Primary Sensory and Motor Cortex Quiz

Primary Sensory Cortex and Motor Cortex

• Primary sensory cortex: raw data localize and identify sensory stimuli
• Primary motor cortex: trigger and execute movement commands
• Primary motor cortex contains UPN and sends signals to LPN to trigger and modulate for execution
• Two types of association cortex: Unimodal and Multimodal

Somatosensory Cortex and Motor Association Cortex

• Somatic sensory cortex: driven by primary motor cortex due to basic muscle contraction
• Motor association cortex: integrates many sensory modalities
• Pre-motor cortex: set related and directional specific, affects contralateral limbs
• Supplementary motor cortex: responsible for formulating motor programs and level of complex movements

Basal Ganglia

• Basal ganglia: 5 interconnected nuclei (Caudate, Globus pallidus externus, Globus pallidus internus, Putamen, and Subthalamic nucleus)
• Striatum consists of Caudate and Putamen
• Lenticular nucleus consists of Putamen and Globus pallidus
• Inputs from the entire cerebral cortex project to the striatum
• Motor channel, Oculomotor channel, Prefrontal channel, and Limbic channel are the four channels of basal ganglia
• Direct pathway: acts to increase thalamus output to cerebral cortex
• Indirect pathway: acts to decrease thalamus output to cerebral cortex
• Dopamine effects: direct pathway is excited by dopamine, indirect pathway is inhibited by dopamine

Parkinson's Disease and Huntington's Disease

• Parkinson's disease: degeneration of dopamine neurons in the subthalamic nucleus, indirect pathway
• Parkinson's disease symptoms: bradykinesia, resting tremor, rigidity, postural instability
• Huntington's disease: genetic component, onset between 30-50 years, cells in indirect pathway mostly affected
• Huntington's disease symptoms: chorea, dystonia, abnormal eye movement, dementia, depression, anxiety, or OC emotional disorders

Vascular Supply and Brain Injury

• Vascular supply: Common carotid artery, External and internal carotid artery, Anterior and middle cerebral artery, Basilar artery, Posterior cerebral artery, Circle of Willis
• Vascular injury types: blockage/occlusion, hemorrhage, ruptured aneurysm, thrombus, embolism
• Symptoms dependent on the location of the block or bleed

Brain Systems for Content and Level of Consciousness

• Content of consciousness: provided by hierarchically organized sensory and motor systems, brain systems for memory, emotions, and drives
• Level of consciousness: regulated by the consciousness system
• Symptoms: alien hand, damage to corpus callosum and/or SMA area of the non-dominant hemisphere

Cerebellum

• Anatomy: major lobes (Anterior, Posterior, Flocculo-nodular), divided by Postero-lateral fissure and Primary fissure
• 4 functional regions: Vermis, Intermediate zone, Lateral, Flocculo-nodular
• Input pathways: Ipsilateral, Pontocerebellar fibers, Spinocerebellar pathways, Vestibular inputs
• Output pathways: Vermis, Intermediate, Lateral
• Lesions to intermediate hemisphere: Ipsilateral symptoms with abnormal reflexes, Pendular reflexes with ataxia, Dysrhythmia, Dysmetria, Intention tremor, Dysdiadochokinesia, Dysarthria