Brain stem lesion

Ray DE, Brown AW, Cavanagh JB, et al. 1992. Functional/metabolic modulation of the brain stem lesions caused by 1,3-dinitrobenzene in the rat. NeuroToxicology 13 379-388. 

A detailed description of the neuroanatomical structures involved in sleep is provided in the excellent reviews, of Jones (1989) and Hobson et al. (1998). Alertness and sleep are dependent on the activity of the brain as a whole, although different levels of consciousness are determined primarily by areas of the brain stem. Lesion and stimulation studies have been used to identify specific regions and delineate relevant neuronal systems (reviewed by Parkes, 1985). 

Histochemical fluorescent techniques have revealed the existence in most mammalian species of a nigro-striatal neuron system, containing dopamine, with cell bodies in the substantia nigra and axon terminations in the striatum [99-104]. These structures are confirmed by electron microscopic studies of the terminal boutons in the striatum which contain dense dopamine vesicles [105]. Striatal dopamine levels were reduced after experimental brain stem lesions which resulted in nigral degeneration [106-108], while removal of the caudate and putamen produced similar decreases together with nigral... 

Nattie, E. E. Erlichman, J. S. Li, A. Brain stem lesion size determined by DEAD red or conjugation of neurotoxin to fluorescent beads. J. Appl. Physiol. 1998, 85, 2370-2375. 

Tetanus occurs when Cl. tetani, ubiquitous in the soil and faeces, contaminates wounds, especially deep puncture-type lesions. These might be minor traumas such as a splinter, or major ones such as battle injury. At these sites, tissue necrosis and possibly microbial growth reduce the oxygen tension to allow this anaerobe to multiply. Its growth is accompanied by the production of a highly potent toxin which passes up peripheral nerves and diSuses locally within the central nervous system. It acts like strychnine by affecting normal function at the synapses. Since the motor nerves of the brain stem are the shortest, the cranial nerves are the first affected, with twitches of the eyes and spasms of the jaw (lockjaw). 

Fuxe 1965) and throughout the brain stem and spinal cord. A series of studies employing small intracerebral lesions (Anden et al. 1966 Ungerstedt 1971) indicated that most 5-HT nerve terminals in the forebrain arise from raphe nuclei in the midbrain and that the axons ascend through the lateral hypothalamus within the medial forebrain bundle (Moore and Heller 1967 Azmitia 1978 Conrad et al. 1974). 

Radiation therapy is the treatment of choice for most patients with brain metastases. Most patients receive whole-brain radiation because the majority of brain metastases are multifocal. Another method known as stereotactic radiosurgery provides intense focal radiation, typically using a linear accelerator or gamma knife, in patients who cannot tolerate surgery or have lesions that are surgically inaccessible (e.g., in the brain stem). 

Several types of abnormal movement are recognized. Tremor consists of a rhythmic oscillatory movement around a joint and is best characterized by its relation to activity. Tremor at rest is characteristic of parkinsonism, when it is often associated with rigidity and an impairment of voluntary activity. Tremor may occur during maintenance of sustained posture (postural tremor) or during movement (intention tremor). A conspicuous postural tremor is the cardinal feature of benign essential or familial tremor. Intention tremor occurs in patients with a lesion of the brain stem or cerebellum, especially when the superior cerebellar peduncle is involved it may also occur as a manifestation of toxicity from alcohol or certain other drugs. 

Because it was known by 1960 that the pontine brain stem was crucial to REM sleep generation, it was natural to assume that the newly discovered modulatory elements played an important role in its generation. It was even reasonable, on an a priori basis, that each of the elements had responsibility for one state, viz, dopamine controls waking, serotonin controls slow wave sleep, and norepinephrine controls REM. Early lesion and parenteral pharmacological studies—some even armed with measures of amine concentrations in the brain—gave initial support to this concept. For example, Michel Jouvet produced insomnia in cats by blocking the enzyme that is essential to convert tryptophane into serotonin. He interpreted this result to mean that serotonin was a sleep mediator. 

MorrowMJ, Sharpe JA (1993) Retinotopic and directional deficits of smooth pursuit initiation after posterior cerebral hemispheric lesions. Neurology 43 595-603 Moruzzi G, Magoun HW (1949) Brain stem reticular formation and activation of the EEG. Electroencephalogr Clin Neurophysiol 1 455... 

Fig. 7.9. Lacunar brain stem stroke. Typical example of a lacunar brain stem stroke that would be missed if only transverse DWI images were obtained ( DWI negative stroke ). In this case, a faint DWI lesion was seen on coronal sections at the acute time point, but both transverse and sagittal planes did not show an unequivocal lesion. PI, on the other hand, showed a clear-cut perfusion deficit in the brain stem. Follow-up images confirmed a small infarct in the brain stem. (Images were acquired in collaboration with P. Sterzer, Neurology, Frankfurt, and R. du Mesnil de Rochemont, H. Lanfermann, Neuroradiology, Frankfurt)...

It was suggested that the sensitivity of DWI for acute ischemic lesions within the first 12 h of stroke onset is substantially superior as compared to CT (Fiebach et al. 2002 Saur et al. 2003), whereas after 12 h, accuracy is equivalent (Mullins et al. 2002). However, even DWI maybe negative in transient ischemic attacks (TIA), brain stem lacunes or mild stroke syndromes (Fig. 19.1). Normal diffusion... 

Cellular plaques or lesions are distributed throughout the CNS and range in size from a few millimetres in diameter to confluent areas involving most of the cross section of the spinal cord, brain stem, or large areas of the cerebral hemispheres.104 The lesions usually encircle a venule or small vein and extend for considerable distances along the course of individual vessels.105 An early lesion appears as a perivascular area of hypercellularity with infiltrating lymphocytes and monocytes... 

The NA and 5-HT fibres arise from NA- and 5-HT-containing neurones in the brain stem. They have been described as ascending in the medial forebrain bundle and reaching the hippocampus through fimbria and fornix superior (Fuxe, 1965). After lesions involving the medial forebrain bundle, 5-HT decreased by 68 % in the hippocampus (Moore and Heller, 1967), and NA decreased by 71 % in the hippocampus and amygdala (Heller et al., 1966). We observed an almost total (about 90%) loss of 5-HT from the hippocampus on the operated side 6 days after unilateral trans-... 

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