Neuroscience and Neurobiology Commons^™

Brainstorm: Of Princesses And Football Players, John J. Medina Ph.D.

Brainstorm

Sports-­related head injuries are getting a lot of press these days. Learning from injuries sustained by prize fighters, hockey players, and American football players, researchers are beginning to understand there are severe consequences to sustained trauma on the mental life of professional athletes — even amateur, Saturday­afternoon athletes. Sports officials could do well to remember the cautionary tale I am about to relate here.

The Effects Of Prenatal Exposure To Altered Melatonin Levels On Hippocampal Gene Expression In The Male Rat, Anna Uehara

Honors Theses

The stability of the circadian rhythm for mammals depends on the levels of serotonin and melatonin, neurohormones that signal for lightness and darkness, respectively. Disruption in the stability of neurohormones has been shown to be a critical factor in psychopathological disorders in humans. For example, altering levels of melatonin in utero through administration of melatonin or the melatonin receptor antagonist, luzindole, has been shown to cause changes in developmental growth and adult behavior in the male rat. Analysis of relative adult hippocampal gene expression with RT-PCR revealed differences in ARNTL expression that suggested abnormality in clock gene expression of the …

Data Sharing In Neuroimaging Research, Jean-Baptiste Poline, Janis L. Breeze, Satrajit Ghosh, Krzysztof Gorgolewski, Yaroslav O. Halchenko

Dartmouth Scholarship

Significant resources around the world have been invested in neuroimaging studies of brain function and disease. Easier access to this large body of work should have profound impact on research in cognitive neuroscience and psychiatry, leading to advances in the diagnosis and treatment of psychiatric and neurological disease. A trend toward increased sharing of neuroimaging data has emerged in recent years. Nevertheless, a number of barriers continue to impede momentum. Many researchers and institutions remain uncertain about how to share data or lack the tools and expertise to participate in data sharing. The use of electronic data capture (EDC) methods …

Effects Of Hypoxia-Ischemia And Anti-Inflammatory Prophylactic Treatment On Cortical And Hippocampal Volumes In The Developing Rat Brain, Llian Mabardi

Honors Projects

Very low body weight as a result of premature birth is a common problem all around the world. Many of these infants have medical issues that arise as a direct result of their very low body weight. One of the biggest issues is a lack of oxygen, which is also known as hypoxia. Hypoxia and ischemia (lack of blood flow) are a problem at any age, but they can be especially devastating to infants who have not undergone critical periods of brain development. Hypoxia-ischemia (or HI) can cause problems that start as inflammation and end with large-scale cell death in …

Dysregulation Of System Xc- And Its Impact On Cocaine Seeking, Aric Madayag

Dissertations (1934 -)

Abnormal glutamate signaling in the brain, particularly in the nucleus accumbens core, contributes to compulsive cocaine-seeking behavior. In the nucleus accumbens, two distinct pools of glutamate exist. The synaptic pool stimulates excitatory postsynaptic receptors, leading to cocaine seeking. Cystine-glutamate exchange by system xc- contributes to the extrasynaptic pool and regulates neurotransmission by activating extrasynaptic receptors including inhibitory Group II metabotropic glutamate receptors, positioning this as an important mechanism for regulating nucleus accumbens activity. We and others have found decreased levels of cystine-glutamate exchange in animals withdrawn from chronic cocaine administration. In chapter 1, we describe studies directly implicating diminished system …

Neural Synchrony In The Zebra Finch Brain, Sydney Pia Goings

Scripps Senior Theses

I am interested in discovering the role of field potential oscillations in producing synchrony within the song system of the male zebra finch brain. An important function attributed to neural synchrony is sensorimotor integration. In the production of birdsong, sensorimotor integration is crucial, as auditory feedback is necessary for the maintenance of the song. A cortical-thalamic-cortical feedback loop is thought to play a role in the integration of auditory and motor information for the purpose of producing song. Synchronous activity has been observed between at least two nuclei in this feedback loop, MMAN and HVC. Since low frequency field potential …

Cosmetic Neurology: Enhancement Of The Mind And Attention Deficit Hyperactive Disorder Medication Abuse Among College Students, Mary M. Huff

Senior Honors Theses

Cosmetic neurology is becoming increasingly popular, and it is not just sleep deprived, over worked college students who are interested. People are beginning to seek off-label prescriptions for medications that are typically used to treat disorders such as attention deficit hyperactive disorder (ADHD) or narcolepsy, while researchers are trying to create drugs used solely for mind enhancement purposes. Along with these drugs come many legal and ethical quandaries relating to the regulation of current use as well as the what ifs of future possibilities. A survey was conducted among college students regarding the diagnosis of ADHD, the abuse of ADHD …

Role Of Neurosteroids In The Anticonvulsant Activity Of Midazolam, Ashish Dhir, Michael A. Rogawski

Michael A. Rogawski

BACKGROUND AND PURPOSE Midazolam is a short-acting benzodiazepine that is widely used as an intravenous sedative and anticonvulsant. Besides interacting with the benzodiazepine site associated with GABA-A receptors, some benzodiazepines act as agonists of translocator protein (18 kDa) (TSPO) to enhance the synthesis of steroids, including neurosteroids with positive modulatory actions on GABA-A receptors. We sought to determine if neurosteroidogenesis induced by midazolam contributes to its anticonvulsant action. EXPERIMENTAL APPROACH Mice were pretreated with neurosteroid synthesis inhibitors and potentiators followed by midazolam or clonazepam, a weak TSPO ligand. Anticonvulsant activity was assessed with the intravenous pentylenetetrazol (PTZ) threshold test. KEY …

Flatbed Scanner Report - Optical Density Dynamic Range, George Mcnamara

George McNamara

George McNamara (now at University of Miami) report for Hua Yu and Richard Jove, City of Hope National Medical Center, on optical density dynamic range of several flatbed scanners.

A Drosophila Deg/Enac Subunit Functions Specifically In Gustatory Neurons Required For Male Courtship Behavior, E. Starostina, T. Liu, V. Vijayan, Zheng Zheng , '11, Kathleen King Siwicki, C. W. Pikielny

Biology Faculty Works

Detection of specific female pheromones stimulates courtship behavior in Drosophila melanogaster males, but the chemosensory molecules, cells, and mechanisms involved remain poorly understood. Here we show that ppk25, a DEG/ENaC ion channel subunit required for normal male response to females, is expressed at highest levels in a single sexually dimorphic gustatory neuron of most taste hairs on legs and wings, but not in neurons that detect courtship-inhibiting pheromones or food. Synaptic inactivation of ppk25-expressing neurons, or knockdown of ppk25 expression in all gustatory neurons, significantly impairs male response to females, whereas gustatory expression of ppk25 rescues the courtship behavior of …

Brainstorm: Of Sign Language And Combat Veterans, Part 2, John J. Medina Ph.D.

Brainstorm

In the last entry I talked about sign language, and I promised in this space to talk about combat veterans. This entry fulfills the promise (though I am also going to talk about business cards).

Integration Of Subthreshold And Suprathreshold Excitatory Barrages Along The Somatodendritic Axis Of Pyramidal Neurons, Hysell V. Oviedo, Alex D. Reyes

Publications and Research

Neurons integrate inputs arriving in different cellular compartments to produce action potentials that are transmitted to other neurons. Because of the voltage- and time-dependent conductances in the dendrites and soma, summation of synaptic inputs is complex. To examine summation of membrane potentials and firing rates, we performed whole-cell recordings from layer 5 cortical pyramidal neurons in acute slices of the rat’s somatosensory cortex. We delivered subthreshold and suprathreshold stimuli at the soma and several sites on the apical dendrite, and injected inputs that mimic synaptic barrages at individual or distributed sites. We found that summation of subthreshold potentials differed from …

Selective Serotonergic Excitation Of Callosal Projection Neurons, Daniel Avesar, Allan T. Gulledge

Dartmouth Scholarship

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) in the mouse medial prefrontal cortex (mPFC), and found three distinct response types: long-lasting 5-HT_1A (1A) receptor-dependent inhibitory responses (84% of L5PNs), 5-HT_2A (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 …

Vestibular And Attractor Network Basis Of The Head Direction Cell Signal In Subcortical Circuits, Benjamin J. Clark, Jeffrey S. Taube

Dartmouth Scholarship

Accurate navigation depends on a network of neural systems that encode the moment-to-moment changes in an animal's directional orientation and location in space. Within this navigation system are head direction (HD) cells, which fire persistently when an animal's head is pointed in a particular direction (Sharp et al., 2001a; Taube, 2007). HD cells are widely thought to underlie an animal's sense of spatial orientation, and research over the last 25+ years has revealed that this robust spatial signal is widely distributed across subcortical and cortical limbic areas. The purpose of the present review is to summarize some of …

Brainstorm: Of Sign Language And Combat Veterans, Part 1, John J. Medina Ph.D.

Brainstorm

Dr. McNeill has been researching the relationship between verbal and nonverbal communications for most of his career, a subject we began discussing last entry. His work is very relevant to our ongoing conversation about nature, nurture, and human behavior.

Roles Of The Ion Channel Nalcn In Neuronal Excitability Control, Boxun Lu

Boxun Lu

The resting membrane potential (RMP) of a neuron is set by a complex balance between charged ions, ion channels and transporters. Many of the ion channels have been identified at the molecular level. Missing from the molecular identification has been the voltage-insensitive background sodium ‘‘leak’’ conductance that depolarizes the RMP from the equilibrium potential of potassium and provides a crucial contribution to neuronal excitability One candidate for the molecular identity of this conductance is the protein NALCN. NALCN is a previously uncharacterized orphan member in the sodium/calcium channel family. It is widely expressed in the nervous system. My thesis project …

Propofol Hemisuccinate Suppresses Cortical Spreading Depression, Ashish Dhir, Christoph Lossin, Michael A. Rogawski

Michael A. Rogawski

Propofol is a rapidly acting water-insoluble non-barbiturate anesthetic agent that is widely used as an intravenous sedative-hypnotic agent. Anecdotal evidence indicates that propofol may be effective at terminating intractable migraine headache. Cortical spreading depression (CSD) is believed to be the neural correlate of migraine aura and may be a trigger for migraine pain. Agents that block the induction or slow the spread of CSD may be of utility in treating migraine. Here we examined the ability of propofol hemisuccinate (PHS), a water-soluble prodrug of propofol, to affect CSD in mice. For comparison, we examinined dizocilpine, an NMDA receptor antagonist, that …

Brainstorm: Nature And Nurture And Dogs, John J. Medina Ph.D.

Brainstorm

It is easy to run across the intersection between nature and nurture in the everyday routines of life. You can even find it in a crisis, as the following true story relates.

Introduction To Nanoscopy Nano-Talk, George Mcnamara

George McNamara

T7-1 is the designation for the LMRG Nanoscopy session at ABRF in Orlando, FL, on March 20, 2012. The PDF file here is a draft of my presentation.

May not be very helpful since (1) would probably help to know what is in my head and each slide will [hopefully] prompt me to say, and (2) 10 minute talk so I am going to push the "next slide" button after saying very little.

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Publisher statement:

The T7-1 Introduction to Nanoscopy Nano Talk is copyrighted (c) George McNamara, 2012. Except for (1) screenshots from research articles (which are copyrighted by …

Pubspectra - Open Data Access Fluorescence Spectra, George Mcnamara

George McNamara

The Internet is enabling greater access to spectral imaging publications, spectral graphs, and data than that was available a generation ago. The spectral imaging systems discussed in this issue of Cytometry work because reagent and hardware spectra are reproducible, reusable, and provide input to spectral unmixing and spectral components recognition algorithms. These spectra need to be readily available in order to determine what to purchase, how to use it, and what the output means. We refer to several commercially sponsored and academic spectral web sites and discuss our spectral graphing and data sites. Sites include fluorescent dye graph servers from …