摘要:

Studies suggest that emotionally influenced events enhance long-term memory. This study aimed to uncover whether this phenomenon exists in Alzheimer's Disease (AD) by comparing patients' performance with that of controls on a memory task. Overall, controls performed better than AD subjects on a delayed recognition task of a story containing emotional elements (95.8 ± 2.4%vs66.6 ± 28.5%; mean ± s.d.), respectively. Among AD subjects, there was relative sparing of emotionally influenced memory, which was not seen in controls because of a ceiling effect. Retention of the emotional phase of the story differed significantly from that of the neutral phases. These findings suggest that the influence of emotion on memory is spared, at least to some degree, in AD.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The present study was conducted to develop a new animal model of neuropathic pain employing injury to the distal sciatic nerve branches. Under halothane anesthesia, the tibial, sural, and/or common peroneal nerves were injured and neuropathic pain behaviors were compared among different groups of rats. Different types of injury produced different levels of neuropathic pain. Rats with injury to the tibial and sural nerves showed the most vigorous mechanical allodynia, cold allodynia, and spontaneous pain. These neuropathic pain behaviors were not relieved by functional sympathectomy using guanethidine. The results suggested that injury to the tibial and sural nerves, while leaving the common peroneal nerve intact, can be used as a new animal model of neuropathic pain and that this model represents sympathetically independent pain (SIP). The present animal model is very simple to produce injury and can produce profound and reliable pain behaviors. These features enable the new animal model to be a useful tool in elucidating the mechanisms of neuropathic pain, especially SIP.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

We investigated the possible induction of apoptosis of dorsal root ganglion (DRG) neurons and the defect of nerve regeneration after crush injury with reference to the JNK/c-jun and cAMP pathway in streptozocin-induced diabetic rats. In addition, the effects of a PGE1analogue were tested in diabetic rats. At day 0 (before axonal injury), no TUNEL-positive DRG neurons were observed in any group. From day 1 to 7 after axonal injury, TUNEL-positive DRG neurons were seen in diabetic rats, but not in non-diabetic or PGE1-treated diabetic rats. The regeneration distance at day 7 after crush injury was shorter in diabetic rats than in the other groups of rats. The time course of JNK/c-jun phosphorylation did not parallel apoptosis. At day 7, the cAMP content of DRG was higher than that at day 0 in non-diabetic and PGE1-treated rats, whereas it was not increased after 7 days in diabetic rats. These results indicate that in diabetic rats apoptosis of DRG neurons is induced by axonal injury independently of the JNK/c-jun and cAMP pathway and that PGE1rescues DRG neurons from apoptosis and improves axonal regeneration in diabetic rats.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Widespread synchronous oscillatory activity, particularly in the gamma (‘40 Hz’) band, has been postulated to exist in the brain as a mechanism underlying binding. A new method of examining phase synchronicity across multiple electrode sites in specific EEG frequency bands as a function of time was employed, in a conventional cognitive ERP paradigm in 40 normal subjects. A significant late post-stimulus gamma synchronicity response occurred for task-relevant stimuli, whereas for task-irrelevant stimuli no such response was evident. However, an early response was seen for both task-relevant and irrelevant stimuli. This is the first empirical demonstration that widespread synchronous high frequency oscillations occur in humans in relation to cognition.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Nitric oxide-induced calcium transients in growth cones are believed to be mediated by cyclic nucleotides. Because nitric oxide is thought to influence the development of olfactory receptor cells (ORCs), we have begun to explore the effect of cyclic nucleotides on ORC growth cones. Cultured ORCs were loaded with fluo-3 AM and confocal imaging was employed to monitor calcium transients following cyclic nucleotide-gated channel activation. Application of 8-bromo-cGMP at the growth cone caused transient increases influorescence which were restricted to the growth cone and lasted tens of seconds. The signal was abolished by LY83583, an inhibitor of cyclic nucleotide-gated channels. 8-Bromo-cGMP also inhibited further extension of growth cones. The data indicate that ORC growth cones exhibit cGMP-dependent calcium transients that are consistent with those generated by cyclic nucleotide-gated channels.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The distribution of PKCε and its co-localization with various GABAAreceptor subunits within limbic structures of the mouse brain was examined by fluorescence immunohistochemistry. Levels of PKCε immunoreactivity were highest in the cingulate cortex and dentate gyrus, moderate in the nucleus accumbens, and lowest in the prelimbic cortex and basolateral amygdala. Co-localization of PKCε immunoreactivity with the GABAAreceptor α1, β2/3, and γ2subunits varied by subunit and brain region examined, with the majority of co-localization occuring in the dentate gyrus, nucleus accumbens and basolateral amygdala. These results demonstrate that PKCε may interact with GABAAreceptors in a subunit- and region-specific manner, and provide a potential anatomical basis for recent behavioral and biochemical evidence that PKCε modulates GABAAreceptor function.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The study of the cooperativity among cortical areas is essential to our understanding of brain functioning. Here we investigated the relative contributions of top-down and bottom-up directed interactions between area 17 and area 7 of the cat visual system. Bipolar local field potentials were recorded while the animals performed a go/no-go task or were in a quiet resting state. The data were analyzed by applying measures of interaction based on the Wiener–Granger causality concept. We found that during the visual task top-down directed interactions were of a similar magnitude as the bottom-up component. Second, interareal couplings tended to increase in conditions requiring a discriminative effort. Third, during behaviors not dominated by visual processing non-directed interactions increased.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Underlying impairments in rapid auditory processing may contribute to disrupted phonological processing, which in turn characterizes developmental language impairment (LI). Identification of a neurobiological feature of LI that is associated with auditory deficits would further support this model. Accordingly, we found that adult male rats with induced cortical malformations were impaired in rapid auditory processing. Since 40–60% of BXSB mice exhibit spontaneous focal cerebrocortical ectopias (as seen in dyslexics brains), we assessed auditory gap detection in adult male BXSB mice. Ectopic mice were significantly worse than non-ectopics in detecting a 5 ms silent gap, but were not significantly impaired at longer gap durations (10–100 ms). Our results confirm that focal cortical malformations are associated with impairments in rapid auditory processing.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The present study investigated expression of β-amyloid protein (AP) and Amyloid precursor protein (APP) in spinal motor neurons of young adult (3 month old) and aged (26–30 month old) rats. The total number of spinal motor neurons in the seventh cervical (C7) spinal segment was also examined in both young adult and aged rats. There was an ∼21% (p< 0.001) decrease in the number of motor neurons of the C7 spinal segment in aged rats compared with young ones. Immunoreactivity (IR) of AP and APP was not observed in spinal motor neurons of young adult rats. In contrast, ∼50% of the spinal motor neurons of the aged rats were APP positive. Furthermore, extensive immunoreactivity was found in the processes of spinal motor neurons of aged rats. These results have shown that AP and APP is coincident with the loss of motor neurons in the spinal cord of aged rats, and might be associated with the degenerative processes of ageing motor neurons.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Transcranial magnetic stimulation (TCS) was applied to both hemispheres of 16 patients affected by criptogenic focal epilepsy to evaluate the interhemispheric symmetry of the motor cortex excitability. The amplitude of the motor evoked potentials (MEPs) and the duration of the post-MEP silent period (SP) were measured at threshold (THR) and at increasing TCS stimulation intensities. The THR was significantly higher in patients than in 16 age-matched control subjects (p< 0.01). No interhemispheric differences were found in MEP amplitude. In controls, the correlation between SP duration and increasing TCS stimulus intensity was linear with a symmetrical progression of the SP duration over the two hemispheres. In patients this linear SP progression was lacking on the ‘epileptic’ hemisphere: the SP duration did not increase following TCS. > 40% above THR, indicating abnormal interhemispheric asymmetry. This finding suggests a selective dysfunction of inhibition in the epileptic hemisphere as signaled by an abnormal SP duration in response to progressively higher TCS intensities.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID