Premotor Cortex plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
The Premotor Cortex (PMC), also known as Brodmann area 6 (lateral part), is a critical region of the frontal lobe located anterior to the primary motor cortex, on the lateral surface of the frontal gyrus. The PMC is fundamentally involved in movement planning, the selection of motor programs based on sensory cues, the guidance of movements through visual and somatosensory feedback, and higher-order motor functions including action understanding through mirror neuron activity [1][2]. This cortical region is significantly impacted in neurodegenerative diseases such as Parkinson's disease (PD), where it contributes to bradykinesia and movement selection deficits, and in Alzheimer's disease (AD), where it underlies apraxia and motor planning impairments. [1]
The premotor cortex occupies the lateral portion of Brodmann area 6 [3]: [2]
The PMC has distinct laminar organization: [3]
The premotor cortex comprises several functional subregions: [4]
| Region | Function |
|---|---|
| Dorsal premotor cortex (PMd) | Spatial selection, arbitrary mappings |
| Ventral premotor cortex (PMv) | Object manipulation, action understanding |
| Area F5 (monkey) | Mirror neurons, hand actions |
Major inputs:
Major outputs:
Glutamate (excitatory):
GABA (inhibitory):
| Receptor Type | Distribution | Function |
|---|---|---|
| NMDA | Pyramidal neurons | Synaptic plasticity |
| AMPA | Widespread | Fast excitation |
| GABA-A | Interneurons | Inhibition |
| D1 Dopamine | Layer III, V | Motor learning |
| D2 Dopamine | Layer I, II | Motor suppression |
The PMC is crucial for translating motor intentions into concrete motor plans [2][4]:
The PMC performs critical coordinate transformations:
The ventral premotor cortex contains mirror neurons [1][5]:
Properties:
Functions:
Unlike the SMA (internally-cued movements), the PMC:
The PMC contributes to motor learning:
| Frequency | Function |
|---|---|
| Beta (15-30 Hz) | Movement suppression, maintenance |
| Gamma (40-100 Hz) | Movement preparation, execution |
| Alpha (8-12 Hz) | Sensory gating |
PMC dysfunction in PD contributes to multiple symptoms [6][7]:
Movement Selection Deficits:
Bradykinesia:
Freezing of Gait:
Treatment Effects:
PMC involvement in AD [8]:
Apraxia:
Motor Planning Deficits:
Neuroimaging:
The PMC learns arbitrary relationships:
| Method | Application |
|---|---|
| fMRI | Localize activity during tasks |
| PET | Metabolic mapping |
| TMS | Disruption studies |
| EEG/MEG | Temporal dynamics |
[1] Rizzolatti et al., Premotor cortex and recognition (1996)
[2] Plotnik et al., Premotor cortex in Parkinson's disease (2008)
[3] Brodmann, Localisation in the cerebral cortex (1909/2006)
[4] Wise, Motor area of the cerebral cortex (1985)
[5] Gallese et al., Action recognition in the premotor cortex (1996)
[6] Jahanshahi et al., Self-initiated versus externally-cued movements in PD (2000)
[7] Thobois et al., Premotor dysfunction in PD (2000)
[8] Morrison & Hof, Changes in motor cortex in AD (2007)
Premotor Cortex plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
The study of Premotor Cortex has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
Hoshi E, Tanji J. Distinctions between dorsal and ventral premotor areas: anatomical connectivity and functional properties. 2007. ↩︎
Toni I, et al. Movement preparation and motor intention. 2001. ↩︎
Kurata K, Hoshi E. Reappraising the cortical motor areas. 2009. ↩︎
Davare M, et al. Functional organization of primary motor cortex. 2010. ↩︎