MOTOR CORTEX Flashcards
Primary motor area
- … distribution
- The firing rate de of each individual neuron correlates with the … exerted
- The kinematic of the movement is coded in M1 (primary motor cortex) by a …, not by single neurons
- somatotopic (IT IS PLASTIC)
- muscle force
- neuronal population
Primary motor cortex is BA…
4
Posterior parietal cortex is BA…
5-7
Supplementary motor area and premotor cortex are BA…
6
The direction of the movement is coded in M1 by a … ,not by a single neuron
population of neurons
Primary motor cortex vascularization
Leg area: anterior cerebral artery
Arm and face: branches of middle cerebral artery
IMPORTANCIA CLÍNICA
Secondary motor areas
- In secondary areas, neurons can discharge during the … movement
- They are more related to … than to a determined kinematic (writing)
- preparation of
- specific tasks (complex tasks, not simple movements as primary motor cortex)
Afferences to the motor cortex: primary motor cortex
Receives info from: cerebellum (by means of thalamus nuclei), S1, posterior parietal area, (area 5), secondary motor areas.
Afferences to the motor cortex: secondary motor areas
Receive info from: cerebellum, BASAL GANGLIA (involved in movement preparation), parietal area and prefrontal cortex
Supplementary motor area
• Participates in the preparation of … movements, particularly if they are bimanual and/or complex
• Receives afferences from the motor circuit of the…
• It is the main origin of the …
• Its bilateral lesion causes…
- self-initiated (different from stimulus-induced movements: clapping hands when they tell you, grab the keys when someone throws them to you)
- basal ganglia
- premovement potential
- akinesia: you do not make any spontaneous movement, unless there is an stimulus (someone throws a ball to you). But there is no self-initiated movement.
The premotor cortex participates in movements induced by …
It also participates in the control of axial and
proximal…
- The … is also involved in retarded actions
- The … is involved in the adaptation of the hand to the shape of grasped objects
external stimuli (associative)
muscles
- dorsal lateral premotor area
- ventral lateral premotor area
The posterior parietal cortex is responsable of transforming … into motor orders
visual information
- Pre-SMA is a region located just anterior to the SMA (projecting on it), without clear somatotopy, that participates in …
- When learning advances, the highest activation level goes from … (execution).
- motor learning
- pre-SMA to SMA and to MI
The mirror system
• Group of neurons that are activated both by the ….
• In the monkey these neurons are mainly located in the …(equivalent to Broca in humans)
- execution of a movement and by the observation of that same movement (un bebé repitiendo “papá” por qué su padre lo exagera)
- ventral premotor area
Mirror system might be malfunctioning in people with…
Autism (they do not recognise people’s emotions)
CORTICOSPINAL PATWHAY
- Betz piramidal cells from M1 just account for a 3% of the total amount of axons, even though their axons have … (70 m/s)
• In the tract there are axons coming from neurons in … (40%), … (30%) and … (30%)
• There are direct and indirect synapses (through …) on the spinal motor neurons
• Lesion of the corticospinal tract: loss of … (fingers)
- the highest conduction velocities
- M1, premotor areas, parietal areas
- inteneurons
- precision movements, but you do not lose the ability to move (you do not lose force). You would lose force if you damage the 2nd motor neuron, and not the 1st.
If we damage corticospinal pathway we get… reflexes
Exaggerated
FIRST MOTOR NEURON
- Localized in the…
- Axon: …
- Synapse with the second motor neuron in the…
- Its lesion causes: … (IMPORTANT)
- cortex
- Corticospinal pathway
- anterior horn of the spinal cord
- Spasticity, Hypereflexia, Normal strength, but loss of fine movements
SECOND MOTOR NEURON
- Localized in the …
- Axon: …
- Synapse with…
- Its lesion causes:…
- anterior horn of the spinal cord
- Motor nerve
- muscle fibers (motor unit)
- Hypotonia or atonia, Hyporeflexia, Loss of strength
Cortico-nuclear pathway
Bilateral projections, with exceptions:
- Lower part of the face (CL)
- Genioglossal muscle (CL)
– Soft pallate and uvula (CL)
– XI cranial nerve (IL)
An aneurysm in the anterior cerebral artery may cause problems that affect ….
The leg (due to the Somatotopic organization of the primary motor cortex)
An aneurysm in the middle cerebral artery may cause problems that affect….
Face, eye, arms… (due to the Somatotopic organization of M1)
Cerebellum mainly projects to the … motor cortex.
1ary, for movements to be precise (it then goes to the VL and VPL nuclei of the thalamus)
Basal ganglia are involved in preparatory processes, so they mostly provide inputs to the … motor areas, reaching later on the thalamus (VPL and VA nuclei)
2ary
Self initiated movements are carried out by…
Supplementary motor area
Dancing to music or doing something on the count of 3 is controlled by …
Premotor cortex
Catching a ball when it is being thrown at me is carried out by the…
POSTERIOR PARIETAL AREA (transforming visual info into motor responses)
Corticospinal tract decussates …
At the level of the pyramids in the medulla
The corticospinal pathway activates some neurons while inhibits others, this can be seen during the …
PATELLAR REFLEX: while the quadriceps contract, the ischiotibial muscles relax
A lesion in the corticospinal tract manifests mainly as…
A LOSS OF MOVEMENT PRECISION, but we still preserve force movements + REFLECTS BECOME HEIGHTENED
Exacerbated reflexes (hyperreflexia) (CLONUS) might be caused due to a lesion in…motor neuron
The first
Loss of precision in voluntary movements might be caused due to a lesion in the … motor neuron
Upper (1st)
Spasticity might be caused due to a lesion in the … motor neuron
1st
Reflexes might be abolished due to a lesion in the … motor neuron
2nd
If there is NO basal muscle tone, there might be a lesion in the… motor neuron
Secondary
Muscle atonia (loss of strenght) might be caused due to a lesion in the … motor neuron
2nd
The vestíbulospinal tract has direct projections from the vestibular nuclei to…
Axial muscles (in order to keep balance)
Drawing on the blackboard, we need adjustments of more proximal muscles in the upper limb in order to keep the arm up and allow the rest of the distal limb to perform a movement correctly. The … tract aids in this
rubrospinal
RUBROSPINAL TRACT
Projections from the … in the midbrain to the spinal cord.
The … receives … fibres from the cerebellum.
The fibres exiting from it go to the cortex, others go to the spinal cord: they mostly go to the …, and thanks to the inputs received from the cerebellum, helps make the necessary adjustments to do movements with our … .
red nuclei
red nucleus, superior cerebellar peduncle
upper limb , hands
RETICULOSPINAL TRACT
The cerebellum connects with …, and then fibers from it descend to the spinal cord. Involved in …
Reticular nuclei in the brainstem, posture control and axial muscle adjustments.
Ascending (blue) and descending (red) pathways in the spinal cord
Medial brainstem pathways are more related to…
Posture and balance
The right glossal muscle moves the tip of the tongue to the …, the left glossal muscle moves the tip of the tongue to the…
left, right
(pensar que - y- es +: el nervio que sale del núcleo izquierdo decusa para inervar el músculo derecho, pero luego la función normal de ese músculo es hacer que la lengua protruya hacia la izquierda, por lo que es como si no hubiese cruzado)
CORTICONUCLEAR PATHWAY: LESION IN THE XII CN
- A peripheral lesion: the tongue will deviate to the …
- Central lesion: the tongue will deviate to the …
- SAME SIDE OF THE LESION
- OPPOSITE SIDE OF THE LESION
If there is a central lesion in the CORTICONUCLEAR PATHWAY, the uvula would move … the side of the lesion and the tongue would move … the side of the lesion.
towards, away
(This is because of how the glossal muscles moves the tongue)
Other motor pathways originated in the cortex
Corticorubral tract
Corticoreticular tract
Corticopontocerebellar tract
BRAZO ANTERIOR CÁPSULA INTERNA
Radiaciones talámicas anteriores y haz frontopontino
RODILLA DE LA CÁPSULA INTERNA
Haz corticonuclear
BRAZO POSTERIOR DE LA CÁPSULA INTERNA
CORTICOSPINAL PATHWAY
MOTOR PATHWAYS TO THE SPINAL CORD
Corticospinal tract
Rubrospinal tract
Vestibulospinal tract
Reticulospinal tract
Olivospinal tract
Tectospinal tract
Adjustment of upper limb (flexors) position in relation to balance and body support is mainly carried out by…
RUBROSPINAL TRACT (mostly crossed)
Postural adjustments to keep balance is carried out by…
VESTIBULOSPINAL TRACT (medial: bilateral; lateral: direct)
Helping in balance control is carried out by…
Reticulospinal tract (bilateral or direct), mainly lower limbs
Adjustment of head position in connection
with visual stimuli is mainly carried out by…
Tectospinal tract (mostly crossed)
