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Stimulation of the prefrontal cortex in the rat induces patterns of activity in midbrain dopaminergic neurons which resemble natural burst events
Author(s) -
Tong Z.Y.,
Overton P.G.,
Clark D.
Publication year - 1996
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/(sici)1098-2396(199603)22:3<195::aid-syn1>3.0.co;2-7
Subject(s) - excitatory postsynaptic potential , neuroscience , stimulation , bursting , midbrain , dopaminergic , prefrontal cortex , stimulus (psychology) , chemistry , biology , psychology , dopamine , inhibitory postsynaptic potential , central nervous system , cognition , psychotherapist
Evidence suggests that excitatory amino acid‐containing afferents from the prefrontalcortex (PFC) play an important role in the induction of burst firing in midbrain dopaminergic(DA) neurons. In the present study, the extracellular activity of individual DA neurons (A10and A9 cell groups) was recorded during single pulse electrical stimulation (0.25 and 1 mA)of the PFC. The majority of cells were responsive, and two main patterns of activity wereelicited: responses characterised by an initial excitation (E responses; 41.8% of responses at0.25 mA and 26.6% at 1 mA; cell groups combined) and responses characterised byexcitation following an initial inhibition (IE responses; 43.3% of responses at 0.25 mA and56.6% at 1 mA; cell groups combined). Burst analysis performed on the excitatory phase of Eand IE responses revealed that the excitation contained events which fulfilled the criteria fornatural bursts in DA neurons. A procedure was developed for assessing whether these burstswere time‐locked to the stimulus. This showed that 27.9% of E responses and 33.3% of IEresponses were accompanied by time‐locked bursts (currents and cell groups combined). It isargued that time‐locked bursts during IE responses were produced by rebound activation of alow threshold calcium conductance, whereas time‐locked bursts during E responses wereproduced by excitatory afferents. Since natural bursts in DA neurons also seem to involvecortically induced excitation, the hypothesis that the PFC plays a role in the production ofnatural bursts in DA neurons is strengthened. © 1996 Wiley‐Liss, Inc.