Event Abstract

Representation of freely-explored objects in the primary somatosensory cortex and hippocampus

  • 1 FARN, Brazil
  • 2 UFRN, Brazil
  • 3 UFCG, Brazil

When a rat freely explores an object in the dark and its whiskers  touch different parts of the object with different velocities and  angles, tactile information reaches the telencephalon with tantalizing  spatio-temporal complexity. To investigate the tactile representation  of freely-explored objects in the telencephalon, we performed  multielectrode extracellular spike recordings from the primary  somatosensory cortex (S1) and hippocampus (HP) of adult rats, as they  freely explored novel objects in the dark. Neuronal data were fed to  five different binary classifiers: multilayer perceptron, radial basis  functions, support vector machines, decision tree and naive Bayes  classifier. The classifiers were evaluated using the area under a  receiver operating characteristic curve (AUROC). In most cases, it was  possible to achieve substantial and significant object classification  in both S1 and HP (>0.75 AUROC medians, corrected p<0.05). To assess  the distribution of information across neuronal ensembles recorded  from S1 and HP we performed a neuron dropping analysis, a bootstrap  method that reveals how much information is lost, on average, as  neuronal ensembles decrease their size from “n” to 1 neuron. We found  that significant object classification is achieved with ensembles as  small as 10 neurons in both S1 and HP. The best fit for the neuron  dropping curves was akin to a type II functional response curve, which  in ecology describes the decelerating intake rate of a consumer as a  function of food density. We propose that the representation of  freely-explored complex objects by neuronal ensembles in S1 and HP is  robust, highly distributed, and shaped by the limited availability of  non-redundant information to individual neurons.
 
Support: FINEP, NIDCR, MCT, CNPq, INCT and CAPES.

Figure 1

Keywords: computational neuroscience, Electrophysiology

Conference: 4th INCF Congress of Neuroinformatics, Boston, United States, 4 Sep - 6 Sep, 2011.

Presentation Type: Poster Presentation

Topic: Computational neuroscience

Citation: Vasconcelos N, Macedo E, Gomes H, Corso G and Ribeiro S (2011). Representation of freely-explored objects in the primary somatosensory cortex and hippocampus. Front. Neuroinform. Conference Abstract: 4th INCF Congress of Neuroinformatics. doi: 10.3389/conf.fninf.2011.08.00048

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Received: 17 Oct 2011; Published Online: 19 Oct 2011.

* Correspondence: Dr. Nivaldo A P Vasconcelos, FARN, Paranamirim, Brazil, napvasconcelos@gmail.com