Molluscan memory of injury: evolutionary insights into chronic pain and neurological disorders.

Molluscan preparations have yielded seminal discoveries in neuroscience, but the experimental advantages of this group have not, until now, been complemented by adequate molecular or genomic information for comparisons to genetically defined model organisms in other phyla. The recent sequencing of the transcriptome and genome of Aplysia californica, however, will enable extensive comparative studies at the molecular level. Among other benefits, this will bring the power of individually identifiable and manipulable neurons to bear upon questions of cellular function for evolutionarily conserved genes associated with clinically important neural dysfunction. Because of the slower rate of gene evolution in this molluscan lineage, more homologs of genes associated with human disease are present in Aplysia than in leading model organisms from Arthropoda (Drosophila) or Nematoda (Caenorhabditis elegans). Research has hardly begun in molluscs on the cellular functions of gene products that in humans are associated with neurological diseases. On the other hand, much is known about molecular and cellular mechanisms of long-term neuronal plasticity. Persistent nociceptive sensitization of nociceptors in Aplysia displays many functional similarities to alterations in mammalian nociceptors associated with the clinical problem of chronic pain. Moreover, in Aplysia and mammals the same cell signaling pathways trigger persistent enhancement of excitability and synaptic transmission following noxious stimulation, and these highly conserved pathways are also used to induce memory traces in neural circuits of diverse species. This functional and molecular overlap in distantly related lineages and neuronal types supports the proposal that fundamental plasticity mechanisms important for memory, chronic pain, and other lasting alterations evolved from adaptive responses to peripheral injury in the earliest neurons. Molluscan preparations should become increasingly useful for comparative studies across phyla that can provide insight into cellular functions of clinically important genes.

Yoga off the mat: How far and to whom do the benefits extend?

At least 15 million American adults have participated in yoga at least once in their lifetime (Saper, Eisenberg, Davis, Culpepper, & Phillips, 2004). The field of yoga research is relatively new in the United States, and the majority of studies have concentrated on yoga's effect on measures of physiology (cardiovascular disease, diabetes, obesity) or psychological measures of stress and anxiety. This review attempted to identify studies that had been conducted measuring a different set of outcome measures, specifically violence, trauma, eating, and other behavioral disorders. In 9 of 10 studies reviewed, researchers observed statistically significant effects of yoga interventions. Effects were most evident within multifaceted studies that combined intensive yoga practice with group discussion and training. Only one group (Mitchell, Mazzeo, Rausch, & Cooke, 2007) failed to observe any significant differences between yoga practice groups and control groups. Effects were seen in both sexes, although a majority of the studies were aimed specifically at women. All studies were limited by small sample size and lack of follow-up data. Future research should seek to increase sample size, to diversify recruitment to allow for the randomization of treatment and control groups, and to allow for long-term follow-up.^