Physiology & behavior
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Physiology & behavior · Oct 2013
Enkephalin and dynorphin mRNA expression are associated with resilience or vulnerability to chronic social defeat stress.
There are important and enduring differences between individuals in the magnitude of all aspects of the stress response. Among the neuropeptide systems, the endogenous opioids enkephalin (ENK) and dynorphin (DYN), are very interesting candidates to participate in the naturally occurring variations in coping styles and to determine the individual capacity for adaptation during chronic stress exposure. Under chronic social stress exposure, we hypothesize that changes in the ENKergic vs DYNergic neuronal systems within specific nuclei of the basal forebrain contribute to naturally occurring variations in coping styles and will determine individual capacities for stress adaptation. ⋯ DYN mRNA is increased in resilient individuals in the central area of the striatum, caudal part, compared to control individuals. DYN is also increased in medial area of the striatum, caudal part in resilient and vulnerable compared to control individuals. These results have broad implications for understanding the functional roles of opioid neurotransmission following repeated social stress and suggest that ENK could facilitate the adaptation of behavioral responses by opposition to the DYN neurotransmission that appears to promote maladaptive behavioral response to chronic social stress.
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Physiology & behavior · Oct 2013
Dynamic behavioral strategies during sonar signal emission in roundleaf bats.
For echolocating bats which emit biosonar pulses nasally, their nostrils are surrounded by fleshy appendages that diffract the outgoing ultrasonic waves. The posterior leaf, as a prominent part of the noseleaf, was mentioned in previous preliminary observations to move during flight in some species of bats, yet the detailed motion patterns and thus the possible functional role of the posterior leaf movement in biosonar systems remain unclear. In the current work, the motion of the posterior leaf of living pratt's roundleaf bats has been investigated quantitatively. ⋯ The bats were able to switch the motions on or off. From the comparison with the previously reported noseleaf dynamics in horseshoe bat, we find similar ratio sizes and displacements of the noseleaves compared to the used wavelengths, implying that similar behavioral strategies are utilized by species of bats and it may be applied to different components of the signal emitting apparatus. It suggests that the dynamic sensing principles may widely play a role in the biosonar systems and the investigation on time-variant mechanisms is of capital importance to understand the biosonar sensing strategies used by echolocating bats.