HOW HAVE THE FUNCTIONS OF THE REGIONS OF THE BRAIN BEEN DISCOVERED? Simeon Kirov

Parts of the Brain Cerebrum/Cortex Cerebellum Hypothalamus Medulla Oblongata Pons

History of Neuroscience Edwin Smith Surgical Papyrus – 17 th century BC Pythagorean Alcmaeon of Croton theorises that the brain is where the mind is located – 6 th century BC Ancient Egyptians discover and distinguish between different parts of the brain – 4 th century BC onwards Romans begin experimenting on the brain which furthers human knowledge – 1 st century AD

History of Neuroscience (continued) No real development in neuroscience for a long time until Leonardo da Vinci and Thomas Willis Invention of microscope triggered a vast development in research and understanding in neuroscience Neuron doctrine – 19 th century

Cerebrum/Cortex Largest part of the brain – associated with thought and action Divided into 4 sections called ‘lobes’ Frontal lobe Parietal lobe Temporal lobe Occipital lobe Highly wrinkled to increase surface area as well as number of neurons within it

Cerebrum/Cortex Functions of the cerebrum include: Movement Sensory Processing Olfaction Language and communication Learning and memory

Cerebellum The ‘little brain’ Similar in structure to the cerebrum Mainly associated with the coordination of movement, posture and balance Also involved in regulating emotions, such as fear, or pleasure responses

Hypothalamus Located below the thalamus – the size of an acorn Two main functions are to link the endocrine and nervous systems and to maintain the internal environment of the body – this is called homeostasis

Medulla Oblongata Continuation of the spinal cord Houses the regulatory centres of the body – includes breathing and heart rates Also involved in reflex actions

CT scans Computerised Axial Topography scans Involves a series of narrow X-ray beams being fired at the body and detecting different soft tissues Produces a cross-sectional view of the interior of the body

Advantages of CT scans CT scans are much faster than MRI scans Can be obtained at considerably smaller cost than MRI Easier to perform on claustrophobic patients Provides detailed evaluation of cortical bone Can be performed with no risk on patients with implantable devices such as pacemakers, nerve stimulators, etc.

MRI scans Magnetic Resonance Imaging Can accurately map precise parts of a healthy brain Uses a very strong magnet to produce detailed images Radio waves 10,000 to 30,000 stronger than the magnetic field of the earth are sent through the body

Advantages of MRI scans MRI does not use ionising radiation, meaning it is more preferable in kids or patients who need multiple examinations Has a much greater range of soft tissue contrast – depicts anatomy in greater detail and is more sensitive to specific abnormalities in the brain itself MRI contrast agents have a considerably smaller risk of causing potentially lethal allergic reactions Allows the evaluation of structures that may be obscured by artifacts from bone in CT images

fMRI scans Functional Magnetic Resonance Imaging Measures brain activity by detecting changes associated with blood flow

Comparing MRI and fMRI scans MRI views the anatomical structure while the fMRI views the metabolic function MRI studies the water molecule’s hydrogen nuclei whereas an fMRI calculates the levels of oxygen fMRI is yet to be introduced for diagnostic purposes and is only used in experiments unlike the MRI fMRI is more expensive than the MRI because of the additional software and hardware required for it

Worksheet 1. What are the 4 lobes of the cerebrum? (4) 2. Describe how a CT scan works, using the diagram below to help.(3) 3. Which region of the brain is associated with homeostasis?(1) 4. Explain the need for the medulla oblongata. (3) 5. Compare the CT scanner and the MRI scanner by giving 2 advantages for each method.(4)