Lecture 1 Brain & Behaviour PSYC11212 Gorana Pobric gorana.pobric@manchester.ac.uk Lecture overview Course Introduction Course organization and overview Why do we study the brain? Research methods in behavioural neuroscience Format of the Course Lecture session: 1.5 hours, Fri. 11:30 – 13:00, Simon, Theatre E Seminar sessions: 4 sessions in weeks 4, 6, 8, 10 Seminars will take place on Mondays and Thursdays (e.g. from 13:00-14:00, Group 1 and from 14:00 – 15:00 Group 2) in University Place rooms All seminar sessions will be activity based Seminar teaching staff: Jaydan Pratts, Irem Eraydin, Jayesha Chudasama, Owen Waddington, Josephine Kearney Weekly drop-in sessions (weeks 2-5) – Fri. 13:00-14:00, Simon, room 1.34 Your Lecturers Dr Gorana Pobric Dr Nils Muhlert Dr Elizabeth Lewis Dr Annie Pye Assessment Exam MCQ (50 questions) – 70% of your mark SAQs (2 short answer questions) – 30% of your mark 3 mini quizzes with answers on Blackboard: week 4, week 8 and week 12 You will have the opportunity to practice both MCQs and SAQs by completing quizzes The quiz is NOT part of your mark (practice purposes only), so please take them as many times as needed Syllabus Week Dates Lecturer Fri. 11:30-13:00 Simon Theatre E Teaching week 1 31-Jan-20 Dr Pobric 1 Intro to Brain and Cognition Teaching week 2 07-Feb-20 Dr Pobric 2 Structure of the Nervous System Teaching week 3 14-Feb-20 Dr Pobric 3 Structure and Functions of cells in the Nervous System Teaching week 4 21-Feb-20 Dr Pobric 4 Neurotransmitters Teaching week 5 28-Feb-20 Dr Lewis 5 Emotion I Teaching week 6 06-Mar-20 Dr Lewis 6 Emotion II Teaching week 7 13-Mar-20 Dr Muhlert 7 Stress I Teaching week 8 20-Mar-20 Dr Muhlert 8 Stress II Teaching week 9 27-Mar-20 Dr Pye 11 Sleep EASTER BREAK 30 March -17 April 2020 Teaching week 10 24-Apr-20 Dr Pye 10 Autism and ADHD THEATRE B Teaching week 11 01-May-20 Dr Pye 11 Substance abuse Teaching Week 12 08-May-19 Examination period 11 May - 5 June 2020 BANK HOLIDAY Textbook 1. Carlson, N.R. (2014). Foundations of Behavioral Neuroscience (9th ed.). Boston, MA: Pearson Education Inc - available in e-book format] Intended learning outcomes • Identify the functions of main brain structures • Demonstrate an understanding of basic topics in cognition and physiology of behaviour • Understand research methods in behavioural neuroscience, and discuss their strengths and weaknesses • Critically reflect current issues in behavioural neuroscience research • Apply knowledge of brain and cognition to interpret research findings and everyday situations Why study the Brain and Behaviour? How the brain produces behaviour is a major unanswered scientific question. Understanding brain function will allow improvements in many aspects of our daily lives: educational systems, economic systems and social systems The brain is the most complex living organ on earth and is found in many animals. We would like to understand its place in biological order of our planet A growing list of behavioural disorders can be explained and treated as we increase our understanding of the brain Why study the Brain and Behaviour? COGNITION – higher mental processes: thinking, perceiving, imagining, speaking, acting and planning Cognitive Neuroscience relates to the study of the neural basis of behaviour. It bridges the gap between biological sciences and psychology and psychiatry. Psychologists have been investigating the details of mental processes for well over a century without knowing (or even caring) what part(s) of the brain are involved Understanding the neural basis of a mental process can help distinguish between different theories relating to how that process is performed Representations in the Head • Mental representation - the sense in which properties of the outside world (e.g. colours, objects) are copied/simulated by cognition • Neural representation - the way in which properties of the outside world manifest themselves in the neural signal (e.g. different spiking rates for different stimuli) Historical perspectives Plato Plato compared the body to a prison in which the soul is confined While confined by the body, the soul is forced to seek truth (knowledge) via the organs of perception We perceive beautiful things but not Beauty itself. In the body , the natural place for the immortal soul is the brain Historical perspectives Aristotle Mind / soul / psyche controls behaviour from the heart According to Aristotle, psyche is a nonmaterial entity responsible for human consciousness, perceptions, emotions, processes such as imagination, desire, pain, memory and reason Mentalism is a philosophical position that a person’s mind (psyche) is responsible for Behaviour. Behaviour is a function of the nonmaterial mind Historical perspectives • Do mental experiences arise in the heart (e.g. Aristotle) or brain (e.g. Plato)? • How can a physical substance (brain/body) give rise to mental experiences? = MIND–BRAIN PROBLEM • Dualism – mind (eternal) and body (mortal) are separate substances Dualism – mind and body are separate substances (Descartes) The “soul” (the mind) controls the movements of the muscles through its influence on the pineal body The eyes send visual information to the brain, where it could be examined by the soul. When the soul decided to act, it would tilt the pineal body (labeled H in the diagram), which would divert pressurized fluid through nerves to the appropriate muscles. It did not take long for biologists to prove that Descartes was wrong Luigi Galvani • Eighteenth-century Italian physiologist found electrical stimulation of frog's nerve caused contraction of attached muscle • Ability of muscle to contract and ability of nerve to send a message to muscle were characteristics of the tissues themselves • Brain did not inflate muscles by directing pressurized fluid/air through the nerve (balloonist theory) • Galvani’s experiment prompted others to study nature of message transmitted by nerve and means by which muscles contracted • The results of these efforts gave rise to the physiology of behavior History (cont.) • Dual-aspect theory – mind and body are two levels of explanation of the same thing (e.g. photons: wave–particle duality) • Reductionism – mind eventually explained solely in terms of physical/biological theory • These issues still relevant to modern cognitive neuroscience • Most psychologists deal with generalization Particular instances of behavior as examples of general laws, which they deduce from their experiments explained • Most physiologists deal with reduction Complex phenomena explained in terms of simpler ones Modern History of Behavioral Neuroscience • Written by psychologists who combined experimental methods of psychology with those of physiology • Applied them to issues that concern all psychologists • In recent years, there is specific interest in studying physiology of pathological conditions, such as addictions and mental health disorders How to study human consciousness Split Brains For patients with frequent and violent epileptic seizures, surgically splitting the corpus callosum was the only relief Corpus callosum is a bundle of nerve fibers which serve to connect the right and left cerebral hemispheres How does severing the corpus callosum change mental functioning and conscious awareness? Split - Brain Phenomenon Over 30 years ago studies of patients with a severed corpus callosum discovered some interesting side effects Roger Sperry & Michael Gazzaniga were in the forefront in utilizing these discoveries to determine significant ideas concerning brain function Language production, right-side motor control is in left hemisphere Left-side motor control is in right hemisphere Things to remember The RIGHT side of the brain controls limbs on the LEFT half of body The LEFT side of brain controls limbs on the RIGHT half of body Visual information Cognitive testing A brief tachistoscopic presentation insures that stimuli are presented to one hemisphere only Once the callosum is completely sectioned, information can not be shared between the two hemispheres However, eye movements can cause loss of lateralization – therefore the stimulus needed to be presented for 150ms or less (faster than the eye can move from central fixation to the stimulus) Testing setup - visual Testing setup - tactile Use left hand to find object https://www.youtube.com/watch?v=tgf3uiCZMHo Split Brains Smelling with a split brain https://www.youtube.com/watch?v=ZMLzP1VCANo Interim Summary Brain is the physical organ that makes all our mental life possible Cognitive psychology has developed as a discipline without making explicit references to the brain Biological measures can provide an alternative source of evidence to inform cognitive theories The brain provides a constraining factor on development and nature of cognitive theories Methods for looking at the brain • Single unit recording • Electroencephalography (EEG) • Magnetoencephalography (MEG) • Magnetic Resonance Imaging (MRI) • Positron Emission Tomography (PET) • Transcranial Magnetic Stimulation (TMS) Methods of Behavioural Neuroscience Ideally we would like to record from single neurons…. Single unit recording Electrodes, consisting of thin wires, are implanted into specific areas of the brain. Recordings of brain cell activities are made by measuring the electrical potential of nearby neurons that are in close proximity to the electrode. W. W. Norton What neuroimaging techniques can we use in humans? EEG Electroencephalography (EEG) is the measurement of the electrical activity of the brain by recording from electrodes placed on the scalp. The resulting traces are known as an electroencephalogram (EEG) and represent an electrical signal from a large number of neurons The 10–20 system of electrodes used in a typical EEG/ERP experiment. EEG EEG signals represent the the change in the potential difference between two electrodes placed on the scalp. The EEG obtained on several trials can be averaged together time locked to the stimulus to form an Event-Related Potential (ERP) ERPs are voltage fluctuations that are associated in time with particular event or stimulus (visual, auditory, olfactory stimuli) ERPs can be recorded from the human scalp and extracted from the ongoing EEG by means of filtering and signal averaging. Using ERP to Study Face Recognition Different ERP peaks associated with different aspects of face processing • The N170 is relatively specialized for faces, recorded from right temporal sites • The P250 – famous and familiar faces Rousselet et al. (2004). A comparison between the ERPs from patients with Alzheimer’s disease and those from control subjects. A markedly reduced P300 is seen for the demented patients at each electrode site MEG Magnetoencephalography (MEG) is an imaging technique used to measure the magnetic fields produced by electrical activity in the brain via extremely sensitive devices known as SQUIDs. These measurements are commonly used in both research and clinical settings. Excellent temporal and spatial resolution Interim Summary – Recording Techniques Neuronal activity generates electrical and magnetic fields that can be measured invasively (single cell recordings) or non-invasively (EEG, MEG) Single cells studies tell us how neurons code information, by measuring their response to external stimuli When populations of neurons are active in synchrony, they produce an electric field that can be detected at the scalp (EEG). When many waves are averaged and linked to the onset of the stimulus, then an ERP is obtained An ERP is an electrical signature of all different cognitive components that contribute to processing of that stimulus. Systematically varying aspects of a stimulus (e.g. any face vs. famous face) may lead to variations in aspects of ERP waveform. This can tell us about the timing and independence of cognitive processes Magnetic Resonance Imaging MRI Uses differential magnetic properties of types of tissue and of blood to produce images of the brain Structural vs. Functional imaging Structural: different types of tissue (skull, gray matter, white matter, CSF fluid) have different physical properties – used to create STATIC maps (CT and structural MRI) Functional: temporary changes in brain physiology associated with cognitive processing (PET & fMRI) CT Scan Computed tomography (CT) scanning builds up a picture of the brain based on the differential absorption of X-rays. CT scans reveal the gross features of the brain but do not resolve its structure well. Structural MRI scanning allows: •Detection of brain damage •Detection of lesion (brain damage) location •Measurement of lesion extent •Detection of damage to connections PET – functional imaging Positron Emission Tomography (PET) uses trace amounts of short-lived radioactive material to map functional processes in the brain. When the material undergoes radioactive decay a positron is emitted, which can be picked up be the detector. Areas of high radioactivity are associated with brain activity. Functional MRI - fMRI Basic principles: • Neuronal activity requires oxygen and glucose (energy) • Neuronal activity produces changes in blood oxygenation levels • fMRI uses the contrast between oxygenated and deoxygenated blood • They have different magnetic properties and so fMRI can provide information about brain activity The BOLD response Blood oxygenation dependent level (BOLD) Canonical HRF 0.12 Peak 0.1 Magnitude (arbitary) 0.08 0.06 0.04 0.02 Late undershoot 0 Stimulus -0.02 0 5 10 15 20 25 30 35 Seconds Blood flow increases when stimulus is applied Study correlation between brain activity and stimulus timings fMRI can be used to produce activation maps showing which parts of the brain are involved in a particular mental process. Measure activity in voxels — or volume pixels the smallest distinguishable box- shaped part in 3D image fMRI experiment results Reading in normal participants and dyslexics (a) Areas of common activation (b) Controls > dyslexics (c) Dyslexics > controls DTI – Diffusion Tensor Imaging An imaging method that uses a modified MRI scanner to reveal bundles of axons in the living brain We can visualize connections in the brain Transcranial magnetic stimulation • TMS: a means of disrupting normal brain activity by introducing neural noise – ‘virtual lesion’ • Michael Faraday (1791-1867) • Faraday’s Coil • His experiment involved passing an electrical current through one coil and measuring the effect in an adjacent coil • The effect in the adjacent coil was present only when magnetic field was changing (switching on/off) • This was the first demonstration of magnetic induction the entire basis of TMS http://www.youtube.com/watch?v=txmKr69jGBk How does it work? 8kA TMS coil current 2.5T Magnetic field pulse 30kT/s Rate of change of magnetic field 500v/m Induced electric field 15mA/cm2 Induced tissue current Why do TMS studies? • Task: (i.e. reading) : a neural network comprised of different brain areas is active in supporting the reading task. • Apply TMS pulse at any cortical node of the network, TMS will interfere with the reading relevant neural signal: – efficacy of that signal will be degraded – behavioural decrement (speed of response (RT) change – it will take us longer to read) Advantages of TMS: • Interference/virtual lesion technique. • Transient and reversible • Control location of stimulation • Establishes a causal link of different brain areas and a behavioural task Convergent approach is the best way to explore brain function Walsh and Cowey (2000). Nat Rev Neurosci. Summary Why do we study the brain Split brain patients Methods for studying the brain Single cell recording Electroencephalography (EEG) Magnetoencephalography (MEG) Magnetic Resonance Imaging (MRI) Positron Emission Tomography (PET) Functional Magnetic Resonance Imaging (fMRI) Transcranial Magnetic Stimulation (TMS) Readings: Carlson Text Chapter 1 – pgs. 2-8 Carlson Text Chapter 5 – pgs. 119-125
