Haemodynamic responses to radial motion in the visual cortex

Sobanawartiny Wijeakumar, Uma Shahani, William A. Simpson, Daphne McCulloch

Research output: Contribution to journalArticle

93 Downloads (Pure)

Abstract

Functional near-infrared spectroscopy (fNIRS) is an optical imaging technique that relies on emitting near-infrared light into cortical tissue to measure changes in haemoglobin concentrations as a result of stimulation. The purpose of this study was to observe haemodynamic changes in response to moving stimuli over the primary visual cortex. The test stimuli were radially expanding and contracting concentric gratings and the control stimulus was a matched stationary pattern. A two-channel oximeter (Oxiplex TS) was
used to record changes in oxyhaemoglobin (HbO), de-oxyhaemoglobin (Hb) and total haemoglobin concentrations (THb). An increase in
haemodynamic activation was observed 20 s after the onset of motion and maintained for up to 20 s following motion offset (30 s time
window). This was compared to a time window of 10 s before the offset of the stationary presentation. Differences between expanding
and contracting motion did not achieve significance at any of the locations. However, a significantly larger HbO response was observed
across the 30 s time window when compared to the baseline window at both occipital locations. Preliminary results from more temporal
locations also showed a similar trend. It is suggested that the delayed rise in HbO levels could be due to an inconsistent maintenance
of luminance and contrast-related features of the moving stimuli in V1 receptive fields. Furthermore, motion-after effects could have
contributed to delaying the drop to baseline levels. The current study has shown some evidence that fNIRS can be used to record
haemodynamic responses to moving stimuli from the visual cortex. We suggest that longer durations of randomised moving, stationary
and grey screen presentations would be useful in teasing apart pure motion responses and after-effects. fNIRS could also potentially be
used to investigate haemodynamic changes in disorders such as amblyopia that present with motion processing deficits.
Original languageEnglish
Pages (from-to)231-236
Number of pages6
JournalJournal of Near Infrared Spectroscopy
Volume21
Issue number4
DOIs
Publication statusPublished - 12 Aug 2013

Fingerprint

Near infrared spectroscopy
Hemodynamics
Oxyhemoglobins
Hemoglobins
Oximeters
Luminance
Chemical activation
Tissue
Infrared radiation
Imaging techniques
Processing

Keywords

  • fNIRS
  • motion
  • visual cortex
  • imaging

Cite this

Wijeakumar, Sobanawartiny ; Shahani, Uma ; Simpson, William A. ; McCulloch, Daphne. / Haemodynamic responses to radial motion in the visual cortex. In: Journal of Near Infrared Spectroscopy. 2013 ; Vol. 21, No. 4. pp. 231-236.
@article{d34f9fcb5de94ab888dd5c37a3574d42,
title = "Haemodynamic responses to radial motion in the visual cortex",
abstract = "Functional near-infrared spectroscopy (fNIRS) is an optical imaging technique that relies on emitting near-infrared light into cortical tissue to measure changes in haemoglobin concentrations as a result of stimulation. The purpose of this study was to observe haemodynamic changes in response to moving stimuli over the primary visual cortex. The test stimuli were radially expanding and contracting concentric gratings and the control stimulus was a matched stationary pattern. A two-channel oximeter (Oxiplex TS) wasused to record changes in oxyhaemoglobin (HbO), de-oxyhaemoglobin (Hb) and total haemoglobin concentrations (THb). An increase inhaemodynamic activation was observed 20 s after the onset of motion and maintained for up to 20 s following motion offset (30 s timewindow). This was compared to a time window of 10 s before the offset of the stationary presentation. Differences between expandingand contracting motion did not achieve significance at any of the locations. However, a significantly larger HbO response was observedacross the 30 s time window when compared to the baseline window at both occipital locations. Preliminary results from more temporallocations also showed a similar trend. It is suggested that the delayed rise in HbO levels could be due to an inconsistent maintenanceof luminance and contrast-related features of the moving stimuli in V1 receptive fields. Furthermore, motion-after effects could havecontributed to delaying the drop to baseline levels. The current study has shown some evidence that fNIRS can be used to recordhaemodynamic responses to moving stimuli from the visual cortex. We suggest that longer durations of randomised moving, stationaryand grey screen presentations would be useful in teasing apart pure motion responses and after-effects. fNIRS could also potentially beused to investigate haemodynamic changes in disorders such as amblyopia that present with motion processing deficits.",
keywords = "fNIRS, motion, visual cortex, imaging",
author = "Sobanawartiny Wijeakumar and Uma Shahani and Simpson, {William A.} and Daphne McCulloch",
year = "2013",
month = "8",
day = "12",
doi = "10.1255/jnirs.1056",
language = "English",
volume = "21",
pages = "231--236",
journal = "Journal of Near Infrared Spectroscopy",
issn = "0967-0335",
publisher = "SAGE Publications",
number = "4",

}

Haemodynamic responses to radial motion in the visual cortex. / Wijeakumar, Sobanawartiny; Shahani, Uma; Simpson, William A.; McCulloch, Daphne.

In: Journal of Near Infrared Spectroscopy, Vol. 21, No. 4, 12.08.2013, p. 231-236.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Haemodynamic responses to radial motion in the visual cortex

AU - Wijeakumar, Sobanawartiny

AU - Shahani, Uma

AU - Simpson, William A.

AU - McCulloch, Daphne

PY - 2013/8/12

Y1 - 2013/8/12

N2 - Functional near-infrared spectroscopy (fNIRS) is an optical imaging technique that relies on emitting near-infrared light into cortical tissue to measure changes in haemoglobin concentrations as a result of stimulation. The purpose of this study was to observe haemodynamic changes in response to moving stimuli over the primary visual cortex. The test stimuli were radially expanding and contracting concentric gratings and the control stimulus was a matched stationary pattern. A two-channel oximeter (Oxiplex TS) wasused to record changes in oxyhaemoglobin (HbO), de-oxyhaemoglobin (Hb) and total haemoglobin concentrations (THb). An increase inhaemodynamic activation was observed 20 s after the onset of motion and maintained for up to 20 s following motion offset (30 s timewindow). This was compared to a time window of 10 s before the offset of the stationary presentation. Differences between expandingand contracting motion did not achieve significance at any of the locations. However, a significantly larger HbO response was observedacross the 30 s time window when compared to the baseline window at both occipital locations. Preliminary results from more temporallocations also showed a similar trend. It is suggested that the delayed rise in HbO levels could be due to an inconsistent maintenanceof luminance and contrast-related features of the moving stimuli in V1 receptive fields. Furthermore, motion-after effects could havecontributed to delaying the drop to baseline levels. The current study has shown some evidence that fNIRS can be used to recordhaemodynamic responses to moving stimuli from the visual cortex. We suggest that longer durations of randomised moving, stationaryand grey screen presentations would be useful in teasing apart pure motion responses and after-effects. fNIRS could also potentially beused to investigate haemodynamic changes in disorders such as amblyopia that present with motion processing deficits.

AB - Functional near-infrared spectroscopy (fNIRS) is an optical imaging technique that relies on emitting near-infrared light into cortical tissue to measure changes in haemoglobin concentrations as a result of stimulation. The purpose of this study was to observe haemodynamic changes in response to moving stimuli over the primary visual cortex. The test stimuli were radially expanding and contracting concentric gratings and the control stimulus was a matched stationary pattern. A two-channel oximeter (Oxiplex TS) wasused to record changes in oxyhaemoglobin (HbO), de-oxyhaemoglobin (Hb) and total haemoglobin concentrations (THb). An increase inhaemodynamic activation was observed 20 s after the onset of motion and maintained for up to 20 s following motion offset (30 s timewindow). This was compared to a time window of 10 s before the offset of the stationary presentation. Differences between expandingand contracting motion did not achieve significance at any of the locations. However, a significantly larger HbO response was observedacross the 30 s time window when compared to the baseline window at both occipital locations. Preliminary results from more temporallocations also showed a similar trend. It is suggested that the delayed rise in HbO levels could be due to an inconsistent maintenanceof luminance and contrast-related features of the moving stimuli in V1 receptive fields. Furthermore, motion-after effects could havecontributed to delaying the drop to baseline levels. The current study has shown some evidence that fNIRS can be used to recordhaemodynamic responses to moving stimuli from the visual cortex. We suggest that longer durations of randomised moving, stationaryand grey screen presentations would be useful in teasing apart pure motion responses and after-effects. fNIRS could also potentially beused to investigate haemodynamic changes in disorders such as amblyopia that present with motion processing deficits.

KW - fNIRS

KW - motion

KW - visual cortex

KW - imaging

U2 - 10.1255/jnirs.1056

DO - 10.1255/jnirs.1056

M3 - Article

VL - 21

SP - 231

EP - 236

JO - Journal of Near Infrared Spectroscopy

JF - Journal of Near Infrared Spectroscopy

SN - 0967-0335

IS - 4

ER -