Submitted on September 5, 2008
Revised on January 23, 2009
Accepted on January 23, 2009
Cortically activated interneurons shape spatial aspects of cortico-accumbens processing
Aaron J. Gruber1*, Elizabeth M Powell1, and Patricio O'Donnell2
1 University of Maryland School of Medicine
2 univ of maryland
* To whom correspondence should be addressed. E-mail: agrub001{at}umaryland.edu.
Basal ganglia circuits are organized as parallel loops that have been proposed to compete in a winner-take-all fashion to determine the appropriate behavioral outcome. However, limited experimental support for strong lateral inhibition mechanisms within striatal regions questions this model. Here, stimulation of the prefrontal cortex (PFC) using naturally occurring bursty patterns inhibited firing in most nucleus accumbens (NA) projection neurons. When an excitatory response was observed for one stimulation site, neighboring PFC sites evoked inhibition in the same neuron. Furthermore, PFC stimulation activated interneurons, and PFC-evoked inhibition was blocked by GABA-A antagonists in corticoaccumbens slice preparations. Thus, bursting PFC activity recruits local inhibition in the NA, shaping responses of projection neurons with a topographical arrangement that allows inhibition among parallel corticoaccumbens channels. The data indicate a high order of information processing within striatal circuits that should be considered in models of basal ganglia function and disease.
