Lecture 6 Flashcards
What are the three sensory tracts?
•Dorsal Columns-Medial Lemniscal Tract
•Spinothalamic (Anterolateral Tract)
•Spinocerebellar and Cuneocerebellar Tracts
What is the motor tract?
Corticospinal
What are the two pathways in the Dorsal Columns-Medial Lemniscal Tract?
•Gracile Tract
•Cuneate Tract
What does the Gracile Tract sense?
Discriminative touch and conscious proprioception for on the contralateral side for lower limbs
What does the Cuneate Tract sense?
Discriminative touch and conscious proprioception for on the contralateral side for upper limbs
What is the difference between the Gracile Tract and the Cuneate Tract?
Gracile tract senses lower limbs and the Cuneate tract senses upper limbs
How many neurons are in the Gracile Tract pathway?
Three
How many neurons are in the Cuneate Tract pathway?
Three
What pathway are the Gracile and Cuneate tracts both apart of?
The Dorsal Column-Medial Lemniscus pathway
Where do the Gracile and Cuneate tracts synapse?
At the medulla and the VPL nucleus of the thalamus
Do the gracile and cuneate tracts switch sides and if so where?
Yes they do when they synapse at the medulla
What is Conscious Proprioception?
The ability to sense the position of your body in space and to feel where your natural range of movement should take you
What are the steps in the Gracile pathway?
- Sensory information is sensed in lower limbs by the PNS and carried in the CNS by the Gracile Tract
- The Gracile Tract synapses at the medulla and switches sides
- Information is then carried up the Medial Lemniscus pathway to the VPL nucleus of the Thalamus
- It synapses at the thalamus and then information is carried to the corresponding section of the primary somatosensory cortex
What are the steps in the Cuneate pathway? (DCML)
- Sensory information is sensed in upper limbs by the PNS and carried in the CNS by the Cuneate Tract
- The Cuneate Tract synapses at the medulla and switches sides
- Information is then carried up the Medial Lemniscus pathway to the VPL nucleus of the Thalamus
- It synapses at the thalamus and then information is carried to the corresponding section of the primary somatosensory cortex
Where do the Gracile and Cuneate pathway synapse?
At the Medulla and the VPL nucleus of the thalamus
How many neurons are in the Gracile and Cuneate pathways?
Three neurons
Where do the Gracile and Cuneate pathways crossover?
At the first synapse at the medulla
What is the organization of neurons from the PNS in the Gracile and Cuneate tracts?
Neuron 1 - From PNS to Medulla
Neuron 2 - Medulla to VPL nucleus in the thalamus
Neuron 3 - VPL nucleus in the thalamus to corresponding area of primary somatosensory cortex
What side of the brain is something processed in the Dorsal Column-Medial Lemniscal Pathway sensed?
The contralateral side
What side of the brain is something processed in the Cuneate Pathway sensed?
The contralateral side
What side of the brain is something processed in the Gracile pathway sensed?
The contralateral side
Of the Gracile and Cuneate tract which one is more medial and which one is more lateral?
•Gracile is medial
•Cuneate is lateral
What would a lesion to any of the Dorsal Column-Medial Lemniscus pathways cause?
Contralateral inability to have conscious proprioception and discriminative touch
What would cause contralateral inability to have conscious proprioception and discriminative touch?
A lesion to any of the Dorsal Column-Medial Lemniscus pathway