• What are the three core principles of the sensorimotor system?
◦ Organization is hierarchical and parallel – association cortex is at the top and muscles are at
the bottom, processing of information occurs simultaneously in various areas of the brain
◦ Motor output is guided by sensory input
◦ Learning changes the nature and locus of sensorimotor control
• What are the two main regions of the brain used as sensorimotor association cortex?
◦ Posterior ParietalAssociation Cortex
◦ Dorsolateral PrefrontalAssociation Cortex
• What is the purpose of sensorimotor association cortex?
◦ Integrates, visual, auditory and somatosensory information
◦ Directs movement based on sensory information of the world or environment
◦ The association cortex projects to other areas of the sensorimotor cortex, including the
frontal eye field and the dorsolateral prefrontal association cortex
◦ Apraxia is the inability to initiate voluntary movement in isolation
◦ Behaviours that are part of a practiced or well-known sequence can still be performed as
part of the sequence
• Define Contralateral Neglect
◦ Contralateral neglect is the inability to respond to stimuli presented on one side of the body
◦ Typically contralateral neglect prevents individuals from perceiving stimuli on the left side
and is caused by damage on the right side of the brain
◦ Contralaternal neglect occurs according to gravity coordinates (ie. The stimuli not perceived
are not different when the head is tilted compared to when the head is straight) and also
according to object coordinates (ie. The left half of stimuli are often not perceived, even
when presented in the right half of the visual field)
• What is the function of the dorsolateral prefrontal cortex? Where does it project to and get its
◦ The dorsolateral prefrontal cortex is involved in evaluating stimuli and initiating voluntary
◦ The dorsolateral prefrontal cortex projects to the primary motor cortes, secondary motor
cortex and the frontal eye fields
◦ The dorsolateral prefrontal cortex receives input from the posterior parietal cortex
• How is the secondary motor cortex divided?
◦ Secondary motor cortex is comprised of over 8 different regions in the brain
◦ There are 3 supplementary areas of the secondary motor cortex (Supplementary MotorArea,
Pre-supplementary MotorArea and Supplementary Eye Field)
◦ There are 3 premotor areas of the secondary motor cortex
◦ There are 2 areas of cingulate motor cortex
• What are mirror neurons and why are they important? Is there evidence that mirror neurons
exist in humans? Why or why not?
◦ Mirror neurons are neurons that are activated either when an action is seen performed by
another or when the action is performed by the self
◦ Mirror neurons are important because they are a potential biological basis for social
◦ There is indirect evidence of the existance of mirror neurons in humans ▪ fMRI data suggests mirror neurons may exist in humans
▪ Mirror neurons have been identified in primates
• Where is the primary motor cortex and what is its function?
◦ The primary motor cortex is located at the pre-central gyrus of the frontal lobes
◦ The primary motor cortex is a major area of convergence for sensorimotor signals from the
◦ Primary motor cortex is a major point of departure for descending motor signals
• What is the motor hummunculus and how is it laide out?
◦ The motor hummunculus is the somatotopic layout of the primary motor cortex
◦ Muscles that are close together in the body are represented in adjacent portions of the
primary motor cortex
◦ Ares of the body that require more fine motor control (ie. Hand and lips) have larger
portions of the primary motor cortex devoted to them
• How has our understanding of neuronal functioning in the primary motor cortex changed since
the beginning of its study?
◦ Scientists used to believe that each individual neuron in the primary motor cortex encoded a
specific direction of movement
◦ Now believed that neurons in the primary motor cortex do not code specific motor
directions, but rather initiate species-common behaviour and well-learned sequences of
◦ Neurons code instead for the target of the movement, rather than the specific direction the
movement is being guided in
• What is the effect of lesions in the primary motor cortex?
◦ Small lesions in the primary motor cortex often do not produce severe motor impairments,
particularly if the lesions are unilateral
◦ Larger lesions may cause an inability to move specific body parts independently of others
◦ Lesions can also produce astereognosia, the inability to recognize objects by touch
• What three functions do the cerebellum and basal ganglia share in terms of motor control?
◦ Both are involved in directing and coordinating movement as it is occurring
◦ Both interact with varying levels of the motor hierarchy to refine movement
◦ These areas of the brain may allow for visually guided movement in individuals who cannot
see due to cortical damage
• What is the cerebellum's function? Where does it receive input from?
◦ The cerebellum comprises 10% of the brain's volume but contains over 50% of the brain's
◦ It is involved in coordinating movement and controlling precise or timed movements.
◦ Involved in motor learning and may play a role in cognitive learning as well
◦ Receives input from primary and secondary motor cortices as well as from brain stem and
• What is the basal ganglia and what is its function? Where does it send and receive input?
◦ The basal ganglia is a collection of homogenous nuclei
◦ Receive input from various cortical locations and sends output to the rest of the brain via the
◦ Modulates motor functioning and may do the same for cognitive functioning
• What are the two categories and four pathways of descending motor control?
◦ Two dorsolateral pathways ▪ Corticospinal tract
▪ Corticorubrospinal tract
◦ Two v