No abstract available.
Animals ; Brain* ; Corpus Striatum* ; Neurons* ; Neuropeptides* ; Rats*

It has been reported that single-unit activity in the prefrontal cortex (PFC) and striatum represented visual stimulus and reward information. But how to encode these pieces of information is quite complex from the view of single-neuron activity. Different neurons represented stimulus or reward information in different task epochs with increasing or decreasing their activities relative to their baseline firing rates. The present paper was aimed to study whether population neurons in the two brain areas could stably encode task-relevant parameters in a whole trial period. We recorded single-unit activities in the lateral PFC (LPFC) and striatum while the monkey was performing a stimulus- reward prediction task, and analyzed the neuronal activities by the method of a multi-variable regression model and the linear support vector machine. The results showed that, although proportions of task-related neurons in the two areas varied largely in the whole trial period, LPFC population neurons encoded reward and stimulus information stably and reliably. Population neurons in the striatum encoded only reward information, not stimulus information. A group of neurons in the two areas represented combined information of stimulus and reward. Further analysis showed that LPFC neurons encoded reward information for a group of relevant stimuli, while striatal neurons encoded reward information for a specific stimulus. These results suggest that both LPFC and striatal population neurons are able to stably represent task-relevant information, but from different aspects of the task. The different strategies to encode information in the LPFC and striatum suggest their different contributions in reward-based decision making.
Animals ; Corpus Striatum ; Neurons ; Prefrontal Cortex ; Primates ; Reward

Autapses selectively form in specific cell types in many brain regions. Previous studies have also found putative autapses in principal spiny projection neurons (SPNs) in the striatum. However, it remains unclear whether these neurons indeed form physiologically functional autapses. We applied whole-cell recording in striatal slices and identified autaptic cells by the occurrence of prolonged asynchronous release (AR) of neurotransmitters after bursts of high-frequency action potentials (APs). Surprisingly, we found no autaptic AR in SPNs, even in the presence of Sr²⁺. However, robust autaptic AR was recorded in parvalbumin (PV)-expressing neurons. The autaptic responses were mediated by GABA_A receptors and their strength was dependent on AP frequency and number. Further computer simulations suggest that autapses regulate spiking activity in PV cells by providing self-inhibition and thus shape network oscillations. Together, our results indicate that PV neurons, but not SPNs, form functional autapses, which may play important roles in striatal functions.
Parvalbumins/metabolism* ; Corpus Striatum/metabolism* ; Interneurons/physiology* ; Neurons/metabolism* ; Neostriatum

PURPOSE: To determine whether 1H magnetic resonance spectroscopy (MRS) is useful in differentiating idiopathic Parkinson's disease (IPD) from progressive supranuclear palsy (PSP), based on metabolite ratios. MATERIALS AND METHODS: Using a 1.5 T MR Unit, single voxel 1H MRS using STEAM with a TR of 2000ms and a TE of 135ms was performed in seven PD and eight PSP patients. Five age-matched volunteers(mean age, 63 years) andanother five younger healthy volunteers(mean age, 30 years) were studied as normal controls. The regions of interest were the putamen and pallidum, with a size of 2 X 2 X 2cm. After measuring the spectral intensities ofeach metabolite (N-acetylaspartate=NAA, choline=Cho, creatine=Cr and lactate), relative peak height ratios ofNAA/Cr, Cho/Cr and Naa/Cho, and lactate levels among four groups were compared. ESULTS: NAA/Cho and NAA/Crratios were statistically lower in the PSP group than the IPD group (1.21 +/-0.26 versus 1.45 +/-0.20, and 1.26 +/-.23 versus 1.38 +/-0.19, respectively : p<0.05). NAA/Cho and NAA/Cr ratios were significantly lower inage-matched controls than in younger normal controls (1.39 +/-0.21 versus 1.76 +/-0.15, and 1.36 +/-0.13 versus1.79 +/-0.17, respectively : p<0.05). However, NAA/Cho and NAA/Cr ratios between age-matched controls and IPD werenot significantly different (p>0.05). Cho/Cr ratios were not different among four groups. Lactate was not detectedin any patients. CONCLUSION: NAA/Cho and NAA/Cr ratios in the corpus striatum were significantly lower in the PSP group than in the age-matched control and IPD groups. These results suggest that loss of neuron cells in thecorpus striatum is more prominent in PSP than in IPD, and that NAA/Cho and NAA/Cr ratios may help in differential diagnosis of IPD and PSP.
Corpus Striatum ; Humans ; Lactic Acid ; Magnetic Resonance Spectroscopy* ; Neurons ; Parkinson Disease* ; Putamen ; Steam ; Supranuclear Palsy, Progressive*

We report a rare case of cavernous hemangioma (CH) which developed in adjacent location to a preexisting CH after gamma knife radiosurgery (GKRS). A 36-year-old woman underwent GKRS for a CH in the left lentiform nucleus. Three-and-half years after radiosurgery, MRI revealed a new CH in the left caudate nucleus. Surgical excision of the new lesion was performed. The pathological examination confirmed the diagnosis of CH. In radiosurgery for CH, it should be noted that a new CH may develop, which is likely to result from the interaction between radiation and predisposing factors of the patient.
Adult ; Caudate Nucleus ; Caves ; Corpus Striatum ; Female ; Hemangioma, Cavernous ; Humans ; Radiosurgery

OBJECTIVETo explore the mechanism of neurotoxicity induced by manganese, and observe the effects on the apoptosis of neurons in rat striatum.

METHODSSD rats were divided into four groups, six rats each group. Three dose groups were exposed to high, middle, and low level of MnCl(2). At the end of experiment, all rats of the exposed groups and control group were decapitated, their striatums were removed and the Mn content of striatum, the apoptotic morphology, ratio and ultrastructural organization were analyzed.

RESULTSThe Mn content of striatum and apoptosis index of the three dose groups exposed to high, middle, and low level of Mn were significantly higher than control group (P < 0.05). The Mn content of striatum of the three dose groups exposed to high, middle, low level of MnCl(2) and control group were 2.98 +/- 0.52, 2.75 +/- 0.37, 2.61 +/- 0.73, 0.60 +/- 0.20 respectively. The apoptosis index of striatum of the three dose groups exposed to high, middle, low level of MnCl(2) and control group were 24.83 +/- 5.98, 17.00 +/- 5.33, 15.33 +/- 2.58, 2.83 +/- 0.41 respectively, and following higher level dose, the apoptosis index increased. The nucleus of neurons in striatum become smaller, condensed, etc, and these character showed apoptosis of neurons.

CONCLUSIONMn can result in apoptotic morphology and increase level of apoptosis in striatum. The level of apoptos varies with Mn concentration.

Animals ; Apoptosis ; drug effects ; Corpus Striatum ; drug effects ; Manganese ; Neurons ; drug effects ; Rats ; Rats, Sprague-Dawley

The self-made high sensitivity and selectivity micro-biosensor was applied to monitor the change of dopamine in cerebral nucleus in rats in vivo. The micro-biosensor was prepared and used to detect dopamine level in vitro and monitor the dynamic change of dopamine in different cerebral nucleus in vivo. The results showed the lowest concentration of dopamine that could be detected by the biosensor was 32.5 nmol/L. Its positive peak was significantly different from that of AA, 5-HTP and E. The biosensor could keep working for monitoring the dopamine concentration in the cerebral tissue for more than 10 h. It was concluded that the microsensor has high sensitivity and selectivity to dopamine and can be used to dynamically monitor the change of dopamine in vivo.
Biosensing Techniques/*instrumentation ; Biosensing Techniques/methods ; Brain Chemistry ; Corpus Striatum/*metabolism ; Dopamine/*analysis ; Microelectrodes ; Monitoring, Physiologic

To study the effects of estrogen on the contents of dopamine (DA) and its metabolites in the amygdala (Amy) and striatum (Str) of rats, high performance liquid chromatography (HPLC) was used to measure the contents of DA and its metabolites in untreated ovariectomized (OVX) rats and OVX rats treated with estrogen. The contents of DA and its metabolites in Amy but not Str were significantly higher when the OVX rats were treated with a high dose of estradiol benzoate (EB). The turnover rate of DA in Amy of the OVX rats was lower than that of normal and EB-treated OVX rats. The turnover rate of DA in Amy was about twice as high as in the Str, while the content of DA in Amy was only one-sixth of that in the Str. The results obtained imply that serum concentration of estrogen is one of the important factors which affect the DA metabolism and content in the Amy of female rats, while the Str is not influenced by estrogen.
Amygdala ; metabolism ; Animals ; Corpus Striatum ; metabolism ; Dopamine ; metabolism ; Estrogens ; blood ; physiology ; Female ; Rats ; Rats, Wistar

Corpus Striatum ; Dopaminergic Neurons ; Humans ; Mesencephalon ; Parkinson Disease/drug therapy* ; Pars Compacta ; Substantia Nigra

The secondary motor cortex (M2) encodes choice-related information and plays an important role in cue-guided actions. M2 neurons innervate the dorsal striatum (DS), which also contributes to decision-making behavior, yet how M2 modulates signals in the DS to influence perceptual decision-making is unclear. Using mice performing a visual Go/No-Go task, we showed that inactivating M2 projections to the DS impaired performance by increasing the false alarm (FA) rate to the reward-irrelevant No-Go stimulus. The choice signal of M2 neurons correlated with behavioral performance, and the inactivation of M2 neurons projecting to the DS reduced the choice signal in the DS. By measuring and manipulating the responses of direct or indirect pathway striatal neurons defined by M2 inputs, we found that the indirect pathway neurons exhibited a shorter response latency to the No-Go stimulus, and inactivating their early responses increased the FA rate. These results demonstrate that the M2-to-DS pathway is crucial for suppressing inappropriate responses in perceptual decision behavior.
Mice ; Animals ; Motor Cortex ; Corpus Striatum/physiology* ; Neostriatum ; Neurons/physiology* ; Reaction Time