Increase of the hippocampal theta activity in the Morris water maze reflects learning rather than motor activity

Abstract

We present an optical method for nondirectional edge extraction/enhancement in color images. The method is based on the capability of twisted-nematic LCDs to traduce the image information in changes of the state of polarization of light, which allows us to generate simultaneously two replicas of the digital image displayed on the LCD: a true-color ("positive") image and a complementary-color ("negative") one. In our setup the imaging system consists of a lens plus a pupil mask formed with concentric apertures and orthogonal polarizers. This layout allows us to simultaneously image a well-focused positive replica (due to the circular aperture) superimposed to a slightly de-focused negative one (due to the annular aperture). It is not difficult to demonstrate that this generates a nondirectional (Laplacian) edge enhancement. Unlike Fourier, our proposal works with incoherent illumination and does not require precise alignment, and thus, it could be a useful tool for edge extraction/enhancement in large images in real-time applications. Validation experiments are presented. " 2011 Optical Society of America.",,,,,,,,,"http://hdl.handle.net/20.500.12104/42172","http://www.scopus.com/inward/record.url?eid=2-s2.0-82955178721&partnerID=40&md5=ae281564468c16fc0aa33c64dd9652d2

http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=prem&AN=22139254",,,,,,"23",,"Optics Letters",,"4596

4598",,"36",,"Scopus

WOS

MEDLINE",,,,,,,,,,,,"Incoherent optical processor for nondirectional edge enhancement of color images",,"Article" "43961","123456789/35008",,,,"Díaz Pérez, C.",,"1996",,,,,,,,,,"0185-2760","http://hdl.handle.net/20.500.12104/42182",,,"Español",,,,"98",,"Relaciones (Zamora,",,"103-129",,"25",,"CLASE",,,,,,,,"Recursos humanos",,,,"El proceso de desarrollo de grupos de investigacion",,"journalArticle" "43958","123456789/35008",,"Olvera-Cortés, E., Lab. de Neurofisiol. Experimental, Ctro. Invest. Biomedica de Michoacan, Instituto Mexicano del Seguro Social, A.P. 7-70, C.P. 58261 Morelia, Mich., Mexico; Guevara, M.A., Lab. Analisis Senales Bioelectricas, Instituto de Neurociencias, Universidad de Guadalajara, Guadalajara, Jal., Mexico; González-Burgos, I., Laboratorio de Psicobiología, Ctro. Invest. Biomedica de Michoacan, Instituto Mexicano del Seguro Social, Morelia, Mich., Mexico",,"Olvera-Cortes, E.

Guevara, M.A.

Gonzalez-Burgos, I.",,"2004",,"The change in the percentage of rat hippocampal high-frequency theta activity from being immobile and awake to swimming behaviour was calculated for three groups of rats, trained in either place learning, cue learning or egocentric learning in the Morris water maze. The place-learning-trained rats showed an increase in the percentage of theta activity, along with a significant reduction in escape latency over the last 3 days of training. No changes were observed in the other two groups. Because the motor activity displayed by the three groups of rats was similar, we suggest that the increase in the percentage of theta activity concomitant with place-learning training could be related to the processing of information by the hippocampus, rather than to the displayed motor activity. " 2003 Elsevier Inc. All rights reserved.