Trends in Neurosciences
Paying attention to the thalamic reticular nucleus
Section snippets
Multiple inputs to single sectors of TRN
For any single functional thalamocortical pathway and its related TRN sector, there is usually more than one connected thalamic nucleus or cortical area. Thus, visual, auditory and somatosensory systems have many cortical areas22, 23, 24 and more than one related thalamic nucleus connected to TRN (6, 9, 10, 11, 12). The way in which several thalamocortical circuits relate to each other in TRN must be crucial to the influence that any one cortical area can exert on the modulation going from a
Functional implications
At present, evidence on details of reticular connections is incomplete. One reason for writing this article is to stress the importance of defining the connections. It is clear that no simple general rule governing cortical and thalamic connections in TRN applies to all sectors. Each sector appears to follow distinct rules. To understand how any one sector responds to its several inputs and then produces modulatory effects in the thalamus, we have to look at its particular pattern of
Concluding remarks
The organization of TRN involves the interaction of several thalamocortical circuits for each functionally distinct sector of TRN. We have discussed two cortical areas and two thalamic nuclei for each sector, but generally more cortical areas and more thalamic nuclei are involved in any one sector. The important point is that each sector provides a nexus for the interaction of several thalamocortical and corticothalamic circuits, and will prove to be a key site where many cortical areas
Acknowledgements
This work was supported by grants from the Wellcome Trust and the NIH (EY11494). We thank Dr D. Pinault for a critical reading of the manuscript.
References (44)
- et al.
Brain Res
(1966) Brain Res
(1976)Prog. Neurobiol
(1992)- et al.
Neuroscience
(1990) - et al.
Trends Neurosci
(1983) - et al.
Neuroscience
(1985) - et al.
Neuroscience
(1995) - et al.
Hearing Res
(1991) - et al.
Trends Neurosci
(1993) - et al.
Brain Res
(1996)
Brain Res. Bull
Curr. Opinion Neurobiol
Proc. Natl. Acad. Sci. U. S. A
The Thalamus,
J. Neurocytol
Science
Eur. J. Neurosci
Eur. J. Neurosci
Eur. J. Neurosci
J. Comp. Neurol
Eur. J. Neurosci
Eur. J. Neurosci
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