胎脑顶叶 枕叶脑沟及外侧沟发育规律的研究

目的 探讨顶叶、枕叶脑沟及外侧沟的发育规律,为研究成人脑的结构和功能提供参考资料。方法 将收集到的８９具不同胎龄的标本经１０％福尔马林固定３个月后取及脑,观察顶叶、枕叶各脑沟及外侧沟的出现时间、长度及深度,并对各胎龄组脑沟的发育情况进行对比分析。结果 顶叶、枕叶脑沟出现时间差别较大,中央后沟从第５月龄开始出现,至第８月龄全部出现;顶枕沟和距状沟从第４月龄开始出现,至第６月全部出现;外侧沟出现最早,     

Dementia lacking distinctive histopathology: clinicopathological evaluation of 32 cases

We report the neuropathological findings in 32 patients, aged 46–86 years, with demential lacking distinctive histopathology. All of the patients were classified clinically as having Pick's or atypical Pick's disease, but the routine neuropathological evaluation showed no specific histopathological changes such as Pick bodies, senile plaques, neurofibrillary tangles or Lewy bodies. In 50% of the cases the first symptoms appeared before 65 years of age. However, there were 9 patients with onset in the eighth decade. Positive family history was found only in 6 presenile cases. The retrospective evaluation of the clinical records revealed the consistent presence of frontal symptomatology, including loss of personal awareness, inappropriate euphoria and stereotyped behavior. Speech disorders were observed in 80% of the cases, whereas temporospatial disorientation and memory impairment were less frequent. Praxis and gnosis were strikingly preserved in most of the cases. The macroscopic neuropathological examination revealed frontal or temporopolar atrophy in 97% of the cases, while the hippocampus and subcortical structures were relatively spared in the majority of the cases. Histologically, four groups were recognized. Group A showed moderate to severe neuron loss and gliosis in the frontal and/or temporopolar cortex without subcortical involvement. In group B, the neocortical cell loss was widespread, and the striatum and substantia nigra displayed differential degrees of gliosis but no neuron loss. Group C patients showed a lesion distribution comparable to that observed in group B but with severe neuron loss in at least one subcortical region. Four cases formed group D, which was characterized by the preservation of the pyramidal neurons in the neocortex and variable subcortical changes. Despite these differences in the topography of pathological changes, all of the cases shared a similar clinical profile. These findings further demonstrate the epidemiological and neuropathological heterogeneity of dementia lacking distinctive histopathology. Furthermore, they suggest that the same clinical manifestations may correspond to several distinct pathological processes in this condition.     

An angiographically occult arteriovenous malformation in the medial parietal lobe presenting as seizures of medial temporal lobe origin

We present an unusual case of a patient who was diagnosed with temporal lobe epilepsy and whose seizures were reduced markedly after excision of an angiographically occult arteriovenous malformation (AVM) located in the left medial parietal lobe. A 38-year-old man had complex partial seizures characterized by motionless staring with oroalimentary and behavioral automatisms since the age of 15 years. Magnetic resonance imaging (MRI) demonstrated a small lesion extending from the left posterior cingulate gyrus to the precuneus. There was no MRI evidence of mesial temporal sclerosis. Intracranial EEG recordings showed ictal onset from the left medial parietal lobe propagating to the medial temporal lobes. Clinical signs appeared when these discharges reached the temporal lobes. After excision of the lesion (which was histologically confirmed as an AVM), together with the marginal cortex, seizures were reduced significantly. Careful diagnostic evaluation of lesions such as the this one may reveal an epileptogenic lesion (zone) far from the region where scalp ictal discharges seem to arise. In our case, we hypothesize that false localization was due to propagation of ictal discharges from the parietal focus through the limbic system.     

The effects of chronic administration of hydrocortisone on cognitive function in normal male volunteers

Rationale: Corticosteroids are elevated in certain neuropsychiatric disorders and this may contribute to the neuropsychological impairments reported in these disorders. Objective: To examine the effects of hydrocortisone on learning, memory and executive function. Methods: Hydrocortisone 20 mg was administered twice daily for 10 days to normal male volunteers in a randomized, placebo control, crossover, within-subject design. Learning, memory and executive function were measured using selected subtests from the Cambridge Neuropsychological Test Automated Battery. Results: Hydrocortisone caused impairments of visuo-spatial memory. These included increased within search errors and impaired use of strategies on the spatial working memory subtest. In addition, administration of hydrocortisone was associated with more errors in the paired associate learning subtest, although no effect was found on the Tower of London. Hydrocortisone speeded response latencies in certain tests (pattern and spatial recognition memory). Conclusion: These results indicate that chronic administration of hydrocortisone leads to deficits in certain tests of cognitive function sensitive to frontal lobe dysfunction and may contribute to the cognitive impairment reported in certain neuropsychiatric disorders. Received: 27 July 1998 / Final version: 9 February 1999     

Converging visual and somatic sensory cortical input to the intraparietal sulcus of the rhesus monkey

A cyto- and myeloarchitectonic study reveals the presence of a distinct cortical zone ("area POa") in the lower bank of the intraparietal sulcus of the rhesus monkey. Using both autoradiographic and silver impregnation techniques, an analysis of cortical connections shows two overlapping projections to this sulcal zone. These come from (1) the middle portion of the preoccipital gyrus (area OA) and (2) the rostral inferior parietal lobule (area PF).     

Cerebral metabolic and vasopressin and oxytocin responses during osmotic stimulation in conscious rats

Intravenous infusion of hypertonic saline increased plasma [Na (+) ] and osmolality and induced a short-latency drinking response. These changes were associated with increased glucose utilization in the supraoptic and paraventricular nuclei and neural lobe, and decreases in the medial septum and nucleus ambiguus. The increases in glucose utilization were more accentuated in the supraoptic nuclei than in paraventricular nuclei, indicating that they are more sensitive to osmotic stimulation than the paraventricular nuclei. In association with enhanced activity in the hypothalamo-neurohypophysial system, plasma vasopressin and oxytocin concentrations increased, with a preferential increase of oxytocin over vasopressin. The hormonal contents in the neural lobe were not depleted by the osmotic stimulus despite the large increases of their concentrations in the plasma.     

Neuropsychological outcome after traumatic temporal lobe damage

Summary The most frequent sequelae after severe brain injury include changes in personality traits, disturbances of emotional behaviour and impairment of cognitive functions. In particular, emotional changes and/or verbal and non verbal dysfunctions were found in patients with bilateral or unilateral temporal lobe lesions. The aim of our study is to correlate the localization of the brain damage after severe brain injury, in particular of the temporal lobe, with the cognitive impairment and the emotional and behavioural changes resulting from these lesions.The patients with right temporal lobe lesions showed significantly better scores in verbal intelligence and verbal memory in comparison with patients with left temporal lobe lesions and those with other focal brain lesions or diffuse brain damage. In contradistinction, study of the personality and the emotional changes (MMPI and FAF) failed to demonstrate pathological scores in the 3 groups with different CT lesions, without any significant difference being found between the groups with temporal lesions and those with other focal brain lesions or diffuse brain damage.The severity of the brain injury and the prolongation of the disturbance of consciousness could, in our patients, account for prevalence of congnitive impairment on personality and emotional changes.     

Arachnoid cyst of the middle fossa with paradoxical changes of the bony structures

Summary Two patients with an arachnoid cyst of the middle fossa showed paradoxical changes of the adjoining bony structures of the skull. There was a diminution of the middle fossa and hyperplasia of the sphenoid sinus (pneumosinus dilatans) as well as a marked bulging of the squamous part of the temporal bone. In one case in which scinticisternography was performed, communication between the cyst and the subarachnoidal space was proven as well as an extremely slow cerebrospinal fluid circulation in the cyst. The pathogenesis of the cyst is discussed, based upon the structural changes of the skull, the angiographic findings and the locally disturbed cerebrospinal fluid circulation. The primary disturbance seems to be a temporal lobe agenesis.     

Cortical activation during retrieval of arithmetical facts and actual calculation: a functional magnetic resonance imaging study

By using functional magnetic resonance imaging (fMRI), the neural substrates involved in mental recitation of the single-digit multiplication table and serial subtraction were studied. The former depends mostly on well-learned arithmetical facts, while the latter requires arithmetic processing. Activation during each task was compared with that in a number counting control. During the recitation of single-digit multiplication, the activated regions included the area lying along the left intraparietal sulcus, the premotor and supplementary motor areas, and the posterior portion of the left inferior frontal gyrus. The areas activated during serial subtraction included these areas as well as the bilateral prefrontal and right parietal areas. From the results obtained during retrieval of the multiplication table in this study and previous studies, it was concluded that semantic memory of the multiplication table is stored in the area lying along the intraparietal sulcus and that the frontal areas play an executive role in utilizing the semantic memory of arithmetical facts. It was assumed that the arithmetical facts requiring actual calculation are also stored in the same region. The additional activation during serial subtraction compared with the activation during retrieval of the multiplication table is probably due to the processes of actual calculation. These processes include proper alignment of digits, which may have caused the right parietal activation, and maintaining digits needed for the mental serial subtractions, which may have caused the bilateral prefrontal activation.     

Frequency of bitemporal independent interictal epileptiform discharges in temporal lobe epilepsy

PURPOSE: Bitemporal interictal epileptiform discharges (IEDs) occur in < or =42% of scalp EEGs in patients with temporal lobe epilepsy (TLE) studied with routine EEGs or partial analysis of long-term recordings. METHODS: Twenty-eight patients with TLE demonstrating exclusively unilateral temporal IEDs on routine EEGs underwent 24-h continuous recording. The entire record was visually inspected for epileptiform discharges. We used continuous EEG to assess the significance of long-term recording in detecting bilateral IEDs. RESULTS: Twenty-two patients had left temporal IEDs; 21 had right temporal IEDs. Seventeen (61%) patients had IEDs originating from both the right and left temporal lobes. The probability of detecting bilateral independent IEDs was correlated with the duration of continuous EEG recording. There was no correlation between the number of IEDs originating from one side and the probability of detecting independent IEDs on the other side. The frequencies of IEDs were not correlated with the length of time since onset of epilepsy. CONCLUSIONS: The findings suggest that when long-term recordings are performed, the incidence of bilateral discharges in TLE is higher than previously reported in the literature and supports the view that TLE is commonly a bilateral disease.