Browsing by Author "Alafuzoff, Aleksander"

The terms brain signals and brain activity are widely used in cognitive neuroscience. These terms are used to refer to both the signals produced by the methods used in neuroscience as well as the signals produced by the brain for its own purposes. This dichotomy can be made apparent by making a conceptual distinction between signals from the brain, produced in neuroscientific research, and signals in the brain, used by neurons to communicate. Understanding the relationship between the signals being recorded and the signals used by the brain is crucial for interpreting the results and conclusions of cognitive neuroscience research. Signals in the brain can be divided into three groups: synaptic, ephaptic, and diffusive. These groups can be characterized by the mechanism by which the signals propagate, the speed, range, and selectivity of the signals, as well as the number of unique signals that can be sent in each. Similarly, signals from the brain can be divided into three groups, according to the physical phenomenon being measured: electrophysiological, blood-flow dependent, and optical signals. These signals and methods that produce them can be distinguished in terms of their recording region, spatial summation, time resolution and invasiveness. Modern methods in neuroscience do not measure all or even the most significant signals in the brain. In particular, no non-invasive method is capable of discerning the activity of single neurons or microcircuits. If the mechanisms underlying cognitive processes are on the cellular level, one of the central challenges of cognitive neuroscience is and will be to resolve the incommensurability between signals recorded from and signals used by the brain.