Cortical oscillatory dysfunction in Parkinson disease during movement activation and inhibition

Abstract

Response activation and inhibition are functions fundamental to executive control that are disrupted in Parkinson disease (PD). We used magnetoencephalography to examine event related changes in oscillatory power amplitude, peak latency and frequency in cortical networks subserving these functions and identified abnormalities associated with PD. Participants (N = 18 PD, 18 control) performed a cue/target task that required initiation of an un-cued movement (activation) or inhibition of a cued movement. Reaction times were variable but similar across groups. Task related responses in gamma, alpha, and beta power were found across cortical networks including motor cortex, supplementary and pre- supplementary motor cortex, posterior parietal cortex, prefrontal cortex and anterior cingulate. PD-related changes in power and latency were noted most frequently in the beta band, however, abnormal power and delayed peak latency in the alpha band in the pre-supplementary motor area was suggestive of a compensatory mechanism. PD peak power was delayed in pre-supplementary motor area, motor cortex, and medial frontal gyrus only for activation, which is consistent with deficits in un-cued (as opposed to cued) movement initiation characteristic of PD.

Impaired pre-synaptic plasticity and visual responses in auxilin-knockout mice

“…The unit population responses in Aux-KO mice exhibited delayed oscillation peaks, and slower oscillation frequencies, compared to the oscillations in WT. Such altered cortical oscillations were also reported in parkinsonian patients in different contexts, 70 , 71 suggesting temporally altered circuit activity. The shifted frequency of the familiarity-evoked oscillations in Aux-KO mice is similar to the previously described frequency shift in Fmr1 KO mice, which was accompanied by reduced functional connectivity between excitatory neurons and inhibitory neurons.…”

Oscillation-Specific Nodal Differences in Parkinson’s Disease Patients with Anxiety

“…A study found increased functional connectivity between the limbic system (which is involved in emotion processing) and various cortical regions in anxious PD patients compared to PD patients without anxiety [ 25 ]. Another study using magnetoencephalography (MEG) found abnormal oscillatory power and functional connectivity in the frontal cortex of PD patients [ 26 ]. These findings suggest that there may be significant oscillation-specific node differences in the brains of PD patients with anxiety, which may account for the presence and severity of anxiety symptoms in these individuals.…”