The functional logic of corticostriatal connections

摘要: Unidirectional connections from the cortex to matrix of corpus striatum initiate cortico-basal ganglia (BG)-thalamocortical loop, thought be important in momentary action selection and longer-term fine tuning behavioural repertoire; a discrete set striatal compartments, striosomes, has complementary role registering or anticipating reward that shapes corticostriatal plasticity. Re-entrant signals traversing cortico-BG loop impact predominantly frontal cortices, conveyed through topographically ordered output channels; by contrast, input originate far broader span cortex, are more divergent their termination. The term 'disclosed loop' is introduced describe this organisation: closed circuit open outside influence at initial stage cortical input. component afferents newly dubbed 'operative', as it proposed establish bid for on part an incipient plan; converging described contextual. A corollary proposal every unit volume, including long, C-shaped tail caudate nucleus, should receive mandatory operative input, hence include least one area BG-recipient amongst sources its afferents. Individual contact twin classes GABAergic projection neuron (SPN), distinguished neurochemical character, onward circuitry. This basis classic direct indirect pathway model loop. Each utilises serial chain inhibition, with two such links, three, providing positive negative feedback, respectively. Operative co-activation SPNs is, therefore, pictured simultaneously promote action, restrain it. balance rival activity determined contextual inputs, which summarise external internal sensory environment, state ongoing priorities. Notably, distributed convergence upon locus mirror transcortical network harnessed origin locus, thereby capturing similar contingencies relevant determining action. disclosed formulation subsequent BG circuitry, advanced here, refines operating rationale allows integration recent anatomical physiological data, some can appear variance model. Equally, provides lucid functional context continuing cellular studies SPN biophysics mechanisms synaptic