Introduction to the brain and Introduction to the brain and behaviourbehaviour

Amazing brain factsAmazing brain factsCerebral cortexCerebral cortex

Cerebral hemispheresCerebral hemispheresCorpus callosumCorpus callosum

Amazing brain factsAmazing brain facts

Your skin weighs twice as much Your skin weighs twice as much as your brain.as your brain.Your brain uses 20% of total Your brain uses 20% of total oxygen pumping around your oxygen pumping around your body.body.750ml of blood pumps through 750ml of blood pumps through your brain every minuteyour brain every minuteIt consists of 100 billion neurons.It consists of 100 billion neurons.Time until unconsciousness after Time until unconsciousness after loss of blood supply to brain is 8 – loss of blood supply to brain is 8 – 10 secs.10 secs.Approximately 75% of it is water.Approximately 75% of it is water.If you could harness the power If you could harness the power used by your brain you could used by your brain you could power as a 10 watt light bulb!power as a 10 watt light bulb!

Male brainMale brain

Female brainFemale brain

Cerebral cortexCerebral cortexIt is the convoluted or folded outer It is the convoluted or folded outer layer or covering of the two layer or covering of the two hemispheres.hemispheres.

It is around 2mm thickIt is around 2mm thick

It contains ¾ of the entire brain’s It contains ¾ of the entire brain’s neurons.neurons.

Its bulges and grooves account for Its bulges and grooves account for the increased surface area.the increased surface area.

It is involved with information It is involved with information processing activities such as processing activities such as perception, language, learning, perception, language, learning, memory, thinking, problem solving, memory, thinking, problem solving, control of voluntary body control of voluntary body movements.movements.

The cerebral cortexThe cerebral cortex

It is believed that the size of a It is believed that the size of a species’ cerebral cortex is species’ cerebral cortex is linked to intellectual ability.linked to intellectual ability.

The bigger the cerebral cortex, The bigger the cerebral cortex, the more capable the organism the more capable the organism is of intelligent behaviour such is of intelligent behaviour such as thinking, problem solving as thinking, problem solving and decision making.and decision making.

Homer Simpson’s BrainHomer Simpson’s Brain

Four cortical lobesFour cortical lobes

Cortical areasCortical areas

Cortical areasCortical areas1. 1. Sensory cortex areasSensory cortex areas – receive and – receive and

process information from the senses.process information from the senses.

2. 2. Motor cortex areaMotor cortex area – receives, – receives,

processes and sends information about processes and sends information about

voluntary bodily movements.voluntary bodily movements.

3. 3. Association cortex areasAssociation cortex areas – integrate – integrate

sensory, motor and other information sensory, motor and other information

and are involved in complex mental and are involved in complex mental

abilities.abilities.

Cerebral hemispheresCerebral hemispheresThese are the two almost symmetrical These are the two almost symmetrical brain structures that appear to be brain structures that appear to be separated by a deep groove separated by a deep groove (longitudinal fissure) running from the (longitudinal fissure) running from the front to back of the brain.front to back of the brain.They are connected at several points They are connected at several points by strands of nerve tissue.by strands of nerve tissue.They are referred to respectively as They are referred to respectively as the left and right hemispheres.the left and right hemispheres.While they share some common While they share some common functions, they also have specialised functions, they also have specialised functions.functions.Eg. the left hemisphere receives Eg. the left hemisphere receives sensory information from the right side sensory information from the right side of the body and controls movements of the body and controls movements on the right side.on the right side.Left hemisphere is primarily involved Left hemisphere is primarily involved with language, right hemisphere is with language, right hemisphere is primarily involved with spatial tasks primarily involved with spatial tasks and recognition of faces.and recognition of faces.

Corpus callosumCorpus callosum

The corpus callosum is a The corpus callosum is a bridge of nerve tissue that bridge of nerve tissue that connects the left and right connects the left and right cerebral hemispheres.cerebral hemispheres.It serves as the main It serves as the main communication pathway communication pathway or cross over station for or cross over station for neural messages neural messages between the two cerebral between the two cerebral hemispheres.hemispheres.It comprises over 200 It comprises over 200 million nerve fibres.million nerve fibres.

Can you find the corpus callosum Can you find the corpus callosum on this MRI image?on this MRI image?

Sample exam questionsSample exam questions

Question 1 (VCAA 2005)

The major function of the corpus callosum is to

A. coordinate autonomic functions such as breathing and heart rate.

B. connect the somatosensory cortex to the motor cortex.

C. transfer information between the right and left hemispheres.

D. connect Wernicke’s area to Broca’s area.

Sample exam questionsSample exam questions

Question 1 (VCAA 2005)a. The deeply furrowed or grooved layer of tissue that covers the cerebral hemispheres is known as the __________________. (1 mark)b. List two main functions of this grooved layer of tissue.1. _________________________________2. _________________________________ (2 marks)

Sample exam questionsSample exam questionsQuestion 1 (Checkpoints 2006)Question 1 (Checkpoints 2006)

What purpose is served by the convolutions in the What purpose is served by the convolutions in the cerebral cortex of the brain?cerebral cortex of the brain?

A. They allow more blood to flow to the neurons as the A. They allow more blood to flow to the neurons as the brain requires more oxygen and nutrients than other brain requires more oxygen and nutrients than other organs of the body.organs of the body.

B. They provide some protection against injury by acting B. They provide some protection against injury by acting as a shock absorber if the brain is jolted.as a shock absorber if the brain is jolted.

C. They allow the brain more room to grow because C. They allow the brain more room to grow because they progressively unfold as the person ages.they progressively unfold as the person ages.

D. They give the brain a larger surface area which D. They give the brain a larger surface area which means more neurons can be packed into a smaller area.means more neurons can be packed into a smaller area.

Sample exam questionsSample exam questions

Question 1Question 1

What is the ‘corpus callosum’?What is the ‘corpus callosum’?

__________________________________ __________________________________

(1 mark)(1 mark)

What is its main function?What is its main function?

____________________________________________________________________

(1 mark)(1 mark)

Sample exam question from VCAA Sample exam question from VCAA 20062006

Question 1Question 1The cerebral cortexThe cerebral cortexA. A. acts as a protective layer covering the brain.acts as a protective layer covering the brain.B. B. connects the right hemisphere with the left hemisphere.connects the right hemisphere with the left hemisphere.C. C. is responsible for voluntary muscle movements.is responsible for voluntary muscle movements.D. D. increases the strength of the immune system.increases the strength of the immune system.Question 2Question 2The cerebral cortex is approximately ____________ thick.The cerebral cortex is approximately ____________ thick.A. A. 2 to 5 millimetres2 to 5 millimetresB. B. 6 to 10 millimetres6 to 10 millimetresC. C. 2 to 5 centimetres2 to 5 centimetresD. D. 6 to 10 centimetres6 to 10 centimetresQuestion 3Question 3The ________________ is a band of nerve fibres connecting the left and The ________________ is a band of nerve fibres connecting the left and right hemispheres.right hemispheres.A. A. cerebral cortexcerebral cortexB. B. cerebral hemispherecerebral hemisphereC. C. corpus callosumcorpus callosumD. D. cerebellumcerebellum