Control of the Visual relay Through LGN

简介(申请人提供)：我们建议继续调查 丘脑视网膜信息传递到皮层和大脑的动态控制 它如何受到行为状态和注意力的影响。根据进展情况 我们在上一个资助期内所做的工作，我们的目标基本上是 继续探索更复杂的行为对大脑活动的影响 并将这些研究扩展到其他丘脑核团。超过了 我们提供的证据反驳了这样一种观点 LON只是将视网膜信息传递到大脑皮层的被动中继器。 我们已经补充了越来越多的证据表明LGN 动态地影响视觉感觉信息在大脑皮质的传递。 控制下降的皮质和上升的脑干输入。我们有 证实了对非灵长类哺乳动物的研究结果，并提供了 更多证据表明，在清醒状态下，表现为猴子的行为 动物的限制决定了LON细胞的激发水平和模式； 因此，到达大脑皮层的信息的性质受到控制。我们有 表明意识的状态，包括觉醒到 睡眠，通过影响LGN的失活状态，显著影响LGN的放电 一种电压敏感的钙电流，它反过来又决定了触发 继电信元的模式-突发或强直。其他丘脑核团看起来是均匀的。 比起LGN，受意识状态的影响更大。我们也 发现眼球跳动增加了M(但不是P)细胞的LGN活性， 同时减少了两种情况下的爆裂。我们训练的初步实验 猴子注意感受野(RF)中的物体，而不是非RF 提示RF内的注意力显著增强了脑电活动 一些LUN单元。我们将继续我们的研究，使用更复杂的行为 为进一步阐明丘脑的动态性质而建立的范例 接力赛。具体地说，我们将研究涉及检测的注意要求 任务及其与突发模式活动的关系。我们还将查看 感觉模式(例如，听觉和视觉)之间的相互作用 丘脑其他核团和初级视皮层的爆裂程度。 最后，我们注意到有证据表明，许多视觉皮层神经元也可以在 突触模式，这似乎提供了特别有效的突触后 反应，这似乎是在调节控制之下。这样，我们就会 探索不同的行为和注意力状态影响 初级视皮层细胞的放电模式。

DESCRIPTION (Provided by applicant): We propose to continue to investigate the dynamic control of the thalamic relay of retinal information to the cortex and how it is affected by behavioral state and attention. In light of the progress we have made during the last funding period, our aims essentially will be to continue to explore the effects of more complex behaviors on the activity of the LGN relay and to extend these studies to other thalamic nuclei. Over the period of the last grant we have provided evidence that refutes the idea that the LON acts as a mere passive relay of retinal information bound for cortex. We have added to the accumulating body of evidence showing that the LGN dynamically affects the relay of visual sensory information to cortex under the control of descending cortical and ascending brainstem inputs. We have confirmed the findings from studies of non-primate mammals and provided additional evidence that in the awake, behaving monkey the behavioral constraints of the animal dictates the firing level and pattern of LON cells; thus the nature of the information reaching the cortex is controlled. We have shown that the state of consciousness, encompassing wakefulness through to sleep, significantly affects LGN firing by affecting the inactivation state of a voltage sensitive Ca2+ current that, in turn, determines the firing mode-burst or tonic-of relay cells. Other thalamic nuclei appear to be even more significantly affected by state of consciousness than the LGN. We also found that saccadic eye movements increase LGN activity of M (but not P) cells, while it reduces bursting in both. Preliminary experiments in which we trained monkeys to attend to objects in the receptive field (RF) as opposed to non-RF suggest that attention within the RF significantly enhances the activity of some LUN cells. We shall continue our studies by using more complex behavioral paradigms in order to further elucidate the dynamic nature of the thalamic relay. Specifically, we shall look at attentional demands involving detection tasks and its relationship to burst mode activity. We will also look at the interactions between sensory modalities (e.g. auditory and visual) and at the level of bursting across other thalamic nuclei and primary visual cortex. Finally, we note evidence that many visual cortical neurons also can fire in burst mode, which appears to provide especially effective postsynaptic responses, and that this seems to be under modulatory control. Thus we shall explore the possibility that various behavioral and attentional states affects firing mode of cells in primary visual cortex.