Search results for "Cephalon"
showing 10 items of 99 documents
Diabetic 3rd nerve palsy: evidence for a mesencephalic lesion.
1990
Eleven consecutive adult chronic diabetic patients presented with an isolated 3rd nerve palsy (8 with pupillary sparing) of which 10 had abnormal ipsilateral or bilateral masseter reflexes (MassR). Three patients had an MRI lesion in the ipsilateral oculomotor fasciculus and 3 had subsequent mild brainstem signs. An additional 13 patients with Weber's syndrome had similar ipsilateral or bilateral MassR abnormalities, while 7 patients with 3rd nerve palsies on a known extra-axial basis had none. The findings suggest that an isolated diabetic 3rd nerve palsy, with or without pupillary sparing, is much more likely on the basis of a focal mesencephalic infarct than a peripheral nerve lesion.
Temporal retrogasserian resection of trigeminal root versus controlled elective percutaneous electrocoagulation of the ganglion of gasser in the trea…
1972
In his experience with 531 surgical procedures for the relief of trigeminal neuralgia between 1955 to 1970, the author developed a strong preference for the percutaneous electro-coagulation of the gasserian ganglion. Although the method was repeatedly modified in the early years, a standardized technique of controlled, selective and fractional coagulation in the semiawake state of neurolept-anaesthesia was used since 1963 in 183 of his 311 patients, treated in this manner. The advantages of the method, particularly in comparison to open intracranial root sections, are: Minimal operative risk, control of operative effect during the operation, small sensibility deficit, low rate of complicati…
Evidence for the presence of two 24-h rhythms 180 degrees out of phase in the pineal gland of male Pirbright-White guinea pigs as monitored by counti…
1987
Previous studies have shown that the "synaptic" bodies of mammalian pinealocytes are a heterogeneous group of organelles. Whereas "synaptic" ribbons (SR) exhibit a day/night rhythm with small numbers during daytime and high numbers at night, the so-called "synaptic" spherules (SS) show species-specific differences in their rhythmicity. In the present study the numbers of SR and SS were monitored in male guinea pigs over a full 24-h period at 4-hourly intervals (LD 12:12, lights on at 7:00). The results obtained show that the rhythms of SR numbers and SS numbers are out of phase by 180 degrees. SR numbers are small during daytime and high at night, whereas SS numbers are high during daytime …
Early-onset tolerance in rat global cerebral ischemia induced by a mitochondrial inhibitor
2000
It was studied whether a subtoxic dose of the mitochondrial neurotoxin, 3-nitropropionic acid (3-NPA), can initiate early-onset tolerance induction for subsequent ischemic injury. Wistar rats were pretreated for 3 h by intraperitoneal 3-NPA (20 mg/kg body weight; n=13) or solvent (n=12). Fifteen minutes global cerebral ischemia was induced by bilateral carotid artery occlusion and hypobaric hypotension. rCBF and tissue hemoglobin oxygen saturation were measured by laser Doppler scanning and a microspectrophotometric method. Ischemic insult and brain temperature were identical in both groups. Body weight and neurological scores recovered in the pretreated group but further deteriorated in th…
Neurons in the pigeon nidopallium caudolaterale signal the selection and execution of perceptual decisions
2014
Sensory systems provide organisms with information on the current status of the environment, thus enabling adaptive behavior. The neural mechanisms by which sensory information is exploited for action selection are typically studied with mammalian subjects performing perceptual decision-making tasks, and most of what is known about these mechanisms at the single-neuron level is derived from cortical recordings in behaving monkeys. To explore the generality of neural mechanisms underlying perceptual decision making across species, we recorded single-neuron activity in the pigeon nidopallium caudolaterale (NCL), a non-laminated associative forebrain structure thought to be functionally equiva…
Forebrain specialization and the olfactory system in anseriform birds. An architectonic and tracing study.
1992
In anseriform birds the mediodorsal part of the rostral forebrain is covered by a corticoid (= layered) structure, establishing a unique feature of this avian group since in other birds the non-cortical accessory or dorsal hyperstriatum occupies the corresponding surface area of the hemisphere. The efferents of the olfactory bulb are shown to reach this region, which thus can be identified as a heavily enlarged retrobulbar area. The large expansion of this olfactory representation may indicate an important biological function. In comparison to the mammalian olfactory system the three stratified olfactory projection centers of birds should be regarded as retrobulbar, prepiriform and periamyg…
Piriform Cortex and Amygdala
2012
Publisher Summary A ventral view of the cerebral hemispheres of mammals shows an array of structures ultimately connected with the olfactory bulbs through the olfactory tracts. This is the basis for the old concept of rhinencephalon, a series of neural centers in the cerebral hemispheres, located ventral to the rhinal fissure, for which an olfactory role was assumed. Although mice lack a conspicuous rhinal fissure, their “rhinencephalon” is well developed. The concept of the rhinencephalon is difficult to sustain nowadays, as it includes neural centers of diverse origin, organization and nature. The rhinencephalon comprises several allocortical areas that constitute the olfactory cortex, de…
Human brain organoids assemble functionally integrated bilateral optic vesicles
2021
During embryogenesis, optic vesicles develop from the diencephalon via a multistep process of organogenesis. Using induced pluripotent stem cell (iPSC)-derived human brain organoids, we attempted to simplify the complexities and demonstrate formation of forebrain-associated bilateral optic vesicles, cellular diversity, and functionality. Around day 30, brain organoids attempt to assemble optic vesicles, which develop progressively as visible structures within 60 days. These optic vesicle-containing brain organoids (OVB-organoids) constitute a developing optic vesicle's cellular components, including primitive corneal epithelial and lens-like cells, retinal pigment epithelia, retinal progeni…
Effects of rewarding electrical stimulation of lateral hypothalamus on classical conditioning of the nictitating membrane response.
1997
1. Adult New Zealand albino rabbits were prepared with chronic hypothalamic stimulating electrodes and hippocampal recording electrodes. 2. Rabbits were restrained and classically conditioned by a tone CS and an airpuff US either followed or preceded by a hypothalamic stimulation (HS). Control rabbits were conditioned without the HS. 3. It was found that HS following the CS facilitated both behavioral and hippocampal responses, while HS preceding the CS inhibited them. 4. Enhanced hippocampal learning-related unit firing to the CS may represent an early indication of conditioning before the behavioral activity produces any observable change.