Development of longitudinal two-photon imaging in awake marmosets: an optical technique for studies of cerebral microcirculation and neuronal activation in primates

Monday, September 22, 2014 — Poster Session I
12:00 p.m. – 2:00 p.m.	FAES Academic Center	NINDS	NEURO-26

Authors

• TP Santisakultarm
• JL Ciuchta
• S Choi
• J Park
• LD Notardonato
• AC Silva

Abstract

Two-photon microscopy (2PM) allows visualization of cellular structure and function within the cortex. Recently, transgenic marmoset models of Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis, and schizophrenia have been produced with successful germline transmission. We aim to develop a longitudinal approach to quantify cerebral hemodynamics and neuronal activity in awake marmosets. An adult marmoset was acclimated to a body-and-head restraint in the sphinx position. Following training, a 12-mm diameter chamber was implanted over Broadman Area 3b, along with a headpost to stabilize imaging. After 10 days of recovery, 2PM of intravenously labeled blood plasma revealed vascular topology and enabled measurement of blood cell motion in microvessels 500 µm below the cortical surface in awake marmosets. 99.5% of capillaries had blood cell flowing during the awake imaging, indicating a robust circulation. Capillary density was 5,601 capillaries/mm3. To visualize neuronal activity, AAV1-GCaMP5G was injected into the somatosensory cortex. Post-mortem immunohistochemistry confirmed ~3-mm3 GCaMP5G expression in cortical neurons. These results demonstrate our capability to perform longitudinal 2PM imaging of neuronal activity and hemodynamics in awake marmosets. Our work provides a powerful technique to assess neurovascular coupling at the level of neurovascular unit, and allows for investigation of critical mechanisms in many neurological disorders.

back to top