Processing of Salient Emotional Stimuli as a Function of Tetrahydrocannabinol (THC) and Cannabidiol (CBD)
Status:
Completed
Trial end date:
2014-12-01
Target enrollment:
Participant gender:
Summary
Attentional blink refers to a phenomenon where the detection of the second of two target
stimuli that are presented in Short succession within a stream of stimuli is impaired. This
is explained by an insufficient availability of attentional resources. Additionally,
emotionally salient stimuli, like for example pictures with a positive or negative content,
are detected more often compared to neutral pictures during this attentional blink period.
Cannabinoids are involved in the modulation of cognitive, attentional, and emotional
processes. Interestingly, data from animals suggests that THC and CBD, both active
ingredients in the Cannabis sativa plant, have opposing effects on brain cannabinoid (CB1)
receptors. CB1 receptors modulate the expression of emotionally salient conditioned
association in rats, if salience processes in humans are modulated in the same way remains
unclear.
Employing a task to detect salient stimuli, Bhattacharyya et al. (2012) showed that THC seems
to make non-salient standard stimuli more salient. They showed decreased activation of the
right caudate and increased right prefrontal cortex stimuli during processing of salient
stimuli. Importantly, this was associated with decreased response times to standard relative
to oddball stimuli. Generally, THC and CBD differentially modulate brain areas associated
with attentional salience processing. For example THC seems to increase prefrontal and
striatal activation whereas CBD seems to decrease it.
The investigators assume that THC increases the number of correctly detected emotional
stimuli during the attentional blink period, whereas CBD has no effect. Additionally, the
investigators assume that pictures of the positive category are detected with higher accuracy
than negative ones under the influence of THC.