Modulation of auditory and visual processing by Delta-9-Tetrahydrocannabinol and Cannabidiol: an fMRI study

Toby T Winton-Brown (1) , Paul Allen (1) , Sagnik Bhattacharyya (1) , Stefan J Borgwardt (1) , Paolo Fusar-Poli (1)

1 Department of Psychosis Studies

Background Although the effects of cannabis on perception are well documented, little is known about the neural basis of these effects or how they may contribute to the formation of psychotic symptoms. We used fMRI to assess the effects of Delta-9-Tetrahydrocannabinol (THC) and Cannabidiol (CBD) during visual and auditory processing in healthy volunteers. Methods Fourteen healthy volunteers were scanned on 3 occasions. Identical 10mg THC, 600mg CBD and placebo capsules were allocated in a balanced double blinded pseudorandomised crossover design. Plasma levels of each substance, physiological parameters and measures of psychopathology were taken at baseline and at regular intervals following ingestion of substances. Volunteers listened passively to words read and viewed a radial visual chequerboard in alternating blocks during fMRI scanning. Results Administration of THC was associated with increases in anxiety, intoxication and positive psychotic symptoms, whereas CBD had no significant symptomatic effects. THC decreased activation relative to placebo in bilateral temporal cortices during auditory processing, and had mixed effects in visual areas during visual processing. CBD was associated with activation in right temporal cortex during auditory processing, and when contrasted, THC and CBD had opposite effects in the right posterior superior temporal gyrus, the right sided homologue to Wernicke's area. Moreover, the attenuation of activation in this area (maximum 61, -15, -2) by THC during auditory processing was correlated with its acute effect on psychotic symptoms. Conclusions Single doses of THC and CBD differently modulate brain function during auditory and visual stimulation in areas that process auditory and visual stimuli and relate to induced psychotic symptoms.

Mots clés: Biological Psychiatry; Cannabinoids; Imaging; Clinical or Preclinical; Functional Magnetic Resonance Imaging; Sensory Processing; Psychosis; Schizophrenia; Antipsychotics

Toby T Winton-Brown, Paul Allen, Sagnik Bhattacharyya, Stefan J Borgwardt, Paolo Fusar-Poli. Modulation of auditory and visual processing by Delta-9-Tetrahydrocannabinol and Cannabidiol: an fMRI study. Neuropsychopharmacology, 2011, ⟨10.1038/npp.2011.17⟩. ⟨hal-00624169⟩