Biological Psychology-Lecture Slides 08-Psychology-Andrew Weeks, Slides of Biological Psychology

Download Biological Psychology-Lecture Slides 08-Psychology-Andrew Weeks and more Slides Biological Psychology in PDF only on Docsity!

8.1 Three Principles of Sensorimotor Function

8.2 Sensorimotor Association Cortex

8.3 Secondary Motor Cortex

8.4 Primary Motor Cortex

8.5 Cerebellum and Basal Ganglia

8.6 Descending Motor Pathways

8.7 Sensorimotor Spinal Circuits

8.8 Central Sensorimotor Programs

Topics

A General Model of Sensorimotor System Function

FIGURE 8.1: A general model of the sensorimotor system

• Posterior parietal association cortex
• Dorsolateral prefrontal association cortex
• Each composed of several different areas with different functions
• Some disagreement exists about how to divide the areas up

Sensorimotor Association Cortex

Apraxia Contralateral neglect

• Disorder of voluntary movement – problem only evident when instructed to perform an action – usually a consequence of damage to the area on the left. - Unable to respond to stimuli contralateral to the side of the lesion – usually seen with large lesions on the right.

Damage to the Posterior Parietal Cortex

Principles of Sensory System Organization

FIGURE 8.3:Contralateral neglect is sometimes manifested in terms of gravitationalcoordinates, sometimes in terms of object-basedcoordinates.

Secondary Motor Cortex

• Input mainly from association cortex
• Output mainly to primary motor cortex

Identifying the Areas of the Secondary Motor Cortex

FIGURE 8.5: Four areas of secondary motor cortex

At least eight different areas:

• Three supplementary motor areas (SMA and preSMA, and supplementary eye field)
• Two premotor areas (dorsal and ventral)
• Three cingulate motor areas

Principles of Sensory System Organization

FIGURE 8.6: Responses of a mirror neuron of a monkey

In monkey studies, mirror neurons fired while:

• grasping or watching another grasp a particular object but not other objects
• grasping or watching another grasp an object for a specific purpose but not for another purpose

Primary Motor Cortex

• Precentral gyrus of the frontal lobe
• Major point of convergence of cortical sensorimotor signals
• Major point of departure of signals from cortex

Current View of Primary Motor Cortex Function

• Regions of primary motor cortex support initiation of species- typical movements
• Neurons direct to target of movement, rather than simply a pre-coded direction

• Small lesions often with minimal effects
• Large lesions may disrupt a patient’s ability to move one body part independently of others
• Large lesions may also produce stereognosia - deficit in stereognosia (ability to identify an object by touch)

Effects of Primary Motor Cortex Lesions

Subject: José Delgado

Claimed a charging bull could be tamed using stimulation of its caudate nucleus

Two dorsolateral

• Corticospinal
• Corticorubrospinal Two ventromedial
• Corticospinal
• Cortico-brainstem-spinal tract Both corticospinal tracts are direct

Descending Motor Pathways