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Full-Text Articles in Life Sciences
Antennal Circadian Clocks Coordinate Sun Compass Orientation In Migratory Monarch Butterflies, Christine Merlin, Robert Gegear, Steven Reppert
Antennal Circadian Clocks Coordinate Sun Compass Orientation In Migratory Monarch Butterflies, Christine Merlin, Robert Gegear, Steven Reppert
Robert J. Gegear
During their fall migration, Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated Sun compass to aid navigation to their overwintering grounds in central Mexico. It has been assumed that the circadian clock that provides time compensation resides in the brain, although this assumption has never been examined directly. Here, we show that the antennae are necessary for proper time-compensated Sun compass orientation in migratory monarch butterflies, that antennal clocks exist in monarchs, and that they likely provide the primary timing mechanism for Sun compass orientation. These unexpected findings pose a novel function for the antennae and open a …
Defining Behavioral And Molecular Differences Between Summer And Migratory Monarch Butterflies, Haisun Zhu, Robert Gegear, Amy Casselman, Sriramana Kanginakudru, Steven Reppert
Defining Behavioral And Molecular Differences Between Summer And Migratory Monarch Butterflies, Haisun Zhu, Robert Gegear, Amy Casselman, Sriramana Kanginakudru, Steven Reppert
Robert J. Gegear
BACKGROUND: In the fall, Eastern North American monarch butterflies (Danaus plexippus) undergo a magnificent long-range migration. In contrast to spring and summer butterflies, fall migrants are juvenile hormone deficient, which leads to reproductive arrest and increased longevity. Migrants also use a time-compensated sun compass to help them navigate in the south/southwesterly direction en route for Mexico. Central issues in this area are defining the relationship between juvenile hormone status and oriented flight, critical features that differentiate summer monarchs from fall migrants, and identifying molecular correlates of behavioral state. RESULTS: Here we show that increasing juvenile hormone activity to induce summer-like …
Assessing The Feasibility Of Acceptance And Commitment Therapy In Promoting Psychological Adjustment After Severe Traumatic Brain Injury, Diane Whiting, Grahame Simpson, Joseph Ciarrochi, Hamish Mcleod
Assessing The Feasibility Of Acceptance And Commitment Therapy In Promoting Psychological Adjustment After Severe Traumatic Brain Injury, Diane Whiting, Grahame Simpson, Joseph Ciarrochi, Hamish Mcleod
joseph Ciarrochi
This study evaluated the feasibility of a treatment program utilising Acceptance and Commitment Therapy (ACT) to address psychological adjustment to severe traumatic brain injury (TBI). ACT focuses on persons’ relationship with internal experiences such as thoughts, emotions and memories in order for them to live a life consistent with their values. Treatment goals include increasing psychological flexibility, participation in valued life roles and reducing psychological distress. Method: Two participants (both male, P1 aged 20 years, P2 aged 28 years) with severe TBI and demonstrating psychological distress, as measured by the Depression Anxiety and Stress Scale (DASS- 588 Abstract Brain Inj …
Relative Volume Of The Cerebellum In Dolphins And Comparison With Anthropoid Primates, L. Marino, James K. Rilling, Shinko K. Lin, Sam H. Ridgway
Relative Volume Of The Cerebellum In Dolphins And Comparison With Anthropoid Primates, L. Marino, James K. Rilling, Shinko K. Lin, Sam H. Ridgway
Lori Marino, PhD
According to the ‘developmental constraint hypothesis’ of comparative mammalian neuroanatomy, brain growth follows predictable allometric trends. Therefore, brain structures should scale to the entire brain in the same way across mammals. Evidence for a departure from this pattern for cerebellum volume has recently been reported among the anthropoid primates. One of the mammalian groups that has been neglected in tests of the ‘developmental constraint hypothesis’ is the cetaceans (dolphins, whales, and porpoises). Because many cetaceans possess relative brain sizes in the range of primates comparative tests of the ‘developmental constraint hypothesis’ across these two groups could help to delineate the …
Post-Transcriptional Regulation Of Myelin Formation, Nancy Zearfoss, Brian Farley, Sean Ryder
Post-Transcriptional Regulation Of Myelin Formation, Nancy Zearfoss, Brian Farley, Sean Ryder
Sean P. Ryder
Myelin is a specialized structure of the nervous system that both enhances electrical conductance and protects neurons from degeneration. In the central nervous system, extensively polarized oligodendrocytes form myelin by wrapping cellular processes in a spiral pattern around neuronal axons. Myelin formation requires the oligodendrocyte to regulate gene expression in response to changes in its extracellular environment. Because these changes occur at a distance from the cell body, post-transcriptional control of gene expression allows the cell to fine-tune its response. Here, we review the RNA-binding proteins that control myelin formation in the brain, highlighting the molecular mechanisms by which they …
Convergent Evolution Of Brain Morphology And Communication Modalities In Lizards, Christopher Robinson, Michael Patton, Brittany Andre, Michele Johnson
Convergent Evolution Of Brain Morphology And Communication Modalities In Lizards, Christopher Robinson, Michael Patton, Brittany Andre, Michele Johnson
Michele A Johnson
Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modality is generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality. We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species (Anolis carolinensis and Leiocephalus carinatus) primarily use visual signals to communicate with conspecifics and detect potential prey, and two (Aspidoscelis gularis and Scincella lateralis) communicate and forage primarily …
Characterizing Tissue Fate After Transient Cerebral Ischemia Of Varying Duration Using Quantitative Diffusion And Perfusion Imaging, Juergen Bardutzky, Qiang Shen, Nils Henninger, Stefan Schwab, Timothy Duong, Marc Fisher
Characterizing Tissue Fate After Transient Cerebral Ischemia Of Varying Duration Using Quantitative Diffusion And Perfusion Imaging, Juergen Bardutzky, Qiang Shen, Nils Henninger, Stefan Schwab, Timothy Duong, Marc Fisher
Nils Henninger
BACKGROUND AND PURPOSE: The purpose of this study was to investigate the effects of reperfusion on ischemic lesion evolution and pixel-by-pixel apparent diffusion coefficient-cerebral blood flow (ADC-CBF) dynamics of core and mismatch tissues after 35, 60, and 95 minutes of transient focal ischemia in rats (n=28). METHODS: Serial diffusion-, perfusion-, and T2-weighted imaging were performed up to 24 hours. The evolution of the magnetic resonance image-derived lesion volume was investigated and ADC-CBF scatterplots were performed to prospectively characterize the ADC and CBF dynamics of core and mismatch tissues with different fates. For comparison, similar analysis was performed on a historical …
Ischemic Lesion Volume Determination On Diffusion Weighted Images Vs. Apparent Diffusion Coefficient Maps, Bernt Bratane, Birgül Bastan, Marc Fisher, James Bouley, Nils Henninger
Ischemic Lesion Volume Determination On Diffusion Weighted Images Vs. Apparent Diffusion Coefficient Maps, Bernt Bratane, Birgül Bastan, Marc Fisher, James Bouley, Nils Henninger
Nils Henninger
Though diffusion weighted imaging (DWI) is frequently used for identifying the ischemic lesion in focal cerebral ischemia, the understanding of spatiotemporal evolution patterns observed with different analysis methods remains imprecise. DWI and calculated apparent diffusion coefficient (ADC) maps were serially obtained in rat stroke models (MCAO): permanent, 90 min, and 180 min temporary MCAO. Lesion volumes were analyzed in a blinded and randomized manner by 2 investigators using (i) a previously validated ADC threshold, (ii) visual determination of hypointense regions on ADC maps, and (iii) visual determination of hyperintense regions on DWI. Lesion volumes were correlated with 24 hour 2,3,5-triphenyltetrazoliumchloride …