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Full-Text Articles in Physiology

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 …


Interactions Between Connected Half-Sarcomeres Produce Emergent Mechanical Behavior In A Mathematical Model Of Muscle, Kenneth S. Campbell Nov 2009

Interactions Between Connected Half-Sarcomeres Produce Emergent Mechanical Behavior In A Mathematical Model Of Muscle, Kenneth S. Campbell

Physiology Faculty Publications

Most reductionist theories of muscle attribute a fiber's mechanical properties to the scaled behavior of a single half-sarcomere. Mathematical models of this type can explain many of the known mechanical properties of muscle but have to incorporate a passive mechanical component that becomes approximately 300% stiffer in activating conditions to reproduce the force response elicited by stretching a fast mammalian muscle fiber. The available experimental data suggests that titin filaments, which are the mostly likely source of the passive component, become at most approximately 30% stiffer in saturating Ca2+ solutions. The work described in this manuscript used computer modeling to …


Manipulating Testosterone To Assess Links Between Behavior, Morphology, And Performance In The Brown Anole Anolis Sagrei, Robert M. Cox, Derek S. Stenquist, Justin P. Henningsen, Ryan Calsbeek Aug 2009

Manipulating Testosterone To Assess Links Between Behavior, Morphology, And Performance In The Brown Anole Anolis Sagrei, Robert M. Cox, Derek S. Stenquist, Justin P. Henningsen, Ryan Calsbeek

Dartmouth Scholarship

Survival and reproductive success are determined by the complex interplay between behavior, physiology, morphology, and performance. When optimal trait combinations along these various phenotypic axes differ between sexes or across seasons, regulatory mechanisms such as sex steroids can often facilitate sex‐specific and/or seasonal trait expression. In this study, we used surgical castration and replacement of exogenous testosterone in adult male brown anoles (Anolis sagrei) to simultaneously examine the effects of testosterone on a suite of morphological (dewlap area, body size), physiological (immune function), behavioral (dewlap, head bob, and push‐up displays), and performance (stamina, sprint speed, bite force) traits. …


Passive Limb Movement Augments Ventilatory Response To Co2 Via Sciatic Inputs In Anesthetized Rats, Jianguo Zhuang, Fadi Xu, Cancan Zhang, Donald T. Frazier Jun 2009

Passive Limb Movement Augments Ventilatory Response To Co2 Via Sciatic Inputs In Anesthetized Rats, Jianguo Zhuang, Fadi Xu, Cancan Zhang, Donald T. Frazier

Physiology Faculty Publications

Passive limb movement (PLM) in humans induces a phasic hyperpnea, but the underlying physiological mechanisms remain unclear. We asked whether PLM in anesthetized rats would produce a similar phasic hyperpnea associated with an augmented ventilatory (E) response to CO2 that is dependent on sciatic afferents. The animals underwent 5 min threshold PLM, 3 min hypercapnia (5% CO2), and their combination (CO2 exposure at the end of 2nd min of 5-min PLM) before and after bilateral transection of the sciatic nerves. We found that a threshold PLM evoked a phasic hyperpnea, similar to …


Reactive Oxygen Species Mediate Tnfr1 Increase After Trpv1 Activation In Mouse Drg Neurons, Fei Ma, Liping Zhang, Karin N. Westlund Jun 2009

Reactive Oxygen Species Mediate Tnfr1 Increase After Trpv1 Activation In Mouse Drg Neurons, Fei Ma, Liping Zhang, Karin N. Westlund

Physiology Faculty Publications

Background: Transient receptor potential vanilloid subtype 1 (TRPV1) is activated by low pH/protons and is well known to be involved in hyperalgesia during inflammation. Tumor necrosis factor α (TNF-α), a proinflammatory cytokine, is involved in nociceptive responses causing hyperalgesia through TNF receptor type 1 (TNFR1) activation. Reactive oxygen species (ROS) production is also prominently increased in inflamed tissue. The present study investigated TNFR1 receptors in primary cultured mouse dorsal root ganglion (DRG) neurons after TRPV1 activation and the involvement of ROS. C57BL/6 mice, both TRPV1 knockout and wild type, were used for immunofluorescent and live cell imaging. The L4 and …


Minimum Criteria For Dna Damage-Induced Phase Advances In Circadian Rhythms, Christian I. Hong, Judit Zámborszky, Attila Csikász-Nagy May 2009

Minimum Criteria For Dna Damage-Induced Phase Advances In Circadian Rhythms, Christian I. Hong, Judit Zámborszky, Attila Csikász-Nagy

Dartmouth Scholarship

Robust oscillatory behaviors are common features of circadian and cell cycle rhythms. These cyclic processes, however, behave distinctively in terms of their periods and phases in response to external influences such as light, temperature, nutrients, etc. Nevertheless, several links have been found between these two oscillators. Cell division cycles gated by the circadian clock have been observed since the late 1950s. On the other hand, ionizing radiation (IR) treatments cause cells to undergo a DNA damage response, which leads to phase shifts (mostly advances) in circadian rhythms. Circadian gating of the cell cycle can be attributed to the cell cycle …