Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive loss of dopaminergic neurons in the substantia nigra pars compacta, leading to significant motor and non-motor symptoms. Beta oscillations in cortical areas are a pathognomonic sign. Here we ask whether these oscillations can be recorded in in vitro cortical tissue despite severing the cortico-basal ganglia-thalamo-cortical loop. M1/M2 cortex of hemi parkinsonian mice (6-OHDA) was recorded with multielectrode arrays (MEAs). Spectral decomposition analysis shows a significantly augmented beta band power with respect to controls. The administration of L-DOPA diminished this exacerbated beta rhythm. This result suggests that plastic changes induced by dopamine (DA) depletion remain in isolated cortical tissue even when the complete circuit is no longer present. This finding brings the opportunity to test anti-parkinsonian drugs in vitro by quantifying cortical beta band power.