Temporal Binding via Cortical Coincidence Detection of Specific and Non-specific Thalamocortical Inputs: A Voltage Dependent Dye Imaging Study in Mouse Brain Slices

LLINÁS, RR; LEZNIK E; URBANO FJ

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Lugar: Washington, DC. USA.; Año: 2002 vol. 99 p. 449 - 454

0027-8424

Voltage-sensitive dye imaging of mouse thalamocortical slices demonstrated that electrical stimulation of the centrolateral intralaminar thalamic nucleus (CL) resulted in the specific activation of thalamic reticular nucleus, striatum_putamen, and cortical layers 5, 6, and 1. By contrast, ventrobasal (VB) thalamic stimulation, while activating the reticular and basal ganglia nuclei, also activated directly layers 4 and deep 5 of the cortex. Conjoined stimulation of the VB and CL nuclei resulted in supralinear summation of the two inputs at cortical output layer 5, demonstrating coincidence detection along the apical dendrites. This supralinear summation was also noticed at gamma band stimulus frequency (40 Hz). Direct stimulation of cortical layer 1, after a radial section of the cortex that spared only that layer was shown to sum supralinearly with the cortical activation triggered by VB stimulation, providing a second demonstration for coincidence detection. Coincidence detection by coactivation of the specific (VB) and nonspecific (CL) thalamic nuclei has been proposed as the basis for the temporal conjunction that supports cognitive binding in the brain.