New view of the organization of the pulvinar nucleus in Tupaia as revealed by tectopulvinar and pulvinar-cortical projections

The projections of the superficial layers of the superior colliculus to the pulvinar nucleus in Tupaia were reexamined by injecting WGA-HRP into the tectum. The main result was finding two different patterns of terminations in the pulvinar nucleus: a zone remote from the lateral geniculate nucleus, which occupies the dorsomedial and caudal poles of the pulvinar nucleus, was almost entirely filled with terminals in every case irrespective of the location of the injection site; and a second division of the pulvinar nucleus, adjacent to the lateral geniculate nucleus, contained irregular patches--much more densely populated--and the distribution of patches varied from case to case. We call the first projection "diffuse" and the patchy projection "specific." Next we injected several divisions of the extrastriate visual cortex to find the cortical target of each pathway. The diffuse path terminates in the ventral temporal area (Tv). The specific path terminates in the dorsal temporal area (Td) and area 18. We speculated about the significance of the two pathways: the specific path may be responsible for the preservation of vision after removal of the striate cortex; the diffuse path may have an important place in the evolution of the visual areas of the temporal and occipital lobe. We argued that the target of the diffuse path is in a position to relate limbic and visual impulses and relay the product of such integration to the other visual areas, striate as well as extrastriate cortex.     

Psychopathology and personality characteristics of epileptic patients: epilepsy, psychopathology and personality

The psychiatric investigation of a sample of 101 epileptic patients (65 temporal lobe epileptics (TLE) and 36 non-TLE) through various methods of evaluation, showed that only a minority of TLE with DSM-III diagnoses of Organic Brain Syndromes had severe psychopathology and manifested some personality traits. Thus, these patients seem to be differentiated from the rest of epileptics, TLE and non-TLE, who had quite "benign" psychological problems, if at all. It is quite probable that this sub-group of TLE could be the main instigators and perpetrators of the "bad image" of epileptics. The findings are discussed in relation to the pertinent literature and some hypotheses are offered for their explanation.     

Hot-Water Epilepsy: A Variant of Reflex Epilepsy in Southern India

"Hot water epilepsy" (HWE), precipitated by a bath or shower in hot water, has been described infrequently in the literature. We report 279 cases of HWE that were seen between 1980 to 1983 in Bangalore, South India. We found HWE to be more common in children, with cases more frequent among male than female patients (2.6:1). Complex partial seizures constituted the main clinical presentation (67.0%); HWE accounted for 4.4% of all complex partial seizures and generalize tonic-clonic seizures seen at our center during the 1980-1983 period. Although prognosis seems favorable 25.4% of our patients developed nonreflex epilepsy within 1-3 years. They were managed with antiepileptic drugs and the use of lukewarm water for bathing.     

Deposition of amyloid β protein in non-Alzheimer dementias: evidence for a neuronal origin of parenchymal deposits of β protein in neurodegenerative disease

Summary In two elderly patients with frontal lobe dementia and in two others with progressive aphasia an inverse relationship between the severity of protein deposition and the principal pathology of these disorders was noted. Deposition of protein occurred only in areas of cortex where functional (viable) neurones were still present and was absent where neuronal decimation had taken place. Such findings suggest that the presence of functional neurones is necessary for protein deposition to occur and, therefore, that neurones may be the source of the amyloid protein that is deposited within brain parenchyma not only in these disorders but also in other conditions, particularly Alzheimer's disease.Supported by a grant from the North Western Regional Health Authority (DJ) and a B.Sc Intercalated Studentship from the MRC (PWS)     

Enhancement of activity of an epileptogenic focus in the frog hippocampus by kynurenins and its depression by serotonin

Experiments on frogs with an epileptogenic focus produced by injection of 1000 units penicillin (0.4 l) into the primordial hippocampus showed that preliminary injection of two kynurenins — quinolinic acid (QA, 0.1 g) and kynurenin itself (K, 1 g) — into the region of the focus or their injection into an already functioning epileptogenic focus led to an increase in the frequency of interictal epileptiform discharges and of electrographic correlates of fits on the EEG. Anthranilic acid (AA, 5 g) had no effect on activity of the focus whereas serotonin (S, 1 g) and 5-methoxytryptamine (1 g) substantially depressed it. The provoking action of the kynurenins on epileptically predisposed brain neurons, it is suggested, may play an important role in the pathogenesis of epilepsy.Department of Pharmacology, Leningrad Pediatric Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 2, pp. 158–160, February, 1979.     

癫痫病人不对称性δ、θ活动的地形图研究

利用BEAM分析技术,以50例正常人为对照,用Z值概率差异地形图,对83例部分性与全面性发作的癫痫病人脑电背景活动的δ与θ不对称性情况进行分析,并与其它结果比较后显示,BEAM对癫痫病人的不对称性δ、θ的检出率达72％,较EEG目测分析敏感,其显示的病变区与EEG目测分析、CT、SPECT结果大多符合,可用作痫灶的定侧定位,亦有助于全面性癫痫与部分性癫痫的鉴别。     

Source Localization of P300 from Oddball, Single Stimulus, and Omitted-Stimulus Paradigms

Three different auditory stimulus paradigms were used to elicit P300 potentials. Normal subjects were tested on the classical rare target stimulus, single-stimulus and omitted-stimulus conditions. Noninvasive identification of the cerebral sources of the event-related potentials (ERPs) was performed using spatio-temporal multiple dipole modeling (BESA software) with individually sized spherical head models. The grand average data of each condition was first independently modeled and these models were used as starting values for modeling each individual subject's data. Models for the rare-stimulus condition and single-stimulus condition both consisted of 6 dipoles. Models for the omitted-stimulus condition consisted of 2 dipoles. The dipole locations of the final individual 6-dipole models for the rare and single-stimulus conditions did not differ significantly from each other or from one previous result obtained from a another group of subjects (Tarkka et al. 1995). Super-imposition of the dipole coordinates on the sterotaxic brain atlas suggests that bilateral deep medial temporal lobe structures are the major contributors to rare and single-stimulus P300s. Because both the wave form morphology and the source model of the P300 elicited by single stimulus were close to those of the rare-stimulus P300 it may be that the underlying neural mechanisms eliciting these P300 potentials are essentially the same.     

Functional interactions among neurons in inferior temporal cortex of the awake macaque

Summary Functional interactions among inferior temporal cortex (IT) neurons were studied in the awake, fixating macaque monkey during the presentation of visual stimuli. Extracellular recordings were obtained simultaneously from several microelectrodes, and in many cases, spike trains from more than one neuron were extracted from each electrode by the use of spike shape sorting technology. Functional interactions between pairs of neurons were measured using cross-correlation. Discharge patterns of single neurons were evaluated using auto-correlation and PST histograms. Neurons recorded on the same electrode (within about 100 n) had more similar stimulus selectivity and were more likely to show functional interactions than those recorded on different electrodes spaced about 250 to 500 microns apart. Most neurons tended to fire in bursts tens to hundreds of milliseconds in duration, and asynchronously from the stimulus induced rate changes. Correlated neuronal firing indicative of shared inputs and direct interactions was observed. Occurrence of shared input was significantly lower for neuron pairs recorded on different electrodes than for neurons recorded on the same electrode. Direct connections occurred about as often for neurons on different electrodes as for neurons on the same electrode. These results suggest that input projections are usually restricted to less than 500 m patches and are then distributed over greater distances by intrinsic connections. Measurements of synaptic contribution suggest that typically more than 5 near-simultaneous inputs are required to cause an IT neuron to discharge.     

Effect of acoustic stimulation on GABAergic neurons in limbic structures of Krushinskii-Molodkina rats

Quantitative study of GABAergic and main cells in the hippocampus and piriform cortex of Krushinskii-Molodkina rats was performed 1 month after the incidence of seizure activity evoked by acoustic stimulation. The number of neurons significantly decreased in both regions and, particularly, in the hippocampus and central area of the piriform cortex. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 4, pp. 375–377, April, 2008     

颞叶癫痫的临床特点与脑电图分析

目的：分析颞叶癫痫患的临床特点及脑电图定位的意义。方法：回顾分析92例颞叶癫痫患的脑电图。结果：左颞有癫痫样波42例，右颞有癫痫样波29例，双颞有癫痫样波21例，临床表现与癫痫样波发放部位有关，癫痫波的传导主要有容积传导和神经传导方式。结论：结合患临床表现与脑电图癫痫样波起始部位分析有助于致痫灶的定位。