Research on Brain Structure and

Function

SYLLABUS STATEMENTS:

• Animal Research to develop research techniques

• Application of Techniques for Brain Injury treatment and understanding brain functions.

• Use of Case Studies

Video Clip: Importance of Animal Research

• Catalyst Program – ABC

• Research on use of motivation and electrical stimulation to treat and manage spinal injuries in lab rats.

ANIMAL RESEARCH – led to development of techniques for treatment of brain disorders and human brain researchABLATION – surgical removal of (brain) tissue.

Techniques: laser vaporisation, incision or chemical erosion.

Technique was first practiced and standardised by Karl Lashley (1890-1958).

Karl Lashley made ablations on the cerebral cortex of rats to determine localized areas for memory and learning (‘engrams’).

Lashley found that memory and learning was widespread and delocalized throughout the cortex.

Animal Research used to develop techniques for treating brain injury:

LESIONS – damage to (brain) tissue as a result of disease or wounding.

Some Examples of Lesion technique used in Animals:

1. Lesioning the hypothalamus in rat’s brain reduced eating, causing the rat to starve itself.

2. Lesions in the amygdala of a rhesus monkey resulted in loss of any aggressive behaviour.

Lesions in the Brain causing uncontrollable tremors, seizures:

Roger Sperry (1913-94)

• Received the Nobel Prize in Physiology and Medicine (1981) for his Split Brain studies (p17-18).

Split Brain studies led to a surgical technique for treating epileptic patients. Part of the corpus callosum is cut to prevent excessive neural impulse travel between left and right hemispheres.

See Also Split Brain Experiments (Roger Sperry):http://www.nobelprize.org/educational/medicine/split-brain/splitbrainexp.html

Electrical Stimulation

(Definition) Neural activity is altered by applying a small electrical current to a specific area of the brain/nervous system.

Some Examples of Animal Studies:

1. Electrical stimulation to specific areas of the cortex of dogs could make specific body parts move.

2. Electrically stimulating a region of a rat’s hypothalamus made the rat come back for more stimulation – discovery of a pleasure/reward centre.

Significance of Animal Research to Understanding the Anatomy and

Physiology of the Brain•Similarities between animal and human brains means that studying animal brains allows us to make predictions and inferences about the functioning of the brain and behaviour in humans.•Study of animal brains has furthered what we know and understand about behaviour and brain functions such as visual perception, sleep, motor skills, motivation, attention, reproductive behaviour, avoidance behaviour in humans•Experiments on humans might not have been given ethical approval, so if this research on animals was not done, it might mean that certain discoveries might not have been made.

Significance of Animal Research to Understanding the Anatomy and

Physiology of the Brain

•Researchers can manipulate/control the environment of animals to study the effects of these changes on behaviour•The shorter life spans of many animal species that are used in research mean that experimenters can study changes related to ageing much more easily.•The simplified nervous system of some animals can be used to study basic processes more easily, which can then be generalized to humans.

Case Study: Awake Brain Surgery to remove brain tumors

Case Study: Deep Brain Stimulation to treat Essential Tremor condition

Use of Case Studies

• Clinical study of patients who have suffered brain injury. (e.g. Brain Damage Registry (>1500 entries, University of Iowa)

LIMITATIONS:

• Individual responses cannot be generalized to wider population

• Brain plasticity masks behavioural consequences of injury due to other parts of the brain taking over the functions of damaged area.

Ethical Issues to Consider with Case Studies:

Role of the Researcher:

• DO NO HARM, BENEFICENCE

Benefits to the person must outweigh the risks

Participant’s Rights:

• INFORMED CONSENT

• WITHDRAWAL RIGHTS

• CONFIDENTIALITY, ANONYMITY

Links to videos and interactive sites:

http://www.nobelprize.org/educational/medicine/split-brain/splitbrainexp.html

Split Brain Experiments (Roger Sperry):

Awake Surgery to remove brain tumors:http://www.youtube.com/watch?v=0KwYdtX21iI

Deep Brain Stimulation: http://www.youtube.com/watch?v=ksjHNbb6NFQ