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The neostriatum is the largest component of the basal ganglia, and the main recipient of afferents to the basal ganglia from the cerebral cortex and thalamus. Studies of the cellular organization of the neostriatum have focused upon the spiny projection neurones, which represent the vast majority of neurones, but the identity and functions of interneurones(More)
In vivo intracellular recordings of spontaneous activity of neostriatal spiny cells revealed two-state behavior, i.e., characteristic shifts of membrane potential between two preferred levels. The more polarized level, called the Down state, varied among neurons from -61 to -94 mV. The more depolarized level, called the Up state, varied among neurons form(More)
1. Spontaneous fluctuations of membrane potential, patterns of spontaneous firing, dendritic branching patterns, and intracortical and striatal axonal arborizations were compared for two types of corticostriatal neurons in the medial agranular cortex of urethan-anesthetized rats: 1) pyramidal tract (PT) cells identified by antidromic activation from the(More)
Individual neostriatal-matrix spiny neurons were stained intracellularly with biocytin after intracellular recording in vivo, and their axons were traced into the globus pallidus (GP), entopeduncular nucleus (EP), and/or substantia nigra (SN). The locations of the neurons within the matrix compartment of the neostriatum (NS) were established by(More)
Intracellular recordings were made in vivo from 9 giant aspiny neurons in the neostriatum of urethane-anesthetized rats. The cells were identified by intracellular staining with HRP or biocytin. The neurons exhibited morphological features typical of neostriatal cholinergic interneurons. Six of the cells were obtained from intact animals, while 3 were(More)
1. The morphology, electrical membrane properties, and corticostriatal excitatory postsynaptic potentials (EPSPs) of two groups of neostriatal projection cells, patch cells, and matrix spiny cells were compared in the rat by the use of an in vitro slice preparation that preserves inputs from medial agranular cortex. Spiny cells were stained intracellularly(More)
Dendritic spines of rat neostriatal neurons were examined by light microscopy and high voltage stereo electron microscopy (HVEM) following selective staining by intracellular microinjection of horseradish peroxidase. Conventionally prepared material also was used for quantitative analysis of dendritic spines from serial thin sections of neostriatum. Stereo(More)
Many of the nonlinear membrane properties displayed by neostriatal spiny projection neurons are conferred by their voltage-gated potassium (K+) currents, including an inwardly rectifying current (IKir), fast (IAt), and slowly (IAs)-inactivating A-currents, and a slow, noninactivating current. The relative contribution of these K+ currents to the pronounced(More)
1. Neostriatal spiny projection neurons display a prominent slowly depolarizing (ramp) potential and long latency to spike discharge in response to intracellular current pulses. The contribution of a slowly inactivating A-current (IAs) to this delayed excitation was investigated in a neostriatal slice preparation using current pulse protocols incorporating(More)
Spontaneous firing patterns of 94 unidentified neurons and 34 identified spiny neurons were compared in the neostriatum of locally anesthetized immobilized rats. Intracellular and extracellular recordings were analyzed using first order interval histograms and autocorrelograms, and neurons were identified by their somatodendritic morphology after(More)