Neuroscience and Neurobiology Commons^™

Imaging Prior Information In The Brain, Scott Gorlin, Ming Meng, Jitendra Sharma, Hiroki Sugihara

Dartmouth Scholarship

In making sense of the visual world, the brain's processing is driven by two factors: the physical information provided by the eyes (“bottom-up” data) and the expectancies driven by past experience (“top-down” influences). We use degraded stimuli to tease apart the effects of bottom-up and top-down processes because they are easier to recognize with prior knowledge of undegraded images. Using machine learning algorithms, we quantify the amount of information that brain regions contain about stimuli as the subject learns the coherent images. Our results show that several distinct regions, including high-level visual areas and the retinotopic cortex, contain more information …

Synaptic And Systems Memory Consolidation In The Black-Capped Chickadee (Poecile Atricapillus), Matthew Barrett

Electronic Thesis and Dissertation Repository

ABSTRACT

Memory consolidation - the time-dependent stabilization of information- involves two processes: 1) synaptic consolidation and 2) systems consolidation. Synaptic consolidation uses a series of protein synthesis cascades that make lasting changes in the underlying neural architecture of a memory. Systems consolidation involves the reorganization of memory such that, with the passage of time, memory that is initially hippocampus-dependent can be retrieved and activated independent of the hippocampus. Black-capped chickadees (Poecile atricapillus) store and relocate food using hippocampus-dependent spatial memory. In Chapter 2 inhibition of protein synthesis by anisomycin, either 0 and 2 h or 4 and 6 …

Navigating The Diverse Dimensions Of Stereotypes, With Domain Specific Deficits: Processes Of Trait Judgments About Individuals With Disabilities, Christina G. Boardman

Scripps Senior Theses

Stereotype groups are interrelated. For example, in Australia, New Zealand, and the United States, racial minorities are referred to special education at a much higher rate than are majority racial groups (Tse, Lloyd, Petchkovsky, and Manaia, 2005; Harry, Arnaiz, Klingner, Sturges, 2008). The Stereotype Content Model describes stereotype relationships in terms of an interaction between competence and warmth. Warmth is the more consistent dimension. The nature of competence remains elusive (Fiske, Cuddy, and Glick, 2007; Fiske, Cuddy, Glick, and Xu, 2002). Knowledge of relationships between stereotype groups, which themselves may be effects of bias, could factor into observed competence effects. …

Increased Modulation By Cognitive Control Region During Fmri Working Memory Task Suggest Inefficiencies In Network Connectivity In Children With Adhd, Ashley Burgess

Honors College Theses

Attention Deficit / Hyperactivity Disorder is a neurodevelopmental disorder common among children and adolescent populations whose symptoms are believed to be caused by deficits in executive functioning processes such as working memory. Using fMRI analyses, differences in the modulatory influence exhibited by the dorsal anterior cingulate cortex (dACC) on cortico-striatal regions implicated in working memory (2-back) (Owen et al 2005) was assessed between children with ADHD (twenty-three participants; mean age 6 yrs: 6.4-14.9 yrs) and healthy controls (twenty-six participants; mean age 10.1yrs: 6.3-14.1 yrs). Modulatory influence is defined as the degree to which one region exerts control on another region …

Iconic Memory Requires Attention, Marjan Persuh, Boris Genzer, Robert D. Melara

Publications and Research

Two experiments investigated whether attention plays a role in iconic memory, employing either a change detection paradigm (Experiment 1) or a partial-report paradigm (Experiment 2). In each experiment, attention was taxed during initial display presentation, focusing the manipulation on consolidation of information into iconic memory, prior to transfer into working memory. Observers were able to maintain high levels of performance (accuracy of change detection or categorization) even when concurrently performing an easy visual search task (low load). However, when the concurrent search was made difficult (high load), observers' performance dropped to almost chance levels, while search accuracy held at single-task …

Brainstorm: Brain Development, Part 1: Of Mops And Brain Cells And Human Behavior, John J. Medina Ph.D.

Brainstorm

We have been discussing in equal measure the contributions that both natureand nurture make in the creation of human behavior. In this entry and the next, we are going to focus on the nature side of the discussion, summarizing a few features about how the human brain develops in the womb.

Evidence For Pit-Type (Slc20) And Napi-Ii-Type (Slc34) Transporters In The Rat Choroid Plexus, Hien M. Le

Honors Scholar Theses

: A major function of the brain choroid plexus (CP) is to regulate the exchange of solutes between the blood plasma and the cerebrospinal fluid (CSF) using selective transporters. CSF inorganic phosphate (P_i) concentration is maintained at about one-half that of plasma and is potentially important because of its regulatory, structural, and biochemical functions. Phosphate is critical for ATP and DNA formation, the linked regulation between phosphate and calcium, and as an intracellular buffer. The human body has two major P_i transporter gene families known as SLC34 (NaPi-II) and SLC20 (PiT), which have wide tissue distribution. Although …

The Effects Of Rectal Temperature And Hydration Status On Perceptual Ratings In Dehydrating Males, Ethan A. Talbot

Honors Scholar Theses

Athletes push the limits of what the human body can handle every day. When they exercise in the heat, they can attain dangerous levels of internal temperature and dehydration. Since athletes are sometimes not aware when they are experiencing severe hyperthermia or hypohydration, it is of interest to anyone who exercises in the heat to study whether athletes are consciously aware that they are approaching dangerous physiological limits. This study compares the perceptual values of athletes exercising in the heat to the changes in their internal temperature and hydration status, to see if athletes can reliably predict their heat and …

Robust Dynamic Balance Of Ap-1 Transcription Factors In A Neuronal Gene Regulatory Network., Gregory M Miller, Babatunde A Ogunnaike, James S Schwaber, Rajanikanth Vadigepalli

Rajanikanth Vadigepalli

BACKGROUND: The octapeptide Angiotensin II is a key hormone that acts via its receptor AT1R in the brainstem to modulate the blood pressure control circuits and thus plays a central role in the cardiac and respiratory homeostasis. This modulation occurs via activation of a complex network of signaling proteins and transcription factors, leading to changes in levels of key genes and proteins. AT1R initiated activity in the nucleus tractus solitarius (NTS), which regulates blood pressure, has been the subject of extensive molecular analysis. But the adaptive network interactions in the NTS response to AT1R, plausibly related to the development of …

Eye Size At Birth In Prosimian Primates: Life History Correlates And Growth Patterns, Joshua R. Cummings, Magdalena N. Muchlinski, E. Christopher Kirk, Susan J. Rehorek, Valerie B. Deleon, Timothy D. Smith

Neuroscience Faculty Publications

BACKGROUND: Primates have large eyes relative to head size, which profoundly influence the ontogenetic emergence of facial form. However, growth of the primate eye is only understood in a narrow taxonomic perspective, with information biased toward anthropoids.

METHODOLOGY/PRINCIPAL FINDINGS: We measured eye and bony orbit size in perinatal prosimian primates (17 strepsirrhine taxa and Tarsius syrichta) to infer the extent of prenatal as compared to postnatal eye growth. In addition, multiple linear regression was used to detect relationships of relative eye and orbit diameter to life history variables. ANOVA was used to determine if eye size differed according to activity …

Structural Analysis Of The Drosophila Innexin Shakb: Role Of The N-Terminus In Rectifying Electrical Synapses, William Marks

Biology Theses

Gap junction channels mediate direct intercellular communication in all multicellular animals. They are comprised of the connexin family of proteins in vertebrates and the innexin family in prechordates. Connexins and innexins share many functional and structural similarities as orthologous proteins. Both types are capable of forming electrical synapses. Rectifying junctions are specialized electrical synapses found in neural systems that control escape responses. It has been shown that heterotypic gap junction channels mediate asymmetric properties of rectifying junctions. Shaking B N+16 and Shaking B lethal are variants of the ShakB locus in Drosophila and the organization of these innexins into heterotypic …

Effects Of Maternal Low Protein Diet On Expression Of Drug Transporters In The Blood-Brain Barrier Of Adult Offspring, Bonnie L. Hastings

Senior Theses

Adverse uterine environment, manifested as low birth weight (LBW), has been shown to predispose individuals to hypertension, diabetes, and obesity by mechanisms that are just beginning to be understood. One of the mechanisms is the dysregulation of the expression or function of drug transport proteins, such as the organic anion transporter (OAT) family, which are crucial for the transport of various endogenous and exogenous compounds into and out of all organs, especially the brain. Hence, we examined the status of select drug transporters in the blood-brain barrier (BBB), using a LBW rat model. Maternal low protein diet (LPD) during gestation …

Role Of Trp Channels In Mediating The Calcium Signaling Response Of Brain Endothelial Cells To Mechanical Stretch, Jonathan Berrout

Dissertations & Theses (Open Access)

Traumatic brain injury (TBI) often results in disruption of the blood brain barrier (BBB), which is an integral component to maintaining the central nervous system homeostasis. Recently cytosolic calcium levels ([Ca²⁺]i), observed to elevate following TBI, have been shown to influence endothelial barrier integrity. However, the mechanism by which TBI-induced calcium signaling alters the endothelial barrier remains unknown. In the present study, an in vitro BBB model was utilized to address this issue. Exposure of cells to biaxial mechanical stretch, in the range expected for TBI, resulted in a rapid cytosolic calcium increase. Modulation of intracellular and extracellular …

Population Coding In Laminar Cortical Circuits, Bryan J. Hansen

Dissertations & Theses (Open Access)

One of the fundamental questions in neuroscience is to understand how encoding of sensory inputs is distributed across neuronal networks in cerebral cortex to influence sensory processing and behavioral performance. The fact that the structure of neuronal networks is organized according to cortical layers raises the possibility that sensory information could be processed differently in distinct layers. The goal of my thesis research is to understand how laminar circuits encode information in their population activity, how the properties of the population code adapt to changes in visual input, and how population coding influences behavioral performance. To this end, we performed …

Novel Use Of Dual Anti-Inflammatory Therapy To Overcome Drug Resistance And Improve Functional Recovery Following Spinal Cord Injury, Jennifer Dulin

Dissertations & Theses (Open Access)

Over 1.2 million Americans are currently living with a traumatic spinal cord injury (SCI). Despite the need for effective therapies, there are currently no proven effective treatments that can improve recovery of function in SCI patients. Many therapeutic compounds have shown promise in preclinical models of SCI, but all of these have fallen short in clinical trials.

P-glycoprotein (Pgp) is an active transporter expressed on capillary endothelial cell membranes at the blood-spinal cord barrier (BSCB). Pgp limits passive diffusion of blood-borne drugs into the CNS, by actively extruding drugs from the endothelial cell membrane. Pgp can become pathologically up-regulated, thus …

Characterization Of Seizures Induced By Acute And Repeated Exposure To Tetramethylenedisulfotetramine, Dorota Zolkowska, Christopher N. Banks, Ashish Dhir, Bora Inceoglu, James R. Sanborn, Mark R. Mccoy, Donald A. Bruun, Bruce D. Hammock, Pamela J. Lein, Michael A. Rogawski

Michael A. Rogawski

Tetramethylenedisulfotetramine (tetramine; TETS) is a potent convulsant poison that is considered to be a chemical threat agent. To provide a basis for the investigation of antidotes for TETS-induced seizures, we characterized the convulsant activity of TETS in mice and rats when administered by the intraperitoneal, intravenous, oral and intraventricular routes as a single acute dose and with repeated sublethal doses. In mice, parenteral and oral TETS caused immobility, myoclonic body jerks, clonic seizures of the forelimbs and/or hindlimbs, tonic seizures and death. The CD50 values for clonic and tonic seizures following oral administration were 0.11 and 0.22 mg/kg, respectively. Intraventricular …

Smoothness Selection For Penalized Quantile Regression Splines, Philip T. Reiss, Lei Huang

Philip T. Reiss

Modern data-rich analyses may call for fitting a large number of nonparametric quantile regressions. For example, growth charts may be constructed for each of a collection of variables, to identify those for which individuals with a disorder tend to fall in the tails of their age-specific distribution; such variables might serve as developmental biomarkers. When such analyses are carried out by penalized spline smoothing, reliable automatic selection of the smoothing parameter is particularly important. We show that two popular methods for smoothness selection may tend to overfit when estimating extreme quantiles as a smooth function of a predictor such as …

Semiparametric Methods For Mapping Brain Development, Philip T. Reiss, Yin-Hsiu Chen, Lan Huo

Philip T. Reiss

No abstract provided.

Parkinson’S Disease: Molecular Mechanisms And Treatments, Delia Vahey

Senior Honors Theses

Parkinson’s disease is a motor system disorder that is caused primarily by the loss of dopamine-producing brain cells. The most affected brain structure is the pars compacta of the substantia nigra. This area of the brain is essential to the control of voluntary movement, and so its impairment leads to symptoms such as tremors, rigidity, and impaired balance. The neuronal protein alpha-synuclein has been shown to be heavily involved in the pathogenesis of the disease at the cellular level. The currently available treatments for PD mainly target dopamine regulation, and there been no cure developed for the disease at present. …

The Neurobiology Of Decision-Making And Responsibility: Reconciling Mechanism And Mindedness, Michael N. Shadlen, Adina L. Roskies

Dartmouth Scholarship

This essay reviews recent developments in neurobiology which are beginning to expose the mechanisms that underlie some elements of decision-making that bear on attributions of responsibility. These “elements” have been mainly studied in simple perceptual decision tasks, which are performed similarly by humans and non-human primates. Here we consider the role of neural noise, and suggest that thinking about the role of noise can shift the focus of discussions of randomness in decision-making away from its role in enabling alternate possibilities and toward a potential grounding role for responsibility.