Corticostriatal connectivity and its role in disease

Abstract

Corticostriatal projections are essential components of forebrain circuits widely involved in motivated behavior. These axonal projections are formed by two distinct classes of cortical neurons, intratelencephalic (IT) and pyramidal tract (PT) type neurons. Convergent evidence points to IT/PT differentiation of the corticostriatal system at all levels of functional organization, from cellular signaling mechanisms to circuit topology. There is also growing evidence for IT/PT imbalance as an etiological factor in neurodevelopmental, neuropsychiatric, and movement disorders – autism, amyotrophic lateral sclerosis, obsessive-compulsive disorder, schizophrenia, Huntington’s and Parkinson’s diseases, and major depression are highlighted here.

Mouse Intracerebral Hemorrhage Models Produce Different Degrees of Initial and Delayed Damage, Axonal Sprouting, and Recovery

“…Both lesions targeted the dorsolateral striatum, the site of sensorimotor system function. 20,21 However, although these lesions overlap across animals in their location within the dorsolateral striatum of the mouse, their precise anatomic positions were not matched.…”

“…19 It is also a site of termination of axonal projections from cortex and a passage point where cortical projections pass through to thalamus, brainstem, and spinal cord. 20,21 Intracranial hemorrhage damages these connections. 22 The degree of loss of cortical projections to or through the striatum was measured by back-labeling all of the cortical axons that project to the site of the ICH with the axonal tracer CTb, within the collagenase or blood injection, and then measuring the retrogradely labeled cell bodies.…”

“…In human and rodent ICH, the hemorrhage site is in the region of motor cortex projections within the ipsilateral hemisphere and from the ipsilateral hemisphere to contralateral cortex and striatum, 21 . The anatomical tracer BDA was injected into forelimb motor cortex 24 8 weeks after ICH.…”

Striatal cholinergic interneurons generate beta and gamma oscillations in the corticostriatal circuit and produce motor deficits

“…It is possible that unilateral stimulation of SChIs could engage not only the ipsilateral CBT loop but also the contralateral CBT loop through M1 bilaterally projecting intratelencephalic neurons (36). Alternatively, because both ACh and glutamate are released from SChIs (37) and can potentially activate both D1 and D2 populations of MSNs, it is also possible that the direction of rotation depends on the relative excitation level of these two populations.…”

The Crossed Projection to the Striatum in Two Species of Monkey and in Humans: Behavioral and Evolutionary Significance

“…McGuire et al (1991) described, in the rhesus monkey, a crossed projection to n caudatus and putamen from prefrontal cortex and the supplementary motor area (SMA). The existence of crossed cortico-striatal projections is well documented in the rodents (Carman et al 1965;Wilson 1987;Morishima and Kawaguchi 2006;Alloway et al 2009;Shepherd 2013) but somewhat neglected in primates (Lieu and Subramanian 2012). Given the current enhanced interest in the striatal and corticostriatal functions (Kress et al 2013;Smith and Graybiel 2013;Stephenson-Jones et al 2013;Znamenskiy and Zador 2013;Reig and Silberberg 2014) also related to their role in psychosis (Koch et al 2014;Burguière et al 2014;Nakamae et al 2014), we reinvestigated the crossed cortico-striatal connections using modern histological tract tracing in the monkey as well as diffusion tractography (DT) in monkeys and human.…”