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.
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.
What is a hierarchy?
Ordering along a dimensionor
arrangement in a graded series
What are some examples of hierarchies?
Molecular biology
DNA
Cellular Proteins
Cytology
Cells
Histology
Cells and Tissues
Anatomy and Physiology
Organs
Taxonomy
Organisms
Behavior
Organisms and Societies
Complexity Hierarchy
Hierarchical Control by the CNSspinal 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 systemsprimitive responses (orienting, posture, eye movements, etc)background pattern for more differentiated responses
(“arousal”)primitive defensive reactionsautonomic 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 stateshypothalamus -- responsive to internal chemistry
(homeostasis, hormonal regulation)
cortex--finest sensory discrimination, motor coordinationhighest integrative activity
cognition, curiosity, consciousness
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]
“Ontogeny recapitulates phylogeny” means thatthe 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.
Behavior Also Can be Organized
HierarchicallyReflexes
Rhythmic Behaviors
Kineses
Taxes
Species-typical (“instinctive”) behaviors
Motivated (operant) behaviors
Latent learning
Behavior Also Can be Organized
HierarchicallyReflexes
predictable, stereotyped responsesto specific stimuli•usually localized•involuntary•involve relatively few neurons•graded responses•degree of voluntary control over reflex varies
Behavior Also Can be Organized
HierarchicallyReflexes
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
Behavior Also Can be Organized
HierarchicallyReflexes
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
Behavior Also Can be Organized
HierarchicallyReflexes
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
Behavior Also Can be Organized
HierarchicallyReflexes
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
Behavior Also Can be Organized
HierarchicallyReflexes
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
Behavior Also Can be Organized
HierarchicallyReflexes
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
Behavior Also Can be Organized
HierarchicallyReflexes
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
Behavior Also Can be Organized
HierarchicallyReflexes
Rhythmic Behaviors
Kineses
Taxes
Species-typical (“instinctive”) behaviors
Motivated (operant) behaviors
Latent learning