Overview: Organization of the Brain and Behavior

1. Overview: Organization of the Brain and Behavior

2. Swanson, L.W. (2000) What is the brain? Trends Neurosci., 23, 519-527. Segmental Model

3. (Swanson, 2000) Swanson, L.W. (2000) What is the brain? Trends Neurosci., 23, 519-527.

5. Swanson, L.W. (2000) What is the brain? Trends Neurosci., 23, 519-527. Developmental Model

9. Swanson, L.W. (2000) What is the brain? Trends Neurosci., 23, 519-527. Evolutionary Model

11. Swanson, L.W. (2000) What is the brain? Trends Neurosci., 23, 519-527. Genomic Model

15. SYSTEM NERVORUM CENTRALE (Central nervous system) I. ENCEPHALON (brain) A. PROSENCEPHALON (forebrain) 1. TELENCEPHALON (endbrain; limbic system, basal ganglia & cerebral cortex) 2. DIENCEPHALON (between-brain, or interbrain; hypothalamus & thalamus) B. MESENCEPHALON (midbrain; tectum & tegmentum) C. RHOMBENCEPHALON (hindbrain) 1. METENCEPHALON (pons & cerebellum) 2. MYELENCEPHALON (medulla oblongata) II. MEDULLA SPINALIS (spinal cord) Notes: "BRAINSTEM" is an imprecisely defined term which usually refers to the rhombencephalon and mesencephalon together. It may or may not include the cerebellum, and sometimes the diencephalon is included. Similarly, the terms "CEREBRUM" or "CEREBRAL HEMISHPHERES" may refer to the telencephalon or to the entire prosencephalon. The term “basal ganglia” is also used imprecisely, sometimes including the midbrain nucleus, substantia nigra, and sometimes including only forebrain structures. The amygdala may be included as part of the limbic system or as part of the basal ganglia, depending on the author.

16. SYSTEM NERVORUM CENTRALE (Central nervous system) I. ENCEPHALON (brain) A. PROSENCEPHALON (forebrain) 1. TELENCEPHALON (endbrain; limbic system, basal ganglia & cerebral cortex) 2. DIENCEPHALON (between-brain, or interbrain; hypothalamus & thalamus) B. MESENCEPHALON (midbrain; tectum & tegmentum) C. RHOMBENCEPHALON (hindbrain) 1. METENCEPHALON (pons & cerebellum) 2. MYELENCEPHALON (medulla oblongata) II. MEDULLA SPINALIS (spinal cord) Notes: "BRAINSTEM" is an imprecisely defined term which usually refers to the rhombencephalon and mesencephalon together. It may or may not include the cerebellum, and sometimes the diencephalon is included. Similarly, the terms "CEREBRUM" or "CEREBRAL HEMISHPHERES" may refer to the telencephalon or to the entire prosencephalon. The term “basal ganglia” is also used imprecisely, sometimes including the midbrain nucleus, the substantia nigra, and sometimes including only forebrain structures. The amygdala may be included as part of the limbic system or as part of the basal ganglia, depending on the author.

17. Hierarchical Organization of the Brain and Behavior

18. What is a hierarchy? Ordering along a dimension or arrangement in a graded series What are some examples of hierarchies?

19. Behavior Taxonomy Anatomy and Physiology Histology Cytology Molecular biology DNA Cellular Proteins Cells Cells and Tissues Organs Organisms Organisms and Societies Complexity Hierarchy

20. Size Hierarchy

21. Command Hierarchy Partition

22. Lattice Command Hierarchy

24. Hierarchical Control by the CNS Hierarchical sensory processing Hierarchical motor control

25. Hierarchical Control by the CNS spinal cord-- basic sensory reception, integration, motor command e.g. withdrawal reflex reflex arcs, central pattern generators brainstem-- cranial reflexes, central pattern generators (respiration, mastication, etc) command systems primitive responses (orienting, posture, eye movements, etc) background pattern for more differentiated responses (“arousal”) primitive defensive reactions autonomic responses subcortical forebrain-- thalamus -- crude discriminations, e.g. light-dark, pain directs retic. arousal to specific modalities (attention) limbic system -- gives rise to specific emotional states hypothalamus -- responsive to internal chemistry (homeostasis, hormonal regulation) cortex-- finest sensory discrimination, motor coordination highest integrative activity cognition, curiosity, consciousness

28. Amphioxus

29. Encephalization From Wikipedia (it MUST be true!): Encephalization is defined as the amount of brain mass exceeding that related to an animal's total body mass. Quantifying an animal's encephalization has been argued to be directly related to that animal's level of intelligence. Aristotle wrote in 335 B.C. "Of all the animals, man has the brain largest in proportion to his size."[1] Also, in 1871, Charles Darwin wrote in his book The Descent of Man: "No one, I presume, doubts that the large proportion which the size of man's brain bears to his body, compared to the same proportion in the gorilla or orang, is closely connected with his mental powers."[2]

30. “Ontogeny recapitulates phylogeny” means that the evolutionary history of an organism (its phylogeny) is recapitulated (repeated) in its ontogenetic (lifespan) development. In ontogeny, “encephalization” means a relative increase in the importance of progressively more rostral structures of the brain. We will critically examine these notions as the course progresses.

32. Organization of Behavior

33. Behavior Also Can be Organized Hierarchically Reflexes Rhythmic Behaviors Kineses Taxes Species-typical (“instinctive”) behaviors Motivated (operant) behaviors Latent learning

34. Behavior Also Can be Organized Hierarchically Reflexes • predictable, stereotyped responses • to specific stimuli • usually localized • involuntary • involve relatively few neurons • graded responses • degree of voluntary control over reflex varies

35. Behavior Also Can be Organized Hierarchically Reflexes • Micturition reflex is well-controlled • "to pee or not to pee" • elicited by distention of bladder • bladder contraction and internal sphincter relaxation • spinal control • external sphincter relaxation • brainstem control • external sphincter relaxation under cortical inhibitory control • eventually, however, control must give way • Pupillary reflexes are generally not subject to significant voluntary control

36. Behavior Also Can be Organized Hierarchically Reflexes Rhythmic Behaviors • basis of rhythmic behaviors are • Central Pattern Generators (CPGs) • in brainstem and spinal cord • mechanisms that can operate without any sensory input • run a sequence of movements, like computer programs • input may be necessary to initiate them • underlie activities as diverse as chewing, breathing, locomotion, and copulation, even music and speech • long thought to be reflex activities • reflexes act as modifiers via feedback control

37. Behavior Also Can be Organized Hierarchically Reflexes Rhythmic Behaviors Kineses • change in rate of movement • simple change in rate of rhythm (CPG) • may be + (increase in rate) or – (decrease in rate) • named according to evoking stimulus • e.g. + photokinesis, – thermokinesis • general to the species • serve to maximize time in good environment, • minimize time in bad environment • often incorrectly inferred to reflect higher-order processes • e.g. formation of aggregates

38. Behavior Also Can be Organized Hierarchically Reflexes Rhythmic Behaviors Kineses Taxes • movement oriented to a stimulus • may be + (approach) or – (withdraw) • named according to mechanism, type of stimulus • klinotaxis • single receptor integrating over time • tropotaxis • paired receptors--simultaneous comparisons • telotaxis • orientation toward a goal • not necessarily stimulus strength • e.g. swim to shore

39. Behavior Also Can be Organized Hierarchically Reflexes Rhythmic Behaviors Kineses Taxes Species-typical (“instinctive”) behaviors • a.k.a. fixed action patterns • relatively complex behaviors common to members of a species • require minimal learning at most • usually referred to as innate or instinctive

40. Behavior Also Can be Organized Hierarchically Reflexes Rhythmic Behaviors Kineses Taxes Species-typical (“instinctive”) behaviors Motivated (operant) behaviors • goal directed • elicited by physiologically meaningful stimulus • signals food, sex, water, threat, etc. • terminated by consummatory response • eat, drink, fight, flee, copulate • appetitive—approach, aversive-- withdraw

41. Behavior Also Can be Organized Hierarchically Reflexes Rhythmic Behaviors Kineses Taxes Species-typical (instinctive) behaviors Motivated (operant) behaviors Latent learning (learning without a US) • by observation (modeling, imitation) • by performing without reward • by exposure

42. Behavior Also Can be Organized Hierarchically Reflexes Rhythmic Behaviors Kineses Taxes Species-typical (“instinctive”) behaviors Motivated (operant) behaviors Latent learning