Directional spread of activity in synaptic networks of the human lateral amygdala.
Spontaneous epileptiform activity has previously been observed in lateral amygdala (LA) slices derived from patients with intractable-temporal lobe epilepsy. The present study aimed to characterize intranuclear LA synaptic connectivity and to test the hypothesis that differences in the spread of flow of neuronal activity may relate to spontaneous epileptiform activity occurrence. Electrical activity was evoked through electrical microstimulation in acute human brain slices containing the LA, signals were recorded as local field potentials combined with fast optical imaging of voltage-sensitive dye fluorescence. Sites of stimulation and recording were systematically varied. Following recordings, slices were anatomically reconstructed using two-dimensional unitary slices as a reference for coronal and parasagittal planes. Local spatial patterns and spread of activity were assessed by incorporating the coordinates of electrical and optical recording sites into the respective unitary slice. A preferential directional spread of evoked electrical signals was observed from ventral to dorsal, rostral to caudal and medial to lateral regions in the LA. No differences in spread of evoked activity were observed between spontaneously and non-spontaneously active LA slices, i.e. basic properties of evoked synaptic responses were similar in the two functional types of LA slices, including input-output relationship, and paired-pulse depression. These results indicate a directed propagation of synaptic signals within the human LA in spontaneously active epileptic slices. We suggest that the lack of differences in local and in systemic information processing has to be found in confined epileptiform circuits within the amygdala likely involving well-known "epileptic neurons".
Institute of Physiology I, Westfaelische Wilhelms-University Muenster, Germany.
Stéphanie
S
Graebenitz
Department of Neurology and Institute of Translational Neurology, University Hospital and Westfaelische Wilhelms-University Muenster, Germany. Electronic address: manuela.cerina@ukmuenster.de.
Manuela
M
Cerina
Institute of Physiology I, Westfaelische Wilhelms-University Muenster, Germany.
Jörg
J
Lesting
Institute of Neuroscience and Medicine, Research Center Juelich, Germany.
Olga
O
Kedo
Epilepsy Research Center, Westfaelische Wilhelms-University Muenster, Germany; Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran.
Ali
A
Gorji
Bethel Epilepsy Center Bethel, Mara, Bielefeld, Germany.
Heinz
H
Pannek
Institute of Neuropathology, Bethel, Bielefeld, Germany.
Volkmar
V
Hans
Institute of Neuroscience and Medicine, Research Center Juelich, Germany.
Karl
K
Zilles
Institute of Physiology I, Westfaelische Wilhelms-University Muenster, Germany.
Hans-Christian
HC
Pape
Institute of Physiology I, Westfaelische Wilhelms-University Muenster, Germany. Electronic address: speckma@uni-muenster.de.
Erwin-Josef
EJ
Speckmann
D000293:Adolescent; D000328:Adult; D000679:Amygdala / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D004827:Epilepsy / Q000503:physiopathology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D055815:Young Adult
field potentials; lateral amygdala; living human brain slices; temporal lobe epilepsy; voltage-sensitive dyes