Analytical approaches for estimation of temporal frequency preference from visual evoked potentials.

There are various ways to study neuronal processing of information about temporal frequency content of visual stimuli. The two most fundamental methods are 1) direct measurement of response amplitude, e.g. an amplitude of averaged visual evoked potential, and 2) assessment of response magnitude after transformation of electrophysiological signal from time to frequency domain. In our study we found it impossible to use the same paradigm to analyze the whole spectrum of temporal frequencies in local field potentials recorded during visual electrophysiology experiments performed on anesthetized rats. Visual responses were recorded from all layers of primary visual cortex in response to flashing light with temporal frequency in the range of 0.5 – 15 Hz. We found that for frequencies lower than 2 Hz it is difficult to draw conclusions based on power spectrum alone, while for high frequencies (>2Hz) the evoked potential in time domain could not be observed. We discuss possible physiological reasons of these difficulties and the advantages of the Welch method instead of the periodogram to analyze signals in the frequency domain.

Supported by the Polish National Science Center grant Symfonia 1 (2013/08/W/NZ4/00691)

Author: Agnieszka Wierzbicka
Conference: Title