Search results for "Brain"
showing 10 items of 3997 documents
The topographic diagnosis of acquired nystagmus in brainstem disorders.
2002
Evidence is presented for a clinical classification of central vestibular syndromes according to the three major planes of action of the vestibulo-ocular reflex (VOR): yaw, pitch, and roll. The plane-specific vestibular syndromes are determined by ocular motor, postural, and perceptual signs. Yaw plane signs are horizontal nystagmus, horizontal past pointing, rotational and lateral body falls to the right or to the left, and horizontal deviation of perceived straight-ahead. Pitch plane signs are upbeat/downbeat nystagmus, forward/backward tilts and falls, and upward or downward deviations of the perceived horizontal. Roll plane signs are torsional nystagmus, skew deviation, ocular torsion, …
Vaskulärer Schwindel
2002
Ischemia,hemorrhages, and other vascular disorders can result in various central or peripheral vestibular syndromes with vertigo, oculomotor/balance disturbances, and nausea. The vascular vertigo syndromes listed in Table 1 can however be brought about by other causes such as demyelitizing focuses in multiple sclerosis or space-occupying lesions, so that not only localization of the damaged structure but also the various etiologies are decisive for the choice of therapy. Occasionally, combined functional disturbances of the peripheral and central vestibular system appear, such as an infarction of the inferior anterior cerebellar artery, which supplies the labyrinth and parts of the brainste…
Processing of audiovisual associations in the human brain: dependency on expectations and rule complexity
2012
In order to respond to environmental changes appropriately, the human brain must not only be able to detect environmental changes but also to form expectations of forthcoming events. The events in the external environment often have a number of multisensory features such as pitch and form. For integrated percepts of objects and events, crossmodal processing, and crossmodally induced expectations of forthcoming events are needed. The aim of the present study was to determine whether the expectations created by visual stimuli can modulate the deviance detection in the auditory modality, as reflected by auditory event-related potentials (ERPs). Additionally, it was studied whether the complexi…
Evaluating the Effect of Stimuli Color and Frequency on SSVEP
2020
Brain&ndash
Insect brains use image interpolation mechanisms to recognise rotated objects.
2008
Recognising complex three-dimensional objects presents significant challenges to visual systems when these objects are rotated in depth. The image processing requirements for reliable individual recognition under these circumstances are computationally intensive since local features and their spatial relationships may significantly change as an object is rotated in the horizontal plane. Visual experience is known to be important in primate brains learning to recognise rotated objects, but currently it is unknown how animals with comparatively simple brains deal with the problem of reliably recognising objects when seen from different viewpoints. We show that the miniature brain of honeybees…
Human Reaction Times: Linking Individual and Collective Behaviour Through Physics Modeling
2021
An individual’s reaction time data to visual stimuli have usually been represented in Experimental Psychology by means of an ex-Gaussian function. In most previous works, researchers have mainly aimed at finding a meaning for the parameters of the ex-Gaussian function which are known to correlate with cognitive disorders. Based on the recent evidence of correlations between the reaction time series to visual stimuli produced by different individuals within a group, we go beyond and propose a Physics-inspired model to represent the reaction time data of a coetaneous group of individuals. In doing so, a Maxwell–Boltzmann-like distribution appeared, the same distribution as for the velocities …
Suppression of extinction with TMS in humans: from healthy controls to patients.
2006
We review a series of studies exemplifying some applications of single-pulse and paired-transcranial magnetic stimulation (TMS) in the study of spatial attention and of its deficits. We will focus primarily on sensory extinction, the failure to consciously perceive a contralesional sensory stimulus only during bilateral stimulation of homologous surfaces. TMS studies in healthy controls show that it is possible either to interfere or modulate the excitability of the parietal cortex during sensory (i.e. tactile and visual) attentional tasks, thus reproducing a condition of virtual extinction. TMS studies in patients with unilateral (mainly right) brain damage show that the modulation of the …
Fatal cerebellar haemorrhage due to phenprocoumon poisoning.
1996
A 32-year-old patient died of a cerebellar haemorrhage and the blood coagulation analysis before death suggested defective synthesis of vitamin K-dependent clotting factors due to vitamin K deficiency. The post-mortem toxicological examination of different tissues revealed phenprocoumon poisoning as the cause of death. The differential diagnosis of vitamin K deficiency and the toxicology of hydroxycoumarins are discussed.
Vitamin A Inhibits Doxorubicin-Induced Membrane Lipid Peroxidation in Rat Tissues in Vivo
1993
The antioxidant activity of vitamin A against lipid peroxidation induced by doxorubicin in rat tissues in vivo was investigated. A single ip injection of doxorubicin (30 mg/kg body wt) markedly raised the level of peroxidated lipids measured as TBARS and conjugated dienes in heart and brain membrane preparations. Other tissues, such as retina and liver, did not show any increase of lipid peroxides over control values. Pretreatment of rats with two daily subcutaneous injections of retinol palmitate (0.25 g/kg body wt), for 2 days, before injecting doxorubicin, inhibited peroxidation of heart and brain membrane lipids. The antioxidant action of vitamin A does not appear to be mediated by enha…
Two interconnected functional systems in the amygdala of amniote vertebrates.
2008
The amygdala shows ventropallial and lateropallial derivatives that can be compared among vertebrates according to their topological position, either superficial (cortical amygdala) or deep (basolateral amygdala and amygdalo-hippocampal area), connections and histochemical features. On the other hand, the subpallial amygdala, also called extended amygdala, is composed of medial and central divisions. In mammals, both divisions consist of an intra-amygdaloid portion and a part of the bed nucleus of the stria terminalis. In non-mammals, the intratelencephalic trajectory of the stria terminalis is short and both poles of the extended amygdala are close together. Like its mammalian counterpart,…