Circadian behavior is light-reprogrammed by plastic DNA methylation

 At 2014-02-22 12:29:31 PM  |   58

The timing of daily circadian behavior can be highly variable among different individuals, and twin studies have suggested that about half of this variability is environmentally controlled. Similar plasticity can be seen in mice exposed to an altered lighting environment, for example, 22-h instead of 24-h, which stably alters the genetically determined period of circadian behavior for months. Read more

Palmitoylation of δ-catenin by DHHC5 mediates activity-induced synapse plasticity

 At 2014-02-25 07:58:12 PM  |   323

Synaptic cadherin adhesion complexes are known to be key regulators of synapse plasticity. However, the molecular mechanisms that coordinate activity-induced modifications in cadherin localization and adhesion and the subsequent changes in synapse morphology and efficacy remain unknown. We demonstrate that the intracellular cadherin binding protein δ-catenin is transiently palmitoylated by DHHC5 after enhanced synaptic activity and that palmitoylation increases δ-catenin–cadherin interactions at synapses.  Read more

Imagined gait modulates neuronal network dynamics in the human pedunculopontine nucleus

 At 2014-02-24 04:33:06 PM  |   211

The pedunculopontine nucleus (PPN) is a part of the mesencephalic locomotor region and is thought to be important for the initiation and maintenance of gait. Lesions of the PPN induce gait deficits, and the PPN has therefore emerged as a target for deep brain stimulation for the control of gait and postural disability.  Read more

A neural mechanism underlying failure of optimal choice with multiple alternatives

 At 2014-02-24 04:30:39 PM  |   57

Despite widespread interest in neural mechanisms of decision-making, most investigations focus on decisions between just two options. Here we adapt a biophysically plausible model of decision-making to predict how a key decision variable, the value difference signal—encoding how much better one choice is than another—changes with the value of a third, but unavailable, alternative.  Read more

Focus on pain

 At 2014-03-05 07:27:23 PM  |   271

Pain can be defined simply as the subjective experience of harm in a part of one's body. In reality, however, there are multiple forms of pain, which involve a variety of distinct biological processes. Exposure to extreme heat, cold or pressure can be noxious, triggering nociceptive pain. Inflammatory pain, involving the release of cytokines and the infiltration of immune cells, also occurs subsequent to injury, but can be triggered independently by bacterial infections. Although pain has an important physiological role in preserving the integrity of the body, pathological pain also exists. Nerve damage, in surgery patients for instance, sometimes leads to chronic pain conditions that can last years or even decades. Read more