Question

Which is the most appropriate tool for determining sources of input received by dopaminergic neurons in the mouse?

Select one:

a. Serial block-face electron microscopy

b. Optogenetic stimulation

c. Anterograde chemical tracer

d. Diffusion-weighted tractography

e. Monosynaptically restricted glycoprotein-deleted rabies pseudotyped with EnvA

Answer 1

Ans: Option (e) is correct.

Current studies on 'whole brain mapping of direct inputs to midbrain dopamine neurone' shows that dopamine neurones in sabstantiaa nigra pars compacta (SNc) and ventral tegmental area (VTA) send different signals. Dopamine neurones from these two regions recieves excitatory signals from motor cortex and subthalamic nucleus which can elaborate their short-latency response to various events. As, the neuroscience studies help to identify the interactions among all the neuronal networks throughout the body of an organism. Most of the times, it's critical to understand the inputs and outputs of dopamine nuronal signal. Electrophysiological and optical imaging techniques are helpful to understand the outputs but it is difficult for understanding of inputs signals.Electron microscopy technique can be used to resolve other inputs, but in that particular case. electron microscopy is not suitable. To resolve this problem, researchers developed a combined Cre/loxP gene with rabies-virus-based transsynaptic retrograde tracing technique which is helpful to identify the inputs recieved by dopaminergic neurons in the mouse.

See the reference: Watabe-Uchida, M., Zhu, L., Ogawa, S. K., Vamanrao, A., & Uchida, N. (2012). Whole-brain mapping of direct inputs to midbrain dopamine neurons. Neuron, 74(5), 858-873.