INTRODUCTION Parkinson's disease (PD) is characterized by the accumulation of abnormal α-synuclein in selected regions of the brain following a gradient of severity with disease progression. Whether this is accompanied by globally altered protein synthesis is poorly documented. The present study was carried out in PD stages 1-6 of Braak and middle-aged (MA) individuals without alterations in br...

In the absence of sensory information, we rely on past experience or memories to guide our actions. Because previous experimental and clinical reports implicate basal ganglia nuclei in the generation of movement in the absence of sensory stimuli, we ask here whether one output nucleus of the basal ganglia, the substantia nigra pars reticulata (nigra), influences the specification of an eye move...

Mature larvae of the patch butterfly, Chlosyne lacinia (Geyer), exhibit striking color polymorphism. First described by T. D. A. Cockerell in Edwards (1893) and illustrated by Neck et aI. (1971), the three morphs are as follows: rufa, an all orange or orange-red form; nigra, an all black form; and bicolor, a form basically black as in nigra but with a prominent mid-dorsal row of orange to orang...

Mandibular gland secretion o f two Cataglyphis species were chemically analyzed by combined gas chromatography mass spectrometry. The exudates produced by C. bom bycina consisted of citronellol and geraniol while that of C. nigra contained only geraniol. The reaction of both species to the glandular secretions was alarm and recruitment. While the reaction of C. bom bycina was strong, that of C....

Dopamine system disorders ranging from movement disorders to addiction and schizophrenia involve striatal medium spiny neurons (MSNs), yet their functional connectivity has been difficult to determine comprehensively. We generated a mouse with conditional channelrhodopsin-2 expression restricted to medium spiny neurons and assessed the specificity and strength of their intrinsic connections in ...

Substantia nigra neurons are known to play a key role in normal cognitive processes and disease states. While animal models and neuroimaging studies link dopamine neurons to novelty detection, this has not been demonstrated electrophysiologically in humans. We used single neuron extracellular recordings in awake human subjects undergoing surgery for Parkinson disease to characterize the feature...

PURPOSE To determine whether secondary MR changes occur in the thalamus or the substantia nigra after middle cerebral artery (MCA) occlusion in rats. METHODS Sprague-Dawley rats were subjected to MCA occlusion. At varying intervals, proton density-, T1-, and T2-weighted images were obtained with a 4.7-T superconductive MR unit. RESULTS T2-weighted images revealed an area of high signal inte...