摘要:

The present study described the functional characteristics of early phase-locked electroencephalographic gamma band (30-60 Hz) responses (GBRs) in 9- to 12-year-old healthy children. GBRs were elicited in an auditory selective-attention task. Target stimuli required motor responding when presented to the right or to the left (attended side). Effects of stimulus type relevance and attended side were evaluated for GBR power and phase-locking within 0–120 ms. GBRs in children were frontally distributed, were larger and better phase-locked to targets relative to non-targets, but did not depend on the attended side. These results demonstrate that the auditory GBR is related to task-stimulus processing and imply that early target selection in children is guided by a sensory or sensorimotor preparatory set, rather than by an internal attentional focus to the side of stimulation.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Buffered methylmalonate (MMA) was injected s.c. into rats twice a day at 8 h intervals from 5 to 25 days of age (chronic treatment), or into 10-day-old rats three times a day at 1 h intervals (acute treatment). Control rats received saline in the same volumes. Na+,K+-ATPase and Mg2+-ATPase activities were determined in the synaptic plasma membranes from cerebral cortex of rats. Na+, K+-ATPase activity was reduced by 30–40% in MMA-treated rats, whereas Mg2+-ATPase activity was not. In contrast, MMA at final concentrations ranging from 0.1 to 2.0 mM had noin vitroeffect on these enzyme activities. However, when brain homogenates were incubated with 2 mM MMA before membrane preparation, Na+, K+-ATPase activity was decreased by 44%. Furthermore, this reduction was totally prevented by the simultaneous addition of glutathione and MMA, suggesting that oxidation of thiol groups or other oxidative damage to the enzyme could be responsible for this effect.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Seizures can be induced by systemic dopamine D1 receptor agonists or by cortical-limbic neurostimulation non-selectively. Seizures are also often associated with tics and compulsions, which likewise involve cortical-limbic hyperactivity. To determine if selective potentiation of cortical-limbic D1 receptor-expressing (D1+) neurons increases seizure susceptibility, we administered pentylenetetrazole (PTZ) to mice that express a neuropotentiating transgene only in a glutamatergic, corticallimbic subset of D1+ neurons (D1CT-7 line). These mice exhibited increased PTZ-dependent seizure incidence, onset rate and intensity. Because D1CT-7 mice also exhibit tic+compulsion-like behaviors, this implies that glutamatergic hyperactivity induced by cortical-limbic D1+ neuropotentiation facilitates not only epilepsy but also tics and compulsions. This suggests a dopamine-regulated glutamatergic basis for all three states and may explain why they often co-exist in humans.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

We revisited the relationship between brain anatomy and song behavior in zebra finches. Consistent with previous studies in other songbirds, we find that differences in volume of the telencephalic song control nucleus HVc is predictive of differences in repertoire size and phrase duration in zebra finches. We extend the study of brain and behavior correlations in song birds by showing that repertoire size in zebra finches can be predicted by variance in several brain nuclei, providing the first demonstration that volumetric differences across multiple components of a neural network are predictive of song behavior.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID