Adult neural function and behaviour encoded by embryonic gene expression
By combining gene expression studies with electrophysiological recordings, researchers from the MRC Brain Network Dynamics Unit at the University of Oxford, have demonstrated that distinct transcriptional codes of neuronal progenitors lead to different classes of neurons. These neurons take over particular roles in the neural coding of adult behaviour.
First author Paul Dodson and his colleagues addressed the question of how patterns of gene transcription in the embryonic brain later manifest themselves as distinct properties of particular classes of neurons in the adult brain. In this study the authors focus on a key component of the mammalian basal ganglia, the external globus pallidus, which is crucial for the accurate execution of movements.
The researchers, led by Professor Peter Magill, identified the transcription factors FoxP2 and Nkx2-1 as specific genetic markers for GABAergic neurons that perform differently in the adult brain. Neurons expressing Nkx2-1 class fire at high rates during alert rest, and encode movements through heterogeneous firing rate changes, with many neurons decreasing their activity. In contrast, FoxP2 neurons fire at low rates during rest, and encode movements with robust increases in firing.
For the success of their study it was essential to be able to record the unperturbed spike firing of individual neurons in awake, head-fixed mice and then to label the same neurons with neurobiotin after recording. In this way the recorded neurons could be later identified for post hoc testing of FoxP2 and Nkx2-1 immunoreactivity. To achieve this they used the long travel and super-smooth movement of Scientifica's IVM-1000 micromanipulator, together with ELC-01MX and DPA-2FS amplifiers, manufactured by npi electronic (Tamm, Germany). These amplifiers are ideal for the juxtacellular recording and labeling of neurons required in these experiments.
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Paper reference:
Dodson PD, Larvin JT, Duffell JM, Garas FN, Doig NM, Kessaris N, Duguid IC, Bogacz R, Butt SJ, Magill PJ. (2015) Distinct developmental origins manifest in the specialized encoding of movement by adult neurons of the external globus pallidus Neuron 86(2):501-13.
doi: 10.1016/j.neuron.2015.03.007