Biopsych lecture 5

Mirror neurons

What are mirror neurons?

Neurons which fire when individuals perform a motor act and when they observe a similar act being performed by others.

Rizzolati basic bits

Used single unit technology to find neurons called F5 which fired when monkeys did acts like reach/eat. Found that these also responded when another monkey did the same action. Suggests premotor cortex allows us to understand actions of others.

Rizzolati study one methodology

Looked into macaque monkeys PMC, tested on action related and non-action related sounds, presented visibly or not.

Rizzolati study two methodology.

Macaque monkeys given six actions, either with vision and sound, just vision, just sound or the monkey did the action themselves.

Findings from Rizzolati and Kohler et al

Found examples of neuron responses:

Neuron 1: sight and sound of paper tearing

Neuron 2: sound and sight of stick dropping

Neuron 3: sight and sound of peanut break

Neuron 4: strong response when breaking a peanut, need sound most.

= shows that brain area in the premotor cortex of macque monkeys activate when viewing others doing an action.

Mukamel et al study 1 method

Used single unit recordings on paitents with epilepsy. Either observed 3s video of hand grabbing a mugn (precision of whole hand grio) or just saw the words finger or hand on screen, where they had to perform the action shown to them.

Mukamel study 2 method

Two trials, either prompted by the words smile or frown and then asked to smile/frown. Or watched a video or a person smiling or frowning.

Mukamel results

Supplementary motor error responded when individuals saw whole/precision grip.

Found increased mirror neurons in medial frontal and medial temproal cortexes.

multiple parts of the brain have mirror systems.

Iacoboni et al method

Focus on autism, how individuals with autism have less recognition to understand. 11 had implicit instruc ( watch clips) explicit (pay attention to objects in clips). Shown action clips (grabbing cup in precision/whole hand grip), context clips (objects no action) or intention (grasping action shown in context)

Iacobani et al results

Found action and intention to have strong brain activity in temporal, occitipital, pariteal and frontal regions. For intention compared to action, more brain activity in visual areas, more in right inferior context area (mirror neuron area).

It is the combo of action and context which fires most mirror neurons.