Barry K M, Robertson D, Mulders W H A M
The Auditory Laboratory, School of Human Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia.
The Auditory Laboratory, School of Human Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia; Ear Science Institute Australia, 1/1 Salvado Rd, Subiaco, Western Australia, 6008, Australia.
Hear Res. 2017 Sep;353:204-212. doi: 10.1016/j.heares.2017.07.002. Epub 2017 Jul 8.
Phantom perceptions have been proposed to arise due to dysfunctional sensory gating at the level of the thalamus. Recently, it has been suggested that tinnitus, a phantom perception of sound, may arise from altered cortico-limbic circuitry and its connection with the auditory thalamus, the medial geniculate nucleus (MGN). Indeed, some elements of this cortico-limbic circuitry, such as the prefrontal cortex (PFC), as well as elements of the auditory pathway, have been shown to be altered in humans with tinnitus. However, the functional connectivity between PFC and MGN has not yet been explored. We therefore investigated the effects of activation of the PFC on neuronal activity in MGN in normal anaesthetized Wistar rats. Bipolar electrical stimulation was delivered to the PFC while recording single neuron activity in the MGN. The majority (81%) of MGN neurons sampled showed a change in their spontaneous firing rate in response to electrical stimulation of the PFC. The effects observed varied greatly between neurons and included combinations of inhibitory and excitatory effects with a wide range of latencies. The effects were not dependent on acoustic response type or MGN subdivision. These data demonstrate that PFC activation can modulate MGN neuronal activity and this connection could potentially play a role in sensory gating of auditory signals.
幻肢觉被认为是由于丘脑水平的感觉门控功能失调而产生的。最近，有人提出耳鸣，一种声音的幻听，可能源于皮质-边缘回路的改变及其与听觉丘脑即内侧膝状体（MGN）的连接。事实上，这种皮质-边缘回路的一些元素，如前额叶皮质（PFC），以及听觉通路的一些元素，在耳鸣患者中已被证明发生了改变。然而，PFC与MGN之间的功能连接尚未得到研究。因此，我们研究了在正常麻醉的Wistar大鼠中，PFC激活对MGN神经元活动的影响。在记录MGN单个神经元活动时，对PFC进行双极电刺激。所采样的MGN神经元中，大多数（81%）在对PFC进行电刺激时，其自发放电率发生了变化。观察到的效应在神经元之间差异很大，包括抑制和兴奋效应的组合以及广泛的潜伏期。这些效应不依赖于听觉反应类型或MGN分区。这些数据表明，PFC激活可以调节MGN神经元活动，并且这种连接可能在听觉信号的感觉门控中发挥作用。
