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Full-Text Articles in Neuroscience and Neurobiology

Functional And Developmental Identification Of A Molecular Subtype Of Brain Serotonergic Neuron Specialized To Regulate Breathing Dynamics, Rachael D. Brust, Andrea E. Corcoran, George B. Richerson, Eugene Nattie, Susan M. Dymecki Dec 2014

Functional And Developmental Identification Of A Molecular Subtype Of Brain Serotonergic Neuron Specialized To Regulate Breathing Dynamics, Rachael D. Brust, Andrea E. Corcoran, George B. Richerson, Eugene Nattie, Susan M. Dymecki

Dartmouth Scholarship

Serotonergic neurons modulate behavioral and physiological responses from aggression and anxiety to breathing and thermoregulation. Disorders involving serotonin (5HT) dysregulation are commensurately heterogeneous and numerous. We hypothesized that this breadth in functionality derives in part from a developmentally determined substructure of distinct subtypes of 5HT neurons each specialized to modulate specific behaviors. By manipulating developmentally defined subgroups one by one chemogenetically, we find that the Egr2-Pet1 subgroup is specialized to drive increased ventilation in response to carbon dioxide elevation and acidosis. Furthermore, this subtype exhibits intrinsic chemosensitivity and modality-specific projections-increasing firing during hypercapnic acidosis and selectively projecting to respiratory chemosensory …


Enrichment And Training Improve Cognition In Rats With Cortical Malformations, Kyle R. Jenks, Marcella M. Lucas, Ben A. Duffy, Ashlee A. Robbins, Barjor Gimi, Jeremy M. Barry, Rod C. Scott Dec 2013

Enrichment And Training Improve Cognition In Rats With Cortical Malformations, Kyle R. Jenks, Marcella M. Lucas, Ben A. Duffy, Ashlee A. Robbins, Barjor Gimi, Jeremy M. Barry, Rod C. Scott

Dartmouth Scholarship

Children with malformations of cortical development (MCD) frequently have associated cognitive impairments which reduce quality of life. We hypothesized that cognitive deficits associated with MCD can be improved with environmental manipulation or additional training. The E17 methylazoxymethanol acetate (MAM) exposure model bears many anatomical hallmarks seen in human MCDs as well as similar behavioral and cognitive deficits. We divided control and MAM exposed Sprague-Dawley rats into enriched and non-enriched groups and tested performance in the Morris water maze. Another group similarly divided underwent sociability testing and also underwent Magnetic Resonance Imaging (MRI) scans pre and post enrichment. A third group …


Short Duration Waveforms Recorded Extracellularly From Freely Moving Rats Are Representative Of Axonal Activity, Ashlee A. Robbins, Steven E. Fox, Gregory L. Holmes, Rod C. Scott, Jeremy M. Barry Nov 2013

Short Duration Waveforms Recorded Extracellularly From Freely Moving Rats Are Representative Of Axonal Activity, Ashlee A. Robbins, Steven E. Fox, Gregory L. Holmes, Rod C. Scott, Jeremy M. Barry

Dartmouth Scholarship

While extracellular somatic action potentials from freely moving rats have been well characterized, axonal activity has not. We report direct extracellular tetrode recordings of putative axons whose principal feature is a short duration waveform (SDW) with an average peak-trough length less than 179 μs. While SDW recordings using tetrodes have previously been treated as questionable or classified as cells, we hypothesize that they are representative of axonal activity. These waveforms have significantly shorter duration than somatic action potentials, are triphasic and are therefore similar to classic descriptions of microelectrode recordings in white matter and of in vitro action potential propagation …


A Functional Role For The Ventrolateral Prefrontal Cortex In Non-Spatial Auditory Cognition, Y. E. Cohen, B. E. Russ, S. J. Davis, A. E. Baker, A. L. Ackelson, R. Niteck Nov 2009

A Functional Role For The Ventrolateral Prefrontal Cortex In Non-Spatial Auditory Cognition, Y. E. Cohen, B. E. Russ, S. J. Davis, A. E. Baker, A. L. Ackelson, R. Niteck

Dartmouth Scholarship

Spatial and non-spatial sensory information is hypothesized to be evaluated in parallel pathways. In this study, we tested the spatial and non-spatial sensitivity of auditory neurons in the ventrolateral prefrontal cortex (vPFC), a cortical area in the non-spatial pathway. Activity was tested while non-human primates reported changes in an auditory stimulus' spatial or non-spatial features. We found that vPFC neurons were reliably modulated during a non-spatial auditory task but were not modulated during a spatial auditory task. The degree of modulation during the non-spatial task correlated positively with the monkeys' behavioral performance. These results are consistent with the hypotheses that …


Microsaccade Rate Varies With Subjective Visibility During Motion-Induced Blindness, Po-Jang Hsieh, Peter U. Tse Apr 2009

Microsaccade Rate Varies With Subjective Visibility During Motion-Induced Blindness, Po-Jang Hsieh, Peter U. Tse

Dartmouth Scholarship

Motion-induced blindness (MIB) occurs when a dot embedded in a motion field subjectively vanishes. Here we report the first psychophysical data concerning effects of microsaccade/eyeblink rate upon perceptual switches during MIB. We find that the rate of microsaccades/eyeblink rises before and after perceptual transitions from not seeing to seeing the dot, and decreases before perceptual transitions from seeing it to not seeing it. In addition, event-related fMRI data reveal that, when a dot subjectively reappears during MIB, the blood oxygen-level dependent (BOLD) signal increases in V1v and V2v and decreases in contralateral hMT+. These BOLD signal changes observed upon perceptual …


Il-23 Produced By Cns-Resident Cells Controls T Cell Encephalitogenicity During The Effector Phase Of Experimental Autoimmune Encephalomyelitis, Burkhard Becher, Brigit G. Durell, Randolph J. Noelle Oct 2003

Il-23 Produced By Cns-Resident Cells Controls T Cell Encephalitogenicity During The Effector Phase Of Experimental Autoimmune Encephalomyelitis, Burkhard Becher, Brigit G. Durell, Randolph J. Noelle

Dartmouth Scholarship

CNS-resident cells, in particular microglia and macrophages, are a source of inflammatory cytokines during inflammation within the CNS. Expression of IL-23, a recently discovered cytokine, has been shown to be critical for the development of experimental autoimmune encephalomyelitis (EAE) in mice. Expression of the p40 subunit of IL-12 and IL-23 by microglia has been shown in situ and in vitro, but direct evidence for a functional significance of p40 expression by CNS cells during an immune response in vivo is still lacking. Here we report that p40 plays a critical role in maintaining encephalitogenicity during the disease course. By using …