Biopsych Lect1 slides available after lecture 2023_24pptx.pptx

Biological Psychology • Introduction to studying animal cognition • Specialist cases and what they can tell us • The ‘human brain’ – what can we learn from size? Summary • Physical features • Tool use • Cognitive abilities • Social skills • Language • Culture Are humans unique? https://...

Biological Psychology • Introduction to studying animal cognition • Specialist cases and what they can tell us • The ‘human brain’ – what can we learn from size? Summary • Physical features • Tool use • Cognitive abilities • Social skills • Language • Culture Are humans unique? https://youtu.be/YgHrn2VFbvo https://www.youtube.com/watch?v=8cn0kf8mhS4 “…{aim of} understanding cognition across the animal kingdom including how it works, what it is good for in nature, and how it evolved.” (Shettleworth, 2010) • Evolutionary psychology: an approach applying evolutionary principles to the working of the human mind • Comparative psychology: study of animal and human cognition; emphasis on crossspecies comparison • Sociobiology: systematic study of the biological bases of social behaviours … and many more fields Comparative cognition Observation: Individuals differ. Observation: Some of these traits are heritable. Observation: Not all offspring survive. Inference: Individual differences affect the probability that offspring will survive and reproduce Natural Selection & Darwin For an accessible introduction to/refresher on Natural Selection & Genetics, see McFarland, 1999, Part 1. • Natural selection acts on variations of phenotype (observable trait or characteristics; includes morphological structures, neural structures, neural properties and behaviours) • Phenotypes: produced by organism's genotype in combination with environmental and activity-dependent mechanisms • Genotype: total collection of genes within individual • Genes - heritable part of the natural selection equation Sources of genetic variation: • Mendelian variation (see: laws of inheritance) • Chromosome mutation (recombination) • Gene mutation (e.g. deletions or substitutions in nucleotide) Natural Selection For an accessible introduction to/refresher on Natural Selection & Genetics, see MacFarland, 1999, Part 1. • *Adaptation: a phenotype arising from genetic variation that increases the probability of an individual producing offspring * remember: phenotype can include: morphological structures, neural structures, neural properties and behaviours Analogy Similarity of function. Not necessarily similar in appearance. Not evidence of/evolved from common ancestry. Homology Resemblance based on common ancestry. Adapted to provide different functions. Homology of Forelimb structures • What events cause the animal to behave as it does in that moment (internal – e.g. state of hunger & external – e.g. presence of food)? • How do experience and genetic makeup contribute to this behaviour? • What is the adaptive value of the behaviour? • How has this behaviour evolved? Complementary accounts of Behaviour • Simple & model organisms • Comparisons between closely related species • Outstanding features & specialized skills Researchers’ choice of subject • Simple & model organisms Researchers’ choice of subject o o o o Cells, organelles, intracellular fluid, homeostasis Neurons, action potentials, synapses & their modulation Genetics (genome ~ 40% homologous) Basic patterns of behaviour • Rhythms - Ultradian (recurrent cycles in 24-hours – e.g. defecation) - Circadian (endogenously driven 24 hour cycle e.g. locomotory speed) • Basic functions: foraging, alimentation, mating • Hierarchy of needs What do we have in common with worms? e.g. Caenorhabditis elegans Robson, D. (2011) A brief history of the brain. New Scientist, 211, 40-45. • Comparisons between closely related species Researchers’ choice of subject Wildman et al. (2003) • Outstanding features & specialized skills Researchers’ choice of subject “Natural selection operates on the physical characteristics, or phenotype of the individual – including its behaviour; thus we can attribute survival value to behaviour patterns, just as we can to the morphological properties of animals.” (McFarland, 1999) Caution: not all behaviours or abilities are adaptations Specialized Navigational skills Highly sophisticated navigational skills • Insects (e.g. ants, bees) • Fish (e.g. salmon) • Reptiles (e.g. turtles) • Birds (e.g. penguins) • Mammals (e.g. dolphins) Specialized Navigational skills Highly sophisticated navigational skills • Insects (e.g. ants, bees) • Fish (e.g. salmon) • Reptiles (e.g. turtles) • Birds (e.g. penguins) • Mammals (e.g. dolphins) Different methods of navigation • “Dead Reckoning” & path integration • Ultrasound • Magnetic field • External reference points (landmarks, sun, stars) • Leaving traces (e.g. odour) • Remembering the path/time taken Saharan Desert Ant (Cataglyphis fortis) https://www.youtube.com/watch?v=ZrxeROQPtfQ • Energy Hypothesis • but independent of weight Saharan Desert Ant (Cataglyphis fortis) How do ants measure distance? • Optic flow Hypothesis • but possible in darkness • Time-lapse integrator • but possible at different speeds How do ants measure distance? Three groups: - Shortened legs (stumps) - Normal legs - Elongated legs (stilts) Results: - Stump group: undershot - Control group: correct - Stilt group: - overshot Wittlinger, M., Wehner, R. & Wolf, H. (2006) The Ant Odometer: Stepping on stilts and stumps. Science, 312, 1965-1967. http://www.sciencemag.org/content/312/5782/1965/suppl/DC1 If we manipulate the legs of Ants before they leave the nest, what will happen on their return? • Ants with stumps will search before the site of the removed nest (undershoot), while ants with stilts will overshoot • Ants with stumps will search at the site of the removed nest (accurate), while ants with stilts overshoot • Ants with stumps will search before the site of the removed nest (undershoot), while ants with stilts will be accurate • Ants with stumps will search at the site of the removed nest (accurate), and ants with stilts will ALSO be accurate The Hippocampus & navigational abilities Relationship between hippocampal and telencephalic volumes for caching (filled triangles) and non-caching (open triangles) families Source: Sherry et al. (1989, Fig. 4, p. 314) “Whenever a complex, organised structure or a complex, integrated biosynthetic pathway has become an essential adaptive unit of a successful group of organisms, the essential features of this unit are conserved in all of the evolutionary descendants of the group concerned.” (Stebbins, 1969) “As a general rule the relative size of a brain region is a good guide to the importance of function of that region for the adaptations of the species” Total Brain Weight Common shrew Sheep 0.25g 100g Chimpanzee 400g Human Elephant 1,400g 5,000g Brain weight as % of Body weight Elephant Sheep Chimpanzee Human Common shrew 0.20% 0.25% 0.95% 2.33% 3.33% Allometry: describes how traits or processes scale with one another (Huxley, 1932) y = Bxk Or logy= logB+klogx Which takes the form: (Y = mX + C ) Source: Jerison (1991). Source: Jerison (1991). y = Bxk Encephalization Quotient: EQ = Mbrain Ebrain or EQ = Mbrain 0.12Mbody0.67 Source: Jerison (1991). Ebrain= 0.12Mbody0.67 Encephalization Quotient Common shrew Sheep 0.54 0.69 Encephalization Quotient: Elephant Chimpanzee 2.12 Brain Weight 0.12(Body weight)0.67 2.66 Human 7.34 Cortex expansion PFC enlargement in humans: Neocortex size as related to various social or ecological correlates : • • Dunbar (2009) Relationship between size of social group and neocortex ratio (neocortex volume/brain volume). Three genera represented. Cortex expansion Scaling brain(or a brain component) size against body size reveals extent to which organisms invest in brain tissue relative to rest of body Scaling one brain part (e.g. neocortex) against another should reveal neurocognitive specialisation (Barton, 2006) • Neuronal density scales (with e.g. structure mass) differently across mammals (Herculano-Houzel, 2009, 2011) • Primate brain size increases isometrically as function of neuron number (neuronal density does not decrease with increasing size) • Cognition depends on an absolute feature of the brain e.g. total number of cortical neurons & conduction velocity of fibers (Roth & Dicke, 2005) • Across species (Herculano-Houzel, 2011) cerebral cortex and cerebellum gain neurons coordinately (~ 4.2 neurons in cerebellum to 1 in cerebral cortex) • Coordinated scaling masked by different mass-scaling relationships. • In primates, cerebral cortex increases in mass as gains neurons to a greater degree than the cerebellum therefore its relative mass increases. Neuronal Density • Evidence: importance of integrated functions of these two structures; also suggests subject to similar selective pressures & evolve concertedly • In order to understand evolution of brain and cognition we need to analyse the evolution of functional systems distributed across gross brain subdivisions (see Barton, 2006) • “Functions mediated by cortico-cerebellar circuits, such as visually guided reaching and manipulation and programming of complex motor skills were targets of natural selection in primates” Cortico-cerebellar connections Barton, R.A. (2006) Primate brain evolution: Integrating comparative, neurophysiological, and ethological data. Evolutionary Anthropology, 15, 224-236. Cortical regions with reciprocal cerebellar connections: Parietal • • • • Visually guided hand movements Motor planning Verbal processing & storage Spatial Navigation Temporal • Articulatory aspects of language Frontal/Prefrontal • • • • Language Working memory Directed attention Planning Occipital • Vision/visuo-motor Cortico-cerebellar function: - Sensory-motor coordination - Planning of movements: learning, including complex sequences of behaviour - “Adaptive control” within environment Barton (2011) Barton, R.A. (2006) Primate brain evolution: Integrating comparative, neurophysiological, and ethological data. Evolutionary Anthropology, 15, 224-236. Lecture 1: comparative cognition – why should we study other species? •Introduction to studying animal cognition: • Cross species behaviour & structure comparisons can inform us as to the origins and evolution of our own cognition •Specialist cases and what they can tell us: • Specialized skills/abilities and closely related species •The ‘human brain’ – what can we learn from size?: • Differences in behaviour linked to differences in brain across species • What is not covered by size comparisons across species • What is perhaps a more informative measure? Aims and learning outcomes • Pinel, J. P. J., & Barnes, S.J. (2022) Introduction to Biopsychology (11h Ed.) • Chapter 2 • Shettleworth, S.J. (2010) Cognition, Evolution and Behaviour (2nd Ed.). • Chapter 1 (p3-54) --------------------------- Barton, R.A. (2006) Primate brain evolution: Integrating comparative, neurophysiological, and ethological data. Evolutionary Anthropology, 15, 224-236. Recommended reading • McFarland, D. (1999) Animal Behaviour: psychobiology, ethology and evolution (3rd Ed.). • Chapter 1, Part 1 • Carlson, N.R. (2010) Physiology of Behaviour (10th Ed.). • Pages 14-22 & relevant sections of chapter 3 • Gazzaniga, M.S., Ivry, R.B. & Mangun, G.R. (2009) Cognitive Neuroscience: The Biology of the Mind (3rd Ed.) • Chapter15 (p634-666) • ---------------• Etienne, A.S. & Jeffery, K.J. (2004) Path integration in mammals. Hippocampus, 14, 180192. • Deaner, R. O., Isler, K., Burkart, J. & van Schaik, C. (2007) Overall brain size, and not encephalization quotient, best predicts cognitive ability across non-human primates. Brain, Behaviour & Evolution, 70, 115-124. • Herculano-Houzel, S. (2010) Coordinated scaling of cortical and cerebellar numbers of neurons. Frontiers in Neuroanatomy, vol 4: 12. • Herculano-Houzel, S. (2009) The human brain in numbers: a linearly scaled-up primate brain. Frontiers in Human Neuroscience, vol 3: 31 • Herculano-Houzel, S. (2011) Not all brains are made the same: New views on brain scaling in evolution. Brain, Behaviour & Evolution, 78, 22-36. Related Articles