Low-frequency stimulation enhances burst activity in cortical cultures during development

• Published in: Neuroscience Vol. 165; no. 3; pp. 692 - 704
• Main Authors: Bologna, L.L, Nieus, T, Tedesco, M, Chiappalone, M, Benfenati, F, Martinoia, S
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 03.02.2010; Elsevier
• Subjects: Action Potentials; Animals; Biological and medical sciences; Cell Culture Techniques; Cells, Cultured; Cerebral Cortex - physiology; Electric Stimulation; Fundamental and applied biological sciences. Psychology; micro-electrode array; Microelectrodes; multi-site stimulation; network burst; Neurology; Neurons - physiology; rat cortical neurons; Rats; Rats, Sprague-Dawley; Time Factors; Vertebrates: nervous system and sense organs; centre of mass; post stimulus time histogram; DT; IBI; NBD; PSTH; PLP; NBRP; MFR; NBFP; network burst duration; network burst peak value; pmrd; refractory period; micro-electrode array; MBR; increment index; mrd; NBPV; COM; interburst interval; II; mean firing rate; multi-site stimulation; network burst; MEA; mean relative deviation; population mean relative deviation; DIV; differential threshold; rd; NB; network burst falling phase; rat cortical neurons; peak lifetime period; relative deviation; days in vitro; network burst rising phase; RP; mean bursting rate; Rat; Rodentia; Stimulation; Low frequency; Vertebrata; Mammalia; Neuron; Animal; Development
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2009.11.018

Abstract The intact brain is continuously targeted by a wealth of stimuli with distinct spatio-temporal patterns which modify, since the very beginning of development, the activity and the connectivity of neuronal networks. In this paper, we used dissociated neuronal cultures coupled to microelectrode arrays (MEAs) to study the response of cortical neuron assemblies to low-frequency stimuli constantly delivered over weeks in vitro . We monitored the spontaneous activity of the cultures before and after the stimulation sessions, as well as their evoked response to the stimulus. During in vitro development, the vast majority of the cultures responded to the stimulation by significantly increasing the bursting activity and a widespread stabilization of electrical activity was observed after the third week of age. A similar trend was present between the spontaneous activity of the networks observed over 30 min after the stimulus and the responses evoked by the stimulus itself, although no significant differences in spontaneous activity were detected between stimulated and non-stimulated cultures belonging to the same preparations. The data indicate that the stimulation had a delayed effect modulating responsiveness capability of the network without directly affecting its intrinsic in vitro development.