International Research Compendium - Drug Free Australia

The brain distribution of CB-1 binding sites correlates with the effect of cannabis.
( Figure: Location of CB-1 cannabinoid receptors in the brain )
THC increases dopamine activity in the mesolimbic pathway, projecting from the VTA
to the Nuc. Accumbens, which activates the brain reward system.
Cannabis ( and also ecstasy ) acts on the hippocampus. The hippocampus receives
information from all parts of your brain. The hippocampus sends the information on to
the prefrontal cortex.
The hippocampus is crucial for learning, memory, and the integration of sensory
experiences with emotions and motivations. All this information reaches your
hippocampus through the dentate gyrus, which acts as a relay station for the rest of
the hippocampus. This relay station is loaded with cannabinoid receptors. THC
changes the way in which sensory information gets into and is acted on by the
hippocampus. As a result, marijuana can make time appear to slow and can distort
perceptions of the world. Marijuana can make users feel as if they are not really part
of themselves. The ability to carry out short-term memory tasks depends on a
properly working hippocampus. Marijuana disrupts short-term memory by activating
these cannabinoid receptors at the entrance to the hippocampus. This disruption can
have profound effects.
People high on marijuana have a hard time conducting a coherent conversation. The
more complex the subject, the more difficult it is. If they have to deal with a complex
situation in the real world, it can become a significant problem. The inability to hold
thoughts in working memory makes it difficult to have good judgment. This also
makes it difficult to learn effectively because thoughts that can’t be held in working
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