Recordings of extracellular unit activity in the ventrolateral medulla and of electromyographic activity in either the M. scalenus, a principal inspiratory muscle, or the abdominal expiratory muscles, were used to identify inspiratory related (IR) neurons. IR neurons extended from levels caudal to the obex through the caudal level of the descending vestibular nucleus. This distribution was found to correspond to that of a subset of cells retrogradely labeled from injections of neuronal tracers into the upper thoracic spinal cord, where motoneurons innervating the M. scalenus were located by retrograde transport. Injections of biotinylated dextran amine at the recording sites resulted in projections to the spinal cord and brainstem. Bulbospinal axons traveled in the lateral funiculus, predominantly contralaterally, and terminated in relation to the dendrites and cell bodies of motoneurons innervating the M. scalenus. Brainstem nuclei receiving projections from injections at IR loci included the retroambigualis, tracheosyringeal motor nucleus, ventrolateral nucleus of the rostral medulla, infraolivaris superior, ventrolateral parabrachial nucleus, and the dorsomedial nucleus of the intercollicular complex. In the finches, there were also bilateral projections to nucleus uvaeformis of the posterior thalamus. The spinal and brainstem projections are similar to those found in pigeon (Reinke and Wild, [1997] J. Comp. Neurol. 379:347-362), and probably mediate the intricate coordination of the vocal (syringeal) and respiratory systems for the control of vocalization. The distribution of IR neurons in birds is similar to that of the rostral ventral respiratory group (rVRG) in mammals.

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Using sequential BV pacing, generally with LV preactivation, moderate improvements in LV systolic function can be achieved in selected patients. Baseline PR interval may aid in the selection of the optimum cardiac resynchronization therapy (CRT) mode, favoring LV pacing in patients with a PR interval < or =200 ms.

Behavioural impairments caused by brain lesions show a considerable, though often incomplete, recovery. It is hypothesized that cortical and subcortical plasticity of sensory representations contribute to this recovery. In the hindpaw representation of somatosensory cortex of adult rats we investigated the effects of focal unilateral cortical lesions on remote areas. Cortical lesions with a diameter of approximately 2 mm were induced in the parietal cortex by photothrombosis with the photosensitive dye Rose Bengal. Subsequently, animals were kept in standard cages for 7 days. On day seven, animals were anaesthetized and cutaneous receptive fields in the cortical hindpaw representations ipsi- and contralateral to the lesion were constructed from extracellular recordings of neurons in layer IV using glass microelectrodes. Receptive fields in the lesioned animals were compared to receptive fields measured in nonlesioned animals serving as controls. Quantitative analysis of receptive fields revealed a significant increase in size in the lesioned animals. This doubling in receptive field size was observed equally in the hemispheres ipsi- and contralateral to the lesion. The results indicate that the functional consequences of restricted cortical lesions are not limited to the area surrounding the lesion, but affect the cortical maps on the contralateral, nonlesioned hemisphere.

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