Large-scale organization of rat sensorimotor cortex based on a motif of large activation spreads.
Large-scale organization of rat sensorimotor cortex based on a motif of large activation spreads.
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DOI：
10.1523/jneurosci.4074-08.2008
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发表时间：
2008-12-03
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影响因子：
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通讯作者：
Stehberg J
中科院分区：
文献类型：
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作者：
Frostig RD;Xiong Y;Chen-Bee CH;Kvasnák E;Stehberg J
Parcellation according to function (e.g., visual, somatosensory, auditory, motor) is considered a fundamental property of sensorimotor cortical organization, traditionally defined from cytoarchitectonics and mapping studies relying on peak evoked neuronal activity. In the adult rat, stimulation of single whiskers evokes peak activity at topographically appropriate locations within somatosensory cortex and provides an example of cortical functional specificity. Here, we show that single whisker stimulation also evokes symmetrical areas of supra- and sub-threshold neuronal activation that spread extensively away from peak activity, effectively ignoring cortical borders by spilling deeply into multiple cortical territories of different modalities (auditory, visual and motor), where they were blocked by localized neuronal activity blocker injections and thus ruled out as possibly due to ‘volume conductance’. These symmetrical activity spreads were supported by underlying border-crossing, long-range horizontal connections as confirmed with transection experiments and injections of anterograde neuronal tracer experiments. We found such large evoked activation spreads and their underlying connections irrespective of whisker identity, cortical layer, or axis of recorded responses, thereby revealing a large scale nonspecific organization of sensorimotor cortex based on a motif of large symmetrical activation spreads. Because the large activation spreads and their underlying horizontal connections ignore anatomical borders between cortical modalities, sensorimotor cortex could therefore be viewed as a continuous entity rather than a collection of discrete, delineated unimodal regions – an organization that could co-exist with established specificity of cortical organization and that could serve as a substrate for associative learning, direct multimodal integration and recovery of function following injury.
