According to a new study, botox may travel from the injected site to the brain. This study has been published in the Journal of Neuroscience. Researchers conducting the study on rats injected with the botulism toxin discovered botulism in their brain stems. Though critics say that the same results may not occur in humans, there is consensus that further study is needed on the subject. This study was authored by Matteo Caleo from the Italian National Research Council's Institute of Neuroscience in Pisa.

Highlights of the study
a. This study was conducted on rats in a laboratory.
b. Researchers injected a laboratory preparation of botulinum toxin into one side of each rodent's hippocampus and into their visual center, or the superior colliculus.
c. Within three days of the injection, it was noticed that remnants of a protein broken down by the toxin was near the brainstem.
d. The toxin also moved from one hippocampus, which controls long-term memory and spatial navigation, to the hippocampus on the opposite side of the brain.
e. It also moved from the superior colliculus, the part of the brain associated with eye-head coordination, back to the eye.
f. Brain cell activity was disrupted both where botulinum neurotoxin was injected and in some of the distant-but-connected sites.
g. Effects of the injection lasted till six months after the start of the experiment.
h. Researchers say that this neurotoxin may change the circuitry of the spinal cord and interrupt communication through nerve cells.
i. However, data suggest that different preparations of botulinum toxin react differently in both laboratory and in clinical practice.