Opinion in 2010

A subcortical pathway is assumed to mediate non-conscious visual processing of emotional stimuli. In this provocative Perspective, Pessoa and Adolphs argue that this pathway does not exist in primates and propose novel roles for the amygdala and the cortex in visual emotion processing.

Lightman and Conway-Campbell review findings showing that, superimposed on its well-known circadian rhythm, the HPA axis shows ultradian, oscillatory activity. They describe how the resulting pulsatile release of glucocorticoids maintains optimal responsiveness of the HPA axis and the brain processes regulated by these hormones.

In this Perspective, Vollenweider and Kometer discuss the clinical potential of psychedelic drugs for the treatment of various psychiatric disorders, and describe the molecular mechanisms by which classical hallucinogens and dissociative anaesthetics affect serotonin and glutamate systems. An interview with Franz X. Vollenweider for Neuropod is available for download.

The interrelationship between circadian and sleep rhythm abnormalities and neurological disease has long been recognized. Foster and colleagues now provide a conceptual framework regarding common mechanisms of neurological disease and circadian and sleep physiology, and propose new approaches for the treatment of neuropsychiatric and neurodegenerative diseases.

The traditional distinction between declarative and nondeclarative forms of memory is based on conscious versus non-conscious learning and recall. Katharina Henke argues that consciousness is a poor criterion and presents an alternative model of memory systems that is based on processing operations.

Two main features make budding yeast a key model organism for eukaryotic biology: its amenability to analysis and its conserved genome and cellular biology. Here, the authors highlight the valuable mechanistic insights into the cell-autonomous mechanisms of neurodegeneration that are emerging from studies inSaccharomyces cerevisiae.

Pulvermüller and Fadiga address the much discussed question of whether speech comprehension depends on activation of cortical motor areas. Reviewing data from neuroimaging, brain stimulation, lesion and computational studies, they conclude that action and perception circuits have interdependent roles in language comprehension.

Ensheathing glia are essential for the long-term survival of axons; however, the mechanisms by which they contribute to neuronal viability are unclear. Here, Nave proposes that long axons require continuous support from glia to meet their metabolic needs, especially when insulated by myelin.

Epidemiological and pathological evidence points to a link between traumatic brain injury and an increased risk of developing Alzheimer's disease in later life. Smith and colleagues consider the mechanisms underlying this link, with a focus on axonal injury and amyloid-β accumulation after injury.