Organisation of the Motor System

Question 1

How do we know about the organisation of the motor cortex?

Answer 1

1870’s - electrical stimulation of a dog’s cortex produced movement of mouth, limbs and paws

1930’s - Penfield - electrical stimulation to map human patients who were about to have surgery, confirmed role of motor cortex in producing movement in humans

Question 2

What is the organisation of the motor cortex?

Answer 2

Homunculus - little person
Representation of the human body in the sensory or motor cortex, also any topographical representation o the body by a neural area

Topographic organisation - spatial representation of the body or areas of the sensory world perceived by a sensory organ. Parts of the motor cortex that control the hands, fingers, lips and tongue are larger than parts that control other areas - map know we need to devote lots to ares

Question 3

What indicated a more detailed map?

Answer 3

Monkey work using more precise, smaller electrodes

Question 4

What is there in the motor cortex?

Answer 4

Many maps of the body, each representing somewhat different movements. Parts in space in which an action is to take place - and function it is intended to perform

Question 5

What did Graziano find?

Answer 5

Used more precise stimulation - electrical stimulation in non human primates elicits recognisable actions - movement categories have the same end regardless of the location of the monkeys limb or its ongoing behaviour

Motor cortex doesn’t just control simple movement, controls more complex actions

Question 6

What does the motor cortex represent?

Answer 6

3 types of organisation
part of the body that is to be moved
spatial location to which the movement is directed
the movements function