Lecture 2 - Neuroscience and the Human Brain PDF

11/11/2024 PSYC112/132: Introduction to Neuroscience Whilst we wait to get started… PSYCHOLOGY ANAGRAMS! Week 6: Thursday 14th November 2024 Dr Abigail Fiske VELOPALMENDET...

11/11/2024 PSYC112/132: Introduction to Neuroscience Whilst we wait to get started… PSYCHOLOGY ANAGRAMS! Week 6: Thursday 14th November 2024 Dr Abigail Fiske VELOPALMENDET EMROYM [email protected] NGOITIOC NNURSICECEOE 1 2  11/11/2024 Questions, Comments, Concerns? Please do get in touch – I’m very happy to help Office: Fylde C42 [email protected] Book a meeting with me here Message me on Microsoft Teams Post in the Discussion Forum 3 Lecture 2: Neuroscience & The Human Brain 4  11/11/2024 Learning Objectives Define neuroscience as a scientific field of study Understand how the human brain develops from in utero to adulthood Describe evolutionary theories of human brain development By the end of the lecture: you will have a basic understanding of neuroscience as a scientific field and of human brain development 5 The Why Scientific: Psychology is a field of scientific study, as is neuroscience, and we need to understand how the fields overlap and how they differ Brain-Behaviour: Understanding human brain development is crucial for understanding many psychological functions, behaviours and even mental health disorders Theoretical: Understanding evolutionary theories of human brain development will support you to contextualise modern human behaviour within evolutionary frameworks 6  11/11/2024 Part I: What is Neuroscience? 7 Defining Neuroscience Neuroscience is the study of the nervous system The brain is super complex – we need knowledge from many different scientific disciplines to understand how it is structured and how it functions Neuroscience is a multi-faceted field of science with many sub-disciplines Many sub-disciplines will overlap with one another as scientists collaborate to advance knowledge about the nervous system 8  11/11/2024 Types of Neuroscience Studies Experiments – Manipulating two or more groups or conditions in attempt to establish cause and effect (e.g., comparing memory performance of a group of participants who are on anti-depressants with a control group) Quasi-experiments – Studies of groups who have been exposed to the conditions of interest in the real world (e.g., comparing reaction time in alcohol users compared to non-alcohol users) Case studies – Focus on a single subject or a very small number of subjects to investigate in detail a particular phenomenon or condition (e.g., following an accident / injury: Phineas Gage) 9 Quick detour: Phineas Gage 10  11/11/2024 Human and Non-Human Subjects Non-Human Subjects Human Subjects (often mice, rats and non-human primates) Can follow instructions and report their subjective Cannot follow instructions or report on their experiences subjective experiences Cheaper to work with (participant payments) More expensive – must maintain highest standards of animal care and lab facilities They have a human brain! Brains are often simpler: more likely that brain- behaviour interactions will be revealed Humans volunteer to be subjects (usually referred to Non-human animals cannot volunteer (usually as “participants”) referred to as “subjects”) Can compare different human – neurodevelopmental Comparative approach: comparing behaviour of conditions, neurological disorders, mental illness etc. species with and without a cerebral cortex Governed by strict code of ethics – cannot conduct Fewer ethical restrictions – allows for invasive invasive or harmful procedures experiments (allow still governed by strict code of ethics) 11 Physiological Psychology The study of neural mechanisms of perception and behaviour Direct manipulation and recording of the brain in controlled experiments Non-human animals Emphasis on research that contributes to development of theories on the neural control of behaviour Examples of research topics: Emotion – e.g., fear response Sleep – e.g., effects of sleep deprivation Stress – e.g., how stress affects the brain Brain lesions – e.g., impact on function 12  11/11/2024 Psychopharmacology / Neuropharmacology Study the effect of drugs on brain and behaviour Focuses on the manipulation of neural activity and behaviour with drugs (legal and illegal) using controlled experiments Research includes studying the basic principles of how drugs influence the brain- behaviour interaction, developing therapeutic drugs and reducing drug abuse Involves humans (with strict ethical approval) and non-human animals 13 Neuropsychology The study of the psychological effects of brain dysfunction in human patients Research is almost exclusively focused on case studies (patients with brain injury) and quasi-experimental studies (patients with brain dysfunction) Most applied discipline as research is almost always aimed at improving the health and wellbeing of human patients (e.g., diagnoses and treatment) 14  11/11/2024 Psychophysiology / Neurophysiology Studies the relation between physiological activity and psychological processes in humans Non-invasive measurements of the brain and body Brain: EEG, fNIRS, (f)MRI, MEG, CT Autonomic nervous system: Heart rate, blood pressure, pupil dilation, skin conductance Research tries to understand the physiology of psychological processes and can have important clinical applications 15 Cognitive Neuroscience Study of the neural basis of cognition (e.g., thought, memory, attention, language) Involves human participants and uses non- invasive methods to measure the brain Includes functional brain imaging (recording brain activity during a particular task and producing an image) Complex methods – involves collaborations with other neuroscientists 16  11/11/2024 Part II: The Human Brain 17 How the Human Brain Develops 18  11/11/2024 How the Human Brain Develops Birth: Brain is ¼ of the size of the adult brain First year: Brain doubles in size! Age 3: Brain is about 80% of the adult size Age 5: Brain is around 90% of the adult size ~Age 7: Brain is adult-sized! Based on this evidence, should governments prioritise funding for the early years? 19 How the Human Brain Develops From birth and in the first years of life there is significant growth and change in the human brain Increasing size (almost doubling of overall brain size from birth to 1 year) Expansion of cortical surface area Rapid myelination of neurons in the first year Gilmore, Knickmeyer & Gao (2018), Nat Reviews Neuroscience 20  11/11/2024 How the Human Brain Develops Substantial pre-natal development of cortical grey and white matter (and FA – measure of white matter integrity) First 2 years of life – substantial growth of cortical grey matter, white matter growth is slower Cortical thickness peaks around 1-2 years then decreases Surface area develops rapidly in first year Note the grey matter and cortical thickness decrease during adolescence White matter and FA continue to increase throughout adolescence Gilmore, Knickmeyer & Gao (2018), Nat Reviews Neuroscience 21 How the Human Brain Evolved Over the last 2-3 million years, the human brain size has almost tripled! Most of the increase has been in the cerebral cortex (cognition) An increase in the number of convolutions (folds on the cerebral cortex) has increased the surface area The human brain has 86 billion neurons! There are several theories about why humans have evolved such big brains… cc = cubic centimetres 22  11/11/2024 How the Human Brain Compares Human brains are big… but they are not the biggest! However, we have large brains relative to our body size 23 Mapping the Human Brain The Human Connectome Project A connectome is a complete map of neural connections. The goal of these wiring diagrams is to understand how the structure of the brain is connected to its behaviour. Data are now openly available to scientists  24  11/11/2024 A quick brain break! 25 Part III: Is the Human Brain Special? 26  11/11/2024 The “big” human brain is expensive! Despite only accounting for approximately 2% of the total body mass, the brain requires around: 20% of an adult’s daily energy budget 40% of a child’s daily energy budget 80% of an infant’s daily energy budget 27 Evolutionary Theories No single theory can completely account for human brain evolution But there are several theories: Environmental – physical challenges like finding or hunting food Social – interacting, communicating and cooperating with others Cultural – accumulation of local knowledge and practices Natural selection of best qualities If you are interested in evolution, read Chapter 2 of the textbook 28  11/11/2024 Environmental – Tool Use Many traits of human intelligence such as empathy, theory of mind, the use of symbols and tools are also found in great apes Tool use is prevalent across our evolutionary history, but humans became more reliant on tools (rather than their body size and strength) over time as tools became more sophisticated Tools helps us find, hunt and eat food Did tool use place evolutionary pressure on humans to develop big brains to further exploit this ability? 29 Social Brain Hypothesis Machiavellian Intelligence Hypothesis – large brains (and more sophisticated cognition) have evolved via intense social competition where the winner has reproductive success Humans are social creatures – big brains supported the development of communication and language within social groups, which ultimately, would have increased chances of reproductive success Did living in social groups place evolutionary pressure on humans to develop big brains? 30  11/11/2024 Sexual Selection Theory Geoffrey Miller (evolutionary psychologist) proposes that our large brains and minds evolved not just as survival machines, but as “courtship machines” He proposes that the human mind evolved to attract and entertain members of the opposite sex (with the goal of reproducing) As such, brain size is a sexually selected characteristic Brain size itself offers little or no survival advantage, but the skills that go along with it will make us attractive to members of the opposite sex (intelligence as an indicator of genetic fitness) 31 Cultural - Cooking It has been proposed that being able to control fire to cook food has been a major influence on the growth of the human brain Cooking food increases the energy yield of food and the speed with which food is consumed Cooked food is more easily digestible, providing more calories more quickly See TEDTalk by Suzana Herculano-Houzel which freed up energy and time to develop (and use) bigger brains 32  11/11/2024 Other Theories Cultural intelligence hypothesis – social learning and development of cultural skills and strategies for survival Reduction in aggression – this change separated us from other primates and allowed us to develop empathy, social skills, culture and cognition Social exchange theory – mutual exchange of resources to support survival Disease-resistance – Intelligence as an outward sign of disease-resistance Ecological dominance-social competition model – selective pressure shifted for humans to master the natural world and dominate members of its own species (leadership) 33 HOMEWORK 1. Read Chapter 1 of the course textbook! 2. Take a look at the Optional Reading list for Lecture 2 in the module handbook 3. PREP WORK for tomorrow: Watch the 2-min YouTube video “The Neuron” to give you a good starting point ahead of the lecture. 34  11/11/2024 HOMEWORK HAVE YOU READ THE MODULE HANDBOOK YET? 35 Thank you for your attention, engagement and contributions! 36