Electrical information processing in brains and computers relies on different charge carriers, ions and electrons. It is a challenge to join neuronal systems and integrated chips on a microscopic level with the eventual goal to get better insight of brain dynamics and to develop hybrid processors for medical and technological applications. On the side of electronics, we distinguish two levels, simple silicon chips with elementary microelectronic devices and more complex CMOS chips. On the biological side, we distinguish the three levels of molecular ion channels, of individual nerve cells and small networks and of brain tissue.
We characterized iono-electronic interfacing on simple silicon chips with capacitors for neuro-stimulation and transistors for neuro-recording. The structure of the neuron-silicon contact was analyzed with luminescent dyes (fluorescence interference, Stark effect). Using recombinant ion channels we elucidated the mechanism of signal transmission. On that basis, silicon chips were joined to individual nerve cells from snails and rats and to small neuronal networks. Finally, we interfaced tissue layers from rat brains. Chip-induced neuronal learning was implemented.
On the basis of simple silicon chips we proceeded with chips fabricated by classical CMOS technology. Care was taken that the physics of ionic-electronic interfacing remained unchanged. With an array of 128x128 sensor transistors at a pitch of 8 mum we recorded dynamic electrical maps for neuron-chip contact regions, for small nets of snail neurons and for tissue layers from rat brain.
Notice: Some of this talk reports new and unpublished work. Because publication in an archival journal is contingent on the works being "unpublished" those portions of the talk will not be broadcast or webcast, but will be incorporated into the live presentation.
About the speaker:
Peter Fromherz is a director at the Max Planck Institute for Biochemistry in Munich and professor for Biophysics at the Technical University Munich. He studied Chemistry at the Technical University Karlsruhe. In 1969 he completed his PhD in Physical Chemistry at the University Marburg. Then he worked as a postdoctoral fellow at the Max Planck Institute for Biophysical Chemistry at Goettingen. He became a full professor for Experimental Physics at the University Ulm in 1981. In 1994 he was elected as a Scientific Member of the Max Planck Society and joined the Max Planck Institute for Biochemistry in Martinsried near Munich. His main interests are the interfacing of semiconductor chips with neuronal systems and the development of molecular optoelectronic probes for brain research. He is a member of the Academies of Science in Berlin and Heidelberg. In 1998 he won the Julius Springer Prize for Applied Physics and in 2004 the Philip Morris Research Award.
Department of Membrane and Neurophysics
Max Planck Institute for Biochemistry
Munich, Germany 82152
+49 89 8578 2820
+49 89 8578 2822