A Radio-Telemetry System for Navigation and Recording Neuronal Activity in Free-Roaming Rats

A radio-telemetry recording system is presented which is applied to stimulate specific brain areas and record neuronal ac- tivity in a free-roaming rat. The system consists of two major parts： stationary section and mobile section. The stationary section contains a laptop, a Micro Control Unit （MCU）, an FM transmitter and a receiver. The mobile section is composed of the headstage and the backpack （which includes the mainboard, FM transmitter, and receiver）, which can generate biphasic mi- crocurrent pulses and simultaneously acquire neuronal activity. Prior to performing experiments, electrodes are implanted in the Ventral Posterolateral （VPL） thalamic nucleus, primary motor area （M1） and Medial Forebrain Bundle （MFB） of the rat. The stationary section modulates commands from the laptop for stimulation and demodulates signals for neuronal activity recording. The backpack is strapped on the back of the rat and executes commands from the stationary section, acquires neuronal activity, and transmits the neuronal activity singles of the waking rat to the stationary section. All components in the proposed system are commercially available and are fabricated from Surface Mount Devices （SMD） in order to reduce the size （25 mm×15 mm ×2 mm） and weight （10 g with battery）. During actual experiments, the backpack, which is powered by a rechargeable Lithium battery （4 g）, can generate biphasic microcurrent pulse stimuli and can also record neuronal activity via the FM link with a maximum transmission rate of 1 kbps for more than one hour within a 200 m range in an open field or in a neighboring chamber. The test results show that the system is able to remotely navigate and control the rat without any prior training, and acquire neuronal activity with desirable features such as small size, low power consumption and high precision when compared with a commercial 4-channel bio-signal acquisition and processing system.

Habitat Use, Home Range, and Hibernaculum of the Mongolian Racerunner, Eremias argus (Lacertidae, Reptilia) in a Coastal Sand Dune in South Korea

Information on habitat use is critical in sizing protected areas for endangered reptile species. To investigate habitat use, home range, and hibernaculum of the endangered Mongolian Racerunner(Eremias argus), we radio-tracked 40 specimens in a coastal sand dune in South Korea. Of the 163 locations recorded during the breeding season, 150(92.0%) were in grass sand dunes, and the rest(8.0%), all associated with the same lizard, were in shrub sand dunes. All of the 123 locations recorded during the non-breeding season were in grass sand dunes. No lizards were found in the grasslands abutting the dunes. The four lizards with identifiable hibernation sites were found under an average of 17.8 cm of sand and were all located in grass sand dunes. The lizards moved approximately 5 m daily and used 162 m2of home range(computed by minimum convex polygon, MCP) during the breeding season, and they moved approximately 2 m and used 68 m2of home range during the non-breeding season. However, the mean daily moved distances and MCP home ranges were not statistically significantly different between the seasons or between males and females. Our results suggest that in coastal sand dunes, E. argus uses grass sand dunes as its main habitat throughout the year. This finding could be used to determine the appropriate habitat size and to designate for the conservation of this endangered species.

Eastern wild turkey nest site selection in two frequently burned pine savannas

Introduction:Reproductive success is a critical factor affecting avian demographics and can be influenced by many factors including nesting chronology,predation risk,and fine-scale nest site selection.Methods:We modeled the relative influences of habitat-related covariates at six spatial scales(nest site:15-,40-,80-,120-,160-,and 200-m radii)on Eastern wild turkey(Meleagris gallopavo silvestris)nest site selection in two pine savannas managed by frequent prescribed fire(≤3 years)in southwestern Georgia during 2011-2013.Results:Nest site(15-m scale)habitat metrics(mean visual obstruction[cm]and canopy closure[%])had the greatest influence on nest site selection relative to covariates measured at larger spatial scales.Scaled odds ratios suggested that nests were 26.8% more likely to occur for every 10 cm increase in mean vegetation height with a range of 7.5 to 150.0 cm and 18.5% less likely to occur for every 10% increase in canopy closure with a range from 0.0 to 97.8%.Total ground cover,canopy closure,edge density,and percent land cover type(e.g.,mature pine,mixed pine/hardwood,shrub/scrub)had minimal influence on nest site selection.Conclusions:Management of pine savannas for turkey nest sites should focus on creating early-successional vegetation to conceal nests from potential predators.Additionally,we suggest that future studies consider evaluating the influence of spatial scale on turkey nest site selection.