Abstract

Gamma-band (25-140 Hz) oscillations are a hallmark of sensory processing in the forebrain. The optic tectum (OT), a midbrain structure implicated in sensorimotor processing and attention, also exhibits gamma oscillations. However, the origin and mechanisms of these oscillations remain unknown. We discovered that in acute slices of the avian OT, persistent (>100 ms) epochs of large amplitude gamma oscillations can be evoked that closely resemble those recorded in vivo. We found that cholinergic, glutamatergic, and GABAergic mechanisms differentially regulate the structure of the oscillations at various timescales. These persistent oscillations originate in the multisensory layers of the OT and are broadcast to visual layers via the cholinergic nucleus Ipc, providing a potential mechanism for enhancing the processing of visual information within the OT. The finding that the midbrain contains an intrinsic gamma-generating circuit suggests that the OT could use its own oscillatory code to route signals to forebrain networks.

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Publisher Full Text

Authors

Goddard CA, Sridharan D, Huguenard JR, Knudsen EI

Institution

Department of Neurobiology, Stanford University, Stanford, CA 94305, USA.

Source

Neuron 73:3 2012 Feb 9 pg 567-80

MeSH

Animals
Animals, Newborn
Atropine
Attention
Biophysics
Brain Mapping
Chickens
Electric Stimulation
Excitatory Amino Acid Antagonists
GABA Antagonists
GABA Modulators
Mesencephalon
Muscarinic Antagonists
Pentobarbital
Periodicity
Photic Stimulation
Picrotoxin
Receptors, Cholinergic
Receptors, GABA
Receptors, N-Methyl-D-Aspartate
Superior Colliculi
Synaptic Potentials
Valine

Pub Type(s)

In Vitro
Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

22325207