Sunday, May 2, y WEEK 6 · Understand basic terminology (ganglia, brain, nuclei, nerve tracts, grey matter and white matter). · Relate basic neural networks and synaptic communication to possible mechanisms underlying reflexes and memory . Predict the effect of modifications to cell signalling pathways on sensitization, habituation, and long term potentiation · Describe how the central nervous system is protected and how substances are transmitter to and from the rest of the body - Compare and contrast the basic organization of the central nervous system and the peripheral nervous system of vertebrate · Differentiate the 3 subdivisions of the adult brain of vertebrate and name their principal structures and functions · Predict the consequences of damage (such as from injury or disease) to different regions of the mammalian brain and spinal cord - Compare and contrast the form and function of different regions of the peripheral nervous system LECTURE 10 - Nervous System Overview One of the body's homeostatic control systems with endocrine system Broadly composed of sensors, integrating centres, and output pathways Basic Terminology Nerve net diffuse network of neurons without any centralization Ganglion grouping of neuronal cell bodies Nerves grouping of axons Brain complex integrating centre made up of clusters of nuclei and tracts Basic Neural Networks simple to complex integration reflexes -> rhythmic behaviour -> voluntary behaviour -> learning and memory -> creativity-> consciousness neuronal pools - functional groups of interconnected neurons - can be localized or diffuse - several neuronal pools can be interconnected - output can have a variety of nervous system affects 1
Divergence Convergence Serial processing Parallel processing Sunday, May 2, y Reverberation 1 Spread of information from one neuron to several neurons Allows spatial summation Information is relayed from one neuron to another neuron (or one neural pool to another neural pool 15 Several neurons (or neural pools) process the same information simultaneously Positive feedback loop neuronal pool wiring Divergence: ex. Smell classificaiton of reflexes - innate: touching a hot stove - acquired: learning through experiences processing site response complexity of circuit Simple reflexes - sensory input is directly passed to motor neurons in the spinal cord and also to the brain for processing polysynaptic reflex arc pattern generators Learning and memory synaptic plasticity synaptic function changes in response to patterns of use 1. synaptic facilitation - repeated pre-synaptic APs increase NT release 2. synaptic depression - repeated post-synaptic APs decrease Nt release 2
Sunday, May 2, y 3. post-tetanic potentiation - after train of high frequency APs increase Ca2+ synaptic facilitation synaptic depression post-tetanic potentiation Repeated pre-synaptic Repeated post-synaptic occurs after a train of high frequency APs increases NT release decreases NT release increases post synaptic graded potentials decreases post synaptic graded potentials increase in postsynaptic graded potential at a later time ex. aplysia - withdraws it's gill when touched - withdraw declines after repeated touching - habituation is due to inactivation of voltage gated Ca2+ channels (calcium builds up) - electric shock delivered to tail -> gill withdraw is