Neuroscience and Neurobiology Commons^™

Validation On Sodium Channel Dependence By Electrical Stimulation-Induced Dopamine Release, Alice E. Hernandez ^, Mabel N. Terminel, Edward Castaneda *

COURI Symposium Abstracts, Spring 2012

No abstract provided.

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 We and others have found decreased levels of cystine-glutamate exchange in animals withdrawn from chronic cocaine administration.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 …

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 …

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 …

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 …

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.

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.

A Parametric Investigation Of Pattern Separation Processes In The Medial Temporal Lobe, Sarah E. Motley

Theses and Dissertations

The hippocampus is thought to be involved in memory formation and consolidation, with computational models proposing the process of pattern separation as a means for encoding overlapping memories. Previous research has used semantically related targets and lures to investigate hippocampal responses to mnemonic interference. Here, we attempted to define the response function of the hippocampus and its inputs during pattern separation by parametrically varying target-lure similarity in a continuous recognition task. We also investigated the effect of task demands (intentional versus incidental encoding) on pattern separation processes. We collected functional magnetic resonance imaging (fMRI) data while participants were shown a …

Brainstorm: Of Weirds And Sushis And People Who Use Chopsticks, John J. Medina Ph.D.

Brainstorm

Understanding the contributions that nature and nurture make to a given behavior is tricky business, even for professionals in the field. The research world is littered with heroic, but ultimately unsuccessful, attempts to tease these apart.

Medial Pfc Damage Abolishes The Self-Reference Effect, Carissa Philippi, Melissa Duff, Natalie Denburg, Daniel Tranel, David Rudrauf

Psychology Faculty Works

No abstract provided.

Pten Regulation Of Local And Long-Range Connections In Mouse Auditory Cortex, Qiaojie Xiong, Hysell V. Oviedo, Lloyd C. Trotman, Anthony M. Zador

Publications and Research

Autism spectrum disorders (ASDs) are highly heritable developmental disorders caused by a heterogeneous collection of genetic lesions. Here we use a mouse model to study the effect on cortical connectivity of disrupting the ASD candidate gene PTEN (phosphatase and tensin homolog deleted on chromosome 10). Through Cre-mediated recombination, we conditionally knocked out PTEN expression in a subset of auditory cortical neurons. Analysis of long-range connectivity using channelrhodopsin-2 revealed that the strength of synaptic inputs from both the contralateral auditory cortex and from the thalamus onto PTEN-cko neurons was enhanced compared with nearby neurons with normal PTEN expression. Laser-scanning photostimulation showed …

Brainstorm: What Testosterone Has In Common With Schrodinger’S Cat, John J. Medina Ph.D.

Brainstorm

People are often startled by the extent to which environment plays a part in mediating the biological processes behind their behaviors.

Spartin Protein Associates With Phospholipids Via Its Plant-Related Senescence Domain And Functions As A Lipid Transfer Protein, Maureen Ashlee Shaw

Theses (1 year embargo)

Troyer syndrome is a hereditary spastic paraplegia caused by a mutation that leads to a complete loss of expression of spartin protein. The plant-related senescence domain in spartin is highly conserved and present in over 150 proteins, but its function is unknown. Our results indicate that spartin associates with phospholipids via its senescence domain.

Phospholipids are important components of intracellular membranes and play roles in many cellular processes. Knock-down of spartin results in impaired cell division. The phospholipid phosphatidylinositol 3-phosphate (PI3P) is present at midbodies, where it recruits proteins for cytokinesis. Our findings demonstrate that spartin colocalizes with PI3P at …

Serotonin 1a Receptor-Mediated Signaling Through Erk And Pkcα Is Essential For Normal Synaptogenesis In Neonatal Mouse Hippocampus, A. Mogha, Sara R. Guariglia, Priya Ranjan Debata, Guang Y. Wen, Probal Banerjee

Publications and Research

Aberrant expression of the presynaptic serotonin 1A receptor (5-HT_1A-R) because of a polymorphism in the 5-HT_1A-R gene is associated with severe depression in human, whereas its absence up to postnatal day 21 (P21) in the forebrain of mice results in heightened anxiety in adulthood. These observations collectively indicate that the 5-HT1A-R has a crucial role in brain development. To understand the mechanistic underpinnings of this phenomenon, we used organotypic slice cultures of hippocampi from C57BL6 mice (C57) at P15, which coincides with the peak of neonatal synaptogenesis. Stimulation of the hippocampal 5-HT1A-R caused a dramatic increase …

Derivation Of A Novel Efficient Supervised Learning Algorithm From Cortical-Subcortical Loops, Ashok Chandrashekar, Richard Granger

Dartmouth Scholarship

Although brain circuits presumably carry out powerful perceptual algorithms, few instances of derived biological methods have been found to compete favorably against algorithms that have been engineered for specific applications. We forward a novel analysis of a subset of functions of cortical-subcortical loops, which constitute more than 80% of the human brain, thus likely underlying a broad range of cognitive functions. We describe a family of operations performed by the derived method, including a non-standard method for supervised classification, which may underlie some forms of cortically dependent associative learning. The novel supervised classifier is compared against widely used algorithms for …

Hiv-1 Tat Triggers Nuclear Localization Of Zo-1 Via Rho Signaling And Camp Response Element-Binding Protein Activation, Yu Zhong, Bei Zhang, Sung Yong Eum, Michal Toborek

Neurosurgery Faculty Publications

The human immunodeficiency virus (HIV)-specific protein trans-activator of transcription (Tat) can contribute to the dysfunction of brain endothelial cells and HIV trafficking into the brain by disrupting tight junction (TJ) integrity at the blood–brain barrier (BBB) level. Specific TJ proteins, such as zonula occludens (ZO) proteins, localize not only at the cell–cell borders but are also present in the nuclei. The objective of the present study was to evaluate the mechanisms and significance of Tat-induced nuclear localization of ZO-1. Treatment of a brain endothelial cell line (hCMEC/D3 cells) with Tat resulted in a decrease in total levels of ZO-1 but …

Brainstorm: A Tale Of Two Video Clips, John J. Medina Ph.D.

Brainstorm

I have spent a lifetime trying to understand the distance between a gene and a behavior. Using the lens of psychiatric disorders, I’ve spent most of my professional life as a private research consultant, primarily to the pharmaceutical and biotech industries, on issues related to mental health. Despite great strides made in the field by literally thousands of colleagues, I am here to report that the rocky terrain between behaviors and genes lies mostly unmapped. For that I blame two video clips, both featuring legendary golfer and famously troubled ex­husband, Tiger Woods.