Cellular dynamics of cholinergically induced alpha (8-13 Hz) rhythms in sensory thalamic nuclei in vitro.
Although EEG alpha (8-13 Hz) rhythms are traditionally thought to reflect an "idling" brain state, they are also linked to several important aspects of cognition, perception, and memory. Here we show that reactivating cholinergic input, a key component in normal cognition and memory operations, in slices of the cat primary visual and somatosensory thalamus, produces robust alpha rhythms. These rhythms rely on activation of muscarinic receptors and are primarily coordinated by activity in the recently discovered, gap junction-coupled subnetwork of high-threshold (HT) bursting thalamocortical neurons. By performing extracellular field recordings in combination with intracellular recordings of these cells, we show that (1) the coupling of HT bursting cells is sparse, with individual neurons typically receiving discernable network input from one or very few additional cells, (2) the phase of oscillatory activity at which these cells prefer to fire is readily modifiable and determined by a combination of network input, intrinsic properties and membrane polarization, and (3) single HT bursting neurons can potently influence the local network state. These results substantially extend the known effects of cholinergic activation on the thalamus and, in combination with previous studies, show that sensory thalamic nuclei possess powerful and dynamically reconfigurable mechanisms for generating synchronized alpha activity that can be engaged by both descending and ascending arousal systems.
Lörincz
Magor L
ML
School of Biosciences, Cardiff University, Cardiff CF10 3US, United Kingdom.
Crunelli
Vincenzo
V
Hughes
Stuart W
SW
D000109:Acetylcholine / Q000378:metabolism*; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D000513:Alpha Rhythm; D000818:Animals; D002415:Cats; D018678:Cholinergic Agents / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D018683:Excitatory Amino Acid Agents / Q000494:pharmacology; D018682:GABA Agents / Q000494:pharmacology; D066298:In Vitro Techniques; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D017711:Nonlinear Dynamics; D012684:Sensory Thresholds / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D013057:Spectrum Analysis; D013787:Thalamic Nuclei / Q000166:cytology* / Q000187:drug effects / Q000502:physiology
D018678:Cholinergic Agents; D018683:Excitatory Amino Acid Agents; D018682:GABA Agents; D000109:Acetylcholine