Archive for the ‘Uncategorized’ Category

You can listen the Episode 39 of the Brain Science Podcast from Brain Science Podcast, developed by Ginger Campbell

This podcast is an interview with Dr. Michael Arbib from the University of Southern California.

Dr. Arbib’s work with functional brain imaging has established the presence of mirror neurons in the human brain. In our interview we focused on the role of mirror neurons in imitation and language. In particular I questioned Dr. Arbib about the Mirror System Hypothesis (MSH) of Language Evolution that he proposed in 1998 with Giacomo Rizzolatti. We also explored how this hypothesis diverges from the universal grammar proposed by Noam Chomsky. Dr. Arbib also shared his enthusiasm for future research and we talked about the special challenges caused by the interdisciplinary nature of modern neuroscience.


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The Journal of Neuroscience, March 14, 2007, 27(11):2837-2845; doi:10.1523/JNEUROSCI.4121-06.2007
John W. Muschamp, Juan M. Dominguez, Satoru M. Sato, Roh-Yu Shen, and Elaine M. Hull

The role of hypocretin (orexin; hcrt/orx) neurons in regulation of arousal is well established. Recently, hcrt/orx has been implicated in food reward and drug-seeking behavior. We report here that in male rats, Fos immunoreactivity (ir) in hcrt/orx neurons increases markedly during copulation, whereas castration produces decreases in hcrt/orx neuron cell counts and protein levels in a time course consistent with postcastration impairments in copulatory behavior. This effect was reversed by estradiol replacement. Immunolabeling for androgen (AR) and estrogen (ER) receptors revealed no colocalization of hcrt/orx with AR and few hcrt/orx neurons expressing ER, suggesting that hormonal regulation of hcrt/orx expression is via afferents from neurons containing those receptors. We also demonstrate that systemic administration of the orexin-1 receptor antagonist SB 334867 [N-(2-methyl-6-benzoxazolyl)-N”-1,5-naphthyridin-4-yl urea] impairs copulatory behavior. One locus for the prosexual effects of hcrt/orx may be the ventral tegmental area (VTA). We show here that hcrt-1/orx-A produces dose-dependent increases in firing rate and population activity of VTA dopamine (DA) neurons in vivo. Activation of hcrt/orx during copulation, and in turn, excitation of VTA DA neurons by hcrt/orx, may contribute to the robust increases in nucleus accumbens DA previously observed during male sexual behavior. Subsequent triple immunolabeling in anterior VTA showed that Fos-ir in tyrosine hydroxylase-positive neurons apposed to hcrt/orx fibers increases during copulation. Together, these data support the view that hcrt/orx peptides may act in a steroid-sensitive manner to facilitate the energized pursuit of natural rewards like sex via activation of the mesolimbic DA system.

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Nature Neuroscience 11, 62 – 71 (2008)
Published online: 16 December 2007 | doi:10.1038/nn2027
Kazuhiro Nakamura & Shaun F Morrison

Defending body temperature against environmental thermal challenges is one of the most fundamental homeostatic functions that are governed by the nervous system. Here we describe a somatosensory pathway that essentially constitutes the afferent arm of the thermoregulatory reflex that is triggered by cutaneous sensation of environmental temperature changes. Using in vivo electrophysiological and anatomical approaches in the rat, we found that lateral parabrachial neurons are pivotal in this pathway by glutamatergically transmitting cutaneous thermosensory signals received from spinal somatosensory neurons directly to the thermoregulatory command center, the preoptic area. This feedforward pathway mediates not only sympathetic and shivering thermogenic responses but also metabolic and cardiac responses to skin cooling challenges. Notably, this ‘thermoregulatory afferent’ pathway exists in parallel with the spinothalamocortical somatosensory pathway that mediates temperature perception. These findings make an important contribution to our understanding of both the somatosensory system and thermal homeostasis—two mechanisms that are fundamental to the nervous system and to our survival.

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New research shows that the same neurons maintain memory-forming firing patterns for later recall
By Tabitha M. Powledge

…humans and rats employ the same brain mechanisms for memory, but use them somewhat differently. “We suggest that the mechanisms in the hippocampus which evolved first to allow ‘simple’ animals to navigate in space,” Buzsáki wrote, “are the same as the mechanism that allows us to navigate in ‘cognitive space’, that is, from one thought to the next.”

in Scientific American

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See the interview.

Eric R. Kandel shared the Nobel Prize for Physiology or Medicine with Arvid Carlsson and Paul Greengard in 2000 for their discoveries concerning signal transduction in the nervous system. Eric Kandel was rewarded for his discoveries of molecular mechanisms underlying learning and memory. He is a Howard Hughes Medical Institute Senior Investigator at Columbia Universities Center for Neurobiology and Behavior.

Interview jove.com.

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Nature Reviews Neuroscience 9, 370-386. May 2008 | doi:10.1038/nrn2372

Nicholas P. Franks

The mechanisms through which general anaesthetics, an extremely diverse group of drugs, cause reversible loss of consciousness have been a long-standing mystery. Gradually, a relatively small number of important molecular targets have emerged, and how these drugs act at the molecular level is becoming clearer. Finding the link between these molecular studies and anaesthetic-induced loss of consciousness presents an enormous challenge, but comparisons with the features of natural sleep are helping us to understand how these drugs work and the neuronal pathways that they affect. Recent work suggests that the thalamus and the neuronal networks that regulate its activity are the key to understanding how anaesthetics cause loss of consciousness.

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Techniques in neuroscience in jove.com

Micro-dissection of rat brain into various regions is extremely important for the study of different neurodegenerative diseases. This video demonstrates micro-dissection of four major brain regions include olfactory bulb, frontal cortex, striatum and hippocampus in fresh rat brain tissue. Useful tips for quick removal of respective regions to avoid RNA and protein degradation of the tissue are given.

In www.jove.com

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