Problem 1
Learning Goals
To learn the brain anatomy of the parietal and occipital lobe:
- Which brain areas are located in the parietal lobe and which in the occipital lobe?
- Which are the main functions of the parietal and occipital lobe?
- What are the basal ganglia and which functions do they have?
To learn which neuropsychological disorders are associated with lesions of the parietal and
occipital lobe:
- Which neurological disorders are provoked by lesions of the parietal lobe and which
by the lesions of the occipital lobe?
- Which are the symptoms of the aforementioned neurological disorders?
TOPIC 1 – PERCEPTON AND MOTOR SYSTEMS
Chapter 9 – Organization of motor system (232-250)
Neocortex: initiating movement
- posterior cortex specifies movements goals and sends sensory information into the
frontal regions
o automatic movements take a more direct route and the premotor and
primary motor cortex execute the
action
o movements requiring conscious control
take indirect routes, the temporal and
prefrontal cortices make decisions first,
and then premotor and primary motor
cortices execute movements
- from the instructions of the posterior cortex,
the PFC generates plans for movements
- the premotor cortex (Broadmann’s area 6,
supplementary) houses a movement repertoire
-lexicon-, it recognizes other’s movements and
selects similar or different actions
- the primary motor cortex (M1 or Brodmann’s
area 4) consists of more elementary
movements including hand and mouth movements
- hierarchical control of movement:
o tap a finger: S1, M1
o sequence of finger movements: S1, M1 and premotor
o finger to navigate a maze: prefrontal, temporal and parietal
cortex
Motor homunculus (little human) by Penfield:
, - a homunculus spread out across the motor cortex
- each hemisphere contains an almost mirror image representations of this
homunculus
- also located a secondary homunculus in the supplementary premotor cortex
- motor homunculus is upside down relative to the actual body and the arrangement
of body parts is different from a real body
- it has disproportionate relative sizes compared to real sizes: large hands, especially
large thumb, large lips and tongue precise fine motor control over those
- motor map was constructed from electrical stimulation
- new technology has shown that there may be many more homunculi within the
motor and premotor cortices
- multiple representation:
o finger movements can be obtained from many points, not just one
o finger movement points also elicit movements of other parts
Natural movement categories
- stimulation elicits ethological categories of movements that monkeys use in everyday
activities e.g. hand moves to mouth and mouth opens
- but movements evoked by stimulation lack flexibility, when there’s an obstacle the
hand hits the obstacle
- many cortical maps of the body exist and each map represents a different action,
spatial location and function
- whole-body movements are represented in the pre-motor cortex and the more
discrete movements in the motor cortex
Visual-parietal motor connections
, - functional movements can be elicited from the parietal cortex too
- the motor cortex and the parietal cortex have dense anatomical connections
o sensory information about a target is sent to the motor cortex
o the visual cortex has to identify the object (extrinsic and intrinsic properties)
and its location
o the visual cortex instructs the parietal arm region about the location and hand
region about the shape
o the parietal region has sensory receptors that will be activated when the
object is contacted
o the parietal region connects to the motor cortex region that will produce
movement over descending pathways
- connections from visual to parietal to motor cortex create a dual pathway that
produce action to grasp an object
- various combinations of parietal-to-motor cortex pathways underlie the complexity
of our movements
The movement Lexicon
- humans have a lexicon, or repertoire of movement categories
- by 3 months most healthy babies start to use the pincer grip
- most primate species use the same grip
- people who have small lesions of motor cortex around the thumb region have
weakness in the thumb and the arm lesions impair coordinator action of reaching
for and grasping, not individual digit muscles
- skilled movements are encoded in neural connections as basic movement patterns,
they are not learned
- premotor and primary motor cortex share a common movement lexicon and the
repertoire of premotor cortex is more complex than M1
- damage to premotor cortex doesn’t cause muscle weakness but disrupts more-
complex movements
- premotor cortex organizes whole-body movements more than M1
- basic movements elicited in the motor cortex can be extended to other actions
through learning by recruiting neural circuitry
- experiment with monkey:
o before movements: neural activity increases in the motor cortex
Learning Goals
To learn the brain anatomy of the parietal and occipital lobe:
- Which brain areas are located in the parietal lobe and which in the occipital lobe?
- Which are the main functions of the parietal and occipital lobe?
- What are the basal ganglia and which functions do they have?
To learn which neuropsychological disorders are associated with lesions of the parietal and
occipital lobe:
- Which neurological disorders are provoked by lesions of the parietal lobe and which
by the lesions of the occipital lobe?
- Which are the symptoms of the aforementioned neurological disorders?
TOPIC 1 – PERCEPTON AND MOTOR SYSTEMS
Chapter 9 – Organization of motor system (232-250)
Neocortex: initiating movement
- posterior cortex specifies movements goals and sends sensory information into the
frontal regions
o automatic movements take a more direct route and the premotor and
primary motor cortex execute the
action
o movements requiring conscious control
take indirect routes, the temporal and
prefrontal cortices make decisions first,
and then premotor and primary motor
cortices execute movements
- from the instructions of the posterior cortex,
the PFC generates plans for movements
- the premotor cortex (Broadmann’s area 6,
supplementary) houses a movement repertoire
-lexicon-, it recognizes other’s movements and
selects similar or different actions
- the primary motor cortex (M1 or Brodmann’s
area 4) consists of more elementary
movements including hand and mouth movements
- hierarchical control of movement:
o tap a finger: S1, M1
o sequence of finger movements: S1, M1 and premotor
o finger to navigate a maze: prefrontal, temporal and parietal
cortex
Motor homunculus (little human) by Penfield:
, - a homunculus spread out across the motor cortex
- each hemisphere contains an almost mirror image representations of this
homunculus
- also located a secondary homunculus in the supplementary premotor cortex
- motor homunculus is upside down relative to the actual body and the arrangement
of body parts is different from a real body
- it has disproportionate relative sizes compared to real sizes: large hands, especially
large thumb, large lips and tongue precise fine motor control over those
- motor map was constructed from electrical stimulation
- new technology has shown that there may be many more homunculi within the
motor and premotor cortices
- multiple representation:
o finger movements can be obtained from many points, not just one
o finger movement points also elicit movements of other parts
Natural movement categories
- stimulation elicits ethological categories of movements that monkeys use in everyday
activities e.g. hand moves to mouth and mouth opens
- but movements evoked by stimulation lack flexibility, when there’s an obstacle the
hand hits the obstacle
- many cortical maps of the body exist and each map represents a different action,
spatial location and function
- whole-body movements are represented in the pre-motor cortex and the more
discrete movements in the motor cortex
Visual-parietal motor connections
, - functional movements can be elicited from the parietal cortex too
- the motor cortex and the parietal cortex have dense anatomical connections
o sensory information about a target is sent to the motor cortex
o the visual cortex has to identify the object (extrinsic and intrinsic properties)
and its location
o the visual cortex instructs the parietal arm region about the location and hand
region about the shape
o the parietal region has sensory receptors that will be activated when the
object is contacted
o the parietal region connects to the motor cortex region that will produce
movement over descending pathways
- connections from visual to parietal to motor cortex create a dual pathway that
produce action to grasp an object
- various combinations of parietal-to-motor cortex pathways underlie the complexity
of our movements
The movement Lexicon
- humans have a lexicon, or repertoire of movement categories
- by 3 months most healthy babies start to use the pincer grip
- most primate species use the same grip
- people who have small lesions of motor cortex around the thumb region have
weakness in the thumb and the arm lesions impair coordinator action of reaching
for and grasping, not individual digit muscles
- skilled movements are encoded in neural connections as basic movement patterns,
they are not learned
- premotor and primary motor cortex share a common movement lexicon and the
repertoire of premotor cortex is more complex than M1
- damage to premotor cortex doesn’t cause muscle weakness but disrupts more-
complex movements
- premotor cortex organizes whole-body movements more than M1
- basic movements elicited in the motor cortex can be extended to other actions
through learning by recruiting neural circuitry
- experiment with monkey:
o before movements: neural activity increases in the motor cortex
