Background: Measuring perceptual judgments about stimuli while manipulating their physical characteristics can uncover the neural algorithms underlying sensory processing. We carried out psychophysical experiments to examine how humans discriminate vibrotactile stimuli. Methodology/Principal Findings: Subjects compared the frequencies of two sinusoidal vibrations applied sequentially to one fingertip. Performance was reduced when (1) the root mean square velocity (or energy) of the vibrations was equated by adjusting their amplitudes, and (2) the vibrations were noisy (their temporal structure was irregular). These effects were super-additive when subjects compared noisy vibrations that had equal velocity, indicating that frequency judgments became more dependent on the vibrations' temporal structure when differential information about velocity was eliminated. To investigate which areas of the somatosensory system use information about velocity and temporal structure, we required subjects to compare vibrations applied sequentially to opposite hands. This paradigm exploits the fact that tactile input to neurons at early levels (e.g., the primary somatosensory cortex, SI) is largely confined to the contralateral side of the body, so these neurons are less able to contribute to vibration comparisons between hands. The subjects' performance was still sensitive to differences in vibration velocity, but became less sensitive to noise. Conclusions/Significance: We conclude that vibration frequency is represented in different ways by different mechanisms distributed across multiple cortical regions. Which mechanisms support the "readout" of frequency varies according to the information present in the vibration. Overall, the present findings are consistent with a model in which information about vibration velocity is coded in regions beyond SI. While adaptive processes within SI also contribute to the representation of frequency, this adaptation is influenced by the temporal regularity of the vibration. © 2006 Harris et al.

Factors affecting frequency discrimination of vibrotactile stimuli: Implications for cortical encoding / Harris, Justin A.; Arabzadeh, Ehsan; Fairhall, Adrienne L.; Benito, Claire; Diamond, Mathew E.. - In: PLOS ONE. - ISSN 1932-6203. - 1:1(2006), pp. 1-9. [10.1371/journal.pone.0000100]

Factors affecting frequency discrimination of vibrotactile stimuli: Implications for cortical encoding

Harris, Justin A.;Arabzadeh, Ehsan;Diamond, Mathew E.
2006-01-01

Abstract

Background: Measuring perceptual judgments about stimuli while manipulating their physical characteristics can uncover the neural algorithms underlying sensory processing. We carried out psychophysical experiments to examine how humans discriminate vibrotactile stimuli. Methodology/Principal Findings: Subjects compared the frequencies of two sinusoidal vibrations applied sequentially to one fingertip. Performance was reduced when (1) the root mean square velocity (or energy) of the vibrations was equated by adjusting their amplitudes, and (2) the vibrations were noisy (their temporal structure was irregular). These effects were super-additive when subjects compared noisy vibrations that had equal velocity, indicating that frequency judgments became more dependent on the vibrations' temporal structure when differential information about velocity was eliminated. To investigate which areas of the somatosensory system use information about velocity and temporal structure, we required subjects to compare vibrations applied sequentially to opposite hands. This paradigm exploits the fact that tactile input to neurons at early levels (e.g., the primary somatosensory cortex, SI) is largely confined to the contralateral side of the body, so these neurons are less able to contribute to vibration comparisons between hands. The subjects' performance was still sensitive to differences in vibration velocity, but became less sensitive to noise. Conclusions/Significance: We conclude that vibration frequency is represented in different ways by different mechanisms distributed across multiple cortical regions. Which mechanisms support the "readout" of frequency varies according to the information present in the vibration. Overall, the present findings are consistent with a model in which information about vibration velocity is coded in regions beyond SI. While adaptive processes within SI also contribute to the representation of frequency, this adaptation is influenced by the temporal regularity of the vibration. © 2006 Harris et al.
2006
1
1
1
9
e100
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0000100
Harris, Justin A.; Arabzadeh, Ehsan; Fairhall, Adrienne L.; Benito, Claire; Diamond, Mathew E.
File in questo prodotto:
File Dimensione Formato  
journal.pone.0000100.PDF

accesso aperto

Descrizione: Open Access
Tipologia: Versione Editoriale (PDF)
Licenza: Creative commons
Dimensione 248.57 kB
Formato Adobe PDF
248.57 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/88033
Citazioni
  • ???jsp.display-item.citation.pmc??? 11
  • Scopus 35
  • ???jsp.display-item.citation.isi??? 37
social impact