Higher-order thalamic relays burst more than first-order relays.
There is a strong correlation between the behavior of an animal and the firing mode (burst or tonic) of thalamic relay neurons. Certain differences between first- and higher-order thalamic relays (which relay peripheral information to the cortex versus information from one cortical area to another, respectively) suggest that more bursting might occur in the higher-order relays. Accordingly, we recorded bursting behavior in single cells from awake, behaving rhesus monkeys in first-order (the lateral geniculate nucleus, the ventral posterior nucleus, and the ventral portion of the medial geniculate nucleus) and higher-order (pulvinar and the medial dorsal nucleus) thalamic relays. We found that the extent of bursting was dramatically greater in the higher-order than in the first-order relays, and this increased bursting correlated with lower spontaneous activity in the higher-order relays. If bursting effectively signals the introduction of new information to a cortical area, as suggested, this increased bursting may be more important in corticocortical transmission than in transmission of primary information to cortex.
Ramcharan
E J
EJ
Center for Complex Systems and Brain Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
Gnadt
J W
JW
Sherman
S M
SM
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001931:Brain Mapping; D008251:Macaca; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation; D013787:Thalamic Nuclei / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*