Local and afferent synaptic pathways in the striatal microcircuitry
Section snippets
Striatal neuron types
The striatum consists of a majority of projection neurons, the medium spiny neurons (MSNs) and a small, yet diverse population of interneurons. Interneurons were initially divided into four subtypes, including three types of GABAergic interneurons, and the tonically active cholinergic interneurons [1, 2]. These electrophysiologically defined subtypes also fitted a molecular profile based on immunostaining for markers such as parvalbumin (PV), calretinin (CR), somatostatin (SOM), and
Striatal interneuron connectivity
Striatal interneurons of the different types are instrumental in sculpting striatal output via intrastriatal synaptic connections. Perhaps the most prominent of the intrastriatal synapses are the GABAergic synapses formed between FS interneurons and MSNs [16] (Figure 1). These synapses are characterized by a very high connection probability, with each FS interneuron contacting a majority of its neighboring (within ∼100 μm radius) MSNs [17]. A single FS-MSN IPSP is sufficient to alter the
Striatal afferents
The striatum acts as a hub upon which numerous streams of information converge from different brain regions, mediated by different types of neurotransmitter. In recent years several new pathways have been discovered and characterized that are likely to have profound effects on the flow of information through the striatum (Figure 2).
Conflict of interest statement
Nothing declared.
References and recommended reading
Papers of particular interest, published within the period of review, have been highlighted as:
• of special interest
•• of outstanding interest
Acknowledgements
We thank Sten Grillner, Andrew Sharott, and Natalie Doig for comments on early versions of the manuscript. This work was supported by the Medical Research Council UK, the European Research Council, the Knut & Alice Wallenberg Foundation, and the Karolinska Institutet Strategic research program in Neuroscience (StratNeuro).
References (62)
- et al.
Striatal interneurones: chemical, physiological and morphological characterization
Trends Neurosci
(1995) - et al.
Functional diversity and specificity of neostriatal interneurons
Curr Opin Neurobiol
(2004) - et al.
Distinct developmental origins manifest in the specialized encoding of movement by adult neurons of the external globus pallidus
Neuron
(2015) - et al.
Rapid target-specific remodeling of fast-spiking inhibitory circuits after loss of dopamine
Neuron
(2011) - et al.
Target selectivity of feedforward inhibition by striatal fast-spiking interneurons
J Neurosci
(2013) - et al.
Differential innervation of direct- and indirect-pathway striatal projection neurons
Neuron
(2013) - et al.
Whole-brain mapping of inputs to projection neurons and cholinergic interneurons in the dorsal striatum
PLOS ONE
(2015) - et al.
Cell-specific spike-timing-dependent plasticity in GABAergic and cholinergic interneurons in corticostriatal rat brain slices
J Physiol
(2008) - et al.
Dopaminergic axons in different divisions of the adult rat striatal complex do not express vesicular glutamate transporters
Eur J Neurosci
(2011) - et al.
Single nigrostriatal dopaminergic neurons form widely spread and highly dense axonal arborizations in the neostriatum
J Neurosci
(2009)
A dopaminergic axon lattice in the striatum and its relationship with cortical and thalamic terminals
J Neurosci
Electrophysiological and morphological characteristics and synaptic connectivity of tyrosine hydroxylase-expressing neurons in adult mouse striatum
J Neurosci
Anatomical and electrophysiological changes in striatal TH interneurons after loss of the nigrostriatal dopaminergic pathway
Brain Struct Funct
Are striatal tyrosine hydroxylase interneurons dopaminergic?
J Neurosci
A novel functionally distinct subtype of striatal neuropeptide Y interneuron
J Neurosci
Complex autonomous firing patterns of striatal low-threshold spike interneurons
J Neurophysiol
Spontaneous activity of neostriatal cholinergic interneurons in vitro
J Neurosci
Relationships between the firing of identified striatal interneurons and spontaneous and driven cortical activities in vivo
J Neurosci
The largest group of superficial neocortical GABAergic interneurons expresses ionotropic serotonin receptors
J Neurosci
Three groups of interneurons account for nearly 100% of neocortical GABAergic neurons
Dev Neurobiol
Novel striatal GABAergic interneuron populations labeled in the 5HT3aEGFP mouse
Cereb Cortex
Novel fast adapting interneurons mediate cholinergic-induced fast GABA IPSCs in striatal spiny neurons
Eur J Neurosci
Brain structure. Cell types in the mouse cortex and hippocampus revealed by single-cell RNA-seq
Science
Inhibitory control of neostriatal projection neurons by GABAergic interneurons
Nat Neurosci
Dynamics of synaptic transmission between fast-spiking interneurons and striatal projection neurons of the direct and indirect pathways
J Neurosci
Feedforward inhibition of projection neurons by fast-spiking GABA interneurons in the rat striatum in vivo
J Neurosci
Distinct roles of GABAergic interneurons in the regulation of striatal output pathways
J Neurosci
Differential connectivity and response dynamics of excitatory and inhibitory neurons in visual cortex
Nat Neurosci
Pyramidal cell communication within local networks in layer 2/3 of rat neocortex
J Physiol
Dense, unspecific connectivity of neocortical parvalbumin-positive interneurons: a canonical microcircuit for inhibition?
J Neurosci
Fine-scale specificity of cortical networks depends on inhibitory cell type and connectivity
Nat Neurosci
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