OBJECTIVE: To characterize local field potentials, high frequency oscillations, and single unit firing patterns in microelectrode recordings of @entity1 limbic onset @entity410 . METHODS: Wide bandwidth local field potential recordings were acquired from microelectrodes implanted in mesial temporal structures during spontaneous @entity410 from six @entity1 with mesial @entity1315 . RESULTS: In the @entity410 onset zone, distinct @entity302 were evident in the local field potential prior to the time of @entity410 onset in the intracranial EEG. In all three @entity410 with hypersynchronous (HYP) @entity410 onset, fast ripples with incrementally increasing power accompanied @entity302 during the transition to the ictal state (p < 0.01). In a single @entity258 ( @entity258 ) onset @entity410 a triad of evolving HYP LFP discharges, increased single unit activity, and fast ripples of incrementally increasing power were identified ~20 s prior to @entity410 onset (p < 0.01). In addition, incrementally increasing fast ripples occurred after @entity410 onset just prior to the transition to @entity258 activity (p < 0.01). HYP onset was associated with an increase in fast ripple and ripple rate (p < 0.05) and commonly each HYP discharge had a superimposed ripple followed by a fast ripple. Putative excitatory and inhibitory single units could be distinguished during limbic @entity410 onset, and heterogeneous shifts in firing rate were observed during @entity258 activity. SIGNIFICANCE: Epileptiform activity is detected by microelectrodes before it is detected by depth macroelectrodes, and the one clinically identified @entity258 ictal onset was a HYP onset at the local level. Patterns of incrementally increasing fast ripple power are consistent with observations in @entity35 with experimental @entity302 , suggesting that limbic @entity410 arise when small clusters of synchronously bursting neurons increase in size, coalesce, and reach a critical mass for propagation.

Ictal onset patterns of local field potentials, high frequency oscillations, and unit activity in @entity1 mesial XXXX .

@entity1 :: ('9606', 'Species') :: ['human', 'patients'] @entity410 :: ('MESH:D012640', 'Disease') :: ['seizure', 'seizures'] @entity1315 :: ('MESH:D004833', 'Disease') :: ['temporal lobe epilepsy'] @entity302 :: ('MESH:D004827', 'Disease') :: ['hippocampal epilepsy', 'epileptiform discharges'] @entity35 :: ('10116', 'Species') :: ['rats'] @entity258 :: ('MESH:D009800', 'Disease') :: ['LVF', 'low voltage fast']
@entity1315 :: (MESH:D004833,Disease) :: ['temporal lobe epilepsy']
