Brain And Behavior PDF

THE HUMAN BRAIN Human Brain Thehuman brain is the most complex object in the Universe. There are more connections in a cubic millimetre of neural tissue than there are stars in the Milky way galaxy. We carry a miniature universe inside our skulls Human Brain Capable of contemplatin...

THE HUMAN BRAIN Human Brain Thehuman brain is the most complex object in the Universe. There are more connections in a cubic millimetre of neural tissue than there are stars in the Milky way galaxy. We carry a miniature universe inside our skulls Human Brain Capable of contemplating its own existence; Capable of perceiving the myriad of impressions from all around it; capable of feelings of awe, joy, sadness, fear, disgust, hatred, and wonder. Biological Psychology The study of the biological processes that support human behaviour The study of the biological (both brain and body) mechanisms of normal and abnormal behaviour The ‘mind’ is a result of biological function (monism) Cognition is NOT distinct from the body (dualism) Biological Psychology Behavioural neuroscience is the modern term for biological psychology. Biopsychology/behavioural neuroscience are synonymous with the terms psychobiology and physiological psychology. In behavioural neuroscience, behaviour has a broad meaning; includes overt acts (external acts that you can see) but also internal events such as learning, thinking, feeling, emotions, and different types of cognition. Subfields Cognitive Neuroscience ‘seeks to determine how the brain processes information, builds memories, navigates decisions…’ (Eagleman & Downar, 2018) Cognitive Neuroscience investigates the emergence of cognitive function from the physical and chemical activity of neurons in the brain ……. seeks to use observations from the study of the brain The Goal of Cognitive Neuroscience Whoare we if not our thoughts, behaviours, decisions, sensations, hopes , dreams, fears and aspirations. Thefield of Cognitive Neuroscience seeks to determine how the brain processes information. builds memories, navigates decisions, and ultimately produces a human being from trillions of smaller parts. Cognitive neuroscience incorporate /includes, physicists, biologists, psychologists, philosophers , engineers.. Goal of Cognitive Neuroscience How are intelligent systems built from simple, senseless parts? Emergent properties: characteristics of a system that do not belong to any individual component. We are not the properties of any given piece; rather the system as a whole.  Goal of Cognitive Neuroscience: Levels of complexity In order to grasp the complexity of the connection between mind and behaviour it is necessary to begin with Two concrete bodies of data: 1. The way humans behave, perceive, and decide 2. The biological mechanisms that underlie those behaviours The Goal of Cognitive Neuroscience To understand the mechanisms by which we can do what may seem like effortless things but when we pause for a moment to consider the complexity; How can we link the diverse, nuanced, complex internal human mind to the overwhelming intricate human brain? Scientific Perspective on Brain and Behaviour All psychological phenomena - including emotion, perception, attention, memory, reasoning, conscious experience - are the product of brain activity. Human Nervous System – Major Divisions Central nervous system (CNS) Brain and spinal cord Peripheral nervous system (PNS) Sensory and motor connections The brain – major structures Cerebrum (forebrain) Hemispheres Brainstem Cerebellum Neuron structure Communicates with other cells Receives and transmits ‘messages’ Produces electrical impulses – action potentials Scientific Perspective on Brain and Behaviour All psychological phenomena - including emotion, perception, attention, memory, reasoning, conscious experience - are the product of brain activity. Human Nervous System – Major Divisions Central nervous system (CNS) Brain and spinal cord Peripheral nervous system (PNS) Sensory and motor connections The brain – major structures Cerebrum (forebrain) Hemispheres Brainstem Cerebellum Neuron structure Communicates with other cells Receives and transmits ‘messages’ Produces electrical impulses – action potentials Scale in studying the nervous system Time Connectional Methods Tracing Connections Diffusion Tensor Imaging DTI Role of a neuron depends on its INPUTS & OUTPUTS Wide variety of methods used to trace connections: 1. to and from a neuron Uses MRI scanner 2. to and from a region of the brain Non - invasive Detailed maps of the diffusion of water within neural tissue Connectional Methods In order for connectional methods to work we need to know the approx. functions of the INPUT & OUTPUT regions. Correlational Methods Involves making observations of brain activity while an individual is performing some type of behaviour.  Correlational Methods Invasive: Record electrical activity of neurons via microelectrodes implanted in brain Less – invasive: 1. Electroencephalography (EEG) 2. Magnetoencephalography (MEG) 3. Positron emission tomography (PET) 4. Functional Magnetic Resonance Imaging fMRI Magnetic Resonance Imaging (MRI) Differences in the properties of tissue create major differences in how protons in the tissue behave when they are placed in a strong magnetic field. Images > must partially magnetize the body. Every MRI contains a superconducting magnet Structural Analysis: Magnetic Resonance Imaging (MRI) Strongmagnetic field passed through the brain, followed by a radio wave Very clear 3D images of various type of tissue within body Excellent spatial resolution < mm Functional Magnetic Resonance Imaging (fMRI) When neurons become more active, they need more oxygen fMRI can detect changes in the magnetic properties of blood Measures ratio of oxygenated to deoxygenated blood Blood oxygen level-dependent (BOLD) response MRI vs. fMRI MRI studies brain fMRI studies brain structure function Studying the damaged brain Neuropsychological testing Effects of brain damage on specific cognitive functions e.g., temporal lobe lesions associated with memory disturbance Memory is not a single function – semantic, procedural, episodic… Rare to be impaired in all forms of memory - each must be tested separately  Lesion Studies We need to back up our findings from correlational studies with causational studies Study the effects of brain damage – lesions. Neuropsychological testing Effects of brain damage on specific cognitive functions Wide variety of events cause lesions: 1. TBI – traumatic brain injury 2. Stroke – bleeding or blockage of blood supply into tbrain region 3. Tumours Studying the damaged brain Single and double dissociations Patient versus control Patient X versus Patient Y Functional and Structural Brain Stimulation: DBS Deep-brain stimulation (DBS) Electrodes implanted in the brain to stimulate a targeted area with a low-voltage electrical current to facilitate behaviour Therapeutic applications: Parkinson’s disease Depression OCD Image: Parkinson’s UK  Functional and Structural Brain Stimulation: TMS Transcranialmagnetic stimulation (TMS) Magnetic coil placed over the skull to stimulate underlying brain area Wire in coil carrying an electric current - rapid change in the current creates a magnetic field This induces a current in the nearby neurons, causing them to ‘fire’ (generate action potentials) Can be used to disrupt ongoing cognitive or motor function (‘virtual lesion’) Transcranial Magnetic Stimulation (TMS) TMS is relatively mild Many natural situations stimulate the brain Not used on people with epilepsy Number/rate of pulses regulated by ethical guidelines Can be used to treat depression  Measuring the Brain’s Electrical Activity The brain is always electrically active Electrical activity can be used to study brain function Four major techniques 1. Single-cell recording 2. Electroencephalography (EEG) 3. Event-related potentials (ERP) 4. Magnetoencephalography (MEG)  Single Cell Recordings Measuring single-neuron action potentials with fine electrodes Electrodes placed next to cells (extracellular) or inside (intracellular) Extracellular recording - distinguish activity of up to 40 neurons Intracellular recording - study of a single neuron’s electrical activity Can be used in humans when electrodes implanted for clinical reasons E.g., DBS surgery Recording Action Potentials from Single Cells Electroencephalography (EEG) Recording from thousands of cells Reveals features of the brain’s electrical activity EEG signal changes with behaviour Recordingsfrom the cortex show an array of patterns – some are rhythmical Electrical activity continues even during sleep or coma Electroencephalography (EEG) Can be used to measure ongoing brain activity or changes in response to a particular event/stimulus  Characteristic EEG Recordings What activity state does each of these waveforms show? Characteristic EEG Recordings Electroencephalography (EEG) and event-related potentials (ERPs) EEG Spatial resolution ~ centimetres Temporal resolution ~ Mapping Brain Function with ERPs Complex electroencephalographic waveforms are related in time to a specific sensory event Tocounter noise effects, the stimulus is presented repeatedly, and the recorded responses are averaged Stimuli can be visual (VEP), auditory (AEP), motor (MEP), somatosensory (SEP) Detecting ERPs E.g., auditory stimulus Tone presented at time 0 EEG response recorded Aftermany successive presentations the EEG wave sequence develops a distinctive shape Comparing Neuroscience Research Methods Considerations Temporal resolution Spatial resolution (accuracy of localization) Invasiveness Cost E.g., Behavioural methods generally less expensive than imaging Research Methods Recap Connectional Methods DTI Correlational Methods fMRI EEG Lesion Methods Case studies (Single & Double dissociation) Stimulation Methods TMS  Measuring the Brain’s Electrical Activity The brain is always electrically active Electrical activity can be used to study brain function Four major techniques 1. Single-cell recording fMRI 2. Electroencephalography (EEG) e ↳ main focus 3. Event-related potentials (ERP) 4. Magnetoencephalography (MEG) Electroencephalography (EEG) Recording from thousands of cells Reveals features of the brain’s electrical activity react EEG signal changes with behaviour - usually have them ↳ can to something ex , a photo Recordingsfrom the cortex show an array of patterns – some are rhythmical Electrical activity continues even during sleep or coma Electroencephalography (EEG) Can be used to measure ongoing brain activity or old photograph changes in response to a particular event/stimulus  Characteristic EEG Recordings ? R.e.m ↳ What activity state does each of these waveforms show? Characteristic EEG Recordings Clinical Applications Detects abnormalities in the electrical activity of your brain Diagnose Epilepsy (seizures: rapid spiking waves) clinic Sleep disorders Use EEG @ sleep Video mobile eeg s now have Structure of the nervous system Central Nervous System (CNS) Brain (in the skull) Spinal Cord (in the spine) Peripheral Nervous System (PNS) Transmits information into and out of the CNS Connects to skin, muscles & internal organs. Connects the spinal cord to the rest of body. Peripheral Nervous system bit of don't walking a MS misnomer think we " about Somatic system: Control voluntary movements " muscles required for the taste → links brains to Autonomic nervous system: involuntary functions ↳ actually ↳ cardiac muscle we do have voluntary ↳ some control rate like heart  Autonomic nervous system Two divisions: 1. Sympathetic Associated with energy expenditure “fight-or-flight” body ready s not just fear , brain getting to do something 2. Parasympathetic Associated with energy conservation “rest and digest” of one above a bit of opposite Autonomic nervous system - overview Sympathetic division - fight or flight  Central Nervous System Brain Control of behaviour (including cognition) Regulation of physiological processes Spinal cord Nerve transmission to/from the brain  The brain more curves ) grooves = t "" "" "" Cerebrum: Largest and uppermost part of the brain Two hemispheres – connected by corpus callosum Cerebrum Cerebellum Corpus callosum Image: http://williamcalvin.com/BrainForAllSeasons/img/bonoboLH-humanLH-viaTWD.gif The brain Cerebral Cortex Outer covering of cerebrum - grey matter 2-3mm thick Includes primary and association cortices : my 1in , axons covers Corpus callosum ↳ connects two hemispheres Cerebral cortex Image; http://www.bioon.com/book/biology/whole/image/1/1- 6.tif.jpg  The brain: lobes Sensory processing Movement Language Higher Visual cognitive processing Attention functions Auditory processing Sensory integration Memory The brain: gyri and sulci Gyrus (ridge) Sulcus (groove) Fissure (deep groove) The brain: gyri and sulci Central Sulcus Longitudinal Fissure Sylvian/Lateral Fissure Transverse Fissure The brain: structure Forebrain Cortex Basal ganglia Thalamus Hypothalamus Midbrain } Colliculi not really Tegmentum getting Cerebral into peduncles Hindbrain Pons Medulla oblongata Cerebellum FOREBRAIN  Forebrain Telencephalon cortex Cortex structures subcortical Subcortical Structures limbic Limbic system → Basal ganglia Diencephalon Thalamus ( relay station to the cerebral cortex) Hypothalamus ( homeostasis & motivation)  Forebrain: Limbic system Hippocampus Learning and memory Amygdala Emotion Fear response Mammillary bodies Aspects of memory Limbic System Brain system for emotion & motivation Hypothalamus: survival ( e.g., motivation to find water when thirsty) Basic drives – hunger, thirst, sexual arousal, sleep, temperature regulation.  Forebrain: Diencephalon Thalamus Prioritises sensory information and transmits it to cortex Hypothalamus Multiple functions Connection to autonomic nervous system Links nervous system to endocrine system (hormones) via pituitary gland  Forebrain: Basal ganglia A collection of subcortical nuclei deep within brain tissue Striatum: caudate nucleus, putamen Globus pallidus Subthalamic nucleus Involved in motor control, learning, motivation/reward Affected in Parkinson’s disease issues ↳ movement  Brain Stem Midbrain - Mesencephalon - integration of sensory input and motor output Hindbrain Midbrain Pons Control of sleep/arousal above medulla Latin for bridge Medulla oblongata Test Yourself Use these slides to create Multiple Choice Questions. Example: What are the two divisions of the automimic nervous system? A) Midbrain & Hindbrain B) Somatic & Parasympathetic C) Limbic system & Somatic system D) Sympathetic nervous system & Parasympathetic nervous system Levels of analysis B Mma:.e Levels of analysis  Cells of the brain Are separate entities Neuron Doctrine Ramon y Cajal > stained brain tissue → distinguished neurons  Cell types in neural tissue 1. Neurons Approx. 86 billion Similar to other cells (membrane, nucleus, proteins) Additional property that distinguishes them from other cells - Can transmit electrical signals quickly over long distances - When the signals arrive at their endpoint(s) they trigger a special kind of chemical signaling  Neurons: Zones of importance 1. Dendrites (collecting) ↳ big branches 2. Soma (integrating) ↳ cell body 3. Axon (conducting) 4. Axon Terminals (outputting) 1. Dendrites Different Shapes Long Branching Extensions from the Cell Body Specialized for Collecting information from chemical signals 2. Soma Dendrites pass information to Soma (cell body) Nucleus: regulates cell activity. 10-25 micrometres Plays key role in integrating signals that come from dendrites 3. Axons Nerve Fibre Long extension, just one (unlike Dendrites) Much longer than dendrites Can carry signals from spinal cord to big toe. 4. Axon Terminals Axon branches at its end splitting into 10,000 axon terminals (axon buttons) Small swellings at end tips Contain packages of chemicals that can be released into the space between cells. Terminals are optimized for output of signals ↳ to next neuron Synapse Main location of signal transmission Number of Synapses: 3 y.o quadrillion ( 1, followed by 15 zeros) Synapse numbers decrease with age Adult brain contains between 1000 and 5000 trillion synapses A cubic mm of cerebral cortex contains more of these tiny connections than people on the planet Different types of neurons Great deal of diversity among neuron types Classified by Function: 1. Sensory Neurons 2. Motor Neurons Afferent neuron (arrival, sensory) Efferent neuron (exit, motor) 3. Interneurons – between the sensation of a signal and the action.  MCQ Neuron structure lithe question 1 1 I 4 3 2 8 7 6 5 Neuron structure  Glial cells (Greek for Glue) 4 types of Glia Oligodendrocytes; Schwann cells; Astrocyte; Microglia Functions of Glia Myelin sheath (accelerates axonal transmission) Transport nutrients to neurons Clean up brain debris Digest parts of dead neurons Helps to hold neurons in place MS Auto-immune disease: The immune system attacks healthy CNS tissue. Mistakes own body’s healthy tissue for foreign tissue Consequence – a process called demyelination Myelin sheaths become scarred – sclerotic Cannot insulate the axon – information flow corrupted Small isolated areas – varied symptoms; balance, speech, muscle weakness, vision, fatigue and pain. Neuron - neuron communication How do Neurons communicate across these small spaces? 1921: Otto Loewi discovered neurotransmission The signal from the Axon is Chemical The method that cells use to communicate across small gulfs of space to targets such as Neuron-to-neuron communication Synaptic cleft: Microscopic gap between two neurons allowing communication via neurotransmitters (20-50 nanometres) Neurotransmitter molecules are contained in Synaptic vesicle Vesicle fuses with outer membrane and molecules spill into the cleft Neurotransmitters Neurotransmitters release their effect by binding to receptors. Chemicals that transmit messages between neurons or from neurons to other cells Many different types of neurotransmitters Action can be excitatory (stimulate), inhibitory (block) or modulatory Each neuron generally synthesizes and releases a single type of neurotransmitter  Some key neurotransmitters Glutamate: primary excitatory transmitter Dopamine: reward learning, muscle control Serotonin: mood, memory, sleep, appetite Norepinephrine/noradrenaline: sympathetic NS; alertness/attention Acetylcholine: autonomic NS; movement; cognition Histamine: metabolism, temperature control, regulating various hormones, the sleep-wake cycle Resource o Pufferfish Tetrodotoxin Poison Prevents the transmission of action potentials Electrical signals by which neurons communicate Resource: Action Potential ACTION POTENTIAL Also called nerve impulse or Spike Two ions play key roles in action potentials N C N N % C " a N l- a N l- a sodium & potassium + a + a + K K +A A K + + K - - + K + At rest = high concentration of A A K A + + + - - - Sodium on the outside of the cell N N N C N a Ca l- a Ca N Much lower concentration of !÷÷ + l- + + + l- a sodium on the inside of a cell. +. The opposite is true for Potassium  Resting potential Ions Extracellular Na Cl Na Na Cl space + Na - + Na - + + + K A A K K Resting potential: Neuron + K - A - K + K + -70 mV A - A A - + + + - c. Extracellular Na - Na differenceeen seward space Na + Cl + Cl - Na + + Cl Na inotsidt or side - - + It 70mV - positive Na+ = sodium ions K+ = potassium ions Cl- = chloride anions A- = protein anions  Action Potential Membrane potential => threshold Triggers opening of voltage – gated ion channels N C N N Channels open and Na+ find a way into C cell a N l- a N l- a + a + a + K K +A A K ++ + K - -K K +A This influx of sodium triggers opening of A A + + + K+ channels - - - Potassium Flows out of cell N N N C N a Ca l- a Ca N + l- + + + l- a Exchange of ions cause a voltage Spike + and the change in voltage closes the Na + channels Action Potential Exchange of ions cause voltage spike Rapid voltage change gives enough time to spread far down the membrane for neighboring Ion NA + channels to open Process repeats in a cycle of polarization and depolarization Signal is passed down membrane = how action potentials propagate.  M E M B R A N E P O T E N T A ILhttps://www.moleculardevices.com/applications/patch-clamp-electrophysiology/what-action-potential Source Neurotransmission and action potentials Cycle of depolarisation and repolarisation = action potential Large brief (approx. 1ms) reversal in polarity Electrical signal travels along the axon to the terminal The neuron ‘spikes’ or ‘fires’ Several hundred mph! This causes the axon terminal to release neurotransmitters into the synapse Dendrites of other neurons absorb neurotransmitters  Revision! Name three methods that link Brain & Behaviour What are single and double dissociations in neuropsychology? If I want to see when something is happening in the brain what technique could I use? If I want to see where something is happening what techniques could I use? How does a neuron fire? What are the divisions of the human nervous system? Levels of analysis Levels of analysis Cells of the brain Are separate entities Neuron Doctrine Ramon y Cajal  Cell types in neural tissue 1. Neurons Approx. 86 billion Similar to other cells (membrane, nucleus, proteins) Additional property that distinguishes them from other cells - Can transmit electrical signals quickly over long distances - When the signals arrive at their endpoint(s) they trigger a special kind of chemical signaling  Neurons: Zones of importance 1. Dendrites (collecting) 2. Soma (integrating) 3. Axon (conducting) 4. Axon Terminals (outputting) 1. Dendrites Different Shapes Long Branching Extensions from the Cell Body Specialized for Collecting information from chemical signals 2. Soma Dendrites pass information to Soma (cell body) Nucleus: regulates cell activity. 10-25 micrometres Plays key role in integrating signals that come from dendrites 3. Axons Nerve Fibre Long extension, just one (unlike Dendrites) Much longer than dendrites Can carry signals from spinal cord to big toe. 4. Axon Terminals Axon branches at its end splitting into 10,000 axon terminals (axon buttons) Small swellings at end tips Contain packages of chemicals that can be released into the space between cells. Terminals are optimized for output of signals Synapse Main location of signal transmission Number of Synapses: 3 y.o quadrillion ( 1, followed by 15 zeros) Synapse numbers decrease with age Adult brain contains between 1000 and 5000 trillion synapses A cubic mm of cerebral cortex contains more of these tiny connections than people on the planet Different types of neurons Great deal of diversity among neuron types Classified by Function: 1. Sensory Neurons 2. Motor Neurons Afferent neuron (arrival, sensory) Efferent neuron (exit, motor) 3. Interneurons – between the sensation of a signal and the action. Neuron structure 1 1 4 3 2 8 7 6 5 Neuron structure  Glial cells (Greek for Glue) 4 types of Glia Oligodendrocytes; Schwann cells; Astrocyte; Microglia Functions of Glia Myelin sheath (accelerates axonal transmission) Transport nutrients to neurons Clean up brain debris Digest parts of dead neurons Helps to hold neurons in place MS Auto-immune disease: The immune system attacks healthy CNS tissue. Mistakes own body’s healthy tissue for foreign tissue Consequence – a process called demyelination Myelin sheaths become scarred – sclerotic Cannot insulate the axon – information flow corrupted Small isolated areas – varied symptoms; balance, speech, muscle weakness, vision, fatigue and pain. Synaptic Transmission: Chemical Signaling in the Brain Neuron - neuron communication How do Neurons communicate across these small spaces? 1921: Otto Loewi discovered neurotransmission The signal from the Axon is Chemical The method that cells use to communicate across small gulfs of space to targets such as Neuron-to-neuron communication Synaptic cleft: Microscopic gap between two neurons allowing communication via neurotransmitters (20-50 nanometres) Neurotransmitter molecules are contained in Synaptic vesicle Vesicle fuses with outer membrane and molecules spill into the cleft Neurotransmitters Neurotransmitters release their effect by binding to receptors. Chemicals that transmit messages between neurons or from neurons to other cells Many different types of neurotransmitters Action can be excitatory (stimulate), inhibitory (block) or modulatory Each neuron generally synthesizes and releases a single type of neurotransmitter  Some key neurotransmitters Glutamate: primary excitatory transmitter Dopamine: reward learning, muscle control Serotonin: mood, memory, sleep, appetite Norepinephrine/noradrenaline: sympathetic NS; alertness/attention Acetylcholine: autonomic NS; movement; cognition Histamine: metabolism, temperature control, regulating various hormones, the sleep-wake cycle Resource Pufferfish Tetrodotoxin Poison Prevents the transmission of action potentials Electrical signals by which neurons communicate Resource: Action Potential ACTION POTENTIAL Also called nerve impulse or Spike Two ions play key roles in action potentials N C N N C a N l- a N l- a sodium & potassium + a + a + K K +A A K + + K - - + K + At rest = high concentration of A A K A + + + - - - Sodium on the outside of the cell N N N C N a Ca l- a Ca N Much lower concentration of + l- + + + l- a sodium on the inside of a cell. + The opposite is true for Potassium  Resting potential Ions Extracellular Na Cl Na Na Cl space + Na - + Na - + + + K A A K K Resting potential: Neuron + K - A - K + K + -70 mV A + - A A + + - - - Extracellular Na Na space Na Cl Na + Cl + - + + Cl Na - - + Na+ = sodium ions K+ = potassium ions Cl- = chloride anions A- = protein anions  Action Potential Membrane potential => threshold Triggers opening of voltage – gated ion channels N C N N Channels open and Na+ find a way into C cell a N l- a N l- a + a + a + K K +A A K ++ + K - -K K +A This influx of sodium triggers opening of A A + + + K+ channels - - - Potassium Flows out of cell N N N C N a Ca l- a Ca N + l- + + + l- a Exchange of ions cause a voltage Spike + and the change in voltage closes the Na + channels Action Potential Exchange of ions cause voltage spike Rapid voltage change gives enough time to spread far down the membrane for neighboring Ion NA + channels to open Process repeats in a cycle of polarization and depolarization Signal is passed down membrane = how action potentials propagate.  M E M B R A N E P O T E N T A ILhttps://www.moleculardevices.com/applications/patch-clamp-electrophysiology/what-action-potential Source Neurotransmission and action potentials Cycle of depolarisation and repolarisation = action potential Large brief (approx. 1ms) reversal in polarity Electrical signal travels along the axon to the terminal The neuron ‘spikes’ or ‘fires’ Several hundred mph! This causes the axon terminal to release neurotransmitters into the synapse Dendrites of other neurons absorb neurotransmitters Lecture 6 Outline Multisensory Perception Synaesthesia (case study) Cross-modal correspondence Molyneaux’s question Combining Sensory Information Multisensory Perception  The Brain is Multisensory Driver & Noesselt, (2008) Multisensory integration in the mammalian brain: diversity and flexibility in health and disease, Volume: 378, Issue: 1886, DOI: (10.1098/rstb.2022.0338)  Sensation & Perception Variety of stimuli to which we are sensitive: 1. Smell and taste molecules in air and saliva (olfaction and gustation) 2. Feel/touch, pressure changes on skin (tactile) 3. Hear sound pressure waves (audition) 4. See electromagnetic waves (vision) 5. Balance position of one's head (vestibular system) 6. Position - Information from muscles & joints ( proprioception) 7. Internal state of body ( interoception ) 8. Temperature ( thermosensation) 9. Pain (nociception) Multisensory Perception Perception is fundamentally a multisensory phenomenon Our senses function in concert Our brains are organized to use the information they derive from the sensory channels cooperatively to enhance the probability that objects and events will be detected rapidly, identified correctly, and responded to appropriately (Calvert, Spence & Stein, 2004) SYNAESTHESIA Synaesthesia Synesthesia, is from the Greek syn- (together) and -aisthes (feeling) ‘Merging of the senses’ Where one attribute of a stimulus (e.g., its sound, shape, or meaning) may inevitably lead to the conscious experience of an additional attribute. Involuntary, consistent & memorable Part of the synesthete’s everyday experience Synaesthesia Many forms/manifestations of Synaesthesia Letter and numerals and colours grapheme –colour Synaesthesia See colours when they hear sounds music–colour synaesthesia Experience tastes in the mouth when reading or speaking lexical–gustatory synaesthesia Involuntary mental maps of any group of numbers Number form synaesthesia Observing someone receive touch invokes physical sensation on corresponding body part Grapheme- Colour Synaesthesia Grapheme- Colour Synaesthesia Neighbouring brain areas communicate with one and another more so in Synaestheses compared to non-Synaesthetes Activity in one area kindles activity in another area – hyper connectivity Probably due to defective neural pruning from prenatal period.  Brang et al., 2010 Neuroimage - Cross-activation theory Grapheme – Colour synaesthetic hears a letter – increased activity in regions specialized for colour in the visual system V4 and the posterior temporal grapheme areas (PTGA) Sequence – Space Synaesthesia Sequences such as months of the year, days of the week, numbers, and letters are experienced as specific forms in space (Simner et al. 2009). Lexical - Gustatory Synaesthesia  Synaesthesia Triggering stimulus = inducer Resultant synaesthetic experience = concurrent Heritable ( runs in families) Prevalence – more common than previously thought Spatial forms 2.2 – 20% Days colour 2.8% Vision touch 1.6% Grapheme colour 1.4% Music colour 0.2% Theories of Synaesthesia Individual differences Mysterious Synesthesia can teach us Synaesthesia as a about important aspects of subjective altered reality Cognition, behaviour, that is superimposed on a genetics. typical mind/brain The brains of synesthetes are different (Cohen – Kadosh, Henik (2007) Key Characteristics of Synaesthesia Involuntary Consistent Induced Memorable What Causes Synaesthesia? Monozygotic twins have a greater pairwise concordance for CSS than dizygotic twins Coloured-sequence synesthesia (CSS) sequences such as letters, numbers, days of the week, trigger colour perception  What Causes Synaesthesia? Genetic disposition But not for the type of Synesthesia Can be probabilistic but not inevitable Might have different neuro cognitive architecture Synaesthesia Triggering stimulus = inducer Resultant synaesthetic experience = concurrent Heritable ( runs in families) Prevalence - more common than previously thought Spatial forms 2.2 – 20% Days colour 2.8% Vision touch 1.6% Grapheme colour 1.4% Music colour 0.2% Synaesthesia and Art The Colour of Music Sound & Colour TedX – Sarah Kraning CROSS MODAL CORRESPONDANCE Cross – modal correspondences Near-universally experienced associations Do you hear anything when watching the between seemingly unrelated sensory moving dots? features: https://www.youtube.com/w atch?v=o39TiACe4mw e.g., auditory stimuli of high and low pitch match with visual stimuli of high and low spatial elevation, respectively (Spence, 2011). CROSS-MODAL TRANSFER William Molyneux Saturday 7 July 1688, Dublin “Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere of the same metal … Suppose then the cube and sphere placed on a table, and the blind man be made to see: query, whether by his sight, before he touched them he could now distinguish and tell which is the globe, which the cube …?” Bishop Berkeley's Answer ‘ The world as we see it is a construct, slowly built up by every one of us in years of experimentation’ - Bishop Berkeley The (formerly) blind man would have to learn through experience of simultaneous touch and sight  to distinguish between the objects Molyneux’s Question (Dublin, 1688) gets answered in 2011 Held et al. (2011) Nature Neuroscience, 14, 551- 553  Held et al. (2011) 5 congenitally blind children who have sight restored after cataract removal Immediately after surgery children can match touch-touch & sight-sight BUT not touch-vision. After short period of experience (5-7 days) they can match touch-vision Molyneux’s question answered Lack of immediate Haptic – Visual Transfer Negative answer to Molyneux's questions But the transfer was fairly rapid after sight was restored. The rapidity of acquisition suggests that the neuronal substrates responsible for cross-modal interaction might already be in place before they become behaviourally manifest ( Held et al., 2011) COMBINING SENSORY INFORMATION Combining sensory information For most multisensory events, observers perceive synchrony among the various senses (e.g., vision, audition, touch) despite the naturally occurring lags in arrival and processing times of the different information streams. Multisensory illusions McGurk effect Audiovisual integration is fundamental for many tasks, such as orientation toward novel stimuli and understanding speech in noisy environments. M cGurk effect Seen lip-movements can alter https://www.youtube.com/watch?v=PWGeUztTkRA which phoneme is heard for a particular sound https://www.youtube.com/watch?v=96Fxj0QfyTA McGurk effect “ba” Voice ( auditory) “ga” Mouth movements ( visual) “da” Illusion Auditory and visual signals are forced to come together in a single percept. Even though independently the senses could recognize & interpret the signal. Vision influences hearing Summary Lecture 5 The brain is multisensory and attempts to integrate information from across the senses in an optimal manner One sense can influence perception of the other (McGurk) Integration sometimes goes beyond the norm and, due to hyper-connectivity, can result in synaesthesia Anatomy of the Visual System The Eye: Photons enter Cornea Iris controls how much light is let in. Goes through the pupil Shines through the lens that focuses the image on the Retina Image inverted on Retina Anatomy of the Visual System Retina contains layers of cells Fovea point of central vision Signals begin to travel to brain via the axons of cells that converge to from the Optic Nerve Visual Perception Perception – our experience of the sensory word. The Rotating Snakes Illusion – Akiyoshi Kitaoka What does this tell us? Visual system is not like a camera. don’t have direct access to physical properties of the world Illusions can reveal the underlying components of veridical perception. The visual pathway: crossing the optic chiasm OCCIPITAL LOBES Occipital lobe Mostposterior part of the cortex Keyfunctions: processing, integration and interpretation of visual stimuli More of the brain dedicated to vision than any other sense Occipital lobe anatomy Perception of light, colour, size, orientation, dimensions… Primary Visual Cortex V1 Visual Association Area Interpretation of information acquired through V1 Retinotopic organisation of V1 Higher Visual Areas V1 feeds information to V2 (secondary visual cortex) Extrastriate Cortex V2, V3, V4, V5 Neurons respond to increasingly abstract stimuli e.g faces, movement, houses. Damage to occipital cortex Hemianopia Loss of sight to half of visual field Usually caused by stroke Lesions from optic tract to occipital cortex Colour processing Colour anomia: inability to name colours Colour agnosia: inability to recognise colours Achromatopsia: inability to perceive colours (colour blindness) Damage to occipital cortex Partial blindness Visual hallucinations Difficulties in: recognising objects naming colours of objects recognising or reading written words locating objects in space (despite being able to see them) recognising if something is moving Damage to V5: Case Study V5 - Visual Motion area (MT) Akinetopsia (Greek: a for "without", kine for "to move" and opsia for "seeing") Case Study: Damage to V5 Patient LM. 43 y.o F Thrombosis bilateral damage Irreversible damage to V5 Could see objects and positions Could not see motion Gross akinetopsia World in snapshots Experienced significant struggle to perform daily activities “What” and “Where” visual pathways Two parallel visual streams Ventral stream (“what”) Projects from occipital cortex to temporal cortex Recognition of objects Dorsal stream (“where”) Projects from occipital cortex to parietal cortex Guidance of actions Aka “how” stream Damage to the “what” pathway Agnosia “without [a-] + knowledge [gnosis]” Visual-form agnosia Inability to recognise objects (including from drawings) Prosopagnosia Inability to recognise faces The man who mistook his wife for a hat Damage to the “where”/ How pathway Optic ataxia Deficit in visually-guided movements Preserved object recognition Damage to posterior parietal cortex Case study comparison Patent D.F Patient A.T Blind (cortical damage) Can see objects & recognize Cannot name objects them Cannot tell a triangle, circle or square Cannot pick them up properly But she can grasp objects Cannot make correct hand configuration to grasp an object Can put an envelope through a slot – though cannot see the He can see but cannot make letter or slot use of the information to interact with objects. Can interact with objects but cannot see them What areas of the brain are damaged? D.F A.T Ventralvisual stream DorsalVisual stream includes temporal lobe includes parietal lobe Video resources – visual processing deficits Achromatopsia (colour-blindness) https://aeon.co/videos/how-the-island-of-the-colourblind- made-oliver-sacks-rethink-normal The Man who mistook his wife for a hat ( dramatization) https://www.youtube.com/watch?v=EW0QocsHluM Optic ataxia (in Balint’s syndrome) https://www.youtube.com/watch?v=4odhSq46vtU Temporal lobe Temporal lobe functions Key functions: Auditory processing Hearing Language processing Comprehension Memory Formation Storage Also involved in: Olfaction (smell) Emotional processing  Temporal lobe anatomy Primary Auditory Auditory processing; Cortex hearing Language Wernicke’s comprehension area (Left temporal lobe) Primary Interpretation of Olfactory smell (received via Cortex olfactory bulb) (deep) Temporal lobe function - asymmetry Left temporal lobe Verbal memory Speech processing Right temporal lobe Non-verbal memory Musical processing Facial processing (fusiform face area) Aphasia Language impairment following localised brain injury Common effect of stroke (~1/3 patients) Main classifications: Broca’s aphasia Expression primarily affected ‘Non-fluent’ aphasia Wernickes aphasia Comprehension primarily affected ‘Fluent’ aphasia Damage to temporal cortex Auditory disturbance Disorders of music perception (amusia) Long-term memory problems Altered personality and affective behaviour (e.g., temporal lobe epilepsy) Summary Occipital lobe: Functions include visual processing, integration, interpretation; ‘what’ and ‘where’ pathways... Damage can cause difficulties with recognition and processing of objects, faces, colours; visually-guided movements… Temporal lobe: Functions include auditory processing, language, memory… Damage can cause language disorders (aphasia), memory impairment, behavioural/emotional changes… Size matters?  Primary Motor Cortex Precentral Gyrus Broca’s Area Orbitofrontal Cortex Olfactory Bulb PRIMARY MOTOR CORTEX MOVEMENT  Primary motor cortex Part of pre-central gyrus next to central sulcus The “motor strip” Focal skilled movements of arms, hands, mouth, etc. Primary motor cortex Fritsch and Hitzig -1870 Electrical stimulation of cortex in an anesthetized dog Produced movements of mouth, limbs and paws on opposite side of body Wilder Penfield – 1930s Used electrical stimulation to map cortex of patients about to undergo neurosurgery Confirmed the role of the primary motor cortex in producing human movement Mapping the motor cortex Homunculus (“little person”) Topographical representation of the body by a neural area Motor homunculus Sensory homunculus Topographic organisation Correspondence between neural areas and body parts they represent Areas of motor cortex that control the hands, fingers, lips, and tongue are disproportionately larger than parts controlling other areas Primary motor cortex Primary motor cortex https://www.flickr.com/photos/bethscupham/7362405446  Modelling movement Early idea: each part of the homunculus controls muscles in that part of the body Information from other cortical regions sent to the motor homunculus Neurons in the appropriate part of the homunculus activate body muscles Recent experiments suggest that motor cortex represents a repertoire of movement categories that can be modified by learning/practice Electrical stimulation of monkey cortex MRI studies in humans Basic movement categories Hand control Ascend/ lower descend; body- jump space Reach; Hand clasp control in central body- space Defensive posture/ expression Chew; Hand to lick mouth  Initiating a motor sequence Most of our motor learning is mastering sequences of action Frontal lobe involvement: Prefrontal cortex: plans complex behaviour Premotor cortex: organises the appropriate movement sequences Primary motor cortex: specifies how each movement is to be carried out or executed PREMOTOR CORTEX Premotor cortex Prepares movement sequences Selects behaviour in response to external cues Increasedactivity found when cues are associated with movement Damage to premotor cortex Disorders of volition Bilateral damage can cause akinetic mutism Absence of voluntary movement or speech Patient appears alert Unable to speak or move Increasingly passive behaviour PREFRONTAL CORTEX Prefrontal cortex Largest of the three frontal divisions Planning and coordinating complex cognitive behaviours - executive functions Expression of personality Appropriate social behaviour Major subdivisions Orbitofrontal Lateral (dorsolateral, ventrolateral) Medial (dorsomedial, ventromedial) Dorsolateral prefrontal cortex Damage to DLPFC Problems with executive functioning: Goal-directed behaviour Sustained attention Dysexecutive syndrome Planning Problem solving Attention Emotional and behavioural problems E.g., social judgement, impulse control/inhibition Orbitofrontal cortex Phineas Gage (1848) Iron rod through frontal lobe First case to suggest a link between brain damage and personality change Orbitofrontal cortex Functions include: Emotional regulation Close links to limbic system Impulse control Decision making Reward evaluation Phineas Gage… Impulsive, disinhibited, irritable, contentious Damage to orbitofrontal cortex Widevariety of behavioural/cognitive/emotional changes ‘Acquired Sociopathy’ General dampening of emotional experience Poorly modulated emotional reactions Disturbance in decision making Disturbance in goal-directed behaviour Disturbance in social behaviour Marked lack of insight into behvioural changes Also associated with addiction, OCD, some dementias PARIETAL LOBES Parietal lobe Parietal lobe anatomy Divided into two functional zones: Anterior: Sensory processing Somatosensory cortex Homunculus Posterior: Spatial processing Superior parietal lobule Inferior parietal lobule Supramarginal gyrus + angular gyrus Primary motor cortex https://www.flickr.com/photos/bethscupham/7362405446  Parietal lobe functions Key functions: Sensory processing and sensory integration (somatosensory-visual-auditory) Spatial awareness and perception Proprioception - awareness of body/ body parts in space and in relation to each other Motor planning (along with motor cortex)  Damage to parietal cortex Disturbances of motor planning – apraxia Verbal apraxia Ideomotor/ideational apraxia Disturbances of spatial processing (Hemi-)spatial neglect Inattention to stimuli on contralateral side to lesion Common after stroke (esp. right side) Damage to parietal cortex Agnosias From Greek: Anosognosia “without [a-] + Unawareness or denial of illness knowledge [gnosis]” Asomatognosia Loss of body ownership Anosodiaphoria Indifference to illness Asymbolia for pain Absence of normal reactions to pain Finger agnosia Inability to point to fingers or show them to examiner Summary Frontal lobe: Functions include planning and executing movements, decision making, inhibition, emotion regulation, motivation... Damage can cause difficulties with self-regulation, decision making, problem solving, social behaviour; problems with motor functions (motor cortex) Parietal lobe: Functions include integrating sensory information, spatial perception and awareness/attention, motor planning… Damage can cause problems with spatial processing (e.g. neglect), motor planning; somatosensory disorders and agnosias.