Humanes-Valera Desire, Foffani Guglielmo, Alonso-Calviño Elena, Fernández-López Elena, Aguilar Juan
Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, 45071 Toledo, Spain.
Department of Systems Neuroscience, Institute of Physiology, Faculty of Medicine, Ruhr-University Bochum, D-44801 Bochum, Germany.
Cereb Cortex. 2017 May 1;27(5):2926-2940. doi: 10.1093/cercor/bhw142.
During cortical development, plasticity reflects the dynamic equilibrium between increasing and decreasing functional connectivity subserved by synaptic sprouting and pruning. After adult cortical deafferentation, plasticity seems to be dominated by increased functional connectivity, leading to the classical expansive reorganization from the intact to the deafferented cortex. In contrast, here we show a striking "decrease" in the fast cortical responses to high-intensity forepaw stimulation 1-3 months after complete thoracic spinal cord transection, as evident in both local field potentials and intracellular in vivo recordings. Importantly, this decrease in fast cortical responses co-exists with an "increase" in cortical activation over slower post-stimulus timescales, as measured by an increased forepaw-to-hindpaw propagation of stimulus-triggered cortical up-states, as well as by the enhanced slow sustained depolarization evoked by high-frequency forepaw stimuli in the deafferented hindpaw cortex. This coincidence of diminished fast cortical responses and enhanced slow cortical activation offers a dual perspective of adult cortical plasticity after spinal cord injury.
在皮质发育过程中，可塑性反映了由突触萌发和修剪所支持的功能连接增加与减少之间的动态平衡。成年后皮质去传入神经支配后，可塑性似乎主要由功能连接增加主导，导致从完整皮质到去传入神经支配皮质的经典扩展性重组。相比之下，我们在此展示了在完全胸段脊髓横断后1 - 3个月，对高强度前爪刺激的快速皮质反应出现显著“降低”，这在局部场电位和体内细胞内记录中均很明显。重要的是，快速皮质反应的这种降低与刺激后较慢时间尺度上皮质激活的“增加”同时存在，这通过刺激触发的皮质上升状态从前爪到后爪的传播增加以及去传入神经支配的后爪皮质中高频前爪刺激诱发的增强的缓慢持续去极化来衡量。快速皮质反应减弱与缓慢皮质激活增强的这种巧合为脊髓损伤后的成年皮质可塑性提供了双重视角。
