Neuroscientific methods

Methods for measuring and manipulating nervous-system structure and function. The inference permitted by a recording, an anatomical reconstruction and a perturbation differs; convergence is more informative than treating them as interchangeable.

An independently specified task contrast used to identify a region for subsequent analysis. Individual localisation can distinguish neighbouring language-selective and domain-general regions, while independent data reduce circularity.^[ref]

Anatomical links among neural regions. Diffusion-based tractography estimates aspects of white-matter organisation indirectly and should not be equated with a direct count of synapses or information flow.

Statistical dependence between activity measurements from different locations. Resting-state correlation does not establish direct anatomical connectivity, the direction of influence or a causal role in behaviour.

A volume element in an imaging measurement. In functional magnetic resonance imaging, one voxel aggregates an indirect signal over many cells, so a shared response at voxel or region scale need not imply the same active neuronal population.

Measurement of the activity attributed to one neuron, commonly through extracellular electrodes and spike isolation. It permits trial-resolved tests of stimulus tuning and interactions. Failure to evoke spikes with one stimulus alone does not exclude a modulatory input from that modality.

A study relating damage to altered or preserved performance. Damage may affect several neighboring areas and connections, and chronic compensation can change the relationship between a lesion and behavior. Deficits are evidence about a network's contribution under the tested conditions, not automatic localization of one abstract faculty.

Noninvasive stimulation in which a changing magnetic field induces electrical effects in neural tissue. Task-specific perturbation and control conditions can test causal hypotheses, but stimulation can affect connected regions and does not isolate a unique cellular mechanism.

Repeated magnetic stimulation used to perturb cortical activity or investigate changes after a stimulation intervention. The physiological effect and network spread depend on site, state and protocol; a nominally inhibitory manipulation does not guarantee a purely local reduction.