Dopamine-induced dissociation of BOLD and neural activity in macaque visual cortex

Zaldivar, D., Rauch, A., Whittingstall, K., Logothetis, N. K. and Goense, J. (2014) Dopamine-induced dissociation of BOLD and neural activity in macaque visual cortex. Current Biology, 24(23), pp. 2805-2811. (doi: 10.1016/j.cub.2014.10.006)

Abstract

Neuromodulators determine how neural circuits process information during cognitive states such as wakefulness, attention, learning, and memory [1]. fMRI can provide insight into their function and dynamics, but their exact effect on BOLD responses remains unclear [2, 3 and 4], limiting our ability to interpret the effects of changes in behavioral state using fMRI. Here, we investigated the effects of dopamine (DA) injections on neural responses and haemodynamic signals in macaque primary visual cortex (V1) using fMRI (7T) and intracortical electrophysiology. Aside from DA’s involvement in diseases such as Parkinson’s and schizophrenia, it also plays a role in visual perception [5, 6, 7 and 8]. We mimicked DAergic neuromodulation by systemic injection of L-DOPA and Carbidopa (LDC) or by local application of DA in V1 and found that systemic application of LDC increased the signal-to-noise ratio (SNR) and amplitude of the visually evoked neural responses in V1. However, visually induced BOLD responses decreased, whereas cerebral blood flow (CBF) responses increased. This dissociation of BOLD and CBF suggests that dopamine increases energy metabolism by a disproportionate amount relative to the CBF response, causing the reduced BOLD response. Local application of DA in V1 had no effect on neural activity, suggesting that the dopaminergic effects are mediated by long-range interactions. The combination of BOLD-based and CBF-based fMRI can provide a signature of dopaminergic neuromodulation, indicating that the application of multimodal methods can improve our ability to distinguish sensory processing from neuromodulatory effects.

• Item Type: Articles
• Additional Information: NOTICE: this is the author’s version of a work that was accepted for publication in Current Biology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Current Biology 24(23):2805-2811, 2014 DOI: 10.1016/j.cub.2014.10.006
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Goense, Dr Jozien
• Authors: Zaldivar, D., Rauch, A., Whittingstall, K., Logothetis, N. K., and Goense, J.
• College/School: College of Science and Engineering > School of Psychology
• Journal Name: Current Biology
• Publisher: Elsevier Ltd.
• ISSN: 0960-9822
• ISSN (Online): 1879-0445
• Copyright Holders: Copyright © 2014 Elsevier Ltd.
• First Published: First published in Current Biology 24(23):2805-2811
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher