Control of the Visual relay Through LGN

描述（由申请人提供）：我们建议继续调查 - 动态控制视网膜信息到皮层的丘脑中继， 它是如何受到行为状态和注意力的影响的。根据进展 我们在上一个资助期内做出的决定，我们的目标本质上是 继续探索更复杂的行为对活动的影响， 并将这些研究扩展到其他丘脑核团。来 在最后一次赠款期间，我们提供了证据，驳斥了以下观点， LON仅仅充当视网膜信息到皮层的被动中继。 我们已经增加了越来越多的证据，表明LGN 动态地影响视觉感觉信息到皮层下的中继， 控制下行皮质和上行脑干输入。我们有 证实了非灵长类哺乳动物的研究结果，并提供了 另外的证据表明，在清醒的，行为猴子的行为 动物的限制决定了LON细胞的放电水平和模式; 因此，到达皮层的信息的性质受到控制。我们有 表明意识状态，包括清醒到 睡眠，通过影响LGN的失活状态， 电压敏感的Ca 2+电流，反过来，决定了点火 模式-突发或音调-中继单元。其他丘脑核团似乎是均匀的 比LGN更受意识状态的影响。我们也 发现扫视性眼球运动增加了M细胞（而不是P细胞）的LGN活性， 同时它减少了两者中的爆裂。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 表明RF内的注意力显著增强了 一些LUN单元格。我们将继续我们的研究，通过使用更复杂的行为， 范例，以进一步阐明丘脑的动态性质， 继电器.具体来说，我们将着眼于涉及检测的注意力需求 任务及其与突发模式活动的关系。我们还将研究 感觉模态（例如听觉和视觉）之间的相互作用， 其他丘脑核团和初级视觉皮层的爆发水平。 最后，我们注意到许多视觉皮层神经元也可以在 突发模式，这似乎提供了特别有效的突触后 反应，这似乎是调节控制。我们将 探索各种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.