Brain Function, Discovery, Imaging and Pictures of it

What I will attempt to cover• What different parts of the brain do• Different types of brain imaging– CT (Computed tomography)– MRI (Magnetic resonance imaging)– fMRI (Functional magnetic resonance imaging)

Brain structure

Medulla oblongata• Located at the base of the brain, at the top of the spinal cord• Automatically controls breathing rate and heart rate• Contains a number of centres:

– Vasomotor centre– Cardiac centre – Reflex centres

Brain structure

Cerebellum• Located under the cereberal hemispheres• Has a folded cortex• Coordinates movement and balance

Brain structure

Hypothalamus• Located in front of the brainstem, and beneath the centre of

the brain• Maintains body temperature (thermoregulation) as well as

thirst, fatigue and sleep• Responsible for linking the nervous and endocrine system

Brain structure

Cerebral Hemispheres• The largest part of the brain, divided into two halves• Highly folded tissue• Many different functions performed by the cereberal

hemispheres including learning, emotions and vision

CT Scans(Computed tomography)

MRI scan(Magnetic resonance imaging)

• Produces a high resolution image more suitable for investigating the soft tissue of the brain

• Cross sectional images of the brain can be generated by using a very strong electromagnet

• The brain can be seen in much more detail with an MRI scan than a CT scan and with an MRI scan, an MRI scan is also useful in medical diagnosis

fMRI scan

(Functional magnetic resonance imaging)

fMRI scan(Functional magnetic resonance imaging)

• The fMRI scan can show changes in brain activity as they occur. uniquely, an fMRI allows the conditions caused by abnormal activity to be studied

• The molecules in oxygenated blood respond in different way to a magnetic field than deoxygenated blood, the more active regions of the brain can be distinguished because there will be more oxygenated blood flowing there to supply oxygen, the scanner can detect different levels of oxygenation in the blood and create an image from where that blood is in the brain

Comparison of different scanning techniquesCT MRI fMRI

Detail good V.good V.good

Ionising? Yes, X-rays not good for you

No No

What can you see?

Brain structure but not function

Brain structure but not function

Structure and function

Cost and scan speed

Cheaper and faster than MRI

and fMRI

V.Expensive equipment and lengthy process

V.Expensive equipment and lengthy process

Advantages? Most useful in imaging bones, less so for soft

tissue

Best suited for imaging soft tissue, not

particularly handy for dense material

like bones

Most useful for monitoring brain activity; where

oxygenated blood is concentrated