintained to near normal levels in RP rats which showed significantly decreased erythrocyte MDA and plasma cortisol and significantly increased erythrocyte GSH levels, erythrocyte GSH-Px and SOD activities when compared with RS rats. The results showed that housing in pyramid counteracts neuroendocrine and oxidative stress caused by chronic restraint in rats.

  20. Anterior cingulate cortex mediates the relationship between O3PUFAs and executive functions in APOE e4 carriers

    Directory of Open Access Journals (Sweden)

    Marta Karolina Zamroziewicz

    2015-05-01

    Full Text Available Introduction: Although diet has a substantial influence on the aging brain, the relationship between biomarkers of diet and aspects of brain health remains unclear. This study examines the neural mechanisms that mediate the relationship between omega-3 polyunsaturated fatty acids (O3PUFAs and executive functions in at-risk (APOE e4 carriers, cognitively intact older adults. We hypothesized that higher levels of O3PUFAs are associated with better performance in a particular component of the executive functions, namely cognitive flexibility, and that this relationship is mediated by gray matter volume of a specific region thought to be important for cognitive flexibility, the anterior cingulate cortex. Methods: We examined 40 cognitively intact adults between the ages of 65 and 75 with the APOE e4 polymorphism to investigate the relationship between biomarkers of O3PUFAs, tests of cognitive flexibility (measured by the Delis-Kaplan Executive Function System Trail Making Test, and gray matter volume within regions of the prefrontal cortex. Results: A mediation analysis revealed that gray matter volume within the left rostral anterior cingulate cortex partially mediates the relationship between O3PUFA biomarkers and cognitive flexibility. Conclusion: These results suggest that the anterior cingulate cortex acts as a mediator of the relationship between O3PUFAs and cognitive flexibility in cognitively intact adults thought to be at risk for cognitive decline. Through their link to executive functions and neuronal measures of prefrontal cortex volume, O3PUFAs show potential as a nutritional therapy to prevent dysfunction in the aging brain.

  1. Oxygen/glucose deprivation induces a reduction in synaptic AMPA receptors on hippocampal CA3 neurons mediated by mGluR1 and adenosine A3 receptors.

    OpenAIRE

    Dennis, Siobhan; Jaafari, Nadia; Cimarosti, Helena; Hanley, Jonathan G.; Henley, Jeremy M.; Mellor, Jack R.

    2011-01-01

    Hippocampal CA1 pyramidal neurons are highly sensitive to ischemic damage, whereas neighboring CA3 pyramidal neurons are less susceptible. It is proposed that switching of AMPA receptor (AMPAR) subunits on CA1 neurons during an in vitro model of ischemia, oxygen/glucose deprivation (OGD), leads to an enhanced permeability of AMPARs to Ca2+, resulting in delayed cell death. However, it is unclear whether the same mechanisms exist in CA3 neurons and whether this underlies the differential sensi...

  2. Oxygen/glucose Deprivation Induces a Reduction in Synaptic AMPA Receptors on Hippocampal CA3 Neurons Mediated by mGluR1 and A3 Receptors

    OpenAIRE

    Dennis, Siobhan H.; Jaafari, Nadia; Cimarosti, Helena; Hanley, Jonathan G.; Henley, Jeremy M.; Mellor, Jack R.

    2011-01-01

    Hippocampal CA1 pyramidal neurons are highly sensitive to ischemic damage, whereas neighbouring CA3 pyramidal neurons are less susceptible. It is proposed that switching of AMPA receptor (AMPAR) subunits on CA1 neurons during an in vitro model of ischemia, oxygen/glucose deprivation (OGD), leads to an enhanced permeability of AMPARs to Ca2+ resulting in delayed cell death. However, it is unclear if the same mechanisms exist in CA3 neurons and whether this underlies the differential sensitivit...

  3. Segregated and integrated coding of reward and punishment in the cingulate cortex.

    Science.gov (United States)

    Fujiwara, Juri; Tobler, Philippe N; Taira, Masato; Iijima, Toshio; Tsutsui, Ken-Ichiro

    2009-06-01

    Reward and punishment have opposite affective value but are both processed by the cingulate cortex. However, it is unclear whether the positive and negative affective values of monetary reward and punishment are processed by separate or common subregions of the cingulate cortex. We performed a functional magnetic resonance imaging study using a free-choice task and compared cingulate activations for different levels of monetary gain and loss. Gain-specific activation (increasing activation for increasing gain, but no activation change in relation to loss) occurred mainly in the anterior part of the anterior cingulate and in the posterior cingulate cortex. Conversely, loss-specific activation (increasing activation for increasing loss, but no activation change in relation to gain) occurred between these areas, in the middle and posterior part of the anterior cingulate. Integrated coding of gain and loss (increasing activation throughout the full range, from biggest loss to biggest gain) occurred in the dorsal part of the anterior cingulate, at the border with the medial prefrontal cortex. Finally, unspecific activation increases to both gains and losses (increasing activation to increasing gains and increasing losses, possibly reflecting attention) occurred in dorsal and middle regions of the cingulate cortex. Together, these results suggest separate and common coding of monetary reward and punishment in distinct subregions of the cingulate cortex. Further meta-analysis suggested that the presently found reward- and punishment-specific areas overlapped with those processing positive and negative emotions, respectively.

  4. 胰岛素治疗对糖尿病大鼠大脑皮层颞叶锥体细胞超微结构改变的影响%The effect of insulin therapy on the ultrastructure of pyramidal neuron in temporal cortex of the streptozotocinn induced diabetic rats

    Institute of Scientific and Technical Information of China (English)

    管庆波; 王桂兰; 董建军; 东野光; 张晓黎

    2001-01-01

    The effect of insulin therapy on the ultrastructure of pyramidalneuron in temporal cortex of the streptozotocin induced diabetic rats was observed under light and electron microscope for 3 months.The histology of pyramidal neurons in temporal cortex was not obviously different among three groups:controls,untreated diabetics and diabetics treated with insulin.The ultrastructral changes was found in untreated diabetics.The nuclear membrane inveginated and the nuclei lost their normal shape.The nuclear inclusions were distributed unevently.Some heterochromatin gathered near the nuclear membrane.The number of the main organelles in the cytoplasm decreased.The rough endoplasmic reticula(rER)became thicker and shorter.The cavities of rER were irregular;Parts of them were dilated.The loss of some ribosomal particles from the rER can also be seen.With dilated cavities and disappeared porlarites,the shape of Golgi′s bodies became irregular.The cristae of mitochordria were less and some of them became indistinct or disappeared;Some double membrane were not distinguishable clearly.However,the ultrastructure in diabetic rat treated with insulin were normal.It is suggested that the ultrastructral damage in temporal cortex observed in the study was induced by diabetes.The ultrastructral change provide the morphological evidense for the cognitive dysfunction observed in diabetes.The damages can be prevented and treated with observed in diabetes.The damages can be prevented and treated with insulin.%应用透射电镜技术观察糖尿病大鼠大脑皮层颞叶锥体细胞超微结构的变化,并对比观察胰岛素治疗对超微结构改变的影响。结果显示:病程3个月的链脲菌素致糖尿病大鼠颞叶皮层光镜下无显著改变,而锥体细胞超微结构出现细胞核形态不规则,染色质分布不均、聚集成块且有边集现象;高尔基氏器、粗面内质网扩张且数量显著减少,核糖核蛋白体脱粒;

  5. Correlation-induced network oscillations of pyramidal cells in the weakly electric fish - theory and experiment

    Science.gov (United States)

    Lindner, Benjamin; Doiron, Brent; Longtin, Andre; Maler, Leonard; Bastian, Joseph

    2004-03-01

    The spiking activity of pyramidal cells in the weakly electric fish is studied. It is experimentally shown that the oscillatory spiking activity of these cells increases with the spatial correlations of external stochastic input. A model network of integrate-and-fire (IF) neurons with delayed inhibitory feedback reproduces this effect. Moreover, a novel analytical approach for stochastic neuron models with weak feedback is presented that leads to a simple expression for the power spectrum of the spike train of a single neuron. The analytical results agree well with simulation results of the leaky IF neurons; they also show the same qualitative features as the experimental spectra and are helpful in understanding the deeper origin of the correlation-induced oscillations.

  6. The Babinski sign and the pyramidal syndrome.

    Science.gov (United States)

    Van Gijn, J

    1978-10-01

    The presence or absence of a Babinski sign can be puzzling, but in the light of existing pathological studies it is more fruitful to consider which pyramidal tract fibres release it than whether they release it. This was investigated clinically, by looking for correlations with other reflex changes and with motor deficits in the leg. A survey of 50 patients with a unilateral Babinski sign and six patients who lacked it in spite of other pyramidal tract signs was supplemented with follow-up of the patients who had acute lesions. Appearance of the Bibinski sign proved to depend on the interaction of two factors: (1) activity (not necessarily hyperactivity) in the segmental pathways of the flexion synergy; (2) a motor deficit of the foot, in some cases consisting only in an impairment of rapid foot movements, and probably representing a disturbance of direct pyramidal tract projections to distal motoneurones.

  7. Different populations of vasoactive intestinal polypeptide-immunoreactive interneurons are specialized to control pyramidal cells or interneurons in the hippocampus.

    Science.gov (United States)

    Acsády, L; Görcs, T J; Freund, T F

    1996-07-01

    The postsynaptic targets of three vasoactive intestinal polypeptide-containing GABAergic interneuron types were examined in the rat hippocampus. Two of them showed remarkable target selectivity for other GABAergic neurons, while the third contacted the somata and proximal dendrites of pyramidal cells. Vasoactive intestinal polypeptide-positive interneurons innervating the stratum oriens/alveus border in the CA1 region were shown to establish multiple contacts with horizontal GABAergic interneurons immunoreactive for type 1 metabotropic glutamate receptor. Similarly, identified axons of vasoactive intestinal polypeptide-positive interneurons projecting to stratum radiatum were found to establish symmetrical synapses largely on GABAergic dendrites. The majority of these postsynaptic GABAergic neurons were shown to contain calbindin or vasoactive intestinal polypeptide. In contrast to the first two vasoactive intestinal polypeptide-containing cell populations, vasoactive intestinal polypeptide-positive interneurons arborizing in stratum pyramidale formed baskets around pyramidal cells. These results revealed a new element in cortical microcircuits, interneurons which are specialized to innervate other GABAergic interneurons. The role of this new component may be the synchronization of dendritic inhibition, or an input-specific disinhibition of pyramidal cells in various dendritic domains. In contrast, vasoactive intestinal polypeptide-containing basket cells are likely to be involved in perisomatic inhibition of pyramidal neurons, and represents a new basket cell type different from that containing parvalbumin.

  8. Pathological Changes of von Economo Neuron and Fork Neuron in Neuropsychiatric Diseases.

    Science.gov (United States)

    Liu, Jia; Wang, Lu-ning; Arzberger, Thomas; Zhu, Ming-wei

    2016-02-01

    von Economo neuron (VEN) is a bipolar neuron characterized by a large spindle-shaped soma. VEN is generally distributed in the layer V of anterior insular lobe and anterior cingulate cortex. Fork neuron is another featured bipolar neuron. In recent years,many studies have illustrated that VEN and fork neurons are correlated with complicated cognition such as self-consciousness and social emotion. Studies in the development and morpholigies of these two neurons as well as their pathological changes in various neurological and psychiatric disorders have found that the abnormal number and functions of VEN can cause corresponding dysfunctions in social recognition and emotions both during the neuro-developmental stages of childhood and during the nerve degeneration in old age stage. Therefore, more attentions should be paid on the research of VEN and fork neurons in neuropsychiatric diseases.

  9. The cortical structure of consolidated memory: a hypothesis on the role of the cingulate-entorhinal cortical connection.

    Science.gov (United States)

    Insel, Nathan; Takehara-Nishiuchi, Kaori

    2013-11-01

    Daily experiences are represented by networks of neurons distributed across the neocortex, bound together for rapid storage and later retrieval by the hippocampus. While the hippocampus is necessary for retrieving recent episode-based memory associations, over time, consolidation processes take place that enable many of these associations to be expressed independent of the hippocampus. It is generally thought that mechanisms of consolidation involve synaptic weight changes between cortical regions; or, in other words, the formation of "horizontal" cortico-cortical connections. Here, we review anatomical, behavioral, and physiological data which suggest that the connections in and between the entorhinal and cingulate cortices may be uniquely important for the long-term storage of memories that initially depend on the hippocampus. We propose that current theories of consolidation that divide memory into dual systems of hippocampus and neocortex might be improved by introducing a third, middle layer of entorhinal and cingulate allocortex, the synaptic weights within which are necessary and potentially sufficient for maintaining initially hippocampus-dependent associations over long time periods. This hypothesis makes a number of still untested predictions, and future experiments designed to address these will help to fill gaps in the current understanding of the cortical structure of consolidated memory.

  10. A 3D pyramid spline element

    Institute of Scientific and Technical Information of China (English)

    Juan Chen; Chong-Jun Li; Wan-Ji Chen

    2011-01-01

    In this paper,a 13-node pyramid spline element is derived by using the tetrahedron volume coordinates and the B-net method,which achieves the second order completeness in Cartesian coordinates.Some appropriate examples were employed to evaluate the performance of the proposed element.The numerical results show that the spline element has much better performance compared with the isoparametric serendipity element Q20 and its degenerate pyramid element P13 especially when mesh is distorted,and it is comparable to the Lagrange element Q27.It has been demonstrated that the spline finite element method is an efficient tool for developing high accuracy elements.

  11. Tiling a Pyramidal Polycube with Dominoes

    Directory of Open Access Journals (Sweden)

    Olivier Bodini

    2007-05-01

    Full Text Available The notion of pyramidal polycubes, namely the piling-up of bricks of a non-increasing size, generalizes in ℝ n the concept of trapezoidal polyominoes. In the present paper, we prove that n-dimensional dominoes can tile a pyramidal polycube if and only if the latter is balanced, that is, if the number of white cubes is equal to the number of black ones for a chessboard-like coloration, generalizing the result of [BC92] when n=2

  12. Differentiation of apical and basal dendrites in pyramidal cells and granule cells in dissociated hippocampal cultures.

    Science.gov (United States)

    Wu, You Kure; Fujishima, Kazuto; Kengaku, Mineko

    2015-01-01

    Hippocampal pyramidal cells and dentate granule cells develop morphologically distinct dendritic arbors, yet also share some common features. Both cell types form a long apical dendrite which extends from the apex of the cell soma, while short basal dendrites are developed only in pyramidal cells. Using quantitative morphometric analyses of mouse hippocampal cultures, we evaluated the differences in dendritic arborization patterns between pyramidal and granule cells. Furthermore, we observed and described the final apical dendrite determination during dendritic polarization by time-lapse imaging. Pyramidal and granule cells in culture exhibited similar dendritic patterns with a single principal dendrite and several minor dendrites so that the cell types were not readily distinguished by appearance. While basal dendrites in granule cells are normally degraded by adulthood in vivo, cultured granule cells retained their minor dendrites. Asymmetric growth of a single principal dendrite harboring the Golgi was observed in both cell types soon after the onset of dendritic growth. Time-lapse imaging revealed that up until the second week in culture, final principal dendrite designation was not stabilized, but was frequently replaced by other minor dendrites. Before dendritic polarity was stabilized, the Golgi moved dynamically within the soma and was repeatedly repositioned at newly emerging principal dendrites. Our results suggest that polarized growth of the apical dendrite is regulated by cell intrinsic programs, while regression of basal dendrites requires cue(s) from the extracellular environment in the dentate gyrus. The apical dendrite designation is determined from among multiple growing dendrites of young developing neurons.

  13. Loss of dopamine D2 receptors increases parvalbumin-positive interneurons in the anterior cingulate cortex.

    Science.gov (United States)

    Graham, Devon L; Durai, Heather H; Garden, Jamie D; Cohen, Evan L; Echevarria, Franklin D; Stanwood, Gregg D

    2015-02-18

    Disruption to dopamine homeostasis during brain development has been implicated in a variety of neuropsychiatric disorders, including depression and schizophrenia. Inappropriate expression or activity of GABAergic interneurons are common features of many of these disorders. We discovered a persistent upregulation of GAD67+ and parvalbumin+ neurons within the anterior cingulate cortex of dopamine D2 receptor knockout mice, while other GABAergic interneuron markers were unaffected. Interneuron distribution and number were not altered in the striatum or in the dopamine-poor somatosensory cortex. The changes were already present by postnatal day 14, indicating a developmental etiology. D2eGFP BAC transgenic mice demonstrated the presence of D2 receptor expression within a subset of parvalbumin-expressing cortical interneurons, suggesting the possibility of a direct cellular mechanism through which D2 receptor stimulation regulates interneuron differentiation or survival. D2 receptor knockout mice also exhibited decreased depressive-like behavior compared with wild-type controls in the tail suspension test. These data indicate that dopamine signaling modulates interneuron number and emotional behavior and that developmental D2 receptor loss or blockade could reveal a potential mechanism for the prodromal basis of neuropsychiatric disorders.

  14. Motivation of extended behaviors by anterior cingulate cortex.

    Science.gov (United States)

    Holroyd, Clay B; Yeung, Nick

    2012-02-01

    Intense research interest over the past decade has yielded diverse and often discrepant theories about the function of anterior cingulate cortex (ACC). In particular, a dichotomy has emerged between neuropsychological theories suggesting a primary role for ACC in motivating or 'energizing' behavior, and neuroimaging-inspired theories emphasizing its contribution to cognitive control and reinforcement learning. To reconcile these views, we propose that ACC supports the selection and maintenance of 'options' - extended, context-specific sequences of behavior directed toward particular goals - that are learned through a process of hierarchical reinforcement learning. This theory accounts for ACC activity in relation to learning and control while simultaneously explaining the effects of ACC damage as disrupting the motivational context supporting the production of goal-directed action sequences.

  15. Action initiation in the human dorsal anterior cingulate cortex.

    Directory of Open Access Journals (Sweden)

    Lakshminarayan Srinivasan

    Full Text Available The dorsal anterior cingulate cortex (dACC has previously been implicated in processes that influence action initiation. In humans however, there has been little direct evidence connecting dACC to the temporal onset of actions. We studied reactive behavior in patients undergoing therapeutic bilateral cingulotomy to determine the immediate effects of dACC ablation on action initiation. In a simple reaction task, three patients were instructed to respond to a specific visual cue with the movement of a joystick. Within minutes of dACC ablation, the frequency of false starts increased, where movements occurred prior to presentation of the visual cue. In a decision making task with three separate patients, the ablation effect on action initiation persisted even when action selection was intact. These findings suggest that human dACC influences action initiation, apart from its role in action selection.

  16. Bilingualism tunes the anterior cingulate cortex for conflict monitoring.

    Science.gov (United States)

    Abutalebi, Jubin; Della Rosa, Pasquale Anthony; Green, David W; Hernandez, Mireia; Scifo, Paola; Keim, Roland; Cappa, Stefano F; Costa, Albert

    2012-09-01

    Monitoring and controlling 2 language systems is fundamental to language use in bilinguals. Here, we reveal in a combined functional (event-related functional magnetic resonance imaging) and structural neuroimaging (voxel-based morphometry) study that dorsal anterior cingulate cortex (ACC), a structure tightly bound to domain-general executive control functions, is a common locus for language control and resolving nonverbal conflict. We also show an experience-dependent effect in the same region: Bilinguals use this structure more efficiently than monolinguals to monitor nonlinguistic cognitive conflicts. They adapted better to conflicting situations showing less ACC activity while outperforming monolinguals. Importantly, for bilinguals, brain activity in the ACC, as well as behavioral measures, also correlated positively with local gray matter volume. These results suggest that early learning and lifelong practice of 2 languages exert a strong impact upon human neocortical development. The bilingual brain adapts better to resolve cognitive conflicts in domain-general cognitive tasks.

  17. Exogenous Glucocorticoids Decrease Subgenual Cingulate Activity Evoked by Sadness

    Science.gov (United States)

    Sudheimer, Keith D; Abelson, James L; Taylor, Stephan F; Martis, Brian; Welsh, Robert C; Warner, Christine; Samet, Mira; Manduzzi, Andrea; Liberzon, Israel

    2013-01-01

    The glucocorticoid hormone cortisol is known to have wide-ranging effects on a variety of physiological systems, including the morphology and physiology of the amygdala and hippocampus. Disruptions of cortisol regulation and signaling are also linked with psychiatric disorders involving emotional disturbances. Although there is much evidence to suggest a relationship between cortisol signaling and the brain physiology underlying emotion, few studies have attempted to test for direct effects of cortisol on the neurophysiology of emotion. We administered exogenous synthetic cortisol (hydrocortisone, HCT) using two different dosing regimens (25 mg/day over 4 days, 100 mg single dose), in a double-blind placebo-controlled functional magnetic resonance imaging (fMRI) study. During fMRI scanning, healthy subjects viewed images designed to induce happy, sad, and neutral emotional states. Subjective emotional reactions were collected for each experimental stimulus after fMRI scanning. Mood ratings were also collected throughout the 4 days of the study. Both dose regimens of HCT resulted in decreased subgenual cingulate activation during sadness conditions. The 25 mg/day regimen also resulted in higher arousal ratings of sad stimuli. No effects of HCT were observed on any mood ratings. Few reliable effects of HCT were observed on brain activity patterns or subjective emotional responses to stimuli that were not sad. The inhibitory effects of cortisol on sadness-induced subgenual cingulate activity may have critical relevance to the pathophysiology of major depression, as both subgenual hyperactivity and decreased sensitivity to cortisol signaling have been documented in patients with depression. PMID:23303057

  18. Khufu, Khafre and Menkaure Pyramids and the Sun

    CERN Document Server

    Sparavigna, Amelia Carolina

    2016-01-01

    In this paper we discuss the orientation of the Egyptian pyramids at Giza with respect to sunrises and sunsets, using SunCalc.net software. We can see that Khufu and Khafre pyramids had been positioned in a manner that, from each pyramid, it was always possible to observe the points of the horizon where the sun was rising and setting on each day of the year. A discussion for the Menkaure pyramid is also proposed.

  19. Modified Mean-Pyramid Coding Scheme

    Science.gov (United States)

    Cheung, Kar-Ming; Romer, Richard

    1996-01-01

    Modified mean-pyramid coding scheme requires transmission of slightly fewer data. Data-expansion factor reduced from 1/3 to 1/12. Schemes for progressive transmission of image data transmitted in sequence of frames in such way coarse version of image reconstructed after receipt of first frame and increasingly refined version of image reconstructed after receipt of each subsequent frame.

  20. Pyramid Servings Database (PSDB) for NHANES III

    Science.gov (United States)

    The National Cancer Institute developed a database to examine dietary data from the National Center for Health Statistics' Third National Health and Nutrition Examination Survey in terms of servings from each of United States Department of Agriculture's The Food Guide Pyramid's major and minor food groups.

  1. Digital pyramid wavefront sensor with tunable modulation.

    Science.gov (United States)

    Akondi, Vyas; Castillo, Sara; Vohnsen, Brian

    2013-07-29

    The pyramid wavefront sensor is known for its high sensitivity and dynamic range that can be tuned by mechanically altering its modulation amplitude. Here, a novel modulating digital scheme employing a reflecting phase only spatial light modulator is demonstrated. The use of the modulator allows an easy reconfigurable pyramid with digital control of the apex angle and modulation geometry without the need of any mechanically moving parts. Aberrations introduced by a 140-actuator deformable mirror were simultaneously sensed with the help of a commercial Hartmann-Shack wavefront sensor. The wavefronts reconstructed using the digital pyramid wavefront sensor matched very closely with those sensed by the Hartmann-Shack. It is noted that a tunable modulation is necessary to operate the wavefront sensor in the linear regime and to accurately sense aberrations. Through simulations, it is shown that the wavefront sensor can be extended to astronomical applications as well. This novel digital pyramid wavefront sensor has the potential to become an attractive option in both open and closed loop adaptive optics systems.

  2. Toddler Teachers' Use of "Teaching Pyramid" Practices

    Science.gov (United States)

    Branson, Diane; Demchak, MaryAnn

    2011-01-01

    Effective strategies to promote social-emotional development and prevent occurrence of challenging behaviors in young children is critical. The "Teaching Pyramid", a framework for supporting social-emotional development and preventing and addressing challenging behaviors, was developed for preschool children. This mixed methods study…

  3. Comparing Volumes of Prisms and Pyramids

    Science.gov (United States)

    Vinogradova, Natalya

    2012-01-01

    Students' experience in using formulas for volumes is often limited to substituting numbers into given formulas. An activity presented in this article may help students make connections between the formulas for volumes of prisms and volumes of pyramids. In addition, some interesting facts from number theory arise, demonstrating strong connections…

  4. Toddler Teachers' Use of "Teaching Pyramid" Practices

    Science.gov (United States)

    Branson, Diane; Demchak, MaryAnn

    2011-01-01

    Effective strategies to promote social-emotional development and prevent occurrence of challenging behaviors in young children is critical. The "Teaching Pyramid", a framework for supporting social-emotional development and preventing and addressing challenging behaviors, was developed for preschool children. This mixed methods study investigated…

  5. The Dairy Group. The Food Guide Pyramid.

    Science.gov (United States)

    Frost, Helen

    This booklet for young children is part of a series that supports national science standards related to physical health and nutrition, describing and illustrating the importance of using the Food Guide Pyramid and eating from the dairy group. Colorful photographs support early readers in understanding the text. The repetition of words and phrases…

  6. Ancient Pyramids Help Students Learn Math Concepts

    Science.gov (United States)

    Smith, Courtney D.; Stump, Amanda M.; Lazaros, Edward J.

    2010-01-01

    This article presents an activity that allows students to use mathematics and critical-thinking skills to emulate processes used by the ancient Egyptians to prepare the site for the Pyramids of Giza. To accomplish this, they use three different methods. First, they create a square using only simple technological tools that were available to the…

  7. Jonestown in the Shadow of Maslow's Pyramid.

    Science.gov (United States)

    Easley, Edgar M.; Wigglesworth, David C.

    1979-01-01

    Reviews Maslow's hierarchy of needs in the light of the Jonestown tragedy. Maintains that members of the People's Temple felt frustrated in attaining the lower levels in the world of reality, and so moved outside the pyramid in search of the top, self-actualization. In the process, their primary needs were met. Journal availability: see SO 507…

  8. Idea Bank: Assessing Your Curriculum with the Creative Rights Pyramid

    Science.gov (United States)

    Thibeault, Matthew D.

    2011-01-01

    This article presents a creative rights pyramid that was developed as part of the author's efforts to: (1) teach about copyright and intellectual property; and (2) increase students' awareness of their own intellectual property in and outside the music classroom. The pyramid is based on the U.S. Department of Agriculture's food pyramid to suggest…

  9. LANDSAT-BASED WATER QUALITY MONITORING OF PYRAMID LAKE

    Science.gov (United States)

    Pyramid Lake Paiute Tribe (PLPT) in cooperation with federal, state and local entities has been able to increase stream flow, establish water quality standards and improve fish habitat in the Truckee River, a primary source of water for pyramid Lake. In the past, pyramid Lake wat...

  10. On the astronomical orientation of the IV dynasty Egyptian pyramids and the dating of the second Giza pyramid

    OpenAIRE

    Magli, Giulio

    2003-01-01

    The data on the astronomical orientation of the IV dynasty Egyptian pyramids are re-analyzed and it is shown that such data suggest an inverse chronology between the `first` and the `second` Giza pyramid.

  11. In vivo blockade of neural activity alters dendritic development of neonatal CA1 pyramidal cells.

    Science.gov (United States)

    Groc, Laurent; Petanjek, Zdravko; Gustafsson, Bengt; Ben-Ari, Yehezkel; Hanse, Eric; Khazipov, Roustem

    2002-11-01

    During development, neural activity has been proposed to promote neuronal growth. During the first postnatal week, the hippocampus is characterized by an oscillating neural network activity and a rapid neuronal growth. In the present study we tested in vivo, by injecting tetanus toxin into the hippocampus of P1 rats, whether this neural activity indeed promotes growth of pyramidal cells. We have previously shown that tetanus toxin injection leads to a strong reduction in the frequency of spontaneous GABA and glutamatergic synaptic currents, and to a complete blockade of the early neural network activity during the first postnatal week. Morphology of neurobiotin-filled CA1 pyramidal cells was analyzed at the end of the first postnatal week (P6-10). In activity-reduced neurons, the total length of basal dendritic tree was three times less than control. The number, but not the length, of basal dendritic branches was affected. The growth impairment was restricted to the basal dendrites. The apical dendrite, the axons, or the soma grew normally during activity deprivation. Thus, the in vivo neural activity in the neonate hippocampus seems to promote neuronal growth by initiating novel branches.

  12. Pyramidal fractal dimension for high resolution images

    Science.gov (United States)

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

    Fractal analysis (FA) should be able to yield reliable and fast results for high-resolution digital images to be applicable in fields that require immediate outcomes. Triggered by an efficient implementation of FA for binary images, we present three new approaches for fractal dimension (D) estimation of images that utilize image pyramids, namely, the pyramid triangular prism, the pyramid gradient, and the pyramid differences method (PTPM, PGM, PDM). We evaluated the performance of the three new and five standard techniques when applied to images with sizes up to 8192 × 8192 pixels. By using artificial fractal images created by three different generator models as ground truth, we determined the scale ranges with minimum deviations between estimation and theory. All pyramidal methods (PM) resulted in reasonable D values for images of all generator models. Especially, for images with sizes ≥1024 ×1024 pixels, the PMs are superior to the investigated standard approaches in terms of accuracy and computation time. A measure for the possibility to differentiate images with different intrinsic D values did show not only that the PMs are well suited for all investigated image sizes, and preferable to standard methods especially for larger images, but also that results of standard D estimation techniques are strongly influenced by the image size. Fastest results were obtained with the PDM and PGM, followed by the PTPM. In terms of absolute D values best performing standard methods were magnitudes slower than the PMs. Concluding, the new PMs yield high quality results in short computation times and are therefore eligible methods for fast FA of high-resolution images.

  13. Postsynaptic blockade of inhibitory postsynaptic currents by plasmin in CA1 pyramidal cells of rat hippocampus.

    Science.gov (United States)

    Mizutani, A; Tanaka, T; Saito, H; Matsuki, N

    1997-06-27

    We have shown previously that plasmin facilitated the generation of long-term potentiation (LTP) in CA1 and dentate region of rat hippocampus. In the present study, we investigated the effects of plasmin on postsynaptic currents in CA1 pyramidal neurons of rat hippocampal slices. Plasmin (100 nM) had no effect on NMDA nor on non-NMDA receptor-mediated excitatory postsynaptic currents. However, plasmin significantly decreased GABA(A) receptor-mediated inhibitory postsynaptic currents. This effect of plasmin disappeared when intracellular Ca2+ was strongly chelated with BAPTA. Furthermore, plasmin attenuated the GABA-induced currents in CA1 pyramidal cells. These results suggest that the STP-enhancing effect of plasmin is due to a blockade of postsynaptic GABA(A) responses and that an increase in intracellular Ca2+ by plasmin may be involved in its mechanism.

  14. Energy substrates that fuel fast neuronal network oscillations

    OpenAIRE

    Galow, Lukas V.; Schneider, Justus; Lewen, Andrea; Ta, Thuy-Truc; Ismini E. Papageorgiou; Kann, Oliver

    2014-01-01

    Fast neuronal network oscillations in the gamma-frequency band (30–−100 Hz) provide a fundamental mechanism of complex neuronal information processing in the hippocampus and neocortex of mammals. Gamma oscillations have been implicated in higher brain functions such as sensory perception, motor activity, and memory formation. The oscillations emerge from precise synapse interactions between excitatory principal neurons such as pyramidal cells and inhibitory GABAergic interneurons, and they ar...

  15. Energy substrates that fuel fast neuronal network oscillations

    OpenAIRE

    Galow, Lukas V.; Justus eSchneider; Andrea eLewen; Thuy-Truc eTa; Ismini E. Papageorgiou; Oliver eKann

    2014-01-01

    Fast neuronal network oscillations in the gamma-frequency band (30-100 Hz) provide a fundamental mechanism of complex neuronal information processing in the hippocampus and neocortex of mammals. Gamma oscillations have been implicated in higher brain functions such as sensory perception, motor activity and memory formation. The oscillations emerge from precise synapse interactions between excitatory principal neurons such as pyramidal cells and inhibitory GABAergic interneurons, and they are ...

  16. Extrinsic and local glutamatergic inputs of the rat hippocampal CA1 area differentially innervate pyramidal cells and interneurons.

    Science.gov (United States)

    Takács, Virág T; Klausberger, Thomas; Somogyi, Peter; Freund, Tamás F; Gulyás, Attila I

    2012-06-01

    The two main glutamatergic pathways to the CA1 area, the Schaffer collateral/commissural input and the entorhinal fibers, as well as the local axons of CA1 pyramidal cells innervate both pyramidal cells and interneurons. To determine whether these inputs differ in their weights of activating GABAergic circuits, we have studied the relative proportion of pyramidal cells and interneurons among their postsynaptic targets in serial electron microscopic sections. Local axons of CA1 pyramidal cells, intracellularly labeled in vitro or in vivo, innervated a relatively high proportion of interneuronal postsynaptic targets (65.9 and 53.8%, in vitro and in vivo, respectively) in stratum (str.) oriens and alveus. In contrast, axons of in vitro labeled CA3 pyramidal cells in str. oriens and str. radiatum of the CA1 area made synaptic junctions predominantly with pyramidal cell spines (92.9%). The postsynaptic targets of anterogradely labeled medial entorhinal cortical boutons in CA1 str. lacunosum-moleculare were primarily pyramidal neuron dendritic spines and shafts (90.8%). The alvear group of the entorhinal afferents, traversing str. oriens, str. pyramidale, and str. radiatum showed a higher preference for innervating GABAergic cells (21.3%), particularly in str. oriens/alveus. These data demonstrate that different glutamatergic pathways innervate CA1 GABAergic cells to different extents. The results suggest that the numerically smaller CA1 local axonal inputs together with the alvear part of the entorhinal input preferentially act on GABAergic interneurons in contrast to the CA3, or the entorhinal input in str. lacunosum-moleculare. The results highlight differences in the postsynaptic target selection of the feed-forward versus recurrent glutamatergic inputs to the CA1 and CA3 areas.

  17. Sodium entry during action potentials of mammalian central neurons: incomplete inactivation and reduced metabolic efficiency in fast-spiking neurons

    OpenAIRE

    Carter, Brett C.; Bean, Bruce P.

    2009-01-01

    We measured the time course of sodium entry during action potentials of mouse central neurons at 37 °C to examine how efficiently sodium entry is coupled to depolarization. In cortical pyramidal neurons, sodium entry was nearly completely confined to the rising phase of the spike: only ~25% more sodium enters than the theoretical minimum necessary for spike depolarization. However, in fast-spiking GABAergic neurons (cerebellar Purkinje cells and cortical interneurons), twice as much sodium en...

  18. The structural involvement of the cingulate cortex in premanifest and early Huntington's disease.

    Science.gov (United States)

    Hobbs, Nicola Z; Pedrick, Amy V; Say, Miranda J; Frost, Chris; Dar Santos, Rachelle; Coleman, Allison; Sturrock, Aaron; Craufurd, David; Stout, Julie C; Leavitt, Blair R; Barnes, Josephine; Tabrizi, Sarah J; Scahill, Rachael I

    2011-08-01

    The impact of Huntington's disease neuropathology on the structure of the cingulate is uncertain, with evidence of both cortical enlargement and atrophy in this structure in early clinical disease. We sought to determine differences in cingulate volume between premanifest Huntington's disease and early Huntington's disease groups compared with controls using detailed manual measurements. Thirty controls, 30 subjects with premanifest Huntington's disease, and 30 subjects with early Huntington's disease were selected from the Vancouver site of the TRACK-HD study. Subjects underwent 3 Tesla magnetic resonance imaging and motor, cognitive, and neuropsychiatric assessment. The cingulate was manually delineated and subdivided into rostral, caudal, and posterior segments. Group differences in volume and associations with performance on 4 tasks thought to utilize cingulate function were examined, with adjustment for appropriate covariates. Cingulate volumes were, on average, 1.7 mL smaller in early Huntington's disease (P=.001) and 0.9 mL smaller in premanifest Huntington's disease (P=.1) compared with controls. Smaller volumes in subsections of the cingulate were associated with impaired recognition of negative emotions (P=.04), heightened depression (P=.009), and worse visual working memory performance (P=.01). There was no evidence of associations between volume and ability on a performance-monitoring task. This study disputes previous findings of enlargement of the cingulate cortex in Huntington's disease and instead suggests that the cingulate undergoes structural degeneration during early Huntington's disease with directionally consistent, nonsignificant differences seen in premanifest Huntington's disease. Cingulate atrophy may contribute to deficits in mood, emotional processing, and visual working memory in Huntington's disease.

  19. Pleasant human touch is represented in pregenual anterior cingulate cortex.

    Science.gov (United States)

    Lindgren, Lenita; Westling, Göran; Brulin, Christine; Lehtipalo, Stefan; Andersson, Micael; Nyberg, Lars

    2012-02-15

    Touch massage (TM) is a form of pleasant touch stimulation used as treatment in clinical settings and found to improve well-being and decrease anxiety, stress, and pain. Emotional responses reported during and after TM have been studied, but the underlying mechanisms are still largely unexplored. In this study, we used functional magnetic resonance (fMRI) to test the hypothesis that the combination of human touch (i.e. skin-to-skin contact) with movement is eliciting a specific response in brain areas coding for pleasant sensations. The design included four different touch conditions; human touch with or without movement and rubber glove with or without movement. Force (2.5 N) and velocity (1.5 cm/s) were held constant across conditions. The pleasantness of the four different touch stimulations was rated on a visual analog scale (VAS-scale) and human touch was rated as most pleasant, particularly in combination with movement. The fMRI results revealed that TM stimulation most strongly activated the pregenual anterior cingulate cortex (pgACC). These results are consistent with findings showing pgACC activation during various rewarding pleasant stimulations. This area is also known to be activated by both opioid analgesia and placebo. Together with these prior results, our finding furthers the understanding of the basis for positive TM treatment effects.

  20. Dorsal anterior cingulate cortex and the value of control.

    Science.gov (United States)

    Shenhav, Amitai; Cohen, Jonathan D; Botvinick, Matthew M

    2016-09-27

    Debates over the function(s) of dorsal anterior cingulate cortex (dACC) have persisted for decades. So too have demonstrations of the region's association with cognitive control. Researchers have struggled to account for this association and, simultaneously, dACC's involvement in phenomena related to evaluation and motivation. We describe a recent integrative theory that achieves this goal. It proposes that dACC serves to specify the currently optimal allocation of control by determining the overall expected value of control (EVC), thereby licensing the associated cognitive effort. The EVC theory accounts for dACC's sensitivity to a wide array of experimental variables, and their relationship to subsequent control adjustments. Finally, we contrast our theory with a recent theory proposing a primary role for dACC in foraging-like decisions. We describe why the EVC theory offers a more comprehensive and coherent account of dACC function, including dACC's particular involvement in decisions regarding foraging or otherwise altering one's behavior.

  1. Three-dimensional structure of CA1 pyramidal cells in rat hippocampus——Optical recording of LSM and computer simulation of fractal structure

    Institute of Scientific and Technical Information of China (English)

    冯春华; 刘力; 刘守忠; 宁红; 孙海坚; 郭爱克

    1995-01-01

    The optical recording of three-dimensional(3-D)reconstruction of CA1 pyramidal cells wasderived from the studies on the CA1 region of the hippocampus in adult male Wistar rats.The recordingwas produced by the Confocal Laser Scan Microscope(LSM-10).The attemption was to outline themorphological neural network of CA1 pyramidal cells organization,following the trail of axo-dendritic connec-tions in 3-D spatial distributions among neurons.The fractal structure of neurons with their dendritic andaxonal trees using fractal algorithm was noticed,and 2—18 simulated cells were obtained using PC-486 comput-er.The simulational cells are similar in morphology to the natural CA1 hippocampal pyramidal cells.There-fore,the exploitation of an advanced neurohistological research technique combining optical recording of theLSM-10 and computer simulation of fractal structure can provide the quantitative fractal structural basis forchaosic dynamics of brain.

  2. Compression asphyxia from a human pyramid.

    Science.gov (United States)

    Tumram, Nilesh Keshav; Ambade, Vipul Namdeorao; Biyabani, Naushad

    2015-12-01

    In compression asphyxia, respiration is stopped by external forces on the body. It is usually due to an external force compressing the trunk such as a heavy weight on the chest or abdomen and is associated with internal injuries. In present case, the victim was trapped and crushed under the falling persons from a human pyramid formation for a "Dahi Handi" festival. There was neither any severe blunt force injury nor any significant pathological natural disease contributing to the cause of death. The victim was unable to remove himself from the situation because his cognitive responses and coordination were impaired due to alcohol intake. The victim died from asphyxia due to compression of his chest and abdomen. Compression asphyxia resulting from the collapse of a human pyramid and the dynamics of its impact force in these circumstances is very rare and is not reported previously to the best of our knowledge.

  3. How they (should have) built the pyramids

    CERN Document Server

    West, J; Waters, K

    2014-01-01

    A novel method is proposed for moving large, pyramid construction size, stone blocks. The method is inspired by a well known introductory physics homework problem, and is implemented by tying 12 identical rods of appropriately chosen radius to the faces of the block. The rods form the corners and new faces that transform the square prism into a dodecagon which can then be moved more easily by rolling than by dragging. Experimental results are presented and compared to independent work by another group which utilized wooden attachments providing a cylindrical shape. It is found that a small scale stone block converted to dodecagons can be moved across level open ground with a dynamic coefficient of friction of the order 0.2. For full scale pyramid blocks, the wooden rods would need to be posts of order 30 cm in diameter, similar in size to those used as masts on ships in the Nile.

  4. Changes of delayed neuronal death of pyramidal cell and mitochondria by transmission electron microscopy in rats' hippocampus after endurance training and exhaustion treadmill running%耐力训练及力竭运动后大鼠大脑CA1区锥体细胞迟发性神经元死亡及其线粒体的超微结构变化

    Institute of Scientific and Technical Information of China (English)

    张雁儒; 张建军; 冯富明; 李月白; 王义生

    2012-01-01

    目的 观察耐力训练及力竭运动后大鼠大脑海马区锥体细胞及其线粒体的超微结构变化.方法 实验于2007年6月至2008年11月在郑州大学完成.选取8周龄雄性SD大鼠40只,随机设耐力训练组:安静组;急性力竭运动后24 h组;耐力训练+急性力竭运动后即刻组;耐力训练+急性力竭运动后24h组.每组10只.安静组不外加运动,其他组次日进行力竭运动,力竭运动开始的速度为10 m/min,逐渐提高速度并在3 min内到达预定的速度(中等强度、大强度力竭运动的速度分别为20 m/min、36 m/min),保持速度直至力竭,并记录力竭运动时间.耐力训练方案:大鼠在动物跑台进行运动训练,1次/d,6d/周.跑台速度由开始的10 m/min逐渐增加至第4周30 m/min,运动时间由30 min/d增加到40 min/d.力竭标准为大鼠用毛刷驱赶无效,在跑台尾端停留2 s仍不愿跑,且失去快速翻正反射.主要观察指标:断头处死分别取材检测大鼠大脑海马区锥体细胞及其线粒体的超微结构变化.结果 40只SD大鼠均完成实验设计方案,全部进入结果分析.结果发现耐力训练和力竭运动后大鼠大脑细胞凋亡数量显著增加,力竭运动强度增加,凋亡细胞数量增多,且多为神经胶质细胞,安静组大脑细胞凋亡率为(6.56±1.24)%、急性运动后24h组为(16.14 ±3.26)%、耐力训练+急性运动后即刻组为(29.78±1.96)%、耐力训练+急性运动后24h组为(32.43±2.35)%.通过图像分析系统的分析研究,海马神经元线粒体变性较为显著.结论 本实验观察到耐力训练和力竭运动对大脑细胞造成一定的损伤,海马区神经元线粒体变性,可能是由于疲劳训练引起脑组织的酸中毒和缺氧引起大脑细胞的一些变性现象.%Objective The pyramid neurons in the CA1 subfield of the hippocampus are vulnerable to ischemic attack,and transient global ischemia can lead to a specific neuronal death called the

  5. Centre of pressure correlates with pyramid performance in acrobatic gymnastics.

    Science.gov (United States)

    Floría, Pablo; Gómez-Landero, Luis Arturo; Harrison, Andrew J

    2015-01-01

    Acrobatic gymnasts need excellent balance control to execute pyramids where one gymnast is supported by another. The objectives of this study were: (1) to describe balance performance by assessing the centre of pressure displacement in a group of acrobatic gymnasts executing pyramids; (2) to determine the relationship between the parameters describing the centre of pressure oscillations and pyramid score; and (3) to examine the role of each foot in providing a solid base of support to maintain the balance of the pyramid. Sixteen acrobatic gymnasts grouped in pairs performed a Half pyramid and a Straddle pyramid held for 7 s on two force platforms. Path length, variance, range trajectory, and surface area of the centre of pressure of each foot were examined to analyse the balance of the pyramid. The path length was correlated with the pyramid score (Straddle: p = 0.692 [large]; Half: p = 0.407 [moderate]). There were differences in the functions of each leg to maintain balance, with the non-preferred leg supporting a higher weight of the pyramid while the preferred leg performed control movements to maintain balance. The results suggested that quantitative analysis of balance can provide important information on pyramid performance.

  6. The Role of the Subgenual Anterior Cingulate Cortex and Amygdala in Environmental Sensitivity to Infant Crying

    Science.gov (United States)

    Mutschler, Isabella; Ball, Tonio; Kirmse, Ursula; Wieckhorst, Birgit; Pluess, Michael; Klarhöfer, Markus; Meyer, Andrea H.; Wilhelm, Frank H.; Seifritz, Erich

    2016-01-01

    Newborns and infants communicate their needs and physiological states through crying and emotional facial expressions. Little is known about individual differences in responding to infant crying. Several theories suggest that people vary in their environmental sensitivity with some responding generally more and some generally less to environmental stimuli. Such differences in environmental sensitivity have been associated with personality traits, including neuroticism. This study investigated whether neuroticism impacts neuronal, physiological, and emotional responses to infant crying by investigating blood-oxygenation-level dependent (BOLD) responses using functional magnetic resonance imaging (fMRI) in a large sample of healthy women (N = 102) with simultaneous skin conductance recordings. Participants were repeatedly exposed to a video clip that showed crying infants and emotional responses (valence, arousal, and irritation) were assessed after every video clip presentation. Increased BOLD signal during the perception of crying infants was found in brain regions that are associated with emotional responding, the amygdala and anterior insula. Significant BOLD signal decrements (i.e., habituation) were found in the fusiform gyrus, middle temporal gyrus, superior temporal gyrus, Broca’s homologue on the right hemisphere, (laterobasal) amygdala, and hippocampus. Individuals with high neuroticism showed stronger activation in the amygdala and subgenual anterior cingulate cortex (sgACC) when exposed to infant crying compared to individuals with low neuroticism. In contrast to our prediction we found no evidence that neuroticism impacts fMRI-based measures of habituation. Individuals with high neuroticism showed elevated skin conductance responses, experienced more irritation, and perceived infant crying as more unpleasant. The results support the hypothesis that individuals high in neuroticism are more emotionally responsive, experience more negative emotions, and

  7. CDYL Deficiency Disrupts Neuronal Migration and Increases Susceptibility to Epilepsy.

    Science.gov (United States)

    Qin, Rui; Cao, Shuai; Lyu, Tianjie; Qi, Cai; Zhang, Weiguang; Wang, Yun

    2017-01-10

    During brain development, the correct migration of newborn neurons is one of the determinants of circuit formation, and neuronal migration defects may lead to neurological and psychiatric disorders. The molecular mechanisms underlying neuronal migration and related disorders are poorly understood. Here, we report that Chromodomain Y-like (CDYL) is critical for neuronal migration in mice. Knocking down CDYL caused neuronal migration defects and disrupted both mobility and multipolar-to-bipolar transition of migrating neurons. We find that CDYL regulates neuronal migration by transcriptionally repressing RhoA. In addition, CDYL deficiency increased the excitability of cortical pyramidal neurons and the susceptibility of mice to convulsant-induced seizures. These results demonstrate that CDYL is a regulator of neuronal migration and shed light on the pathogenesis of seizure-related neurodevelopmental disorders.

  8. Golgi Analysis of Neuron Morphology in the Presumptive Somatosensory Cortex and Visual Cortex of the Florida Manatee (Trichechus manatus latirostris).

    Science.gov (United States)

    Reyes, Laura D; Harland, Tessa; Reep, Roger L; Sherwood, Chet C; Jacobs, Bob

    2016-01-01

    The current study investigates neuron morphology in presumptive primary somatosensory (S1) and primary visual (V1) cortices of the Florida manatee (Trichechus manatus latirostris) as revealed by Golgi impregnation. Sirenians, including manatees, have an aquatic lifestyle, a large body size, and a relatively large lissencephalic brain. The present study examines neuron morphology in 3 cortical areas: in S1, dorsolateral cortex area 1 (DL1) and cluster cortex area 2 (CL2) and in V1, dorsolateral cortex area 4 (DL4). Neurons exhibited a variety of morphological types, with pyramidal neurons being the most common. The large variety of neuron types present in the manatee cortex was comparable to that seen in other eutherian mammals, except for rodents and primates, where pyramid-shaped neurons predominate. A comparison between pyramidal neurons in S1 and V1 indicated relatively greater dendritic branching in S1. Across all 3 areas, the dendritic arborization pattern of pyramidal neurons was also similar to that observed previously in the afrotherian rock hyrax, cetartiodactyls, opossums, and echidnas but did not resemble the widely bifurcated dendrites seen in the large-brained African elephant. Despite adaptations for an aquatic environment, manatees did not share specific neuron types such as tritufted and star-like neurons that have been found in cetaceans. Manatees exhibit an evolutionarily primitive pattern of cortical neuron morphology shared with most other mammals and do not appear to have neuronal specializations for an aquatic niche.

  9. Systematic Regional Variations of GABA, Glutamine, and Glutamate Concentrations Follow Receptor Fingerprints of Human Cingulate Cortex

    NARCIS (Netherlands)

    Dou, Weiqiang; Palomero-Gallagher, Nicola; van Tol, Marie-Jose; Kaufmann, Joern; Zhong, Kai; Bernstein, Hans-Gert; Heinze, Hans-Jochen; Speck, Oliver; Walter, Martin

    2013-01-01

    Magnetic resonance spectroscopy (MRS) of glutamatergic or GABAergic measures in anterior cingulate cortex (ACC) was found altered in psychiatric disorders and predictive of interindividual variations of functional responses in healthy populations. Several ACC subregions have been parcellated into re

  10. Morphometric characteristics of the neurons of the human subiculum proper

    Directory of Open Access Journals (Sweden)

    Živanović-Mačužić Ivana

    2012-01-01

    Full Text Available The human subiculum is a significant part of the hippocampal formation positioned between the hippocampus proper and the entorhinal and other cortices. It plays an important role in spatial navigation, memory processing and control of the response to stress. The aim of our study was identification of the morphometric characteristics of the neurons of the human subiculum proper: the maximum length and width of cell body and total dendritic length and volume of cell body. Comparing the measured parameters of different types of subicular neurons (bipolar, multipolar, pyramidal neurons with triangular-shaped soma and neurons with oval-shaped soma, we can conclude that bipolar neurons have the lowest values of the measured parameters: the maximum length of their cell body is 14.1 ± 0.2 µm, the maximum width is 13.9 ± 0.5 µm, and total dendritic length is 14597 ± 3.1 µm. The lowest volume value was observed in bipolar neurons; the polymorphic layer is 1152.99 ± 662.69 µm3. The pyramidal neurons of the pyramidal layer have the highest value for the maximal length of the cell body (44.43 ± 7.94 µm, maximum width (23.64 ± 1.89 µm, total dendritic length (1830 ± 466.3 µm and volume (11768.65±4004.9 µm3 These characteristics of the pyramidal neurons indicate their importance, because the axons of these neurons make up the greatest part of the fornix, along with the axons of neurons of the CA1 hippocampal field.

  11. The cell-autonomous role of excitatory synaptic transmission in the regulation of neuronal structure and function.

    Science.gov (United States)

    Lu, Wei; Bushong, Eric A; Shih, Tiffany P; Ellisman, Mark H; Nicoll, Roger A

    2013-05-08

    The cell-autonomous role of synaptic transmission in the regulation of neuronal structural and electrical properties is unclear. We have now employed a genetic approach to eliminate glutamatergic synaptic transmission onto individual CA1 pyramidal neurons in a mosaic fashion in vivo. Surprisingly, while electrical properties are profoundly affected in these neurons, as well as inhibitory synaptic transmission, we found little perturbation of neuronal morphology, demonstrating a functional segregation of excitatory synaptic transmission from neuronal morphological development.

  12. Practice explains abolished behavioural adaptation after human dorsal anterior cingulate cortex lesions

    OpenAIRE

    van Steenbergen, H.; E. Haasnoot; Bocanegra, B.R.; Berretty, E.W.; Hommel, B.

    2015-01-01

    The role of mid-cingulate cortex (MCC), also referred to as dorsal anterior cingulate cortex, in regulating cognitive control is a topic of primary importance in cognitive neuroscience. Although many studies have shown that MCC responds to cognitive demands, lesion studies in humans are inconclusive concerning the causal role of the MCC in the adaptation to these demands. By elegantly combining single-cell recordings with behavioural methods, Sheth et al. [Sheth, S. et al. Human dorsal anteri...

  13. A Simulation Study on the Effects of Dendritic Morphology on Layer V Prefontal Pyramidal Cell Firing Behavior

    Directory of Open Access Journals (Sweden)

    Maria ePsarrou

    2014-09-01

    Full Text Available Pyramidal cells, the most abundant neurons in neocortex, exhibit significant structural variability across different brain areas and layers in different species. Moreover, in response to a somatic step current, these cells display a range of firing behaviors, the most common being (1 repetitive action potentials (Regular Spiking - RS, and (2 an initial cluster of 2-5 action potentials with short ISIs followed by single spikes (Intrinsic Bursting - IB. A correlation between firing behavior and dendritic morphology has recently been reported. In this work we use computational modeling to investigate quantitatively the effects of the basal dendritic tree morphology on the firing behavior of 112 three-dimensional reconstructions of layer V PFC rat pyramidal cells. Particularly, we focus on how different morphological (diameter, total length, volume and branch number and passive (Mean Electrotonic Path length features of basal dendritic trees shape somatic firing when the spatial distribution of ionic mechanisms in the basal dendritic trees is uniform or non-uniform. Our results suggest that total length, volume and branch number are the best morphological parameters to discriminate the cells as RS or IB, regardless of the distribution of ionic mechanisms in basal trees. The discriminatory power of total length, volume and branch number remains high in the presence of different apical dendrites. These results suggest that morphological variations in the basal dendritic trees of layer V pyramidal neurons in the PFC influence their firing patterns in a predictive manner and may in turn influence the information processing capabilities of these neurons.

  14. Forebrain overexpression of CaMKII abolishes cingulate long term depression and reduces mechanical allodynia and thermal hyperalgesia

    Directory of Open Access Journals (Sweden)

    Tsien Joe Z

    2006-06-01

    Full Text Available Abstract Activity-dependent synaptic plasticity is known to be important in learning and memory, persistent pain and drug addiction. Glutamate NMDA receptor activation stimulates several protein kinases, which then trigger biochemical cascades that lead to modifications in synaptic efficacy. Genetic and pharmacological techniques have been used to show a role for Ca2+/calmodulin-dependent kinase II (CaMKII in synaptic plasticity and memory formation. However, it is not known if increasing CaMKII activity in forebrain areas affects behavioral responses to tissue injury. Using genetic and pharmacological techniques, we were able to temporally and spatially restrict the over expression of CaMKII in forebrain areas. Here we show that genetic overexpression of CaMKII in the mouse forebrain selectively inhibits tissue injury-induced behavioral sensitization, including allodynia and hyperalgesia, while behavioral responses to acute noxious stimuli remain intact. CaMKII overexpression also inhibited synaptic depression induced by a prolonged repetitive stimulation in the ACC, suggesting an important role for CaMKII in the regulation of cingulate neurons. Our results suggest that neuronal CaMKII activity in the forebrain plays a role in persistent pain.

  15. Optimizing pyramided transgenic Bt crops for sustainable pest management.

    Science.gov (United States)

    Carrière, Yves; Crickmore, Neil; Tabashnik, Bruce E

    2015-02-01

    Transgenic crop pyramids producing two or more Bacillus thuringiensis (Bt) toxins that kill the same insect pest have been widely used to delay evolution of pest resistance. To assess the potential of pyramids to achieve this goal, we analyze data from 38 studies that report effects of ten Bt toxins used in transgenic crops against 15 insect pests. We find that compared with optimal low levels of insect survival, survival on currently used pyramids is often higher for both susceptible insects and insects resistant to one of the toxins in the pyramid. Furthermore, we find that cross-resistance and antagonism between toxins used in pyramids are common, and that these problems are associated with the similarity of the amino acid sequences of domains II and III of the toxins, respectively. This analysis should assist in future pyramid design and the development of sustainable resistance management strategies.

  16. Altered Astrocyte-Neuron Interactions and Epileptogenesis in Tuberous Sclerosis Complex Disorder

    Science.gov (United States)

    2015-06-01

    Tsc1-deficient astrocytes on neuronal morphology and neuronal activity associated with seizures. 2. KEY WORDS epilepsy, seizure, tuberous sclerosis...seizures; and F) increased spine density on recombinant pyramidal neuron dendrites prior to the onset of spontaneous seizures. What was accomplished: We...soma size and morphology , suggesting that these neurons possess a negative feedback mechanism that in part counteracts the effect of the TSC1 deletion

  17. Functional and structural amygdala - anterior cingulate connectivity correlates with attentional bias to masked fearful faces.

    Science.gov (United States)

    Carlson, Joshua M; Cha, Jiook; Mujica-Parodi, Lilianne R

    2013-10-01

    An attentional bias to threat has been causally related to anxiety. Recent research has linked nonconscious attentional bias to threat with variability in the integrity of the amygdala - anterior cingulate pathway, which sheds light on the neuroanatomical basis for a behavioral precursor to anxiety. However, the extent to which structural variability in amygdala - anterior cingulate integrity relates to the functional connectivity within this pathway and how such functional connectivity may relate to attention bias behavior, remain critical missing pieces of the puzzle. In 15 individuals we measured the structural integrity of the amygdala - prefrontal pathway with diffusion tensor-weighted MRI (magnetic resonance imaging), amygdala-seeded intrinsic functional connectivity to the anterior cingulate, and attentional bias toward backward masked fearful faces with a dot-probe task. We found that greater biases in attention to threat predicted greater levels of uncinate fasciculus integrity, greater positive amygdala - anterior cingulate functional connectivity, and greater amygdala coupling with a broader social perception network including the superior temporal sulcus, tempoparietal junction (TPJ), and somatosensory cortex. Additionally, greater levels of uncinate fasciculus integrity correlated with greater levels of amygdala - anterior cingulate intrinsic functional connectivity. Thus, high bias individuals displayed a heightened degree of amygdala - anterior cingulate connectivity during basal conditions, which we believe predisposes these individuals to focus their attention on signals of threat within their environment.

  18. Reduced event-related current density in the anterior cingulate cortex in schizophrenia.

    Science.gov (United States)

    Mulert, C; Gallinat, J; Pascual-Marqui, R; Dorn, H; Frick, K; Schlattmann, P; Mientus, S; Herrmann, W M; Winterer, G

    2001-04-01

    There is good evidence from neuroanatomic postmortem and functional imaging studies that dysfunction of the anterior cingulate cortex plays a prominent role in the pathophysiology of schizophrenia. So far, no electrophysiological localization study has been performed to investigate this deficit. We investigated 18 drug-free schizophrenic patients and 25 normal subjects with an auditory choice reaction task and measured event-related activity with 19 electrodes. Estimation of the current source density distribution in Talairach space was performed with low-resolution electromagnetic tomography (LORETA). In normals, we could differentiate between an early event-related potential peak of the N1 (90-100 ms) and a later N1 peak (120-130 ms). Subsequent current-density LORETA analysis in Talairach space showed increased activity in the auditory cortex area during the first N1 peak and increased activity in the anterior cingulate gyrus during the second N1 peak. No activation difference was observed in the auditory cortex between normals and patients with schizophrenia. However, schizophrenics showed significantly less anterior cingulate gyrus activation and slowed reaction times. Our results confirm previous findings of an electrical source in the anterior cingulate and an anterior cingulate dysfunction in schizophrenics. Our data also suggest that anterior cingulate function in schizophrenics is disturbed at a relatively early time point in the information-processing stream (100-140 ms poststimulus).

  19. Double Pyramidal Central Configurations with a Concave Quadrilateral Base

    Institute of Scientific and Technical Information of China (English)

    LIUXuefei

    2002-01-01

    As for a doudle pyramidal central configuration in 6-body problems,the case when its bese is a concave polygon is studied.By advancing several assumptions according to the definition of double pyramidal central configuration and deducing two theorems and two corollaries on this subject,the essential and sufficient conditions to form a double pyramidal central configuration with a concave quadriateral base are demonstrated.

  20. Content-adaptive pyramid representation for 3D object classification

    DEFF Research Database (Denmark)

    Kounalakis, Tsampikos; Boulgouris, Nikolaos; Triantafyllidis, Georgios

    2016-01-01

    In this paper we introduce a novel representation for the classification of 3D images. Unlike most current approaches, our representation is not based on a fixed pyramid but adapts to image content and uses image regions instead of rectangular pyramid scales. Image characteristics, such as depth ...... and color, are used for defining regions within images. Multiple region scales are formed in order to construct the proposed pyramid image representation. The proposed method achieves excellent results in comparison to conventional representations....

  1. Long term delivery of pulsed magnetic fields does not alter visual discrimination learning or dendritic spine density in the mouse CA1 pyramidal or dentate gyrus neurons [v2; ref status: indexed, http://f1000r.es/2gk

    Directory of Open Access Journals (Sweden)

    Matthew Sykes

    2013-12-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is thought to facilitate brain plasticity. However, few studies address anatomical changes following rTMS in relation to behaviour. We delivered 5 weeks of daily pulsed rTMS stimulation to adult ephrin-A2-/- and wildtype (C57BI/6j mice (n=10 per genotype undergoing a visual learning task and analysed learning performance, as well as spine density, in the dentate gyrus molecular and CA1 pyramidal cell layers in Golgi-stained brain sections. We found that neither learning behaviour, nor hippocampal spine density was affected by long term rTMS. Our negative results highlight the lack of deleterious side effects in normal subjects and are consistent with previous studies suggesting that rTMS has a bigger effect on abnormal or injured brain substrates than on normal/control structures.

  2. Zbtb20 defines a hippocampal neuronal identity through direct repression of genes that control projection neuron development in the isocortex.

    Science.gov (United States)

    Nielsen, Jakob V; Thomassen, Mads; Møllgård, Kjeld; Noraberg, Jens; Jensen, Niels A

    2014-05-01

    Hippocampal pyramidal neurons are important for encoding and retrieval of spatial maps and episodic memories. While previous work has shown that Zbtb20 is a cell fate determinant for CA1 pyramidal neurons, the regulatory mechanisms governing this process are not known. In this study, we demonstrate that Zbtb20 binds to genes that control neuronal subtype specification in the developing isocortex, including Cux1, Cux2, Fezf2, Foxp2, Mef2c, Rorb, Satb2, Sox5, Tbr1, Tle4, and Zfpm2. We show that Zbtb20 represses these genes during ectopic CA1 pyramidal neuron development in transgenic mice. These data reveal a novel regulatory mechanism by which Zbtb20 suppresses the acquisition of an isocortical fate during archicortical neurogenesis to ensure commitment to a CA1 pyramidal neuron fate. We further show that the expression pattern of Zbtb20 is evolutionary conserved in the fetal human hippocampus, where it is complementary to the expression pattern of the Zbtb20 target gene Tbr1. Therefore, the disclosed Zbtb20-mediated transcriptional repressor mechanism may be involved in development of the human archicortex.

  3. Revisiting static modulation in pyramid wavefront sensing

    Science.gov (United States)

    Marafatto, L.; Ragazzoni, R.; Vassallo, D.; Bergomi, M.; Biondi, F.; Farinato, J.; Greggio, D.; Magrin, D.; Viotto, V.

    2016-07-01

    The Pyramid Sensor (PS) is based on the Focault knife-edge test, yielding then, in geometrical approximation, only the sign of the wavefront slope. To provide linear measurements of the wavefront slopes the PS relies on a technique known as modulation, which also plays a central role to improve the linear range of the pyramid WFS, very small in the nonmodulated case. In the main PS using modulation so far, this task is achieved by moving optical components in the WFS, increasing the complexity of the system. An attractive idea to simplify the optical and mechanical design of a pyramid WFS is to work without any dynamic modulation. This concept was only merely described and functionally tested in the framework of MAD, and subsequently, with a holographic diffuser. The latter produce a sort of random distribution of the light coming out from the pupil plane, leading to sort of inefficient modulation, as most of the rays are focused in the central region of the light diffused by such device. The bi-dimensional original grating is, in contrast, producing a well defined deterministic distribution of the light onto a specifically shaped pattern. A crude option has been already discussed as a possibility, and it is here generalized to holographic plates leading to various distribution of lights, including a circle whose diameter would match the required modulation pattern, or more cost effective approaches like the one of a square pattern. These holographic diffusers would exhibit also zero-th and high order patterns and the actual size of the equivalent modulation would be linearly wavelength dependent, leading to colour effects that requires a careful handling in order to properly choose the right amount of equivalent modulation.

  4. Base-of-the-pyramid global strategy

    Directory of Open Access Journals (Sweden)

    Boşcor, D.

    2010-12-01

    Full Text Available Global strategies for MNCs should focus on customers in emerging and developing markets instead of customers in developed economies. The “base-of-the-pyramid segment” comprises 4 billion people in the world. In order to be successful, companies will be required to form unconventional partnerships- with entities ranging from local governments to non-profit organizations - to gain the community’s trust and understand the environmental, infrastructure and political issues that may affect business. Being able to provide affordable, high-quality products and services in this market segment often means new approaches to marketing- new packaging and pricing structures, and using unfamiliar distribution structures.

  5. Plasmonic Tipless Pyramid Arrays for Cell Poration.

    Science.gov (United States)

    Courvoisier, Sébastien; Saklayen, Nabiha; Huber, Marinus; Chen, Jun; Diebold, Eric D; Bonacina, Luigi; Wolf, Jean-Pierre; Mazur, Eric

    2015-07-08

    Improving the efficiency, cell survival, and throughput of methods to modify and control the genetic expression of cells is of great benefit to biology and medicine. We investigate, both computationally and experimentally, a nanostructured substrate made of tipless pyramids for plasmonic-induced transfection. By optimizing the geometrical parameters for an excitation wavelength of 800 nm, we demonstrate a 100-fold intensity enhancement of the electric near field at the cell-substrate contact area, while the low absorption typical for gold is maintained. We demonstrate that such a substrate can induce transient poration of cells by a purely optically induced process.

  6. Extracting the abstraction pyramid from complex networks

    Directory of Open Access Journals (Sweden)

    Hu Yuh-Jyh

    2010-08-01

    Full Text Available Abstract Background At present, the organization of system modules is typically limited to either a multilevel hierarchy that describes the "vertical" relationships between modules at different levels (e.g., module A at level two is included in module B at level one, or a single-level graph that represents the "horizontal" relationships among modules (e.g., genetic interactions between module A and module B. Both types of organizations fail to provide a broader and deeper view of the complex systems that arise from an integration of vertical and horizontal relationships. Results We propose a complex network analysis tool, Pyramabs, which was developed to integrate vertical and horizontal relationships and extract information at various granularities to create a pyramid from a complex system of interacting objects. The pyramid depicts the nested structure implied in a complex system, and shows the vertical relationships between abstract networks at different levels. In addition, at each level the abstract network of modules, which are connected by weighted links, represents the modules' horizontal relationships. We first tested Pyramabs on hierarchical random networks to verify its ability to find the module organization pre-embedded in the networks. We later tested it on a protein-protein interaction (PPI network and a metabolic network. According to Gene Ontology (GO and the Kyoto Encyclopedia of Genes and Genomes (KEGG, the vertical relationships identified from the PPI and metabolic pathways correctly characterized the inclusion (i.e., part-of relationship, and the horizontal relationships provided a good indication of the functional closeness between modules. Our experiments with Pyramabs demonstrated its ability to perform knowledge mining in complex systems. Conclusions Networks are a flexible and convenient method of representing interactions in a complex system, and an increasing amount of information in real-world situations is

  7. Cosmological SUSY Breaking and the Pyramid Schemes

    CERN Document Server

    Banks, T

    2014-01-01

    I review the ideas of holographic space-time (HST), Cosmological SUSY breaking (CSB), and the Pyramid Schemes, which are the only known models of Tera-scale physics consistent with CSB, current particle data, and gauge coupling unification. There is considerable uncertainty in the estimate of the masses of supersymmetric partners of the standard model particles, but the model predicts that the gluino is probably out of reach of the LHC, squarks may be in reach, and the NLSP is a right handed slepton, which should be discovered soon.

  8. Adenosine A1 Receptor Suppresses Tonic GABAA Receptor Currents in Hippocampal Pyramidal Cells and in a Defined Subpopulation of Interneurons.

    Science.gov (United States)

    Rombo, Diogo M; Dias, Raquel B; Duarte, Sofia T; Ribeiro, Joaquim A; Lamsa, Karri P; Sebastião, Ana M

    2016-03-01

    Adenosine is an endogenous neuromodulator that decreases excitability of hippocampal circuits activating membrane-bound metabotropic A1 receptor (A1R). The presynaptic inhibitory action of adenosine A1R in glutamatergic synapses is well documented, but its influence on inhibitory GABAergic transmission is poorly known. We report that GABAA receptor (GABAAR)-mediated tonic, but not phasic, transmission is suppressed by A1R in hippocampal neurons. Adenosine A1R activation strongly inhibits GABAAR agonist (muscimol)-evoked currents in Cornu Ammonis 1 (CA1) pyramidal neurons and in a specific subpopulation of interneurons expressing axonal cannabinoid receptor type 1. In addition, A1R suppresses tonic GABAAR currents measured in the presence of elevated ambient GABA as well as in naïve slices. The inhibition of GABAergic currents involves both protein kinase A (PKA) and protein kinase C (PKC) signaling pathways and decreases GABAAR δ-subunit expression. On the contrary, no A1R-mediated modulation was detected in phasic inhibitory postsynaptic currents evoked either by afferent electrical stimulation or by spontaneous quantal release. The results show that A1R modulates extrasynaptic rather than synaptic GABAAR-mediated signaling, and that this modulation selectively occurs in hippocampal pyramidal neurons and in a specific subpopulation of inhibitory interneurons. We conclude that modulation of tonic GABAAR signaling by adenosine A1R in specific neuron types may regulate neuronal gain and excitability in the hippocampus.

  9. Differentiation of apical and basal dendrites in pyramidal cells and granule cells in dissociated hippocampal cultures.

    Directory of Open Access Journals (Sweden)

    You Kure Wu

    Full Text Available Hippocampal pyramidal cells and dentate granule cells develop morphologically distinct dendritic arbors, yet also share some common features. Both cell types form a long apical dendrite which extends from the apex of the cell soma, while short basal dendrites are developed only in pyramidal cells. Using quantitative morphometric analyses of mouse hippocampal cultures, we evaluated the differences in dendritic arborization patterns between pyramidal and granule cells. Furthermore, we observed and described the final apical dendrite determination during dendritic polarization by time-lapse imaging. Pyramidal and granule cells in culture exhibited similar dendritic patterns with a single principal dendrite and several minor dendrites so that the cell types were not readily distinguished by appearance. While basal dendrites in granule cells are normally degraded by adulthood in vivo, cultured granule cells retained their minor dendrites. Asymmetric growth of a single principal dendrite harboring the Golgi was observed in both cell types soon after the onset of dendritic growth. Time-lapse imaging revealed that up until the second week in culture, final principal dendrite designation was not stabilized, but was frequently replaced by other minor dendrites. Before dendritic polarity was stabilized, the Golgi moved dynamically within the soma and was repeatedly repositioned at newly emerging principal dendrites. Our results suggest that polarized growth of the apical dendrite is regulated by cell intrinsic programs, while regression of basal dendrites requires cue(s from the extracellular environment in the dentate gyrus. The apical dendrite designation is determined from among multiple growing dendrites of young developing neurons.

  10. Propagation of seizures in a case of lesional mid-cingulate gyrus epilepsy studied by stereo-EEG.

    Science.gov (United States)

    Alkawadri, Rafeed; Gonzalez-Martinez, Jorge; Gaspard, Nicolas; Alexopoulos, Andreas V

    2016-12-01

    Little is known about the propagation of seizures arising from the cingulate gyrus, as cingulate coverage with interhemispheric subdural electrodes is usually challenging and incomplete due to inherent anatomical and vascular limitations. We present a case of lesional mid-cingulate epilepsy confirmed by stereotactically implanted intracranial depth electrodes and subsequent surgical resection. Hypermotor symptomatology was seen during the first seven seconds of seizure onset while the seizure was still confined to the mid-cingulate gyrus contacts. The patient had brief contralateral clonic movements as seizure propagated to the primary motor cortex. There was a high concordance between the primary propagation contacts, as delineated by intracranial EEG, and the contacts, with higher coherence values in the connectivity matrix. Interestingly, cingulate-extra-cingulate connectivity and spread to the primary motor, premotor, and prefrontal cortex was seen preceding spread to other cingulate contacts, of which one was less than 15 mm from the onset contact. This report is one of a few published, documenting propagation of seizures arising from the mid-cingulate cortex. As illustrated by these data, hypermotor semiology correlated with direct activation of the cingulate cortex. Subsequent seizure propagation activated an extensive extra-cingulate rather than an intra-cingulate epileptogenic network. Interestingly, had the region of onset not sampled, the seizure onset would have appeared as non-localizing widespread rhythms over the fronto-parietal convexities. Further studies to explore the propagation of seizures arising from the cingulate gyrus and the physiological and pathological connectivity patterns within the cingulate gyrus in humans are needed, preferably using stereotactic implantation. Specific targets to be investigated are also discussed.

  11. The neocortex of cetartiodactyls: I. A comparative Golgi analysis of neuronal morphology in the bottlenose dolphin (Tursiops truncatus), the minke whale (Balaenoptera acutorostrata), and the humpback whale (Megaptera novaeangliae).

    Science.gov (United States)

    Butti, Camilla; Janeway, Caroline M; Townshend, Courtney; Wicinski, Bridget A; Reidenberg, Joy S; Ridgway, Sam H; Sherwood, Chet C; Hof, Patrick R; Jacobs, Bob

    2015-11-01

    The present study documents the morphology of neurons in several regions of the neocortex from the bottlenose dolphin (Tursiops truncatus), the North Atlantic minke whale (Balaenoptera acutorostrata), and the humpback whale (Megaptera novaeangliae). Golgi-stained neurons (n = 210) were analyzed in the frontal and temporal neocortex as well as in the primary visual and primary motor areas. Qualitatively, all three species exhibited a diversity of neuronal morphologies, with spiny neurons including typical pyramidal types, similar to those observed in primates and rodents, as well as other spiny neuron types that had more variable morphology and/or orientation. Five neuron types, with a vertical apical dendrite, approximated the general pyramidal neuron morphology (i.e., typical pyramidal, extraverted, magnopyramidal, multiapical, and bitufted neurons), with a predominance of typical and extraverted pyramidal neurons. In what may represent a cetacean morphological apomorphy, both typical pyramidal and magnopyramidal neurons frequently exhibited a tri-tufted variant. In the humpback whale, there were also large, star-like neurons with no discernable apical dendrite. Aspiny bipolar and multipolar interneurons were morphologically consistent with those reported previously in other mammals. Quantitative analyses showed that neuronal size and dendritic extent increased in association with body size and brain mass (bottlenose dolphin neocortex of cetaceans as compared to other mammals and that neuronal dendritic extent covaries with brain and body size.

  12. [The postnatal development of the lamina V pyramidal cells in the temporal cortex of the albino rat].

    Science.gov (United States)

    Nicolai, B

    1981-01-01

    1. The development of layer V pyramidal neurons is analysed quantitatively in albino rat temporal ("auditory") cortex from the 1st to the 90th postnatal days (12 stages). The length of apical dendrites, the number of primary dendrites and the total amount of apical dendrite spines are registered in Golgi-Cox preparations (55 animals). The diameters of the nucleus, length and width of the perikaryon and the relation between nucleus and perikaryon are measured in Nissl-series (45 animals). 2. Two types of development can be recognised by the examined parameters: --Length of apical dendrites, number of primary dendrites and of apical dendrite spines aspire more or less continuously to a maximum value. --Sizes of nucleus and perikaryon show intermediately a higher value than the terminal one ("overshooting growth"). 3. The postnatal development of the parameters suggests that the dendritic growth (also after initiated phase) starts from the perikaryon and relates with dendritic neuroplasmic flow. 4. In order to give general statements about the evolution of layer V pyramidal neuron's rates of growth are counted and their degree of maturity is determined. The biggest rates of growth are reached up to the 12th day post partum. At this time the pyramidal neurons have a relatively high degree of maturity. 5. There are two periods with especially marked alterations of structure of the layer V pyramidal neurons. These alterations are regarded as morphokineses according to Scharf. I. The morphological changes between the 8th and the 12th day are regarded as "morphokinesis as a reaction to planned crises" (2.2., according to Scharf 1970). In this case the critical situation is the beginning of hearing of the young rats, which is to be prepared. II. The morphological changes between the 24th and 36th day take place in the critical period of primary socialization (Scott et al. 1974). This could be understood as "morphokinesis as a reaction to environmental influences" (2

  13. Digital morphometric study of the extrasulcal surface of the cingulate gyrus in man

    Directory of Open Access Journals (Sweden)

    Spasojević Goran

    2010-01-01

    Full Text Available Introduction. The frequency of different morphological types and extrasulcal (visible surface area of the cingulate gyms, were measured and analyzed in order to obtain more precise data about morphology, right/left and sex differences in the human brain. Material and methods. The study included 42 brains (84 hemispheres from persons of both sexes and of different age (26 males, 16 females, 20-65 years old, without neuropathological changes. After fixation in 10% formaline (3-4 weeks and removal of meninges the brains were photographed under standard conditions by digital camera. Following determination of morphological type, regions of interest of cingulate gyrus were determined in stereotactic system system of coordinates and the extrasulcal surface was measured by digital AutoCAD planimetry. Results and discussion. Three basic morphological types of cingulate gyrus were found: the continuous type (34.5%, segmented type (35.7% and double paralel type (29.8%. There was no statistically significant difference in the frequency of morphological types related to the side (right/left or sex (p>0.05. The area of extrasulcal cortex of cingulate gyrus was statistically significantly (p<0.O5 larger on the left hemispheres (for 1.13 cm than on the right (left: 14.58 cm; right: 13.45 cm. The extrasulcal surface of the left cingulate gyrus was significantly larger (p0.05 in males (males 15.9 cm: females - 13.6 cm, while for the right cingulate gyrus this difference was not significant. Conclusion. Morphometry indicated sex and right/left differences of extrasulcal surface area of the human cingulate gyrus. However, the morphological analysis itself did not indicate corresponding differences, suggesting complexity of the problem of sex dimorphism and of right/left asymmetries in the domain of limbic cortex.

  14. Type I TARPs promote dendritic growth of early postnatal neocortical pyramidal cells in organotypic cultures.

    Science.gov (United States)

    Hamad, Mohammad I K; Jack, Alexander; Klatt, Oliver; Lorkowski, Markus; Strasdeit, Tobias; Kott, Sabine; Sager, Charlotte; Hollmann, Michael; Wahle, Petra

    2014-04-01

    The ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazole propionate glutamate receptors (AMPARs) have been implicated in the establishment of dendritic architecture. The transmembrane AMPA receptor regulatory proteins (TARPs) regulate AMPAR function and trafficking into synaptic membranes. In the current study, we employ type I and type II TARPs to modulate expression levels and function of endogenous AMPARs and investigate in organotypic cultures (OTCs) of rat occipital cortex whether this influences neuronal differentiation. Our results show that in early development [5-10 days in vitro (DIV)] only the type I TARP γ-8 promotes pyramidal cell dendritic growth by increasing spontaneous calcium amplitude and GluA2/3 expression in soma and dendrites. Later in development (10-15 DIV), the type I TARPs γ-2, γ-3 and γ-8 promote dendritic growth, whereas γ-4 reduced dendritic growth. The type II TARPs failed to alter dendritic morphology. The TARP-induced dendritic growth was restricted to the apical dendrites of pyramidal cells and it did not affect interneurons. Moreover, we studied the effects of short hairpin RNA-induced knockdown of endogenous γ-8 and showed a reduction of dendritic complexity and amplitudes of spontaneous calcium transients. In addition, the cytoplasmic tail (CT) of γ-8 was required for dendritic growth. Single-cell calcium imaging showed that the γ-8 CT domain increases amplitude but not frequency of calcium transients, suggesting a regulatory mechanism involving the γ-8 CT domain in the postsynaptic compartment. Indeed, the effect of γ-8 overexpression was reversed by APV, indicating a contribution of NMDA receptors. Our results suggest that selected type I TARPs influence activity-dependent dendritogenesis of immature pyramidal neurons.

  15. The Alphabet Pyramid of Team Development and Situation Leadership.

    Science.gov (United States)

    Jarvis, Roy

    2001-01-01

    This pyramid model of team development has four sides--awareness, behavior, communication, and direction--on a foundation of evaluation. The four equal sides of a pyramid represent the equal importance of the different roles, including leader, within a team. All team members are involved in evaluation and deciding what is important, which empowers…

  16. Commentary on "Management Education and the Base of the Pyramid"

    Science.gov (United States)

    Rosile, Grace Ann

    2008-01-01

    This commentary asks some critical questions concerning the article "Management Education and the Base of the Pyramid" included in this special issue. Are "bottom of the pyramid" (BOP) multidisciplinary action project (MAP) students prepared to critically assess the impact of their interventions beyond a narrow definition of profit in complex and…

  17. A multi octaves directive dielectric lens: The Pyramid Antenna

    NARCIS (Netherlands)

    Marliani, L.; Bruni, S.; Neto, A.

    2005-01-01

    Leaky wave antennas have been investigated for a long time and are typically an inexpensive solution for beam scanning antennas. We have designed a novel antenna topology, named the pyramid antenna, based on the broadband leaky concept. The pyramid antenna, currently covered by a patent application,

  18. Management Education and the Base of the Pyramid

    Science.gov (United States)

    Gordon, Michael D.

    2008-01-01

    Doing business at the base of the pyramid is a topic of increasing interest to business practitioners and academics. Base of the pyramid business offers the promise of great economic gains for companies and the possibility of a powerful new approach to alleviate poverty. At the same time, it may threaten local culture and independence while…

  19. 38 CFR 4.14 - Avoidance of pyramiding.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Avoidance of pyramiding. 4.14 Section 4.14 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES General Policy in Rating § 4.14 Avoidance of pyramiding. The evaluation of...

  20. Tribonacci-like sequences and generalized Pascal's pyramids

    Science.gov (United States)

    Anatriello, Giuseppina; Vincenzi, Giovanni

    2014-11-01

    A well-known result of Feinberg and Shannon states that the tribonacci sequence can be detected by the so-called Pascal's pyramid. Here we will show that any tribonacci-like sequence can be obtained by the diagonals of the Feinberg's triangle associated to a suitable generalized Pascal's pyramid. The results also extend similar properties of Fibonacci-like sequences.

  1. Tunneling and propping : A justification for pyramidal ownership

    NARCIS (Netherlands)

    Riyanto, Y.E.; Toolsema-Veldman, Linda

    2008-01-01

    This paper links existence of the pyramidal ownership structure to tunneling and propping. Tunneling refers to a transfer of resources from a lower-level firm to a higher-level firm in the pyramidal chain, whereas propping concerns a transfer in the opposite direction intended to bail out the receiv

  2. Visual processing of optic flow and motor control in the human posterior cingulate sulcus.

    Science.gov (United States)

    Field, David T; Inman, Laura A; Li, Li

    2015-10-01

    Previous studies have shown that the human posterior cingulate contains a visual processing area selective for optic flow (CSv). However, other studies performed in both humans and monkeys have identified a somatotopic motor region at the same location (CMA). Taken together, these findings suggested the possibility that the posterior cingulate contains a single visuomotor integration region. To test this idea we used fMRI to identify both visual and motor areas of the posterior cingulate in the same brains and to test the activity of those regions during a visuomotor task. Results indicated that rather than a single visuomotor region the posterior cingulate contains adjacent but separate motor and visual regions. CSv lies in the fundus of the cingulate sulcus, while CMA lies in the dorsal bank of the sulcus, slightly superior in terms of stereotaxic coordinates. A surprising and novel finding was that activity in CSv was suppressed during the visuomotor task, despite the visual stimulus being identical to that used to localize the region. This may provide an important clue to the specific role played by this region in the utilization of optic flow to control self-motion.

  3. Positive Association Between Posterior Subgenual Cingulate and Pituitary Volumes in Psychotic Major Depression

    Directory of Open Access Journals (Sweden)

    Konstantina Vassilopoulou

    2015-03-01

    Full Text Available Posterior subgenual cingulate cortex has been consistently linked with the pathophysiology of major depression in both structural and functional brain imaging studies. Likewise, the hyperactivity of the hypothalamic-pituitary-adrenal axis in major depression is well established, especially in its psychotic subtype. Moreover, posterior subgenual cingulate cortex exerts an inhibitory effect on the hypothalamic-pituitary-adrenal axis. While studies show pituitary volume to be a valid marker of hypothalamic-pituitary-adrenal axis activity, none have investigated the volumetric relationships between posterior subgenual cingulate cortex and pituitary volume in subtypes of major depressive disorder, which was precisely the aim of our study. We hypothesized a differential volumetric relationship in psychotic depression. We assessed posterior subgenual cingulate and pituitary volume using Magnetic Resonance Imaging scanning and investigated their volumetric relationships in 39 patients with major depressive disorder (17 psychotic and 22 melancholic and 18 normal controls. We found strong positive correlations between both left and right posterior subgenual volumes and pituitary volume only in the psychotic depression group (left: rs=0.77, p<0.001, right: rs=0.67, p=0.003. These positive associations were confirmed by regression analyses controlling for patient’s age and type of medications. By contrast, no significant volumetric associations were detected in the groups of melancholic patients and normal controls. Our findings provide support to the hypothesis that posterior subgenual cingulate is differentially involved in the pathophysiology of psychotic symptoms in major depressive disorder.

  4. Zbtb20 Defines a Hippocampal Neuronal Identity Through Direct Repression of Genes That Control Projection Neuron Development in the Isocortex

    DEFF Research Database (Denmark)

    Nielsen, Jakob V; Thomassen, Mads; Møllgård, Kjeld;

    2013-01-01

    reveal a novel regulatory mechanism by which Zbtb20 suppresses the acquisition of an isocortical fate during archicortical neurogenesis to ensure commitment to a CA1 pyramidal neuron fate. We further show that the expression pattern of Zbtb20 is evolutionary conserved in the fetal human hippocampus...

  5. Increased spike broadening and slow afterhyperpolarization in CA1 pyramidal cells of streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Kamal, A; Artola, A; Biessels, G J; Gispen, W H; Ramakers, G M J

    2003-01-01

    Diabetes mellitus is associated with impairments of cognitive function both in humans and animal models. In diabetic rats cognitive deficits are related to alterations in activity-dependent synaptic plasticity in the hippocampus. Many similarities with the pathophysiology of normal brain aging have been noted, and the view emerges that the effects of diabetes on the brain are best described as "accelerated brain aging."In the present study we examined whether CA1 pyramidal neurons from streptozotocin-induced diabetic rats display an increased slow afterhyperpolarization, often considered as a hallmark of neuronal aging. We found no differences in resting membrane potential, input resistance, membrane time-constant, and action potential amplitude and duration between CA1 pyramidal neurons from streptozotocin-induced diabetic and age-matched control rats. During a train of action potentials, however, there is an increased broadening of the action potentials in diabetic animals, so-called "spike broadening." The amplitude of the slow afterhyperpolarization elicited by a train of action potentials is indeed increased in diabetic animals. Interestingly, when the slow afterhyperpolarization is elicited by a Ca(2+) spike, there is no difference between control and diabetic rats. This indicates that the increased slow afterhyperpolarization in diabetes is likely to be due to an increased Ca(2+) influx resulting from the increased spike broadening. These data underscore the notion that the diabetic brain at the neuronal level shares properties with brain aging.

  6. The NGS Pyramid wavefront sensor for ERIS

    Science.gov (United States)

    Riccardi, A.; Antichi, J.; Quirós-Pacheco, F.; Esposito, S.; Carbonaro, L.; Agapito, G.; Biliotti, V.; Briguglio, R.; Di Rico, G.; Dolci, M.; Ferruzzi, D.; Pinna, E.; Puglisi, A.; Xompero, M.; Marchetti, E.; Fedrigo, E.; Le Louarn, M.; Conzelmann, R.; Delabre, B.; Amico, P.; Hubin, N.

    2014-07-01

    ERIS is the new Single Conjugate Adaptive Optics (AO) instrument for VLT in construction at ESO with the collaboration of Max-Planck Institut fuer Extraterrestrische Physik, ETH-Institute for Astronomy and INAF - Osservatorio Astrofisico di Arcetri. The ERIS AO system relies on a 40×40 sub-aperture Pyramid Wavefront Sensor (PWFS) for two operating modes: a pure Natural Guide Star high-order sensing for high Strehl and contrast correction and a low-order visible sensing in support of the Laser Guide Star AO mode. In this paper we present in detail the preliminary design of the ERIS PWFS that is developed under the responsibility of INAF-Osservatorio Astrofisico di Arcetri in collaboration with ESO.

  7. Transient Global Amnesia Associated with an Acute Infarction at the Cingulate Gyrus

    Directory of Open Access Journals (Sweden)

    Alejandro Gallardo-Tur

    2014-01-01

    Full Text Available Background. Transient global amnesia (TGA is a syndrome of sudden, unexplained isolated short-term memory loss. In the majority of TGA cases, no causes can be identified and neuroimaging, CSF studies and EEG are usually normal. We present a patient with TGA associated with a small acute infarct at the cingulate gyrus. Case Report. The patient, a 62 year-old man, developed two episodes of TGA. He had hypertension and hypercholesterolemia. He was found to have an acute ischemic stroke of small size (15 mm of maximal diameter at the right cerebral cingulate gyrus diagnosed on brain magnetic resonance imaging. No lesions involving other limbic system structures such as thalamus, fornix, corpus callosum, or hippocampal structures were seen. The remainder of the examination was normal. Conclusion. Unilateral ischemic lesions of limbic system structures may result in TGA. We must bear in mind that TGA can be an associated clinical disorder of cingulate gyrus infarct.

  8. Morphology and ontogeny of rat perirhinal cortical neurons.

    Science.gov (United States)

    Furtak, Sharon Christine; Moyer, James Russell; Brown, Thomas Huntington

    2007-12-10

    Golgi-impregnated neurons from rat perirhinal cortex (PR) were classified into one of 15 distinct morphological categories (N = 6,891). The frequency of neurons in each cell class was determined as a function of the layer of PR and the age of the animal, which ranged from postnatal day 0 (P0) to young adulthood (P45). The developmental appearance of Golgi-impregnated neurons conformed to the expected "inside-out" pattern of development, meaning that cells populated in deep before superficial layers of PR. The relative frequencies of different cell types changed during the first 2 weeks of postnatal development. The largest cells, which were pyramidal and spiny multipolar neurons, appeared earliest. Aspiny stellate neurons were the last to appear. The total number of Golgi-impregnated neurons peaked at P10-12, corresponding to the time of eye-opening. This early increase in the number of impregnated neurons parallels observations in other cortical areas. The relative frequency of the 15 cell types remained constant between P14 to P45. The proportion of pyramidal neurons in PR ( approximately 50%) was much smaller than is typical of neocortex ( approximately 70%). A correspondingly larger proportion of PR neurons were nonpyramidal cells that are less common in neocortex. The relative frequency distribution of cell types creates an overall impression of considerable morphological diversity, which is arguably related to the particular manner in which this periallocortical brain region processes and stores information.

  9. Choline acetyltransferase-containing neurons in the human parietal neocortex

    Directory of Open Access Journals (Sweden)

    V Benagiano

    2009-06-01

    Full Text Available A number of immunocytochemical studies have indicated the presence of cholinergic neurons in the cerebral cortex of various species of mammals. Whether such cholinergic neurons in the human cerebral cortex are exclusively of subcortical origin is still debated. In this immunocytochemical study, the existence of cortical cholinergic neurons was investigated on surgical samples of human parietal association neocortex using a highly specific monoclonal antibody against choline acetyltransferase (ChAT, the acetylcholine biosynthesising enzyme. ChAT immunoreactivity was detected in a subpopulation of neurons located in layers II and III. These were small or medium-sized pyramidal neurons which showed cytoplasmic immunoreactivity in the perikarya and processes, often in close association to blood microvessels. This study, providing demonstration of ChAT neurons in the human parietal neocortex, strongly supports the existence of intrinsic cholinergic innervation of the human neocortex. It is likely that these neurons contribute to the cholinergic innervation of the intracortical microvessels.

  10. The cell-autonomous role of excitatory synaptic transmission in the regulation of neuronal structure and function

    OpenAIRE

    2013-01-01

    The cell-autonomous role of synaptic transmission in the regulation of neuronal structural and electrical properties is unclear. We have now employed a genetic approach to eliminate glutamatergic synaptic transmission onto individual CA1 pyramidal neurons in a mosaic fashion in vivo. Surprisingly, while electrical properties are profoundly affected in these neurons, as well as inhibitory synaptic transmission, we found little perturbation of neuronal morphology, demonstrating a functional seg...

  11. Fabrication and measurement of a flexoelectric micro-pyramid composite

    Directory of Open Access Journals (Sweden)

    Wenbin Huang

    2014-12-01

    Full Text Available A fabrication method by combining precision mechanical dicing and wet etching was developed to prepare micro-pyramid structures based on (Ba0.67Sr0.33TiO3 ceramics. The effective piezoelectric properties of flexoelectric pyramid structures in ten micrometers scale were investigated and measured through converse flexoelectric effect. The scaling effect of the flexoelectric response was demonstrated as the structure size shrinks down. The results do suggest the great potential of flexoelectric micro pyramids as an alternative to lead-free piezoelectric material.

  12. Ischemic stroke of the pyramidal decussation causing quadriplegia and anarthria.

    Science.gov (United States)

    Wilkins, Emilia G; Kamel, Hooman; Johnson, Eric C B; Shalev, Sarah M; Josephson, S Andrew

    2012-10-01

    A 52-year-old man with a history of hypertension and previously irradiated head and neck cancer presented with quadriplegia and anarthria sparing the face and sensory functions. Brain magnetic resonance imaging (MRI) demonstrated acute infarction of the pyramidal decussation. We describe the clinical and radiological characteristics of infarction at the pyramidal decussation and review the arterial supply to this region in the lower brainstem. Although rare, infarction of the pyramidal decussation should be considered in the differential diagnosis when patients present with atraumatic pure motor quadriplegia.

  13. Papillary Carcinoma Arising from the Pyramidal Lobe of the Thyroid

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Gi; Lee, Sarah; Kim, Eun Kyung; Moon, Hee Jung; Kwak, Jin Young [Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2012-03-15

    The authors present a rare case of papillary carcinoma arising from the pyramidal lobe of the thyroid in a 54-year-old woman, who presented with a right submental palpable mass. An ultrasound evaluation depicted a 3 cm mixed echoic mass from the thyroid cartilage level without a focal lesion in the thyroid gland. Surgical specimens obtained during bilateral thyroidectomy confirmed papillary carcinoma of the pyramidal lobe. To the authors' knowledge, this is the first case report to describe papillary carcinoma arising from the pyramidal lobe of the thyroid gland

  14. NONLINEAR BENDING THEORY OF DIAGONAL SQUARE PYRAMID RETICULATED SHALLOW SHELLS

    Institute of Scientific and Technical Information of China (English)

    肖潭; 刘人怀

    2001-01-01

    Double-deck reticulated shells are a main form of large space structures. One of the shells is the diagonal square pyramid reticulated shallow shell, whose its upper and lower faces bear most of the load but its core is comparatively flexible. According to its geometrical and mechanical characteristics, the diagonal square pyramid reticulated shallow shell is treated as a shallow sandwich shell on the basis of three basic assumptions. Its constitutive relations are analyzed from the point of view of energy and internal force equivalence. Basic equations of the geometrically nonlinear bending theory of the diagonal square pyramid reticulated shallow shell are established by means of the virtual work principle .

  15. Inclinations of Egyptian pyramids and finding of the divine essence

    OpenAIRE

    GRIGORIEV STANISLAV ARKADIEVICH

    2015-01-01

    The aim of this research is discovery of astronomical reasons in orientation of slopes of Egyptian pyramids used as tombs for pharaohs of Ancient Egypt. The article contains results of statistical analysis of change in inclination of slopes of the pyramids (3rd 2nd millennia BC) depending on time of their building. The first year of the corresponding pharaoh’s reign has been accepted, as usually it is considered that building of pyramids ones started during either the first or second year of ...

  16. Expression and changes of hyperoxidized peroxiredoxins in non-pyramidal and polymorphic cells in the gerbil hippocampus during normal aging.

    Science.gov (United States)

    Yoo, Ki-Yeon; Park, Ok Kyu; Yu, Jiatian; Yan, Bingchun; Li, Hua; Lee, Choong Hyun; Choi, Jung Hoon; Kim, Dae Won; Hwang, In Koo; Won, Moo-Ho

    2009-05-01

    Oxidative stress is one of predisposing factors to age-related neurodegeneration in the brain. In particular, thiol-containing groups are susceptible to oxidative stress, which induces the formation of the disulfide bond and/or hyperoxidized form of thiol-containing proteins. We observed the protein thiol levels in the hippocampal homogenates and also investigated changes in hyperoxidized form of peroxiredoxin (Prx-SO(3)) immunoreactivity and proteins levels in the gerbil hippocampal subregions during normal aging. Levels of total thiol, non-protein thiol, and protein thiol were decreased in the hippocampal homogenates with age. At post-natal month 1 (PM 1), pyramidal and non-pyramidal cells in the hippocampal CA1 region (CA1) showed Prx-SO(3) immunoreactivity. Prx-SO(3) immunoreactivity in the cells was decreased by PM 12, thereafter, Prx-SO(3) immunoreactivity in the cells increased again with age. In the CA2/3, Prx-SO(3) immunoreactivity in pyramidal cells was not significantly changed; however, the immunoreactivity in pyramidal cells was very low at PM 12. Prx-SO(3) immunoreactivity in the dentate gyrus (DG) was distinctly changed during aging. At PM 1, Prx-SO(3) immunoreactivity in granule and polymorphic cells was weak and strong, respectively. The immunoreactivity in the neurons was decreased with age, not shown in any neurons at PM 12. Thereafter, Prx-SO(3) immunoreactivity increased again with age. In addition, Prx-SO(3) protein level in the hippocampus was lowest at PM 12. These results suggest that thiol-containing proteins are changed during aging and Prx-SO(3) immunoreactivity was different according to cells in the hippocampal subregion during aging.

  17. Subpallial origin of a population of projecting pioneer neurons during corticogenesis

    OpenAIRE

    Morante-Oria, Javier; Carleton, Alan; Ortino, Barbara; Eric J. Kremer; Fairén, Alfonso; Lledo, Pierre-Marie

    2003-01-01

    Pyramidal neurons of the mammalian cerebral cortex are generated in the ventricular zone of the pallium whereas the subpallium provides the cortex with inhibitory interneurons. The marginal zone contains a subpial stream of migratory interneurons and two different classes of transient neurons, the pioneer neurons provided with corticofugal axons, and the reelin-expressing Cajal–Retzius cells. We found in cultured slices that the medial ganglionic eminence provides the reelin-negative pioneer ...

  18. A voltage-dependent persistent sodium current in mammalian hippocampal neurons

    OpenAIRE

    1990-01-01

    Currents generated by depolarizing voltage pulses were recorded in neurons from the pyramidal cell layer of the CA1 region of rat or guinea pig hippocampus with single electrode voltage-clamp or tight- seal whole-cell voltage-clamp techniques. In neurons in situ in slices, and in dissociated neurons, subtraction of currents generated by identical depolarizing voltage pulses before and after exposure to tetrodotoxin revealed a small, persistent current after the transient current. These curren...

  19. Towards bridging the gap between acid-base transporters and neuronal excitability modulation.

    Science.gov (United States)

    Liu, Ying; Chen, Li-Ming

    2014-01-01

    pH homeostasis is a fundamental regulator of the function of the central nervous system. Dysfunction of acid-base transporters often results in disturbance of neuronal excitability. In a latest issue of Journal of Neuroscience, Jones et al. report that increasing intracellular bicarbonate concentration substantially stimulates the excitability of pyramidal neurons from mouse hippocampus by inhibiting KCNQ potassium channel. The finding shed important new light in understanding the molecular mechanism underlying the regulation of neuronal excitability by acid-base transporters.

  20. Responses to Gamma-Aminobutyric Acid of Rat Visual Cortical Neurons in Tissue Slices

    Science.gov (United States)

    1986-04-01

    Neurol. 234: 242-263. Peters, A. and Proskauer, c. C. (1980) Synaptic relationships between a multipolar stellate cell and a pyramidal neuron in rat...APR 1986 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Responses to Gamma-Aminobutyric Acid of Rat Visual Cortical Neurons in...AIR FORCE MEDICAL CENTER Title of Thesis: Responses to Gamma-Aminobutyric Acid of Rat Visual Cortical Neurons in Tissue Slices Name of Candidate

  1. Resting State Functional Connectivity within the Cingulate Cortex Jointly Predicts Agreeableness and Stressor-Evoked Cardiovascular Reactivity

    OpenAIRE

    Ryan, John P.; Sheu, Lei K.; Peter J Gianaros

    2010-01-01

    Exaggerated cardiovascular reactivity to stress confers risk for cardiovascular disease. Further, individual differences in stressor-evoked cardiovascular reactivity covary with the functionality of cortical and limbic brain areas, particularly within the cingulate cortex. What remains unclear, however, is how individual differences in personality traits interact with cingulate functionality in the prediction of stressor-evoked cardiovascular reactivity. Accordingly, we tested the association...

  2. Localization of brain-derived neurotrophic factor to distinct terminals of mossy fiber axons implies regulation of both excitation and feedforward inhibition of CA3 pyramidal cells.

    Science.gov (United States)

    Danzer, Steve C; McNamara, James O

    2004-12-15

    Hippocampal dentate granule cells directly excite and indirectly inhibit CA3 pyramidal cells via distinct presynaptic terminal specializations of their mossy fiber axons. This mossy fiber pathway contains the highest concentration of brain-derived neurotrophic factor (BDNF) in the CNS, yet whether BDNF is positioned to regulate the excitatory and/or inhibitory pathways is unknown. To localize BDNF, confocal microscopy of green fluorescent protein transgenic mice was combined with BDNF immunohistochemistry. Approximately half of presynaptic granule cell-CA3 pyramidal cell contacts were found to contain BDNF. Moreover, enhanced neuronal activity virtually doubled the percentage of BDNF-immunoreactive terminals contacting CA3 pyramidal cells. To our surprise, BDNF was also found in mossy fiber terminals contacting inhibitory neurons. These studies demonstrate that mossy fiber BDNF is poised to regulate both direct excitatory and indirect feedforward inhibitory inputs to CA3 pyramdal cells and reveal that seizure activity increases the pool of BDNF-expressing granule cell presynaptic terminals contacting CA3 pyramidal cells.

  3. Posterior cingulated cortex functional connectivity in deficit schizophrenia: a resting state functional magnetic resonance imaging study

    Institute of Scientific and Technical Information of China (English)

    唐小伟

    2014-01-01

    Objective To explore the discrepancies of the network of resting brain functional connectivity related to posterior cingulated cortex(PCC)between deficit schizophrenia patients and normal control.Methods Thirty male patients of deficit schizophrenia,nondeficit schizophrenia and 30 healthy controls were enrolled,and the age,education level and sex were matched between three

  4. Attention and sentence processing deficits in Parkinson's disease: the role of anterior cingulate cortex.

    Science.gov (United States)

    Grossman, M; Crino, P; Reivich, M; Stern, M B; Hurtig, H I

    1992-01-01

    Parkinson's disease (PD) is a complex neurodegenerative condition involving a motor disorder that is related to reduced dopaminergic input to the striatum. Intellectual deficits are also seen in PD, but the pathophysiology of these difficulties is poorly understood. Regional cerebral blood flow (rCBF) was studied in neurologically intact subjects during the performance of attention-demanding, sentence processing tasks using positron emission tomography (PET). The results demonstrated significantly increased rCBF in a distributed set of cerebral regions during the detection of an adjective or a particular agent in a sentence, including anterior cingulate cortex, left inferior and middle frontal cortex, left inferior temporo-occipital cortex, posterolateral temporal cortex, left caudate, and left thalamus. We identified defects in this cerebral network by studying PD patients with two PET techniques. Resting PET studies revealed a significant correlation between regional cerebral glucose metabolism in anterior cingulate cortex and deficits in attending to subtle grammatical aspects of sentences. Studies of PD patients with the PET activation technique revealed little change in anterior cingulate and left frontal CBF during performance of the adjective detection or agent detection tasks. These data suggest that a defect in anterior cingulate cortex contributes to the cognitive impairments observed in PD.

  5. Anterior Cingulate Volumetric Alterations in Treatment-Naive Adults with ADHD: A Pilot Study

    Science.gov (United States)

    Makris, Nikos; Seidman, Larry J.; Valera, Eve M.; Biederman, Joseph; Monuteaux, Michael C.; Kennedy, David N.; Caviness, Verne S., Jr.; Bush, George; Crum, Katherine; Brown, Ariel B.; Faraone, Stephen V.

    2010-01-01

    Objective: We sought to examine preliminary results of brain alterations in anterior cingulate cortex (ACC) in treatment-naive adults with ADHD. The ACC is a central brain node for the integration of cognitive control and allocation of attention, affect and drive. Thus its anatomical alteration may give rise to impulsivity, hyperactivity and…

  6. Adaptive coding of action values in the human rostral cingulate zone

    NARCIS (Netherlands)

    Jocham, G.; Neumann, J.; Klein, T.A.; Danielmeier, C.; Ullsperger, M.

    2009-01-01

    Correctly selecting appropriate actions in an uncertain environment requires gathering experience about the available actions by sampling them over several trials. Recent findings suggest that the human rostral cingulate zone (RCZ) is important for the integration of extended action-outcome associat

  7. Errors without Conflict: Implications for Performance Monitoring Theories of Anterior Cingulate Cortex

    Science.gov (United States)

    van Veen, V.; Holroyd, C.B.; Cohen, J.D.; Stenger, V.A.; Carter, C.S.

    2004-01-01

    Recent theories of the neural basis of performance monitoring have emphasized a central role for the anterior cingulate cortex (ACC). Replicating an earlier event-related potential (ERP) study, which showed an error feedback negativity that was modeled as having an ACC generator, we used event-related fMRI to investigate whether the ACC would…

  8. Frontal and rostral anterior cingulate (rACC) theta EEG in depression: implications for treatment outcome?

    NARCIS (Netherlands)

    Arns, M.W.; Etkin, A.; Hegerl, U.; Williams, L.M.; DeBattista, C.; Palmer, D.M.; Fitzgerald, P.B.; Harris, A.; deBeuss, R.; Gordon, E.

    2015-01-01

    In major depressive disorder (MDD), elevated theta current density in the rostral anterior cingulate (rACC), as estimated by source localization of scalp-recorded electroencenphalogram (EEG), has been associated with response to antidepressant treatments, whereas elevated frontal theta has been link

  9. A Remark on the Mallat Pyramidal Algorithm of Wavelet Analysis

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    The exact relationships between the lenthgs of scale sequences and wavelet sequences in the Mallat pyramidal algorithm for computing wavelet trans-form coefficients are obtained,and the maximum possible scale of arbitrary discrete signal is derived.

  10. PYRAMIDAL-HOLLOW-BEAM DIPOLE TRAP FOR ALKALI ATOMS

    Institute of Scientific and Technical Information of China (English)

    YIN JIAN-PING; GAO WEI-JIAN; WANG YU-ZHU; ZHU YI-FU; WANG YI-QIU

    2000-01-01

    We propose a dark gravito-optical dipole trap, for alkali atoms, consisting of a blue-detuned, pyramidal-hollow laser beam propagating upward and the gravity field. When cold atoms from a magneto-optical trap are loaded into the pyramidal-hollow beam and bounce inside the pyramidal-hollow beam, they experience efficient Sisyphus cooling and geometric cooling induced by the pyramidal-hollow beam and the weak repumping beam propagating downward. Our study shows that an ultracold and dense atomic sample with an equilibrium 3D momentum of ~ 3hk and an atomic density above the point of Bose-Einstein condensation may be obtained in this pure optical trap.

  11. Residential solar-heating system uses pyramidal optics

    Science.gov (United States)

    1981-01-01

    Report describes reflective panels which optimize annual solar energy collection in attic installation. Subunits include collection, storage, distribution, and 4-mode control systems. Pyramid optical system heats single-family and multi-family dwellings.

  12. The Fishery of Truckee River and Pyramid Lake, Nevada

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report provides an overview of the Washoe Project Act. Trout populations in Pyramid Lake began to decline in the 1930s due to poor water quality and poor...

  13. Improving Drought Tolerance of Rice by Designed QTL Pyramiding

    Institute of Scientific and Technical Information of China (English)

    Z.K. Li; Y. Sun; L.H. Zhu; D. Dwivedi; Y.M. Gao; T.Q. Zheng; R. Lafitte; J.L. Xu; D. Mackill; B.Y. Fu; J.Domingo

    2007-01-01

    @@ Drought is the most important factor limiting rice yields in the rainfed areas of Asia. To overcome the problem, we developed a new strategy 'designed QTL pyramiding' to more efficiently develop drought tolerant (DT)rice cultivars.

  14. Impact of inhibitory constraint of interneurons on neuronal excitability.

    Science.gov (United States)

    Lee, Vallent; Maguire, Jamie

    2013-12-01

    Tonic inhibition is thought to dampen the excitability of principal neurons; however, little is known about the role of tonic GABAergic inhibition in interneurons and the impact on principal neuron excitability. In many brain regions, tonic GABAergic inhibition is mediated by extrasynaptic, δ-subunit-containing GABAA receptors (GABAARs). In the present study we demonstrate the importance of GABAAR δ-subunit-mediated tonic inhibition in interneurons. Selective elimination of the GABAAR δ-subunit from interneurons was achieved by crossing a novel floxed Gabrd mouse model with GAD65-Cre mice (Gabrd/Gad mice). Deficits in GABAAR δ-subunit expression in GAD65-positive neurons result in a decrease in tonic GABAergic inhibition and increased excitability of both molecular layer (ML) and stratum radiatum (SR) interneurons. Disinhibition of interneurons results in robust alterations in the neuronal excitability of principal neurons and decreased seizure susceptibility. Gabrd/Gad mice have enhanced tonic and phasic GABAergic inhibition in both CA1 pyramidal neurons and dentate gyrus granule cells (DGGCs). Consistent with alterations in hippocampal excitability, CA1 pyramidal neurons and DGGCs from Gabrd/Gad mice exhibit a shift in the input-output relationship toward decreased excitability compared with those from Cre(-/-) littermates. Furthermore, seizure susceptibility, in response to 20 mg/kg kainic acid, is significantly decreased in Gabrd/Gad mice compared with Cre(-/-) controls. These data demonstrate a critical role for GABAAR δ-subunit-mediated tonic GABAergic inhibition of interneurons on principal neuronal excitability and seizure susceptibility.

  15. Frequency-dependent signal processing in apical dendrites of hippocampal CA1 pyramidal cells.

    Science.gov (United States)

    Watanabe, H; Tsubokawa, H; Tsukada, M; Aihara, T

    2014-10-10

    Depending on an animal's behavioral state, hippocampal CA1 pyramidal cells receive distinct patterns of excitatory and inhibitory synaptic inputs. The time-dependent changes in the frequencies of these inputs and the nonuniform distribution of voltage-gated channels lead to dynamic fluctuations in membrane conductance. In this study, using a whole-cell patch-clamp method, we attempted to record and analyze the frequency dependencies of membrane responsiveness in Wistar rat hippocampal CA1 pyramidal cells following noise current injection directly into dendrites and somata under pharmacological blockade of all synaptic inputs. To estimate the frequency-dependent properties of membrane potential, membrane impedance was determined from the voltage response divided by the input current in the frequency domain. The cell membrane of most neurons showed low-pass filtering properties in all regions. In particular, the properties were strongly expressed in the somata or proximal dendrites. Moreover, the data revealed nonuniform distribution of dendritic impedance, which was high in the intermediate segment of the apical dendritic shaft (∼220-260μm from the soma). The low-pass filtering properties in the apical dendrites were more enhanced by membrane depolarization than those in the somata. Coherence spectral analysis revealed high coherence between the input signal and the output voltage response in the theta-gamma frequency range, and large lags emerged in the distal dendrites in the gamma frequency range. Our results suggest that apical dendrites of hippocampal CA1 pyramidal cells integrate synaptic inputs according to the frequency components of the input signal along the dendritic segments receiving the inputs.

  16. ASTRONOMICAL ALGORITHMS OF EGYPTIAN PYRAMIDS SLOPES AND THEIR MODULES DIVIDER

    OpenAIRE

    Aboulfotouh, Hossam M. K.

    2015-01-01

    This paper is an attempt to show the astronomical design principles that are encoded in the geometrical forms of the largest five pyramids of the fourth Egyptian dynasty, in Giza and Dahshur plateaus, based on using the pyramids’ design-modules that are mentioned in the so-called Rhind Mathematical Papyrus. It shows the astronomical algorithms for quantifying the slopes of pyramids, with reference to specific range of earth’s axial tilt, within spherical co-ordinates system. Besid...

  17. Positive Allosteric Modulator of GABA Lowers BOLD Responses in the Cingulate Cortex.

    Directory of Open Access Journals (Sweden)

    Susanna A Walter

    Full Text Available Knowledge about the neural underpinnings of the negative blood oxygen level dependent (BOLD responses in functional magnetic resonance imaging (fMRI is still limited. We hypothesized that pharmacological GABAergic modulation attenuates BOLD responses, and that blood concentrations of a positive allosteric modulator of GABA correlate inversely with BOLD responses in the cingulate cortex. We investigated whether or not pure task-related negative BOLD responses were co-localized with pharmacologically modulated BOLD responses. Twenty healthy adults received either 5 mg diazepam or placebo in a double blind, randomized design. During fMRI the subjects performed a working memory task. Results showed that BOLD responses in the cingulate cortex were inversely correlated with diazepam blood concentrations; that is, the higher the blood diazepam concentration, the lower the BOLD response. This inverse correlation was most pronounced in the pregenual anterior cingulate cortex and the anterior mid-cingulate cortex. For subjects with diazepam plasma concentration > 0.1 mg/L we observed negative BOLD responses with respect to fixation baseline. There was minor overlap between cingulate regions with task-related negative BOLD responses and regions where the BOLD responses were inversely correlated with diazepam concentration. We interpret that the inverse correlation between the BOLD response and diazepam was caused by GABA-related neural inhibition. Thus, this study supports the hypothesis that GABA attenuates BOLD responses in fMRI. The minimal overlap between task-related negative BOLD responses and responses attenuated by diazepam suggests that these responses might be caused by different mechanisms.

  18. Pivotal role of anterior cingulate cortex in working memory after traumatic brain injury in youth

    Directory of Open Access Journals (Sweden)

    Fabienne eCazalis

    2011-01-01

    Full Text Available In this fMRI study, the functions of the Anterior Cingulate Cortex were studied in a group of adolescents who had sustained a moderate to severe Traumatic Brain Injury. A spatial working memory task with varying working memory loads, representing experimental conditions of increasing difficulty, was administered.In a cross-sectional comparison between the patients and a matched control group, patients performed worse than Controls, showing longer reaction times and lower response accuracy on the spatial working memory task. Brain imaging findings suggest a possible double-dissociation: activity of the Anterior Cingulate Cortex in the Traumatic Brain Injury group, but not in the Control group, was associated with task difficulty; conversely, activity of the left Sensorimotor Cortex in the Control group, but not in the TBI group, was correlated with task difficulty.In addition to the main cross-sectional study, a longitudinal study of a group of adolescent patients with moderate to severe Traumatic Brain Injury was done using fMRI and the same spatial working memory task. The patient group was studied at two time points: one time point during the post-acute phase and one time point 12 months later, during the chronic phase. Results indicated that patients' behavioral performance improved over time, suggesting cognitive recovery. Brain imaging findings suggest that, over this 12 month period, patients recruited less of the Anterior Cingulate Cortex and more of the left Sensorimotor Cortex in response to increasing task difficulty.The role of Anterior Cingulate Cortex in executive functions following a moderate to severe brain injury in adolescence is discussed within the context of conflicting models of the Anterior Cingulate Cortex functions in the existing literature.

  19. Stress-Related Functional Connectivity Changes Between Auditory Cortex and Cingulate in Tinnitus.

    Science.gov (United States)

    Vanneste, Sven; De Ridder, Dirk

    2015-08-01

    The question arises whether functional connectivity (FC) changes between the distress and tinnitus loudness network during resting state depends on the amount of distress tinnitus patients' experience. Fifty-five patients with constant chronic tinnitus were included in this study. Electroencephalography (EEG) recordings were performed and seed-based (at the auditory cortex) source localized FC (lagged phase synchronization) was computed for the different EEG frequency bands. Results initially demonstrate that the correlation between loudness and distress is nonlinear. Loudness correlates with beta3 and gamma band activity in the auditory cortices, and distress with alpha1 and beta3 changes in the subgenual, dorsal anterior, and posterior cingulate cortex. In comparison to nontinnitus controls, seed-based FC differed between the left auditory cortices for the alpha1 and beta3 bands in a network encompassing the posterior cingulate cortex extending into the parahippocampal area, the anterior cingulate, and insula. Furthermore, distress changes the FC between the auditory cortex, encoding loudness, and different parts of the cingulate, encoding distress: the subgenual anterior, the dorsal anterior, and the posterior cingulate. These changes are specific for the alpha1 and beta3 frequency bands. These results fit with a recently proposed model that states that tinnitus is generated by multiple dynamically active separable but overlapping networks, each characterizing a specific aspect of the unified tinnitus percept, but adds to this concept that the interaction between these networks is a complex interplay of correlations and anti-correlations between areas involved in distress and loudness depending on the distress state of the tinnitus patient.

  20. [TURNING THE PYRAMID IN PRENATAL CARE].

    Science.gov (United States)

    Ohel-Shani, Iris; Daniel-Spiegel, Etty

    2015-10-01

    Most complications of pregnancy manifest towards the latter part of pregnancy. Nevertheless, present day diagnostic techniques, such as sonography, Doppler, biochemical screening tests, and the newly developed ability to study free fetal DNA in maternal blood, enables early identification of high risk groups for maternal and fetal morbidity, as well as fetal genetic and anatomical pathology. Dr. Nicolaides has coined this changing trend with the term "Turning the Pyramid". Early screening enables earlier and more directed follow-up with the application of relevant diagnostic tests. Obvious advantages include the potential to reduce maternal-fetal morbidity before it becomes apparent clinically. Additionally, the earlier diagnosis of fetal pathology, allows more time for parents and medical staff to assess the situation, and reach a decision regarding the continuation of the pregnancy. A possible drawback of such an approach, of early identification of high risk groups, is the uncertainty it arouses, sometimes for a long duration, with the accompanying apprehension and stress parents have to endure. A multidisciplinary team, consisting of specialists in fetal-maternal medicine, genetics, ultrasound, and perinatology, will be needed in order to best deal with the often complex information, which is becoming increasingly available at a very early stage of pregnancy.

  1. Influence of alignment of the pyramid on its beneficial effects.

    Science.gov (United States)

    Bhat, Surekha; Rao, Guruprasad; Murthy, K Dilip; Bhat, P Gopalakrishna

    2007-05-01

    The present study was aimed to find out whether a change in the alignment of the pyramid from the north-south axis causes any variation in the effects produced by it on plasma cortisol levels and markers of oxidative stress in erythrocytes of adult-female Wistar rats. Plasma cortisol and erythrocyte TBARS levels were significantly lower whereas erythrocyte GSH was significantly higher in rats kept in pyramid that was aligned on the four cardinal points--north, east, south and west, as compared to normal control rats. Although there was a significant difference in the plasma cortisol level between normal control group and the group of rats kept in randomly aligned pyramid, there was no significant difference between these two groups for the other parameters. Erythrocyte TBARS levels in the group of rats kept in the randomly aligned pyramid was significantly higher than that in the group kept in the magnetically aligned pyramid. The results suggest that the north-south alignment of the pyramid is crucial for its expected effects.

  2. Macro-pyramid in GaN Film

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jing; YANG Zhi-Jian; XU Shi-Fa; ZHU Xing; ZHANG Guo-Yi

    2001-01-01

    A thin film of GaN with the thickness of 1.0μm was grown on α-Al2Oa substrate by metal organic chemical vapour disposition and then a thick GaN film with thickness of 12μm was grown in the halide vapour phase epitaxy system. Some macro-pyramids appeared on the surface of the sample. The macro-pyramids made the surfaceof the GaN film rough, which was harmful to the devices made by GaN materials. These defects changed the distribution of carrier concentration and affected the optical properties of GaN. The step height of the pyramids was about 30-40 nm measured by atomic force microscopy. A simple model was proposed to explain the macro- pyramid phenomenon compared with the growth spiral The growth of the macro-pyramid was relative to the physical conditions in the reaction zone. Both increasing growth temperature and low pressure may reduce the pyramid size.

  3. Oenanthe Javanica Extract Protects Against Experimentally Induced Ischemic Neuronal Damage via its Antioxidant Effects

    Directory of Open Access Journals (Sweden)

    Joon Ha Park

    2015-01-01

    Full Text Available Background: Water dropwort (Oenanthe javanica as a popular traditional medicine in Asia shows various biological properties including antioxidant activity. In this study, we firstly examined the neuroprotective effect of Oenanthe javanica extract (OJE in the hippocampal cornus ammonis 1 region (CA1 region of the gerbil subjected to transient cerebral ischemia. Methods: Gerbils were established by the occlusion of common carotid arteries for 5 min. The neuroprotective effect of OJE was estimated by cresyl violet staining. In addition, 4 antioxidants (copper, zinc superoxide dismutase [SOD], manganese SOD, catalase, and glutathione peroxidase immunoreactivities were investigated by immunohistochemistry. Results: Pyramidal neurons in the CA1 region showed neuronal death at 5 days postischemia; at this point in time, all antioxidants immunoreactivities disappeared in CA1 pyramidal neurons and showed in many nonpyramidal cells. Treatment with 200 mg/kg, not 100 mg/kg, OJE protected CA1 pyramidal neurons from ischemic damage. In addition, 200 mg/kg OJE treatment increased or maintained antioxidants immunoreactivities. Especially, among the antioxidants, glutathione peroxidase immunoreactivity was effectively increased in the CA1 pyramidal neurons of the OJE-treated sham-operated and ischemia-operated groups. Conclusion: Our present results indicate that treatment with OJE can protect neurons from transient ischemic damage and that the neuroprotective effect may be closely associated with increased or maintained intracellular antioxidant enzymes by OJE.

  4. Oenanthe Javanica Extract Protects Against Experimentally Induced Ischemic Neuronal Damage via its Antioxidant Effects

    Institute of Scientific and Technical Information of China (English)

    Joon Ha Park; Jeong Hwi Cho; In Hye Kim; Ji Hyeon Ahn; Jae-Chul Lee; Bai Hui Chen; Bich-Na Shin

    2015-01-01

    Background:Water dropwort (Oenanthejavanica) as a popular traditional medicine in Asia shows various biological properties including antioxidant activity.In this study,we firstly examined the neuroprotective effect of Oenanthejavanica extract (OJE) in the hippocampal cornus ammonis 1 region (CA1 region) of the gerbil subjected to transient cerebral ischemia.Methods:Gerbils were established by the occlusion of common carotid arteries for 5 min.The neuroprotective effect of OJE was estimated by cresyl violet staining.In addition,4 antioxidants (copper,zinc superoxide dismutase [SOD],manganese SOD,catalase,and glutathione peroxidase) immunoreactivities were investigated by immunohistochemistry.Results:Pyramidal neurons in the CA1 region showed neuronal death at 5 days postischemia;at this point in time,all antioxidants immunoreactivities disappeared in CA1 pyramidal neurons and showed in many nonpyramidal cells.Treatment with 200 mg/kg,not 100 mg/kg,OJE protected CA1 pyramidal neurons from ischemic damage.In addition,200 mg/kg OJE treatment increased or maintained antioxidants immunoreactivities.Especially,among the antioxidants,glutathione peroxidase immunoreactivity was effectively increased in the CA1 pyramidal neurons of the OJE-treated sham-operated and ischemia-operated groups.Conclusion:Our present results indicate that treatment with OJE can protect neurons from transient ischemic damage and that the neuroprotective effect may be closely associated with increased or maintained intracellular antioxidant enzymes by OJE.

  5. Upregulation of excitatory neurons and downregulation of inhibitory neurons in barrel cortex are associated with loss of whisker inputs

    Directory of Open Access Journals (Sweden)

    Zhang Guanjun

    2013-01-01

    Full Text Available Abstract Loss of a sensory input causes the hypersensitivity in other modalities. In addition to cross-modal plasticity, the sensory cortices without receiving inputs undergo the plastic changes. It is not clear how the different types of neurons and synapses in the sensory cortex coordinately change after input deficits in order to prevent loss of their functions and to be used for other modalities. We studied this subject in the barrel cortices from whiskers-trimmed mice vs. controls. After whisker trimming for a week, the intrinsic properties of pyramidal neurons and the transmission of excitatory synapses were upregulated in the barrel cortex, but inhibitory neurons and GABAergic synapses were downregulated. The morphological analyses indicated that the number of processes and spines in pyramidal neurons increased, whereas the processes of GABAergic neurons decreased in the barrel cortex. The upregulation of excitatory neurons and the downregulation of inhibitory neurons boost the activity of network neurons in the barrel cortex to be high levels, which prevent the loss of their functions and enhances their sensitivity to sensory inputs. These changes may prepare for attracting the innervations from sensory cortices and/or peripheral nerves for other modalities during cross-modal plasticity.

  6. The transcriptional repressor Zbtb20 is essential for specification of hippocampal projection neurons and territory in mice

    DEFF Research Database (Denmark)

    Rosenthal, Eva Helga

    for specification of both hippocampal pyramidal neurons and territory in a mouse knockout model. Homozygous Zbtb20-/- mice are viable at birth, but display dwarfism and die during the first month of postnatal life. Characterization of the Zbtb20-/- brain phenotype reveals a small vestigial hippocampus...... as an essential regulator of various aspects of neuronal development and corticogenesis in the hippocampus....

  7. Morphological characterization of spinal cord dorsal horn lamina I neurons projecting to the parabrachial nucleus in the rat.

    Science.gov (United States)

    Almarestani, L; Waters, S M; Krause, J E; Bennett, G J; Ribeiro-da-Silva, A

    2007-09-20

    Many Rexed's lamina I neurons are nociceptive and project to the brain. Lamina I projection neurons can be classified as multipolar, fusiform, or pyramidal, based on cell body shape and characteristics of their proximal dendrites in the horizontal plane. There is also evidence that both multipolar and fusiform cells are nociceptive and pyramidal neurons nonnociceptive. In this investigation we identified which types of lamina I neurons belong to the spinoparabrachial tract in the rat and characterized them regarding the presence or absence of neurokinin-1 receptor (NK-1r) immunoreactivity. For this, cholera toxin subunit B (CTb), conjugated to a fluorescent marker was injected unilaterally into the parabrachial nucleus. Sections were additionally stained for the detection of NK-1r immunoreactivity and were examined using fluorescence and confocal microscopy. Serial confocal optical sections and 3D reconstructions were obtained for a considerable number of neurons per animal. Using immunofluorescence, we assessed the proportion of lamina I neurons belonging to the spinoparabrachial (SPB) tract and/or expressing NK-1r. The relative distribution of neurons belonging to the SPB tract was: 38.7% multipolar, 36.8% fusiform, 22.7% pyramidal, and 1.9% unclassified. Most of the SPB neurons expressing NK-1r were either multipolar or fusiform. Pyramidal SPB neurons were seldom immunoreactive for NK-1r, an observation that provides further support to the concept that most lamina I projection neurons of the pyramidal type are nonnociceptive. In addition, our study provides further evidence that these distinct morphological types of neurons differ in their phenotypic properties, but not in their projection patterns.

  8. Specificity and actions of an arylaspartate inhibitor of glutamate transport at the Schaffer collateral-CA1 pyramidal cell synapse.

    Directory of Open Access Journals (Sweden)

    Weinan Sun

    Full Text Available In this study we characterized the pharmacological selectivity and physiological actions of a new arylaspartate glutamate transporter blocker, L-threo-ß-benzylaspartate (L-TBA. At concentrations up to 100 µM, L-TBA did not act as an AMPA receptor (AMPAR or NMDA receptor (NMDAR agonist or antagonist when applied to outside-out patches from mouse hippocampal CA1 pyramidal neurons. L-TBA had no effect on the amplitude of field excitatory postsynaptic potentials (fEPSPs recorded at the Schaffer collateral-CA1 pyramidal cell synapse. Excitatory postsynaptic currents (EPSCs in CA1 pyramidal neurons were unaffected by L-TBA in the presence of physiological extracellular Mg(2+ concentrations, but in Mg(2+-free solution, EPSCs were significantly prolonged as a consequence of increased NMDAR activity. Although L-TBA exhibited approximately four-fold selectivity for neuronal EAAT3 over glial EAAT1/EAAT2 transporter subtypes expressed in Xenopus oocytes, the L-TBA concentration-dependence of the EPSC charge transfer increase in the absence of Mg(2+ was the same in hippocampal slices from EAAT3 +/+ and EAAT3 -/- mice, suggesting that TBA effects were primarily due to block of glial transporters. Consistent with this, L-TBA blocked synaptically evoked transporter currents in CA1 astrocytes with a potency in accord with its block of heterologously expressed glial transporters. Extracellular recording in the presence of physiological Mg(2+ revealed that L-TBA prolonged fEPSPs in a frequency-dependent manner by selectively increasing the NMDAR-mediated component of the fEPSP during short bursts of activity. The data indicate that glial glutamate transporters play a dominant role in limiting extrasynaptic transmitter diffusion and binding to NMDARs. Furthermore, NMDAR signaling is primarily limited by voltage-dependent Mg(2+ block during low-frequency activity, while the relative contribution of transport increases during short bursts of higher frequency

  9. Persistently active, pacemaker-like neurons in neocortex

    Directory of Open Access Journals (Sweden)

    Morgane Le Bon-Jego

    2007-10-01

    Full Text Available The neocortex is spontaneously active, however, the origin of this self-generated, patterned activity remains unknown. To detect potential pacemaker cells, we use calcium imaging to directly identify neurons that discharge action potentials in the absence of synaptic transmissionin slices from juvenile mouse visual cortex. We characterize 60 of these neurons electrophysiologically and morphologically, finding that they belong to two classes of cells: one class composed of pyramidal neurons with a thin apical dendritic tree and a second class composed of ascending axon interneurons (Martinotti cells located in layer 5. In both types of neurons, persistent sodium currents are necessary for the generation of the spontaneous activity. Our data demonstrate that subtypes of neocortical neurons have intrinsic mechanisms to generate persistent activity. Like in central pattern generators (CPGs, these neurons may act as pacemakers to initiate or pattern spontaneous activity in the neocortex.

  10. Characteristics of the aberrant pyramidal tract in comparison with the pyramidal tract in the human brain

    Directory of Open Access Journals (Sweden)

    Kwon Yong

    2011-11-01

    Full Text Available Abstract Background The aberrant pyramidal tract (APT refers to the collateral pathway of the pyramidal tract (PT through the medial lemniscus in the midbrain and pons. Using diffusion tensor tractography (DTT, we investigated the characteristics of the APT in comparison with the PT in the normal human brain. Results In thirty-four (18.3%, right hemisphere: 20, left hemisphere: 14 of the 186 hemispheres, the APTs separated from the PT at the upper midbrain level, descended through the medial lemniscus from the midbrain to the pons, and then rejoined with the PT at the upper medulla. Nine (26.5% of the 34 APTs were found to originate from the primary somatosensory cortex without a primary motor cortex origin. Values of fractional anisotropy (FA and tract volume of the APT were lower than those of the PT (P P >0.05. Conclusion We found that the APT has different characteristics, including less directionality, fewer neural fibers, and less origin from the primary motor cortex than the PT.

  11. How a (subcellular coincidence detection mechanism featuring layer-5 pyramidal cells may help produce various visual phenomena

    Directory of Open Access Journals (Sweden)

    Talis eBachmann

    2015-12-01

    Full Text Available Perceptual phenomena such as spatio-temporal illusions and masking are typically explained by psychological (cognitive processing theories or large-scale neural theories involving inter-areal connectivity and neural circuits comprising of hundreds or more interconnected single cells. Subcellular mechanisms are hardly used for such purpose. Here a mechanistic theoretical view is presented on how a subcellular brain mechanism of integration of presynaptic signals that arrive at different compartments of layer-5 pyramidal neurons could explain a couple of spatiotemporal visual-phenomenal effects unfolding along very brief time intervals within the range of sub-second temporal scale.

  12. Role of BK(Ca) Potassium Channels in the Mechanisms of Modulatory Effects of IL-10 on Hypoxia-Induced Changes in Activity of Hippocampal Neurons.

    Science.gov (United States)

    Levin, S G; Konakov, M V; Godukhin, O V

    2016-03-01

    We studied the contribution of large conductance Ca(2+)-activated potassium channels (BKCa) in the mechanisms of neuromodulatory effects of anti-inflammatory cytokine IL-10 on hypoxiainduced changes in activity of CA1 pyramidal neurons in rat hippocampus. We used the method of registration of population spikes from CA1 pyramidal neurons in hippocampal slices before, during, and after exposure to short-term episodes of hypoxia. Selective blocker (iberiotoxin) and selective activator of BKCa (BMS-191011) were used to evaluate the contribution of these channels in the mechanisms of suppressive effects of IL-10 on changes in neuronal activity during hypoxia and development of post-hypoxic hyperexcitability. It was shown that BKCa are involved in the modulatory effects of IL-10 on hypoxia-induced suppression of activity of CA1 pyramidal neurons in the hippocampus and development of post-hypoxic hyperexcitability in these neurons.

  13. PARCELLATION OF THE CINGULATE CORTEX AT REST AND DURING TASKS: A META-ANALYTIC CLUSTERING AND EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    Diana M.E. Torta

    2013-06-01

    Full Text Available Anatomical, morphological and histological data have consistently shown that the cingulate cortex can be divided into four main regions. However, less is known about parcellations of the cingulate cortex when involved in active tasks. Here, we aimed at comparing how the pattern of clusterization of the cingulate cortex changes across different levels of task complexity. We parcellated the cingulate cortex using the results of a meta-analytic study and of three experimental studies. The experimental studies, which included two active tasks and a resting state protocol, were used to control the results obtained with the meta-analytic parcellation. We explored the meta-analytic parcellation by applying a meta-analytic clustering (MaC to papers retrieved from the BrainMap database. The MaC is a meta-analytic connectivity driven parcellation technique recently developed by our group which allowed us to parcellate the cingulate cortex on the basis of its pattern of co-activations during active tasks. The MaC results indicated that the cingulate cortex can be parcellated into three clusters. These clusters covered different percentages of the cingulate parenchyma and had a different density of foci, with the first cluster being more densely connected. The control experiments showed different clusterization results, suggesting that the co-activations of the cingulate cortex are highly dependent on the task that is tested. Our results highlight the importance of the cingulate cortex as a hub, which modifies its pattern of co-activations depending on the task requests and on the level of task complexity. The neurobiological meaning of these results is discussed.

  14. Segregated Cell Populations Enable Distinct Parallel Encoding within the Radial Axis of the CA1 Pyramidal Layer

    Science.gov (United States)

    Geiller, Tristan; Royer, Sebastien

    2017-01-01

    Numerous studies have implicated the hippocampus in the encoding and storage of declarative and spatial memories. Several models have considered the hippocampus and its distinct subfields to contain homogeneous pyramidal cell populations. Yet, recent studies have led to a consensus that the dorso-ventral and proximo-distal axes have different connectivities and physiologies. The remaining deep-superficial axis of the pyramidal layer, however, remains relatively unexplored due to a lack of techniques that can record from neurons simultaneously at different depths. Recent advances in transgenic mice, two-photon imaging and dense multisite recording have revealed extensive disparities between the pyramidal cells located in the deep and the superficial layers. Here, we summarize differences between the two populations in terms of gene expression and connectivity with other intra-hippocampal subregions and local interneurons that underlie distinct learning processes and spatial representations. A unified picture will emerge to describe how such local segregations can increase the capacity of the hippocampus to compute and process numerous tasks in parallel. PMID:28243162

  15. Complete axon arborization of a single CA3 pyramidal cell in the rat hippocampus, and its relationship with postsynaptic parvalbumin-containing interneurons.

    Science.gov (United States)

    Sik, A; Tamamaki, N; Freund, T F

    1993-12-01

    The complete axon arborization of a single CA3 pyramidal cell has been reconstructed from 32 (60 microns thick) sections from the rat hippocampus following in vivo intracellular injection of neurobiotin. The same sections were double-immunostained for parvalbumin--a calcium-binding protein selectively present in two types of GABAergic interneurons, the basket and chandelier cells--in order to map boutons of the pyramidal cell in contact with dendrites and somata of these specific subsets of interneurons visualized in a Golgi-like manner. The axon of the pyramidal cell formed 15,295 boutons, 63.8% of which were in stratum oriens, 15.4% in stratum pyramidale and 20.8% in stratum radiatum. Only 2.1% of the axon terminals contacted parvalbumin-positive neurons. Most of these were single contacts (84.7%), but double or triple contacts (15.3%) were also found. The majority of the boutons terminated on dendrites (84.1%) of parvalbumin-positive cells, less frequently on cell bodies (15.9%). In order to estimate the proportion of contacts representing synapses, 16 light microscopically identified contacts between boutons of the filled pyramidal cell axon and the parvalbumin-positive targets were examined by correlated electron microscopy. Thirteen of them were found to be asymmetrical synapses, and in the remaining three cases synapses between the labelled profiles could not be confirmed. We conclude that the physiologically effective excitatory connections between single pyramidal cells and postsynaptic inhibitory neurons are mediated by a small number of contacts, mostly by a single synapse. This results in a high degree of convergence and divergence in hippocampal networks.

  16. Polychromatic white LED using GaN nano pyramid structure

    Science.gov (United States)

    Kim, Taek; Kim, Jusung; Yang, Moonseung; Park, Yongsoo; Chung, U.-In; Ko, Yongho; Cho, Yonghoon

    2013-03-01

    We have developed monolithic white light emitting diodes (LEDs) with a hybrid structure of planar c-planes and nano size hexagonal pyramids. The white spectrum is composed of blue and yellow emissions from the InGaN multi quantum wells (MQWs) on the planar c-planes and on the nano pyramids, respectively. The yellow emission is originated from quantum wells, wires, and dots that are formed at the sides, edges, and tops of the nano-pyramids, respectively. As a result, the emission peaks are different and the entire yellow spectrum is broad enough to make a white in combination with a blue emission. The longer wavelength from the InGaN on nano-pyramids than the wavelength from the InGaN on c-planes is explained by excess In supply from the dielectric selective growth mask. The color temperature is tuned from 3600K to 6400K by controlling the relative area ratio of c-plane and nano-pyramids.

  17. Anterior cingulate dopamine turnover and behavior change in Parkinson’s disease

    Science.gov (United States)

    Gallagher, Catherine L; Bell, Brian; Palotti, Matthew; Oh, Jen; Christian, Bradley T.; Okonkwo, Ozioma; Sojkova, Jitka; Buyan-Dent, Laura; Nickles, Robert J.; Harding, Sandra J.; Stone, Charles K.; Johnson, Sterling C.; Holden, James E.

    2015-01-01

    Subtle cognitive and behavioral changes are common in early Parkinson’s disease. The cause of these symptoms is probably multifactorial but may in part be related to extra-striatal dopamine levels. 6-[18F]-Fluoro-L-dopa (FDOPA) positron emission tomography has been widely used to quantify dopamine metabolism in the brain; the most frequently measured kinetic parameter is the tissue uptake rate constant, Ki. However, estimates of dopamine turnover, which also account for the small rate of FDOPA loss from areas of specific trapping, may be more sensitive than Ki for early disease-related changes in dopamine biosynthesis. The purpose of the present study was to compare effective distribution volume ratio (eDVR), a metric for dopamine turnover, to cognitive and behavioral measures in Parkinson’s patients. We chose to focus the investigation on anterior cingulate cortex, which shows highest FDOPA uptake within frontal regions and has known roles in executive function. 15 Non-demented early-stage PD patients were pretreated with carbidopa and tolcapone, a central catechol-O-methyl transferase (COMT) inhibitor and then underwent extended imaging with FDOPA PET. Anterior cingulate eDVR was compared with composite scores for language, memory, and executive function measured by neuropsychological testing, and behavior change measured using two informant-based questionnaires, the Cambridge Behavioral Inventory and the Behavior Rating Inventory of Executive Function- Adult Version. Lower mean eDVR (thus higher dopamine turnover) in anterior cingulate cortex was related to lower (more impaired) behavior scores. We conclude that subtle changes in anterior cingulate dopamine metabolism may contribute to dysexecutive behaviors in Parkinson’s disease. PMID:25511521

  18. Error Negativity Does Not Reflect Conflict: A Reappraisal of Conflict Monitoring and Anterior Cingulate Cortex Activity

    OpenAIRE

    2008-01-01

    Our ability to detect and correct errors is essential for our adaptive behavior. The conflict-loop theory states that the anterior cingulate cortex (ACC) plays a key role in detecting the need to increase control through conflict monitoring. Such monitoring is assumed to manifest itself in an electroencephalographic (EEG) component, the "error negativity" (Ne or "error-related negativity" [ERN]). We have directly tested the hypothesis that the ACC monitors conflict through simulation and expe...

  19. Reduced anterior cingulate gyrus volume correlates with executive dysfunction in men with first-episode schizophrenia.

    Science.gov (United States)

    Szeszko, P R; Bilder, R M; Lencz, T; Ashtari, M; Goldman, R S; Reiter, G; Wu, H; Lieberman, J A

    2000-06-16

    Although frontal lobe structural and functional abnormalities have been identified in schizophrenia, their relationship remains elusive. Because the frontal lobes are both structurally and functionally heterogeneous, it is possible that some measures of frontal lobe structure may not have accurately identified relevant frontal lobe subregions. The authors hypothesized that the volumes of two dorsal, 'archicortical' subregions (i.e. superior frontal gyrus and anterior cingulate gyrus), but not a ventral, 'paleocortical' subregion (i.e. orbital frontal region) would be significantly and selectively correlated with executive and motor dysfunction in patients with schizophrenia as previously reported for the anterior hippocampal region. Volumes of these frontal lobe subregions were measured from magnetic resonance images based on sulcal anatomy in 20 men and 15 women with first-episode schizophrenia. All patients completed a comprehensive neuropsychological test battery while clinically stabilized that encompassed six domains of functioning: attention, executive, motor, visuospatial, memory and language. Findings indicated that reduced anterior cingulate gyrus volume was significantly correlated with worse executive functioning in men; among women, there were no significant correlations. Among men, anterior cingulate gyrus volume was significantly more strongly correlated with executive functioning than with attention, visuospatial, memory, language and general intellectual functioning. Neither executive nor motor functioning was significantly more strongly correlated with the dorsal 'archicortical' volumes than with orbital frontal volume. These findings suggest a link between executive deficits and dysfunction of the dorsal 'archicortical' system and implicate sex differences in their relationship in first-episode schizophrenia.

  20. Chemical shift magnetic resonance spectroscopy of cingulate grey matter in patients with minimal hepatic encephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Mechtcheriakov, Sergei; Kugener, Andre; Mattedi, Michael; Hinterhuber, Hartmann; Marksteiner, Josef [Innsbruck Medical University, Department of General Psychiatry, Innsbruck (Austria); Schocke, Michael [Innsbruck Medical University, Department of Radiology I, Innsbruck (Austria); Graziadei, Ivo W.; Vogel, Wolfgang [Innsbruck Medical University, Department of Gastroenterology, Innsbruck (Austria)

    2005-01-01

    Minimal hepatic encephalopathy (MHE) is frequently diagnosed in patients with liver cirrhosis who do not show overt clinical cirrhosis-associated neurological deficits. This condition manifests primarily with visuo-motor and attention deficits. We studied the association between visuo-motor deficits and magnetic resonance spectroscopic parameters in cingulate grey matter and white matter of centrum semiovale in patients with liver cirrhosis. The data revealed an increase in the glutamate-glutamine/creatine ratio and a decrease in choline/creatine and inositol/creatine ratios in patients with liver cirrhosis. The analysis of the data showed that cirrhosis-associated deterioration of the visuo-motor function significantly correlates with a decrease in the choline/creatine ratio and an increase in N-acetylaspartate/choline in cingulate grey matter but not in the neighbouring white matter. Furthermore, the increase in the glutamate-glutamine/creatine ratio correlated significantly with the increase in the N-acetylaspartate/creatine ratio. These data suggest an association between altered choline, glutamate-glutamine and NAA metabolism in cingulate grey matter and symptoms of MHE, and underline the importance of differentiation between grey and white matter in magnetic resonance spectroscopic studies on patients with cirrhosis-associated brain dysfunction. (orig.)

  1. Neural dissociations in attitude strength: Distinct regions of cingulate cortex track ambivalence and certainty.

    Science.gov (United States)

    Luttrell, Andrew; Stillman, Paul E; Hasinski, Adam E; Cunningham, William A

    2016-04-01

    People's behaviors are often guided by valenced responses to objects in the environment. Beyond positive and negative evaluations, attitudes research has documented the importance of attitude strength--qualities of an attitude that enhance or attenuate its impact and durability. Although neuroscience research has extensively investigated valence, little work exists on other related variables like metacognitive judgments about one's attitudes. It remains unclear, then, whether the various indicators of attitude strength represent a single underlying neural process or whether they reflect independent processes. To examine this, we used functional MRI (fMRI) to identify the neural correlates of attitude strength. Specifically, we focus on ambivalence and certainty, which represent metacognitive judgments that people can make about their evaluations. Although often correlated, prior neuroscience research suggests that these 2 attributes may have distinct neural underpinnings. We investigate this by having participants make evaluative judgments of visually presented words while undergoing fMRI. After scanning, participants rated the degree of ambivalence and certainty they felt regarding their attitudes toward each word. We found that these 2 judgments corresponded to distinct brain regions' activity during the process of evaluation. Ambivalence corresponded to activation in anterior cingulate cortex, dorsomedial prefrontal cortex, and posterior cingulate cortex. Certainty, however, corresponded to activation in unique areas of the precuneus/posterior cingulate cortex. These results support a model treating ambivalence and certainty as distinct, though related, attitude strength variables, and we discuss implications for both attitudes and neuroscience research.

  2. Mirth and laughter elicited by electrical stimulation of the human anterior cingulate cortex.

    Science.gov (United States)

    Caruana, Fausto; Avanzini, Pietro; Gozzo, Francesca; Francione, Stefano; Cardinale, Francesco; Rizzolatti, Giacomo

    2015-10-01

    Laughter is a complex motor behavior that, typically, expresses mirth. Despite its fundamental role in social life, knowledge about the neural basis of laughter is very limited and mostly based on a few electrical stimulation (ES) studies carried out in epileptic patients. In these studies laughter was elicited from temporal areas where it was accompanied by mirth and from frontal areas plus an anterior cingulate case where laughter without mirth was observed. On the basis of these findings, it has been proposed a dichotomy between temporal lobe areas processing the emotional content of laughter and anterior cingulate cortex (ACC) and motor areas responsible of laughter production. The present study is aimed to understand the role of ACC in laughter. We report the effects of stimulation of 10 rostral, pregenual ACC (pACC) patients in which the ES elicited laughter. In half of the patients ES elicited a clear burst of laughter with mirth, while in the other half mirth was not evident. This large dataset allow us to offer a more reliable picture of the functional contribute of this region in laughter, and to precisely localize it in the cingulate cortex. We conclude that the pACC is involved in both the motor and the affective components of emotions, and challenge the validity of a sharp dichotomy between motor and emotional centers for laughing. Finally, we suggest a possible anatomical network for the production of positive emotional expressions.

  3. Models of neocortical layer 5b pyramidal cells capturing a wide range of dendritic and perisomatic active properties.

    Directory of Open Access Journals (Sweden)

    Etay Hay

    2011-07-01

    Full Text Available The thick-tufted layer 5b pyramidal cell extends its dendritic tree to all six layers of the mammalian neocortex and serves as a major building block for the cortical column. L5b pyramidal cells have been the subject of extensive experimental and modeling studies, yet conductance-based models of these cells that faithfully reproduce both their perisomatic Na(+-spiking behavior as well as key dendritic active properties, including Ca(2+ spikes and back-propagating action potentials, are still lacking. Based on a large body of experimental recordings from both the soma and dendrites of L5b pyramidal cells in adult rats, we characterized key features of the somatic and dendritic firing and quantified their statistics. We used these features to constrain the density of a set of ion channels over the soma and dendritic surface via multi-objective optimization with an evolutionary algorithm, thus generating a set of detailed conductance-based models that faithfully replicate the back-propagating action potential activated Ca(2+ spike firing and the perisomatic firing response to current steps, as well as the experimental variability of the properties. Furthermore, we show a useful way to analyze model parameters with our sets of models, which enabled us to identify some of the mechanisms responsible for the dynamic properties of L5b pyramidal cells as well as mechanisms that are sensitive to morphological changes. This automated framework can be used to develop a database of faithful models for other neuron types. The models we present provide several experimentally-testable predictions and can serve as a powerful tool for theoretical investigations of the contribution of single-cell dynamics to network activity and its computational capabilities.

  4. Inactivation of the anterior cingulate reveals enhanced reliance on cortical networks for remote spatial memory retrieval after sequential memory processing.

    Directory of Open Access Journals (Sweden)

    Brianne C Wartman

    Full Text Available One system consolidation model suggests that as time passes, ensembles of cortical neurons form strong connections to represent remote memories. In this model, the anterior cingulate cortex (ACC serves as a cortical region that represents remote memories. However, there is debate as to whether remote spatial memories go through this systems consolidation process and come to rely on the ACC. The present experiment examined whether increasing the processing demand on the hippocampus, by sequential training on two spatial tasks, would more fully engage the ACC during retrieval of a remote spatial memory. In this scenario, inactivation of the ACC at a remote time point was hypothesized to produce a severe memory deficit if rats had been trained on two, sequential spatial tasks. Rats were trained on a water maze (WM task only or a WM task followed by a radial arm maze task. A WM probe test was given recently or remotely to all rats. Prior to the probe test, rats received an injection of saline or muscimol into the ACC. A subtle deficit in probe performance was found at the remote time point in the group trained on only one spatial task and treated with muscimol. In the group trained on two spatial tasks and treated with muscimol, a subtle deficit in probe performance was noted at the recent time point and a substantial deficit in probe performance was observed at the remote time point. c-Fos labeling in the hippocampus revealed more labeling in the CA1 region in all remotely tested groups than recently tested groups. Findings suggest that spatial remote memories come to rely more fully on the ACC when hippocampal processing requirements are increased. Results also suggest continued involvement of the hippocampus in spatial memory retrieval along with a progressive strengthening of cortical connections as time progresses.

  5. Inactivation of the anterior cingulate reveals enhanced reliance on cortical networks for remote spatial memory retrieval after sequential memory processing.

    Science.gov (United States)

    Wartman, Brianne C; Gabel, Jennifer; Holahan, Matthew R

    2014-01-01

    One system consolidation model suggests that as time passes, ensembles of cortical neurons form strong connections to represent remote memories. In this model, the anterior cingulate cortex (ACC) serves as a cortical region that represents remote memories. However, there is debate as to whether remote spatial memories go through this systems consolidation process and come to rely on the ACC. The present experiment examined whether increasing the processing demand on the hippocampus, by sequential training on two spatial tasks, would more fully engage the ACC during retrieval of a remote spatial memory. In this scenario, inactivation of the ACC at a remote time point was hypothesized to produce a severe memory deficit if rats had been trained on two, sequential spatial tasks. Rats were trained on a water maze (WM) task only or a WM task followed by a radial arm maze task. A WM probe test was given recently or remotely to all rats. Prior to the probe test, rats received an injection of saline or muscimol into the ACC. A subtle deficit in probe performance was found at the remote time point in the group trained on only one spatial task and treated with muscimol. In the group trained on two spatial tasks and treated with muscimol, a subtle deficit in probe performance was noted at the recent time point and a substantial deficit in probe performance was observed at the remote time point. c-Fos labeling in the hippocampus revealed more labeling in the CA1 region in all remotely tested groups than recently tested groups. Findings suggest that spatial remote memories come to rely more fully on the ACC when hippocampal processing requirements are increased. Results also suggest continued involvement of the hippocampus in spatial memory retrieval along with a progressive strengthening of cortical connections as time progresses.

  6. Assessment of Anterior Cingulate Cortex (ACC) and Left Cerebellar Metabolism in Asperger's Syndrome with Proton Magnetic Resonance Spectroscopy (MRS)

    Science.gov (United States)

    Goji, Aya; Ito, Hiromichi; Mori, Kenji; Harada, Masafumi; Hisaoka, Sonoka; Toda, Yoshihiro; Mori, Tatsuo; Abe, Yoko; Miyazaki, Masahito; Kagami, Shoji

    2017-01-01

    Purpose Proton magnetic resonance spectroscopy (1H MRS) is a noninvasive neuroimaging method to quantify biochemical metabolites in vivo and it can serve as a powerful tool to monitor neurobiochemical profiles in the brain. Asperger’s syndrome (AS) is a type of autism spectrum disorder, which is characterized by impaired social skills and restrictive, repetitive patterns of interest and activities, while intellectual levels and language skills are relatively preserved. Despite clinical aspects have been well-characterized, neurometabolic profiling in the brain of AS remains to be clear. The present study used proton magnetic resonance spectroscopy (1H MRS) to investigate whether pediatric AS is associated with measurable neurometabolic abnormalities that can contribute new information on the neurobiological underpinnings of the disorder. Methods Study participants consisted of 34 children with AS (2–12 years old; mean age 5.2 (±2.0); 28 boys) and 19 typically developed children (2–11 years old; mean age 5.6 (±2.6); 12 boys) who served as the normal control group. The 1H MRS data were obtained from two regions of interest: the anterior cingulate cortex (ACC) and left cerebellum. Results In the ACC, levels of N-acetylaspartate (NAA), total creatine (tCr), total choline-containing compounds (tCho) and myo-Inositol (mI) were significantly decreased in children with AS compared to controls. On the other hand, no significant group differences in any of the metabolites were found in the left cerebellum. Neither age nor sex accounted for the metabolic findings in the regions. Conclusion The finding of decreased levels of NAA, tCr, tCho, and mI in the ACC but not in left cerebellar voxels in the AS, suggests a lower ACC neuronal density in the present AS cohort compared to controls. PMID:28060873

  7. Pyramidal ice crystal scattering phase functions and concentric halos

    Directory of Open Access Journals (Sweden)

    C. Liu

    Full Text Available Phase functions have been calculated using the Monte Carlo/geometric ray tracing method for single hexagonal pyramidal ice crystals (such as solid and hollow bullets randomly oriented in space and horizontal plane, in order to study the concentric halo formations. Results from three dimensional model calculations show that 9° halo can be as bright as the common 22° halo for pyramidal angle of 28°, and the 18°, 20°, 24° and 35° halos cannot be seen due to the strong 22° halo domination in the scattering phase function between 18° and 35°. For solid pyramidal ice crystals randomly oriented horizontally, the 35° arc can be produced and its intensity depends on the incident ray solar angle and the particle aspect ratio.

  8. A study of correlation technique on pyramid processed images

    Indian Academy of Sciences (India)

    M Sankar Kishore; K Veerabhadra Rao

    2000-02-01

    The pyramid algorithm is potentially a powerful tool for advanced television image processing and for pattern recognition. An attempt is made to design and develop both hardware and software for a system which performs decomposition and reconstruction of digitized images by implementing the Burt pyramid algorithm. In this work, an attempt is also made to study correlation performance on reconstructed images. That is, the reference image is taken from the original image and correlation is performed on expanded images of the same size. Similarly, correlation performance study is carried out on different pyramid- processed levels. In this paper results are presented in terms of RMS error between original and expanded images. Only still images are considered, and the hardware is designed around an i486 processor and software is developed in PL/M 86.

  9. Ancient Egyptian chronology and the astronomical orientation of pyramids

    Science.gov (United States)

    Spence, Kate

    2000-11-01

    The ancient Egyptian pyramids at Giza have never been accurately dated, although we know that they were built approximately around the middle of the third millennium BC. The chronologies of this period have been reconstructed from surviving lists of kings and the lengths of their reigns, but the lists are rare, seldom complete and contain known inconsistencies and errors. As a result, the existing chronologies for that period (the Old Kingdom) can be considered accurate only to about +/-100 years, a figure that radiocarbon dating cannot at present improve. Here I use trends in the orientation of Old Kingdom pyramids to demonstrate that the Egyptians aligned them to north by using the simultaneous transit of two circumpolar stars. Modelling the precession of these stars yields a date for the start of construction of the Great Pyramid that is accurate to +/-5 yr, thereby providing an anchor for the Old Kingdom chronologies.

  10. A causal role for the anterior mid-cingulate cortex in negative affect and cognitive control.

    Science.gov (United States)

    Tolomeo, Serenella; Christmas, David; Jentzsch, Ines; Johnston, Blair; Sprengelmeyer, Reiner; Matthews, Keith; Douglas Steele, J

    2016-06-01

    Converging evidence has linked the anterior mid-cingulate cortex to negative affect, pain and cognitive control. It has previously been proposed that this region uses information about punishment to control aversively motivated actions. Studies on the effects of lesions allow causal inferences about brain function; however, naturally occurring lesions in the anterior mid-cingulate cortex are rare. In two studies we therefore recruited 94 volunteers, comprising 15 patients with treatment-resistant depression who had received bilateral anterior cingulotomy, which consists of lesions made within the anterior mid-cingulate cortex, 20 patients with treatment-resistant depression who had not received surgery and 59 healthy control subjects. Using the Ekman 60 faces paradigm and two Stroop paradigms, we tested the hypothesis that patients who received anterior cingulotomy were impaired in recognizing negative facial affect expressions but not positive or neutral facial expressions, and impaired in Stroop cognitive control, with larger lesions being associated with more impairment. Consistent with this hypothesis, we found that larger volume lesions predicted more impairment in recognizing fear, disgust and anger, and no impairment in recognizing facial expressions of surprise or happiness. However, we found no impairment in recognizing expressions of sadness. Also consistent with the hypothesis, we found that larger volume lesions predicted impaired Stroop cognitive control. Notably, this relationship was only present when anterior mid-cingulate cortex lesion volume was defined as the overlap between cingulotomy lesion volume and Shackman's meta-analysis-derived binary masks for negative affect and cognitive control. Given substantial evidence from healthy subjects that the anterior mid-cingulate cortex is part of a network associated with the experience of negative affect and pain, engaging cognitive control processes for optimizing behaviour in the presence of such

  11. Weak sinusoidal electric fields entrain spontaneous Ca transients in the dendritic tufts of CA1 pyramidal cells in rat hippocampal slice preparations.

    Science.gov (United States)

    Maeda, Kazuma; Maruyama, Ryuichi; Nagae, Toru; Inoue, Masashi; Aonishi, Toru; Miyakawa, Hiroyoshi

    2015-01-01

    Neurons might interact via electric fields and this notion has been referred to as ephaptic interaction. It has been shown that various types of ion channels are distributed along the dendrites and are capable of supporting generation of dendritic spikes. We hypothesized that generation of dendritic spikes play important roles in the ephaptic interactions either by amplifying the impact of electric fields or by providing current source to generate electric fields. To test if dendritic activities can be modulated by electric fields, we developed a method to monitor local Ca-transients in the dendrites of a neuronal population in acute rat hippocampal slices by applying spinning-disk confocal microscopy and multi-cell dye loading technique. In a condition in which the dendrites of CA1 pyramidal neurons show spontaneous Ca-transients due to added 50 μM 4-aminopyridine to the bathing medium and adjusted extracellular potassium concentration, we examined the impact of sinusoidal electric fields on the Ca-transients. We have found that spontaneously occurring fast-Ca-transients in the tufts of the apical dendrites of CA1 pyramidal neurons can be blocked by applying 1 μM tetrodotoxin, and that the timing of the transients become entrained to sub-threshold 1-4 Hz electric fields with an intensity as weak as 0.84 mV/mm applied parallel to the somato-dendritic axis of the neurons. The extent of entrainment increases with intensity below 5 mV/mm, but does not increase further over the range of 5-20 mV/mm. These results suggest that population of pyramidal cells might be able to detect electric fields with biologically relevant intensity by modulating the timing of dendritic spikes.

  12. Projection neurons in the cortex and hippocampus: differential effects of chronic khat and ethanol exposure in adult male rats

    Science.gov (United States)

    Alele, Paul E; Matovu, Daniel; Imanirampa, Lawrence; Ajayi, Abayomi M; Kasule, Gyaviira T

    2016-01-01

    Background Recent evidence suggests that many individuals who chew khat recreationally also drink ethanol to offset the stimulating effect of khat. The objective of this study was to describe the separate and interactive effects of chronic ethanol and khat exposure on key projection neurons in the cortex and hippocampus of young adult male rats. Methods Young adult male Sprague Dawley rats were divided into six treatment groups: 2 g/kg khat, 4 g/kg khat, 4 g/kg ethanol, combined khat and ethanol (4 g/kg each), a normal saline control, and an untreated group. Treatments were administered orally for 28 continuous days; brains were then harvested, sectioned, and routine hematoxylin–eosin staining was done. Following photomicrography, ImageJ® software captured data regarding neuron number and size. Results No differences occurred in counts of both granular and pyramidal projection neurons in the motor cortex and all four subfields of the hippocampal formation. Khat dose-dependently increased pyramidal neuron size in the motor cortex and the CA3 region, but had different effects on granular neuron size in the dentate gyrus and the motor cortex. Mean pyramidal neuron size for the ethanol-only treatment was larger than that for the 2 g/kg khat group, and the saline control group, in CA3 and in the motor cortex. Concomitant khat and ethanol increased granular neuron size in the motor cortex, compared to the 2 g/kg khat group, the 4 g/kg khat group, and the 4 g/kg ethanol group. In the CA3 region, the 4 g/kg ethanol group showed a larger mean pyramidal neuron size than the combined khat and ethanol group. Conclusion These results suggest that concomitant khat and ethanol exposure changes granular and pyramidal projection neuron sizes differentially in the motor cortex and hippocampus, compared to the effects of chronic exposure to these two drugs separately.

  13. Predictive features of persistent activity emergence in regular spiking and intrinsic bursting model neurons.

    Science.gov (United States)

    Sidiropoulou, Kyriaki; Poirazi, Panayiota

    2012-01-01

    Proper functioning of working memory involves the expression of stimulus-selective persistent activity in pyramidal neurons of the prefrontal cortex (PFC), which refers to neural activity that persists for seconds beyond the end of the stimulus. The mechanisms which PFC pyramidal neurons use to discriminate between preferred vs. neutral inputs at the cellular level are largely unknown. Moreover, the presence of pyramidal cell subtypes with different firing patterns, such as regular spiking and intrinsic bursting, raises the question as to what their distinct role might be in persistent firing in the PFC. Here, we use a compartmental modeling approach to search for discriminatory features in the properties of incoming stimuli to a PFC pyramidal neuron and/or its response that signal which of these stimuli will result in persistent activity emergence. Furthermore, we use our modeling approach to study cell-type specific differences in persistent activity properties, via implementing a regular spiking (RS) and an intrinsic bursting (IB) model neuron. We identify synaptic location within the basal dendrites as a feature of stimulus selectivity. Specifically, persistent activity-inducing stimuli consist of activated synapses that are located more distally from the soma compared to non-inducing stimuli, in both model cells. In addition, the action potential (AP) latency and the first few inter-spike-intervals of the neuronal response can be used to reliably detect inducing vs. non-inducing inputs, suggesting a potential mechanism by which downstream neurons can rapidly decode the upcoming emergence of persistent activity. While the two model neurons did not differ in the coding features of persistent activity emergence, the properties of persistent activity, such as the firing pattern and the duration of temporally-restricted persistent activity were distinct. Collectively, our results pinpoint to specific features of the neuronal response to a given stimulus that code

  14. Predictive features of persistent activity emergence in regular spiking and intrinsic bursting model neurons.

    Directory of Open Access Journals (Sweden)

    Kyriaki Sidiropoulou

    Full Text Available Proper functioning of working memory involves the expression of stimulus-selective persistent activity in pyramidal neurons of the prefrontal cortex (PFC, which refers to neural activity that persists for seconds beyond the end of the stimulus. The mechanisms which PFC pyramidal neurons use to discriminate between preferred vs. neutral inputs at the cellular level are largely unknown. Moreover, the presence of pyramidal cell subtypes with different firing patterns, such as regular spiking and intrinsic bursting, raises the question as to what their distinct role might be in persistent firing in the PFC. Here, we use a compartmental modeling approach to search for discriminatory features in the properties of incoming stimuli to a PFC pyramidal neuron and/or its response that signal which of these stimuli will result in persistent activity emergence. Furthermore, we use our modeling approach to study cell-type specific differences in persistent activity properties, via implementing a regular spiking (RS and an intrinsic bursting (IB model neuron. We identify synaptic location within the basal dendrites as a feature of stimulus selectivity. Specifically, persistent activity-inducing stimuli consist of activated synapses that are located more distally from the soma compared to non-inducing stimuli, in both model cells. In addition, the action potential (AP latency and the first few inter-spike-intervals of the neuronal response can be used to reliably detect inducing vs. non-inducing inputs, suggesting a potential mechanism by which downstream neurons can rapidly decode the upcoming emergence of persistent activity. While the two model neurons did not differ in the coding features of persistent activity emergence, the properties of persistent activity, such as the firing pattern and the duration of temporally-restricted persistent activity were distinct. Collectively, our results pinpoint to specific features of the neuronal response to a given

  15. [Facilitation of the retention and acceleration of operant conditioning extinction after cingulate cortex lesions in BALB/c mice].

    Science.gov (United States)

    Destrade, C; Gauthier, M

    1981-12-21

    One week after receiving bilateral electrolytic lesions of the cingulate cortex, BALB/c Mice underwent acquisition, retention and extinction of an appetitive operant-conditioning task in a Skinner box. There was no significant difference between lesioned and control animals in acquisition; however, lesioned mice exhibited improved retention and faster extinction. These results suggest a possible involvement of the cingulate cortex in memory processes.

  16. Radial microwire array solar cell with pyramidal structure

    Science.gov (United States)

    Priyadarshini, Bindu; Das, Mukul Kumar; Sen, Mrinal; Kumar, Subindu

    2016-10-01

    In this work, a theoretical model for radial p-n junction microwire array solar cell with pyramidal structures in the space between microwires has been developed. Incorporation of pyramidal structures results in reflection of light, which would otherwise be unused, and illuminates side walls of the microwires. This additional illumination enhances absorption and, hence, efficiency of the whole structure. Efficiency enhancement is analyzed by varying different device parameters e.g., radius and length of each microwire and packing fraction of the structure. Results show that the maximum fractional efficiency enhancement can be obtained as 30% by suitable choice of these parameters.

  17. Image fusion based on expectation maximization algorithm and steerable pyramid

    Institute of Scientific and Technical Information of China (English)

    Gang Liu(刘刚); Zhongliang Jing(敬忠良); Shaoyuan Sun(孙韶媛); Jianxun Li(李建勋); Zhenhua Li(李振华); Henry Leung

    2004-01-01

    In this paper, a novel image fusion method based on the expectation maximization (EM) algorithm and steerable pyramid is proposed. The registered images are first decomposed by using steerable pyramid.The EM algorithm is used to fuse the image components in the low frequency band. The selection method involving the informative importance measure is applied to those in the high frequency band. The final fused image is then computed by taking the inverse transform on the composite coefficient representations.Experimental results show that the proposed method outperforms conventional image fusion methods.

  18. Field emission properties of an array of pyramidal structures

    Energy Technology Data Exchange (ETDEWEB)

    De Assis, Thiago A [Departamento de QuImica, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Borondo, F [Departamento de QuImica, Instituto Mixto de Ciencias Matematicas CSIC-UAM-UC3M-UCM, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); De Castilho, C M C; Brito Mota, F [Grupo de Fisica de SuperfIcies e Materiais, Instituto de Fisica, Universidade Federal da Bahia, Campus Universitario da Federacao, 40210-340, Salvador, BA (Brazil); Benito, R M, E-mail: t.albuquerque@uam.e, E-mail: f.borondo@uam.e, E-mail: caio@ufba.b, E-mail: fbmota@ufba.b, E-mail: rosamaria.benito@upm.e [Grupo de Sistemas Complejos, Departamento de Fisica y Mecanica, Escuela Tecnica Superior de Ingenieros Agronomos, Universidad Politecnica de Madrid, Ciudad Universitaria, 28040 Madrid (Spain)

    2009-10-07

    The properties and efficiency of the emission current density produced by a metallic array of pyramidal structures are investigated. The theoretical results obtained by numerical integration of the corresponding Laplace equation using a finite differences scheme offer useful information for the optimization of field emission devices based on cathodes with this geometry. Our study shows that the inter-pyramidal distance strongly affects the current density, and even more important for this issue is the protrusion characteristics of these structures. Another relevant, although less important, parameter determining this density is the anode-cathode distance. The effect of the array characteristics on the maximum local electric field intensity is also discussed.

  19. [Transient brain ischemia: NMDA receptor modulation and delayed neuronal death].

    Science.gov (United States)

    Benquet, Pascal; Gee, Christine E; Gerber, Urs

    2008-02-01

    Transient global ischemia induces delayed neuronal death in certain cell types and brain regions while sparing cells in other areas. A key process through which oxygen-glucose deprivation triggers cell death is the excessive accumulation of the neurotransmitter glutamate leading to over excitation of neurons. In certain neurons this increase in glutamate will potentiate the NMDA type of glutamate receptor, which can then initiate cell death. This review provides an update of the neurophysiological, cellular and molecular mechanisms inducing post-ischemic plasticity of NMDA receptors, focusing on the sensitive CA1 pyramidal neurons in the hippocampus as compared to the relatively resistant neighboring CA3 neurons. Both a change in the equilibrium between protein tyrosine kinases/phosphatases and an increased density of surface NMDA receptors in response to ischemia may explain the selective vulnerability of specific cell types. Implications for the treatment of stroke and reasons for the failures of human clinical trials utilizing NMDA receptor antagonists are also discussed.

  20. Double Labeling Immunoelectron Microscopic Study on the Synaptic Connections between Glutamic Acid Neurons and GABA Neurons in the Hippocampus of Rats

    Institute of Scientific and Technical Information of China (English)

    ZHU Changgeng; CAI Qiuyun; LIU Qingying; WEI Ying

    2000-01-01

    In order to explore the roles of different neurotransmitters in epileptic pathogenesis,the synaptic connections between glutamic acid (Glu) neurons and GABA neurons in normal rat hippocampus were studied by pre-embedding double labeling immunoelectron microscopy. The GABA immunoreaction was first demonstrated by chromogen DAB, then the Glu immunoreaction was demonstrated by molybdic acid-TMB method. After being stabilized by DAB-cobalt chloride,the sections were processed for electron microscopic embedding. Under electron microscope, there were many Glu immunoreaction-positive neurons in the pyramidal layer of hippocampal CA1 area and some GABA immunoreaction-positive neurons with pyramidal or polygonal perikarya in the pyramidal, polymorphic and radiant layer of CA1 area. There were also symmetric dendro-axonic synapses formed by GABA-positive dendrites and Glu-positive axons in the polymorphic layer and symmetric axo-dendritic synapses formed by GABA-positive axons and Glu-positive dendrites in the radiant layer. In addition, there were symmetric autoregulatory axo-dendritic synapses between Glu-positive axons and dendrites and autoregulatory axo-axonic synapses (both symmetric and asymmetric) between GABA-positive axons. Above mentioned results, for the first time,showed that there were complex synaptic regulatory relationships between excitatory Glu neurons and inhibitory GABA neurons in the hippocampal CA1 area, thereby, providing ultrastructural evidence for different neurotransmitters participating in epileptic pathogenesis.