The Journal of Neuroscience, May 15, 2001, 21(10):3674-3687
Susceptibility to Kindling and Neuronal Connections of the
Anterior Claustrum
Xia
Zhang1,
Darren K.
Hannesson2,
Deborah M.
Saucier2,
Amy E.
Wallace2,
John
Howland2, and
Michael E.
Corcoran1, 2
1 Neuropsychiatry Research Unit, Department of
Psychiatry, and 2 Department of Psychology, University of
Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E4
The claustrum has been implicated in the kindling of generalized
seizures from limbic sites. We examined the susceptibility of the
anterior claustrum itself to kindling and correlated this with an
anatomical investigation of its afferent and efferent connections.
Electrical stimulation of the anterior claustrum resulted in a pattern
of rapid kindling with two distinct phases. Early kindling involved
extremely rapid progression to bilaterally generalized seizures of
short duration. With repeated daily kindling stimulations, early-phase
generalized seizures abruptly became more elaborate and prolonged,
resembling limbic-type seizures as triggered from the amygdala. We
suggest that the rapid rate of kindling from the anterior claustrum is
an indication that the claustrum is functionally close to the
mechanisms of seizure generalization.
In support of our hypothesis, we found significant afferent, efferent,
and often reciprocal connections between the anterior claustrum and
areas that have been implicated in the generation of generalized
seizures, including frontal and motor cortex, limbic cortex, amygdala,
and endopiriform nucleus. Additional connections were found with
various other structures, including olfactory areas, nucleus accumbens,
midline thalamus, and brainstem nuclei including the substantia nigra
and the dorsal raphe nucleus. The anatomical connections of the
anterior claustrum are consistent with its very high susceptibility to
kindling and support the view that the claustrum is part of a forebrain
network of structures participating in the generalization of seizures.
Key words:
kindling; epilepsy; seizure; claustrum; PHA-L; Fluoro-Gold; epileptogenesis
Copyright © 2001 Society for Neuroscience 0270-6474/01/21103674-14$05.00/0