How much feedback from visual cortex to lateral geniculate nucleus in cat: A perspective
Corticothalamic feedback is believed to play an important role in selectively regulating the flow of sensory information from thalamus to cortex. But despite its importance, the size and nature of corticothalamic pathway connectivity is not fully understood. In light of recent empirical data, the ai...
Gespeichert in:
Veröffentlicht in: | Visual neuroscience 2004-07, Vol.21 (4), p.487-500 |
---|---|
1. Verfasser: | |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Corticothalamic feedback is believed to play an important role in
selectively regulating the flow of sensory information from thalamus to
cortex. But despite its importance, the size and nature of
corticothalamic pathway connectivity is not fully understood. In light
of recent empirical data, the aim of this paper was to quantify the
contribution of area 17 axon connectivity to the synaptic organization
of A-laminae in dorsal lateral geniculate nucleus (dLGN) in cat, the
best studied corticothalamic pathway. Numerical constraints indicate
that most corticogeniculate synapses are not formed with inhibitory
interneurons. However, the main finding is that there was an order of
magnitude difference between estimates of the mean number of cortical
synapses per A-laminae neuron based on individual corticogeniculate
axon data (12,000–16,000 cortical synapses per cell) than that
previously derived from partial reconstructions of the synaptic input
to two physiologically identified relay cells (1200–1500 cortical
synapses per cell). In an attempt to reconcile these different
estimates, parameter variation and comparative analyses suggest that
previous work may have overestimated the density of corticogeniculate
efferent neurons and underestimated the total number of synapses per
geniculate neuron. But as this analysis did not include area 18
corticogeniculate axons innervating A-laminae, the discrepancy between
different estimates may be greater and require further explanation.
Thus, the analysis presented here suggests geniculate neurons receive
on average a greater number of cortical synapses per cell but from far
fewer corticogeniculate axons than previously thought. |
---|---|
ISSN: | 0952-5238 1469-8714 |
DOI: | 10.1017/S0952523804214018 |