Huntington's disease (HD) is a genetic neurodegenerative disease caused by an expanded CAG-repeat mutation in exon 1 of the gene encoding huntingtin (HTT) which results in an elongated polyglutamine (polyQ) tract. A triad of symptoms encompassing cognitive, motor and psychiatric features are evident in mutant gene carriers, with typical symptom manifestation in adult life; the degeneration of the corticostriatal (CS) pathway and disruption to its connectivity partially underlie the manifestation of these symptoms. The CS pathway is composed of cortical layer V projection neurons (CPNs) and striatal medium spiny neurons (MSNs), which are the principle neuronal subtypes targeted in HD pathology. The aim of this thesis was to recapitulate the CS pathway in vitro using human cells in co-culture, in order to better understand the early pathological events that lead to its disruption in HD. Using human pluripotent stem cells (PSC) derived from an HD family and an isogenic HTT allelic series, MSN- and CPN-containing cultures expressing various HTT polyQ lengths were generated using validated methods that were then adapted and optimised for use in this thesis. HD-associated phenotypes were revealed in both cell types by using a thorough approach to phenotypical profiling. Alterations in cell viability at baseline and after stress were documented, as well as changes to neuronal morphology and adhesive function. Novel investigations into axonal projection revealed a HTT polyQ-length dependent deficiency in HD CPNs, as well as altered neurotrophin production and release. Using microfluidic chambers (MFC), a co-culture system was created to recapitulate the CS pathway. Their use showed that it is possible to culture PSC-derived neurons in MFCs, with evidence of neuronal connectivity as shown by the formation of synapses within the devices. Differences in the level of synapse maintenance suggest that this platform could be useful in further assessing the development of early CS pathology in an HD context.