Standardized F1 - A consistent measure of strength of modulation of visual responses to sine-wave drifting gratings

M. Wypych, C. Wang, A. Nagy, G. Benedek, B. Dreher, W. J. Waleszczyk

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance-contrast-modulated drifting gratings is modulated by the temporal frequency of the stimulation. However, there are serious problems with consistency and reliability of the traditionally used methods of assessment of strength of such modulation. Here we propose an intuitive and simple tool for assessment of the strength of modulations in the form of standardized F1 index, zF1. We define zF1 as the ratio of the difference between the F1 (component of amplitude spectrum of the spike-response at temporal frequency of stimulation) and the mean value of spectrum amplitudes to standard deviation along all frequencies in the spectrum. In order to assess the validity of this measure, we have: (1) examined behavior of zF1 using spike-responses to optimized drifting gratings of single neurons recorded from four 'visual' structures (area V1 of primary visual cortex, superior colliculus, suprageniculate nucleus and caudate nucleus) in the brain of commonly used visual mammal - domestic cat; (2) compared the behavior of zF1 with that of classical statistics commonly employed in the analysis of steady-state responses; (3) tested the zF1 index on simulated spike-trains generated with threshold-linear model. Our analyses indicate that zF1 is resistant to distortions due to the low spike count in responses and therefore can be particularly useful in the case of recordings from neurons with low firing rates and/or low net mean responses. While most V1 and a half of caudate neurons exhibit high zF1 indices, the majorities of collicular and suprageniculate neurons exhibit low zF1 indices. We conclude that despite the general shortcomings of measuring strength of modulation inherent in the linear system approach, zF1 can serve as a sensitive and easy to interpret tool for detection of modulation and assessment of its strength in responses of visual neurons.

Original languageEnglish
Pages (from-to)14-33
Number of pages20
JournalVision Research
Volume72
DOIs
Publication statusPublished - Nov 1 2012

Fingerprint

Neurons
Superior Colliculi
Caudate Nucleus
Visual Cortex
Mammals
Linear Models
Cats
Brain

Keywords

  • Caudate nucleus
  • Gratings induced modulation
  • Modulation index
  • Primary visual cortex
  • Superior colliculus
  • Suprageniculate nucleus

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

Cite this

Standardized F1 - A consistent measure of strength of modulation of visual responses to sine-wave drifting gratings. / Wypych, M.; Wang, C.; Nagy, A.; Benedek, G.; Dreher, B.; Waleszczyk, W. J.

In: Vision Research, Vol. 72, 01.11.2012, p. 14-33.

Research output: Contribution to journalArticle

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