Hartung Henrike, Brockmann Marco D, Pöschel Beatrice, De Feo Vito, Hanganu-Opatz Ileana L
Developmental Neurophysiology, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany, and.
Developmental Neurophysiology, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany, and Laboratory of Neural Computation, Center for Neuroscience and Cognitive Systems, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy.
J Neurosci. 2016 Mar 30;36(13):3676-90. doi: 10.1523/JNEUROSCI.3232-15.2016.
Precise information flow during mnemonic and executive tasks requires the coactivation of adult prefrontal and hippocampal networks in oscillatory rhythms. This interplay emerges early in life, most likely as an anticipatory template of later cognitive performance. At neonatal age, hippocampal theta bursts drive the generation of prefrontal theta-gamma oscillations. In the absence of direct reciprocal interactions, the question arises of which feedback mechanisms control the early entrainment of prefrontal-hippocampal networks. Here, we demonstrate that prefrontal-hippocampal activity couples with discontinuous theta oscillations and neuronal firing in both lateral entorhinal cortex and ventral midline thalamic nuclei of neonatal rats. However, these two brain areas have different contributions to the neonatal long-range communication. The entorhinal cortex mainly modulates the hippocampal activity via direct axonal projections. In contrast, thalamic theta bursts are controlled by the prefrontal cortex via mutual projections and contribute to hippocampal activity. Thus, the neonatal prefrontal cortex modulates the level of hippocampal activation by directed interactions with the ventral midline thalamus. Similar to the adult task-related communication, theta-band activity ensures the feedback control of long-range coupling in the developing brain.
Memories are encoded by finely tuned interactions within large-scale neuronal networks. This cognitive performance is not inherited, but progressively matures in relationship with the establishment of long-range coupling in the immature brain. The hippocampus initiates and unidirectionally drives the oscillatory entrainment of neonatal prefrontal cortex, yet feedback interactions that precisely control this early communication are still unresolved. Here, we identified distinct roles of entorhinal cortex and ventral midline thalamus for the functional development of prefrontal-hippocampal interactions. While entorhinal oscillations modulate the hippocampal activity by timing the neuronal firing via monosynaptic afferents, thalamic nuclei act as a relay station routing prefrontal activation back to hippocampus. Understanding the mechanisms of network maturation represents the prerequisite for assessing circuit dysfunction in neurodevelopmental disorders.
在记忆和执行任务期间，精确的信息流需要成年前额叶和海马网络以振荡节律共同激活。这种相互作用在生命早期就出现了，很可能是后期认知表现的一种预期模板。在新生儿期，海马θ波爆发驱动前额叶θ-γ振荡的产生。在缺乏直接相互作用的情况下，就出现了哪种反馈机制控制前额叶-海马网络早期同步的问题。在这里，我们证明了前额叶-海马活动与新生大鼠外侧内嗅皮质和腹侧中线丘脑核中的不连续θ振荡及神经元放电耦合。然而，这两个脑区对新生儿远程通信有不同的贡献。内嗅皮质主要通过直接轴突投射调节海马活动。相反，丘脑θ波爆发由前额叶皮质通过相互投射控制，并对海马活动有贡献。因此，新生儿前额叶皮质通过与腹侧中线丘脑的定向相互作用调节海马激活水平。与成年任务相关的通信类似，θ波段活动确保发育中大脑远程耦合的反馈控制。
记忆由大规模神经元网络内精细调节的相互作用编码。这种认知表现不是遗传而来的，而是随着未成熟大脑中远程耦合的建立而逐渐成熟。海马启动并单向驱动新生儿前额叶皮质的振荡同步，但精确控制这种早期通信的反馈相互作用仍未解决。在这里，我们确定了内嗅皮质和腹侧中线丘脑在额叶-海马相互作用功能发育中的不同作用。虽然内嗅振荡通过单突触传入神经对神经元放电计时来调节海马活动，但丘脑核作为一个中继站，将前额叶激活路由回海马。理解网络成熟机制是评估神经发育障碍中电路功能障碍的前提条件。
