An inexpensive microdrive for chronic single-unit recording

A remotely controlled lightweight MRI compatible ultrasonic actuator for micrometer positioning of electrodes during neuroethological primate research

The precise positioning of microelectrodes is essential for a reliable electrophysiological exploration of anatomical structures in the brain of laboratory animals, e.g., non-human primates in systemic brain research. Despite recent advances in micromechanics, the majority of small, chronically head mounted devices for advancing and retracting electrodes in freely moving animals reported in the literature are manually operated. In this article, we present a newly developed lightweight microfeed, based on an ultrasonic actuator for micrometer positioning of recording microelectrodes. It has been designed for compatibility with magnetic resonance imaging to allow non-invasive visualization of chronically implanted electrodes. The actuator combines a teleoperation via infrared control to minimize manipulation of animals during neuroethological studies. Its design is believed to add substantially to the well-being of experimental animals.

A lightweight microdrive for single-unit recording in freely moving rats and pigeons

A design for an inexpensive and reliable subminiature microdrive for recording single neurons in the freely moving animal is presented. The Scribe microdrive is small and lightweight and has been used successfully to record in freely moving rats and pigeons. It would also be suitable for recording in mice. The device is simple and inexpensive yet allows for stable and precise manipulation of the recording electrodes. As a result it supports stable recordings conducted over long periods. Because the Scribe microdrive is a small-diameter device it is also suitable for multisite, multielectrode applications. Here we discuss the construction of the device and comment on its use in recording from freely moving rats and pigeons.

A chronic multi-electrode microdrive for small animals

We describe a simple microdrive device appropriate for chronic microelectrode recording in rats. No precision machining is required; all parts are stock or cut from standard stock material with hand tools and assembled with epoxy. The device together with its electrodes can be discarded at the completion of the experiment.

A low cost, high precision subminiature microdrive for extracellular unit recording in behaving animals

A new design for an inexpensive and reliable subminiature microdrive for unit recording in the freely moving animal is presented. The 'Scribe' microdrive is (a) of a small size and low weight, (b) allows for precise advancement of the electrodes, (c) permits stable unit recordings over time, (d) is simple to install, and (e) is economical to construct. These advantages are a result of its simple, single screw-based drive system and the ready availability of component parts. The Scribe microdrive is a small diameter device suitable for multi-site, multi-electrode applications.

A peptidergic basis for sexual behavior in mammals

Vasopressin (VP) is a peptide neurotransmitter in the limbic system of rats. It is synthesized in the medial amygdaloid nucleus in the presence of sex steroids, transported to other limbic structures such as the hippocampus and septum and secreted there by a calcium-dependent process. In the hippocampus, VP acts on cerebral microvessels and local circuit interneurons. Its excitatory action on the inhibitory interneurons produces near-total shutdown of electrical activity of the efferent fibers of pyramidal cells, the projection neurons of the hippocampus. Stimulation of the medial amygdala and release of the endogenous VP duplicates these effects and, since they are blocked by ventricular application of a VP antagonist, the effects are almost certainly mediated by endogenous VP. Recording from the VP-containing cell bodies or of the hippocampal action of the peptide indicates that the system is selectively involved with the early stages of sexual behavior, specifically those appetitive behaviors that anticipate coitus. Stimulation of the VP cells produces alterations in sexual behavior in a manner consistent with the hypothesis that the medial amygdala organizes the appetitive phase of recognition of an appropriate partner and sexual arousal. This role for the medial amygdala complements the proposed role of nearby structures in the consummatory, reward and learned aspects of sexual behavior. Association between VP, oxytocin (OT) and homologs with sexual behavior is very widespread among vertebrates, including amphibians, reptiles, primates and humans. Humans and other primates display a phenomenon called 'concealed ovulation' that may have played a role in the evolution of social structures. The review concludes with a discussion of possible experimental strategies for evaluating the possible role of VP in concealed ovulation and other conditions in which sexual behavior occurs outside of estrus.