Wang Electrotonic Coupling Gap Junction Pyramidal 2010

Jun 12, 2010 11:53 AM

paper is April 2010  Yun Wang seems to be an expert in this field... Asst Prof at Tufts.

Electrotonic couplings (i.e., electrical synapses or gap junctions)

directly connect cytosolic contents of adjacent cells and allows

direct transference of chemical and electrical signals between

coupled cells. Both in vitro electrophysiological recordings and

computer simulations demonstrate that electrical synapses play a

key role in synchronizing large neuronal ensembles at different

frequency bands [1,2,3,4]. Neuronal synchronization has been

revealed to underlie a variety of cognitive processes, such as

perception, motor performance, attention, learning, and memory

[1,5]. Indeed, the significance of electrical synaptic transmission

was just recently revealed to brain functions by in vivo patch-clamp

recordings from behavior animals [6]. Electrical synaptic activity is

page 6

Special Electrical Synaptic Dynamics  (PCs are pyramidal cells)

Electrotonic couplings between PCs are considered essential for

ultrafast frequency synchronizations (100–600 Hz) in hippocam-

pal and neocortical areas [1,21,22,23,24,25] while interneuron

gap junctions are closely related to fast frequency synchronizations

(4–12 Hz for theta and 20–70 Hz for gamma frequencies) [9,10,26]. In

enabling ultrafast frequency synchronizations, electrotonic cou-

plings of PCs should have high conductance and allow direct AP

propagation according to simulation studies [24,27]. Our work

provides experimental evidence supporting this theory. AP firing,

even bursting, triggered in a prejunctional cell is directly

‘propagated’ into a postjunctional cell. This phenomenon has

been observed in previous studies as well [11,12,13]. This property

leads to a sub-millisecond spike coordination between PCs,

representing an extraordinary ability for neuronal synchronization

and signal amplification. However, it could be speculated that the

Attachments