Multiscale Optical Imaging of Mouse Auditory Cortex

two-photon imaging;Ca2+ imaging;mouse auditory cortex;GCaMP3;functional organization of cortex;Biomedical Engineering

Issa, John B.Young, Eric D. ;

Johns Hopkins University

关键词: two-photon imaging;    Ca2+ imaging;    mouse auditory cortex;    GCaMP3;    functional organization of cortex;    Biomedical Engineering;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/39375/ISSA-DISSERTATION-2015.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

A spatially organized pattern of neural encoding, first elucidated by Mountcastle over 50 years ago, comprises a core principle of sensory cortices. Such organization has traditionally been studied by microelectrode mapping experiments. However, these recordings are invasive and may show bias in regards to the neurons they sample. More recently, two-photon imaging and ultrasensitive genetically-encoded Ca2+ indicators have offered the ability to monitor local populations of individual neurons in a non-invasive and unbiased manner. But, without knowing the relation of this local imaging field to a global cortical map, it is difficult to know exactly what neurons are being sampled. In recent years, this ambiguity has led to controversy as to the functional organization of neurons in auditory cortex. To address this question, we utilized a multiscale imaging approach in unanesthetized GCaMP transgenic mice. In particular, a novel use of transcranial widefield imaging provided a ;;zoomed out” global map of cortex, while two-photon imaging yielded a ;;zoomed in” view of activity in single neurons precisely registered to global coordinates. In so doing, we not only resolved the controversy but reveal new features of encoding of sound in mouse auditory cortex. Neurons in the primary field responded well to tones, neighboring neurons were appreciably co-tuned, and preferred frequencies adhered tightly to a tonotopic axis. By contrast, nearby secondary field neurons exhibited heterogeneous tuning. The multiscale imaging approach also readily localized FM sweep and vocalization regions and neurons. Further refinements of the multiscale Ca2+ imaging approach promise significant advances in uncovering the functional organization of cerebral cortex.