In a study published online today in the journal Nature, the team at UCL describe a technique developed in mice which enables them to combine information about the function of neurons together with details of their synaptic connections.
The researchers looked into the visual cortex of the mouse brain, which contains thousands of neurons and millions of different connections. Using high resolution imaging, they were able to detect which of these neurons responded to a particular stimulus, for example a horizontal edge.
Taking a slice of the same tissue, the researchers then applied small currents to a subset of neurons in turn to see which other neurons responded and hence which of these were synaptically connected. By repeating this technique many times, the researchers were able to trace the function and connectivity of hundreds of nerve cells in visual cortex.
The study has resolved the debate about whether local connections between neurons are random in other words, whether nerve cells connect sporadically, independent of function or whether they are ordered, for example constrained by the properties of the neuron in terms of how it responds to particular stimuli. The researchers showed that neurons which responded very similarly to visual stimuli, such as those which respond to edges of the same orientation, tend to connect to each other much more than those that prefer different orientations.
Using this technique, the researchers hope to begin generating a wiring diagram of a brain area with a particular behavioural function, such as the visual cortex. This knowl
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