Prion Disease.

Prion diseases are a phenotypically diverse set of disorders characterized by protease-resistant abnormally shaped proteins known as prions. There are three main groups of prion diseases, termed sporadic (Creutzfeldt-Jakob disease [CJD], sporadic fatal insomnia, and variably protease-sensitive prionopathy), genetic (genetic CJD, fatal familial insomnia, and Gerstmann-Straussler-Scheinker syndrome), and acquired (kuru, variant CJD, and iatrogenic CJD). This article will review the pathophysiology, genetics, clinical presentations, and diagnostic challenges in patients with prion disease. Case discussions, images, and tables will be used to highlight important characteristics of prion disease and prion mimics.

Antibodies in epilepsy.

Antibody mediated limbic encephalitis is an increasingly recognized cause of seizures in cryptogenic epilepsy. Autoimmune encephalitis and epilepsy have been linked to both neuronal intracellular antibodies (GAD65, ANNA-1, and Ma) and neuronal cell surface antibodies (VGKC complex, NMDAR, AMPA, GABA-B, and GluR5). This article outlines the latest data on these various antibodies with a focus on their association with acute seizures in limbic encephalitis and likely increased risk for chronic epilepsy. There is mounting evidence that these antibodies may play a role in acute onset and chronic seizures in the general epilepsy population without manifesting typical limbic encephalitis symptoms. This review will discuss the data supporting early recognition and treatment options, beyond typical antiepileptic medications, necessary to improve outcomes in this epilepsy subgroup.

Chronic cold stress alters prefrontal cortical modulation of amygdala neuronal activity in rats.

BACKGROUND: Recent studies suggest that long-term exposure to stress can sensitize animals to subsequent novel or acute stressors. Stressors affect amygdala activity, and the prefrontal cortex has been implicated in the regulation of responses to stress. Little is known, however, about how the physiology of amygdala neurons is altered by chronic stressors or the role of the prefrontal cortex in these changes. METHODS: We used in vivo extracellular recordings from neurons in the rat central and basolateral amygdala nuclei to examine the effects of chronic stress on the basal firing and responses of amygdala neurons to a novel stressor. Additionally, prefrontal cortical afferents were severed to examine its role in the modulation of the response to stressors. RESULTS: Chronic exposure to cold enhanced the sensitivity of central amygdala neurons to footshock. A portion of this may be due to enhanced basolateral amygdala output. Furthermore, prefrontal cortical regulation of this response is weakened by chronic stress. CONCLUSIONS: The physiology of the amygdala is altered by chronic stress. Furthermore, the prefrontal cortical regulation of these responses may be weakened after chronic stress. This is a potential biological substrate for abnormal affect upon chronic stress and its effect on affective disorders.