Wireless micropower instrumentation for multimodal acquisition of electrical and chemical neural activity

Mohsen Mollazadeh, Kartikeya Murari, Gert Cauwenberghs, Nitish V. Thakor

Research output: Contribution to journalArticlepeer-review

Abstract

The intricate coupling between electrical and chemical activity in neural pathways of the central nervous system, and the implication of this coupling in neuropathologies, such as Parkinson's disease, motivates simultaneous monitoring of neurochemical and neuropotential signals. However, to date, neurochemical sensing has been lacking in integrated clinical instrumentation as well as in brain-computer interfaces (BCI). Here, we present an integrated system capable of continuous acquisition of data modalities in awake, behaving subjects. It features one channel each of a configurable neuropotential and a neurochemical acquisition system. The electrophysiological channel is comprised of a 40-dB gain, fully differential amplifier with tunable bandwidth from 140 Hz to 8.2 kHz. The amplifier offers input-referred noise below 2 μVrms for all bandwidth settings. The neurochemical module features a picoampere sensitivity potentiostat with a dynamic range spanning six decades from picoamperes to microamperes. Both systems have independent on-chip, configurable ΔΣ analog-to-digital converters (ADCs) with programmable digital gain and resolution. The system was also interfaced to a wireless power harvesting and telemetry module capable of powering up the circuits, providing clocks for ADC operation, and telemetering out the data at up to 32 kb/s over 3.5 cm with a bit-error rate of less than 10-5. Characterization and experimental results from the electrophysiological and neurochemical modules as well as the full system are presented.

Original languageEnglish (US)
Pages (from-to)388-397
Number of pages10
JournalIEEE Transactions on Biomedical Circuits and Systems
Volume3
Issue number6
DOIs
StatePublished - Nov 4 2009

Keywords

  • Biopotential amplifier
  • Brain-computer interface (bci)
  • Chemical sensing
  • Digital telemetry
  • Electrocorticogram (ecog)
  • Electroencephalogram (eeg)
  • Inductive coupling
  • Micropower instrumentation
  • Neural interface
  • Neurotransmitters
  • Potentiostat

ASJC Scopus subject areas

  • Biomedical Engineering
  • Electrical and Electronic Engineering

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