Neuroscience and Neurobiology Commons^™

Six Types Of Multistability In A Neuronal Model Based On Slow Calcium Current, Tatiana Malashchenko, Andrey Shilnikov, Gennady Cymbalyuk

Neuroscience Institute Faculty Publications

Background: Multistability of oscillatory and silent regimes is a ubiquitous phenomenon exhibited by excitable systems such as neurons and cardiac cells. Multistability can play functional roles in short-term memory and maintaining posture. It seems to pose an evolutionary advantage for neurons which are part of multifunctional Central Pattern Generators to possess multistability. The mechanisms supporting multistability of bursting regimes are not well understood or classified.

Methodology/Principal Findings: Our study is focused on determining the bio-physical mechanisms underlying different types of co-existence of the oscillatory and silent regimes observed in a neuronal model. We develop a low-dimensional model typifying the dynamics …

Non-Invasive Imaging Of Neuroanatomical Structures And Neural Activation With High-Resolution Mri, Jens Herberholz, Subrata H. Mishra, Divya Uma, Markus W. Germann, Donald H. Edwards, Kimberlee Potter

Neuroscience Institute Faculty Publications

Several years ago, manganese-enhanced magnetic resonance imaging (MEMRI) was introduced as a new powerful tool to image active brain areas and to identify neural connections in living, non-human animals. Primarily restricted to studies in rodents and later adapted for bird species, MEMRI has recently been discovered as a useful technique for neuroimaging of invertebrate animals. Using crayfish as a model system, we highlight the advantages of MEMRI over conventional techniques for imaging of small nervous systems. MEMRI can be applied to image invertebrate nervous systems at relatively high spatial resolution, and permits identification of stimulus-evoked neural activation non-invasively. Since the …

Excitotoxic Lesions Of The Nucleus Paragigantocellularis Facilitate Male Sexual Behavior But Attenuate Female Sexual Behavior In Rats, Joseph J. Normandin, Anne Z. Murphy Phd

Neuroscience Institute Faculty Publications

Little is known regarding the descending inhibitory control of genital reflexes such as ejaculation and vaginal contractions. The brainstem nucleus paragigantocellularis (nPGi) projects bilaterally to the lumbosacral motoneuron pools that innervate the genital musculature of both male and female rats. Electrolytic nPGi lesions facilitate ejaculation in males, leading to the hypothesis that the nPGi is the source of descending inhibition to genital reflexes. However, the function of the nPGi in female sexual behavior remains to be elucidated. To this end, male and female rats received bilateral excitotoxic fiber-sparing lesions of the nPGi, and sexual behavior and sexual behavior-induced Fos expression …

Serotonergic Lesions Of The Periaqueductal Gray, A Primary Source Of Serotonin To The Nucleus Paragigantocellularis, Facilitate Sexual Behavior In Male Rats, Joseph J. Normandin, Anne Z. Murphy Phd

Neuroscience Institute Faculty Publications

While selective serotonin reuptake inhibitors (SSRIs) are widely used to treat anxiety and depression, they also produce profound disruptions of sexual function including delayed orgasm/ejaculation. The nucleus paragigantocellularis (nPGi), a primary source of inhibition of ejaculation in male rats, contains receptors for serotonin (5-HT). The ventrolateral periaqueductal gray (vlPAG) provides serotonin to this region, thus providing an anatomical and neurochemical basis for serotonergic regulation of the nPGi. We hypothesize that 5-HT acting at the nPGi could underlie the SSRI-induced inhibition of ejaculation in rodents. To this end, we produced 5-HT lesions of the source of 5-HT to the nPGi (the …

Somatic Genital Reflexes In Rats With A Nod To Humans: Anatomy, Physiology, And The Role Of The Social Neuropeptides, Joseph J. Normandin, Anne Z. Murphy Phd

Neuroscience Institute Faculty Publications

Somatic genital reflexes such as ejaculation and vaginocervical contractions are produced through the striated muscles associated with the genitalia. The coordination of these reflexes is surprisingly complex and involves a number of lumbosacral spinal and supraspinal systems. The rat model has proved to be an excellent source of information regarding these mechanisms, and many parallels to research in humans can be drawn. An understanding of the spinal systems involving the lumbosacral spinal cord, both efferent and afferent, has been generated through decades of research. Spinal and supraspinal mechanisms of descending excitation, through a spinal ejaculation generator in the lumbar spinal …

Use Of Granger Causality Analysis And Artificial Spike Trains To Examine Pause Coding In Purkinje Cell Spike Activity Related To Rhythmic Licking, Selva K. Maran, Ying Cao, Mukesh Dhamala

Neuroscience Institute Faculty Publications

Cerebellar Purkinje cells in mice show strong activity modulation related to rhythmic licking behavior. Here we examine whether this modulation may preferentially be related to long inter-spike intervals (ISIs), i.e. pauses in spike activity.

Parameter-Sweeping Techniques For Temporal Dynamics Of Neuronal Systems: Case Study Of Hindmarsh-Rose Model, Roberto Barrio, Andrey Shilnikov

Neuroscience Institute Faculty Publications

Background: Development of effective and plausible numerical tools is an imperative task for thorough studies of nonlinear dynamics in life science applications.

Results: We have developed a complementary suite of computational tools for twoparameter screening of dynamics in neuronal models. We test a ‘brute-force’ effectiveness of neuroscience plausible techniques specifically tailored for the examination of temporal characteristics, such duty cycle of bursting, interspike interval, spike number deviation in the phenomenological Hindmarsh-Rose model of a bursting neuron and compare the results obtained by calculus-based tools for evaluations of an entire spectrum of Lyapunov exponents broadly employed in studies of …

Spontaneous Voltage Oscillations And Response Dynamics Of A Hodgkin-Huxley Type Model Of Sensory Hair Cells, Alexander B. Neiman, Kai Dierkes, Benjamin Lindner, Lijuan Han, Andrey Shilnikov

Neuroscience Institute Faculty Publications

We employ a Hodgkin-Huxley-type model of basolateral ionic currents in bullfrog saccular hair cells for studying the genesis of spontaneous voltage oscillations and their role in shaping the response of the hair cell to external mechanical stimuli. Consistent with recent experimental reports, we find that the spontaneous dynamics of the model can be categorized using conductance parameters of calciumactivated potassium, inward rectifier potassium, and mechano-electrical transduction (MET) ionic currents. The model is demonstrated for exhibiting a broad spectrumof autonomous rhythmic activity, including periodic and quasi-periodic oscillations with two independent frequencies as well as various regular and chaotic bursting patterns. Complex …