* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download B6 Brain and Mind
Neural engineering wikipedia , lookup
Limbic system wikipedia , lookup
Development of the nervous system wikipedia , lookup
Synaptogenesis wikipedia , lookup
Neurogenomics wikipedia , lookup
Neuroesthetics wikipedia , lookup
Single-unit recording wikipedia , lookup
Embodied language processing wikipedia , lookup
Functional magnetic resonance imaging wikipedia , lookup
Neurotransmitter wikipedia , lookup
Neuroeconomics wikipedia , lookup
Blood–brain barrier wikipedia , lookup
Psychoneuroimmunology wikipedia , lookup
Neurophilosophy wikipedia , lookup
Neuroinformatics wikipedia , lookup
State-dependent memory wikipedia , lookup
Time perception wikipedia , lookup
Human brain wikipedia , lookup
Signal transduction wikipedia , lookup
Selfish brain theory wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Activity-dependent plasticity wikipedia , lookup
Brain morphometry wikipedia , lookup
Neural correlates of consciousness wikipedia , lookup
Neurolinguistics wikipedia , lookup
Cognitive neuroscience wikipedia , lookup
Haemodynamic response wikipedia , lookup
Endocannabinoid system wikipedia , lookup
Nervous system network models wikipedia , lookup
Neuroplasticity wikipedia , lookup
History of neuroimaging wikipedia , lookup
Aging brain wikipedia , lookup
Neuropsychology wikipedia , lookup
Evoked potential wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Brain Rules wikipedia , lookup
Metastability in the brain wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Neuroanatomy wikipedia , lookup
24/05/2017 B6 Brain and Mind OCR 21st Century Additional Science M Barker Shirebrook Academy 24/05/2017 B6.1 How do animals respond to changes in their environment? The Nervous System 24/05/2017 The CENTRAL NERVOUS SYSTEM (CNS) enables us to react to changes in our surroundings (“stimuli”). It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors. Types of receptor: 1) Light receptors in the eyes 2) Sound receptors in the ears 3) Taste receptors on the tongue 4) Smell receptors in the nose 5) Touch, pressure and temperature receptors in the skin 6) Changes of position receptors in the ears (balance) Nervous Reactions 24/05/2017 When we react to a stimulus our bodies use the following pattern and these signals are sent using electrical impulses: Stimulus Receptor For example, consider a man and a camel: Coordinator Effector Response Oh No! What are the stimulus, receptor, coordinator, effector and response in this situation? Examples of reactions Stimulus Bright light Sour taste Losing balance Sit on a drawing pin Receptor (i.e. the thing that detects the stimulus) Effector (i.e. the thing that will do the reaction) 24/05/2017 Response (i.e. action taken) Simple reflexes in humans 24/05/2017 Babies can demonstrate simple reflexes: 1) Stepping reflex 2) Startle (or moro) reflex 3) Grasping reflex 4) Rooting reflex 5) Sucking reflex The Iris Reflex When the light is bright the radial muscles relax, the circular muscles contract and the pupil increases in size. 24/05/2017 When the light is bright the radial muscles _____, the circular muscles _______ and the pupil ________ in size. Reflex Actions in Animals 24/05/2017 Simple animals rely on reflex actions for most of their behaviour: Stimulus in a simple animal Feeling hungry Feeling cold Feeling threatened What is their response? Slower responses - hormones 24/05/2017 Nervous impulses are electrical signals and are transmitted quickly through the body. The body can also produce a slower response using chemical messengers called hormones. Examples of bodily processes that use hormones: Controlling of water content by the kidneys and the brain: The menstrual cycle, using hormones from the brain and ovaries: The development of nervous and hormonal communication systems depended on the evolution of multicellular organisms. 24/05/2017 B6.2 How is information passed through the nervous system? Conscious actions 24/05/2017 A conscious action is one where the brain makes a considered response. Here’s what happens: 4) The brain 3) Here another sensory neurone decides to move carries the signal to the brain away the hand 5) This impulse is sent by MOTOR NEURONES to the hand muscles (the effectors) via the spinal chord… 2) The impulse is carried by SENSORY NEURONES to the spinal chord 1) Receptors in your skin detect a stimulus Stimulus 6) Which then moves the hand away Receptor Motor Neurone Sensory Neurone Effector Coordinator Response Reflex actions 24/05/2017 Sometimes conscious action is too slow to prevent harm, e.g… In situations like this the body bypasses the brain to produce a quicker response. Here’s how it works… Reflex actions 2. Sensory neurone 1. Receptor 24/05/2017 3. Relay neurone in the spinal chord 4. Motor neurone 5. Effector Types of nerve cell (“neuron”) 24/05/2017 Nerve cells (neurons) are elongated with branched endings to connect to many muscles fibres and aid the transmission of electrical impulses: Nucleus Axon – a long extension of cytoplasm surrounded by a membrane Muscle strands (effector) Fatty sheath to increase the speed of transmission and to insulate the neuron from surrounding cells The CNS and the PNS The Central Nervous System (CNS) is the spinal cord and brain: The Peripheral Nervous System (PNS) is the collection of neurones connected to the CNS: There are two types of neurone we need to consider: 1) Sensory neurone Impulse These carry impulses from the receptors to the CNS 2) Motor neurone Impulse These carry impulses from the CNS to effectors 24/05/2017 Synapses 24/05/2017 Neurones never ____ each other – there is a small gap between them called a _____. A signal is sent from one _______ to the next by a _______ transmitter across the synapse (called a “neurotransmitter”). These transmitters are then ________ back into the sensory neurone to be used again. This process only reacts with specific chemicals that bind to the receptor molecules. Words – chemical, synapse, neurone, touch, reabsorbed Drugs and the Nervous System 24/05/2017 Drugs are classed as “a substance that affects the central nervous system, causing changes in psychological behaviour and possibly addiction”. They do this by affecting the transmission of impulses. Consider Ecstasy for example: Ecstasy (MDMA) blocks the sites in the brain’s synapses where the transmitter substance serotonin is removed. Beta blockers and Prozac can also affect the transmission of impulses. The Cerebral Cortex 24/05/2017 The cerebral cortex is the part of our brain most concerned with intelligence, memory and consciousness. By studying the effects (e.g. memory/sight loss) when different parts of the brain are damaged scientists have been able to identify which parts of the brain control which functions. 24/05/2017 Other techniques of studying the brain 1) An electroencephalogram (EEG) is a visual record of the electrical activity generated by neurons in the brain. It works by amplifying and detecting the electrical signals from the brain. 2) Magnetic resonance imaging (MRI) scanning is a new technique that produces images of different cross sections of the brain and uses colours to represent activity. Conditioned reflexes - Pavlov’s Dog 24/05/2017 I won the Nobel Prize in 1904 and am most famous for investigating “conditioned responses”: Ivan Pavlov, 1849-1936 1) Steak + dog = saliva 2) Steak + bell + dog = saliva 3) Bell + dog = saliva Notice that the final response (saliva) has no direct relation to the stimulus (the bell). Conditioned reflexes can increase an animal’s chance of survival! Reflex actions Sometimes the brain can modify a reflex response via a neuron to the motor neuron of the reflex arc, meaning that you could keep hold of a hot object: 24/05/2017 B6.4 How do humans develop more complex behaviour? 24/05/2017 Human Brains 24/05/2017 Ug. My chances of survival were made a lot better when my brain got bigger. Notice I can now use simple tools! Mammals have complex brains with billions of neurons. The interaction between our ancestors and their environment caused neuron pathways to form in the brain. Learning Complex Behaviour 24/05/2017 PET scan showing areas “activated” by doing algebra. When the brain is asked to do certain tasks different areas are “activated”. New experiences cause new neuron pathways to develop, while pathways that are not used are eventually destroyed. This is why we become better at certain tasks when we practice them more often. Feral children 24/05/2017 Task: to find out what “feral children” are, what has caused their condition and what the consequences are. Memory 24/05/2017 Our memory is divided into two types: short term and long term. Short term memory is capable of storing a limited amount of information for a limited amount of time. Long term memory is when more information is stored over a much longer time. Ways of improving short term memory, e.g. a phone number Ways of improving long term memory e.g. exam revision Using Models to Explain Memory 24/05/2017 We can understand memory better by using models to explain it, for example: What could cause a model to be limited in explaining how memory works?