Cortical damping: Analysis of thalamocortical response transformations in rodent barrel cortex

被引:105
作者
Pinto, DJ
Hartings, JA
Simons, DJ
机构
[1] Brown Univ, Dept Neurosci, Providence, RI 02912 USA
[2] Univ Pittsburgh, Dept Neurobiol, Pittsburgh, PA 15261 USA
[3] CUNY Queens Coll, Dept Psychol, Flushing, NY 11367 USA
关键词
D O I
10.1093/cercor/13.1.33
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
In the whisker-barrel system, layer IV excitatory neurons respond preferentially to high-velocity deflections of their principal whisker, and these responses are inhibited by deflections of adjacent whiskers. Thalamic input neurons are amplitude and velocity sensitive and have larger excitatory and weaker inhibitory receptive fields than cortical neurons. Computational models based on known features of barrel circuitry capture these and other differences between thalamic and cortical neuron response properties. The models' responses are highly sensitive to thalamic firing synchrony, a finding subsequently confirmed in real barrels by in vivo experiments. Here, we use dynamic systems analysis to examine how barrel circuitry attains its sensitivity to input timing, and how this sensitivity explains the transformation of receptive fields between thalamus and cortex. We find that strong inhibition renders the net effect of intracortical connections suppressive or damping, distinguishing it from previous amplifying models of cortical microcircuits. In damping circuits, recurrent excitation enhances response tuning not by amplifying responses to preferred inputs, but by enabling them to better withstand strong inhibitory influences. Dense interconnections among barrel neurons result in considerable response homogeneity. Neurons outside the barrel layer respond more heterogeneously, possibly reflecting diverse networks and multiple transformations within the cortical output layers.
引用
收藏
页码:33 / 44
页数:12
相关论文
共 70 条
[21]   Neural networks as spatio-temporal pattern-forming systems [J].
Ermentrout, B .
REPORTS ON PROGRESS IN PHYSICS, 1998, 61 (04) :353-430
[22]   Neural mechanisms of orientation selectivity in the visual cortex [J].
Ferster, D ;
Miller, KD .
ANNUAL REVIEW OF NEUROSCIENCE, 2000, 23 :441-471
[23]   The structure and function of dynamic cortical and thalamic receptive fields [J].
Ghazanfar, AA ;
Nicolelis, MAL .
CEREBRAL CORTEX, 2001, 11 (03) :183-193
[24]   Two networks of electrically coupled inhibitory neurons in neocortex [J].
Gibson, JR ;
Beierlein, M ;
Connors, BW .
NATURE, 1999, 402 (6757) :75-79
[25]   Differential regulation of neocortical synapses by neuromodulators and activity [J].
Gil, Z ;
Connors, BW ;
Amitai, Y .
NEURON, 1997, 19 (03) :679-686
[26]   Efficacy of thalamocortical and intracortical synaptic connections: Quanta, innervation, and reliability [J].
Gil, Z ;
Connors, BW ;
Amitai, Y .
NEURON, 1999, 23 (02) :385-397
[27]   Functional independence of layer IV barrels in rodent somatosensory cortex [J].
Goldreich, D ;
Kyriazi, HT ;
Simons, DJ .
JOURNAL OF NEUROPHYSIOLOGY, 1999, 82 (03) :1311-1316
[28]  
GRIEVE KL, 1995, J NEUROSCI, V15, P4868
[29]  
HARTINGS JA, 2000, THESIS U PITTSBURGH
[30]  
HARVEY AR, 1980, J PHYSIOL-LONDON, V302, P507