Sökning: "excitability"

Visar resultat 1 - 5 av 74 avhandlingar innehållade ordet excitability.

  1. 1. Mechanisms of excitability in the central and peripheral nervous systems : Implications for epilepsy and chronic pain

    Författare :Jenny Tigerholm; Erik Fransén; Dieter Jaeger; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Dendritic excitability; synchronized synaptic input; multicompartment model; epilepsy; axonal excitability; silent C–fibres; Hodgkin–Huxley dynamics; conduction velocity; KA;

    Sammanfattning : The work in this thesis concerns mechanisms of excitability of neurons. Specifically, it deals with how neurons respond to input, and how their response is controlled by ion channels and other active components of the neuron. LÄS MER

  2. 2. Applying the Pump and Leak Hypothesis. An experimental and theoretical investigation of the principles of ion regulation and excitability in the crustacean stretch receptor neuron

    Författare :Sten Theander; Fysioterapi; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Neurology; neuropsychology; lobster; stretch receptor neuron; leak current; Q-current; K-Cl cotransporter; A-current; mathematical model; excitability; GABA channel; neurophysiology; ion regulation; neuropsykologi; Neurologi; neurofysiologi;

    Sammanfattning : An invertebrate nerve cell preparation, the lobster stretch receptor neuron, was investigated with respect to maintenance of its resting voltage, intracellular ion concentrations and excitability using voltage clamp technique and ion-selective microelectrodes. It was found that the resting voltage (-65 mV) of microelectrode impaled cells is caused by (a) a homogenous population of K+ channels which we denoted as leak channels (b) an electrogenic and voltage-dependent Na-K pump current and (c) an inward microelectrode-induced "impalement" current carried mainly by Na+. LÄS MER

  3. 3. Conductance-based principles of neuronal firing and excitability

    Författare :Hugo Zeberg; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP;

    Sammanfattning : The brain is an electrical organ whose activity is determined by the flow of ions across cell membranes. As such, the conductances that control the ion flux is a key to our understanding of the nervous system. Neurons process information by their ability to rapidly depolarize and fire action potentials. LÄS MER

  4. 4. Spike-Based Bayesian-Hebbian Learning in Cortical and Subcortical Microcircuits

    Författare :Philip Tully; Anders Lansner; Matthias Hennig; Gordon Pipa; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bayes rule; synaptic plasticity and memory modeling; intrinsic excitability; naïve Bayes classifier; spiking neural networks; Hebbian learning; neuromorphic engineering; reinforcement learning; temporal sequence learning; attractor network; Datalogi; Computer Science;

    Sammanfattning : Cortical and subcortical microcircuits are continuously modified throughout life. Despite ongoing changes these networks stubbornly maintain their functions, which persist although destabilizing synaptic and nonsynaptic mechanisms should ostensibly propel them towards runaway excitation or quiescence. LÄS MER

  5. 5. Amyotrophic lateral sclerosis (ALS) associated with superoxide dismutase 1 (SOD1) mutations in British Columbia, Canada : clinical, neurophysiological and neuropathological features

    Författare :Heather G. Stewart; Hiroshi Mitsumoto; Umeå universitet; []
    Nyckelord :ALS; SOD1; complete penetrance; incomplete penetrance; mis-diagnosis; upper motor neuron; clinical neurophysiology; transcranial magnetic stimulation; peristimulus time histogram; corticospinal pathway; cortical inhibition; cortical hyper-excitability;

    Sammanfattning : Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by loss of motor neurons and their supporting cells in the brain, brainstem and spinal cord, resulting in muscle paresis and paralysis including the bulbar (speech, chewing, swallowing) and respiratory muscles. The average age at onset is 55 years, and death due to respiratory failure occurs 2-5 years after symptom onset in ~ 85% of cases. LÄS MER