Blind smell

Brain activation induced by an undetected air-borne chemical

Noam Sobel, Vivek Prabhakaran, Catherine Hartley, John E. Desmond, Gary H. Glover, Edith V. Sullivan, John D E Gabrieli

Research output: Contribution to journalArticle

Abstract

EEG and behavioural evidence suggests that air-borne chemicals can affect the nervous system without being consciously detected. EEG and behaviour, however, do not specify which brain structures are involved in chemical sensing that occurs below a threshold of conscious detection. Here we used functional MRI to localize brain activation induced by high and low concentrations of the air-borne compound oestra-1,3,5(10),16-tetraen-3yl acetate. Following presentations of both concentrations, eight of eight subjects reported verbally that they could not detect any odour (P = 0.004). Forced choice detection performed during the presentations revealed above-chance detection of the high concentration, but no better than chance detection of the low concentration compound. Both concentrations induced significant brain activation, primarily in the anterior medial thalamus and inferior frontal gyrus. Activation in the inferior frontal gyrus during the high concentration condition was significantly greater in the right than in the left hemisphere (P 0.03). A trend towards greater thalamic activation was observed for the high concentration than the low concentration compound (P = 0.08). These findings localize human brain activation that was induced by an undetectable air-borne chemical (the low concentration compound).

Original languageEnglish (US)
Pages (from-to)209-217
Number of pages9
JournalBrain
Volume122
Issue number2
DOIs
StatePublished - Feb 1999

Fingerprint

Smell
Air
Brain
Prefrontal Cortex
Electroencephalography
Thalamus
Nervous System
Brain Activation
Acetates
Magnetic Resonance Imaging

Keywords

  • Awareness
  • Chemical senses
  • Functional imaging
  • Odour detection
  • Olfaction
  • Pheromones

ASJC Scopus subject areas

  • Medicine(all)
  • Arts and Humanities (miscellaneous)
  • Clinical Neurology

Cite this

Sobel, N., Prabhakaran, V., Hartley, C., Desmond, J. E., Glover, G. H., Sullivan, E. V., & Gabrieli, J. D. E. (1999). Blind smell: Brain activation induced by an undetected air-borne chemical. Brain, 122(2), 209-217. https://doi.org/10.1093/brain/122.2.209

Blind smell : Brain activation induced by an undetected air-borne chemical. / Sobel, Noam; Prabhakaran, Vivek; Hartley, Catherine; Desmond, John E.; Glover, Gary H.; Sullivan, Edith V.; Gabrieli, John D E.

In: Brain, Vol. 122, No. 2, 02.1999, p. 209-217.

Research output: Contribution to journalArticle

Sobel, N, Prabhakaran, V, Hartley, C, Desmond, JE, Glover, GH, Sullivan, EV & Gabrieli, JDE 1999, 'Blind smell: Brain activation induced by an undetected air-borne chemical', Brain, vol. 122, no. 2, pp. 209-217. https://doi.org/10.1093/brain/122.2.209
Sobel N, Prabhakaran V, Hartley C, Desmond JE, Glover GH, Sullivan EV et al. Blind smell: Brain activation induced by an undetected air-borne chemical. Brain. 1999 Feb;122(2):209-217. https://doi.org/10.1093/brain/122.2.209
Sobel, Noam ; Prabhakaran, Vivek ; Hartley, Catherine ; Desmond, John E. ; Glover, Gary H. ; Sullivan, Edith V. ; Gabrieli, John D E. / Blind smell : Brain activation induced by an undetected air-borne chemical. In: Brain. 1999 ; Vol. 122, No. 2. pp. 209-217.
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