Neurophysiology: General Introduction

Neurophysiology: General Introduction

• This section covers material from lectures only, no textbook is required
• Lectures explain physiological concepts using visuals and demonstrations
• This document records lecture diagrams and major points, not explanations
• Key information comes solely from lectures and document, not other sources
• Two advanced textbooks for reference are Kandel et al. (2013) and Purves et al. (2012).

How to do well on Examinations

• Attend all lectures; new material not found in the document will be on the exam

• Scenarios discussed in lectures may be used in multiple-choice questions (MCQs)

• Material and diagrams covered in lectures are all examinable

• Don't fall behind in attending lectures.

• Read and answer the objectives for each lecture. The objectives help test understanding

• Use sample questions from past exams to practice and prepare for the new content on the exam

Neurophysiology I: The Brain, Neurons, and Synaptic Transmission

• Objectives include drawing the brain and spinal cord, naming brain cell types, drawing a neuron, identifying synapse features, describing EPSPs and IPSPs, and distinguishing synaptic transmission types.

Objectives (Answers)

• Detailed diagrams of the brain and spinal cord, labelling major anatomical features
• Two brain cell types and their overall functions and roles. Glial cells support neurons in many ways
• A representative neuron, labelling parts and axon terminations (synapses). Dendrites, soma, axon hillock and terminals.
• Description of chemical and electrical synapses. Important differences include electrical resistance, communication methods, and speed
• Explanation of ionic mechanisms behind EPSPs and IPSPs (excitatory and inhibitory postsynaptic potentials) using detailed diagrams and explanations
• Contrasting three main differences between synaptic transmission in the CNS and the neuromuscular junction. Different transmitters, input summation, and output types.

Neurophysiology II: Synaptic Transmission

• Objectives include defining spatial and temporal summation of post-synaptic potentials. Understanding the molecular mechanisms of synaptic transmission and identifying five classes of neurotransmitters/neuromodulators and their functions. Explaining the mechanisms of long-term potentiation (LTP) and describing presynaptic facilitation and inhibition.

Objectives (Answers)

• Explanations of spatial and temporal summation of synaptic potentials (EPSPs and IPSPs)
• Details of synaptic transmission events and diagrams illustrating these.
• Five classes of neurotransmitters/neuromodulators (e.g. acetylcholine, biogenic amines, amino acids, neuropeptides, etc.) and their functions.
• Examples of the major excitatory and inhibitory neurotransmitters in the brain and their actions. Understanding long-term potentiation (LTP).
• Explanations of presynaptic facilitation and inhibition.

Neurophysiology III: Transduction of Environmental Information

• Objectives include defining sensory receptors and their adequate stimuli, explaining transducer mechanisms for various receptors, listing characteristics of generator potentials, illustrating action potential patterns, giving an example of adaptation, and explaining Pacinian corpuscle adaptation.

Objectives (Answers)

• Definition of sensory receptors and their adequate stimuli (e.g., light for rods in the eye)
• Conceptual models explaining transducer mechanisms for mechanoreceptors, chemoreceptors, and photoreceptors — how stimuli are converted into electrical signals.
• Four characteristics of generator potentials (local, graded, not propagated, can summate)
• Example patterns of action potential firing for rapidly adapting and slowly adapting receptors to a sustained stimulus.
• Adaptation in the context of a somatosensory receptor (e.g., a receptor stops firing after a constant stimulus).
• Two reasons why Pacinian corpuscles adapt quickly to pressure (specific structure and ion channel properties of the corpuscles)

Neurophysiology IV: Somatosensory System

• Objectives include explaining how stimulus quality and intensity are signaled, listing receptors for touch, vibration, temperature, pain, and proprioception, defining receptive fields, and naming and describing ascending sensory pathways, and describing somatotopic organization, and its modifiability.

Objectives (Answers)

• Explanations of how the body detects quality and quantity of stimuli.
• List of receptors for touch, vibration, temperature, pain, and proprioception.
• Definition and characteristics of a receptive field for a somatosensory neuron.
• Descriptions of the two major ascending sensory pathways (spinal thalamic and dorsal column-medial lemniscus).
• Description of the somatotopic organization of neurons in the somatosensory cortex.
• Evidence (techniques/disorders) supporting somatotopic organization.
• Discussion of whether somatotopic mapping is fixed or modifiable (and why).
• Definition and characteristics of cortical columns in somatosensory cortex.

Neurophysiology V: Visual System

• Objectives include listing retinal cell types, describing rod and cone functions, illustrating light transduction, drawing retinal ganglion cell receptive fields, describing retinal information processing, drawing receptive fields of simple cortical cells, and listing similarities to the somatosensory system.

Neurophysiology VI: Auditory System

• Objectives include giving an overview of the auditory system, describing impedance matching, listing the transduction sequence for sound into action potentials, describing how sound frequency and intensity are coded, identifying structures in the pathway critical for sound localization, describing auditory cortex organization, and explaining the effect of a lesion.

Neurophysiology VII: Vestibular System and Eye Movement

• Objectives include giving a brief overview of the vestibular system, defining benign positional vertigo, naming vestibular receptor parameters, describing vestibular information pathways, defining major vestibular system functions, describing how leg proprioception and vision contribute to balance, describing eye movements in various situations, and listing the four main types of eye movements.

Neurophysiology VIII: Motor System and Muscle Receptors

• Objectives include drawing a flow diagram of the motor system, naming four muscle receptors and the information they signal, describing Golgi tendon organ responses, demonstrating muscle spindle properties, and describing alpha-gamma coactivation.

Neuro IX: Spinal Reflexes

• Objectives include drawing and describing the stretch reflex arc, defining electromyogram (EMG), describing the outcome of slow, medium, and quick stretches, defining spasticity, drawing and describing the flexion (withdrawal) reflex, describing characteristics of the scratch reflex, and identifying the neural locations for locomotion circuits.

Neuro X: Motor Cortex

• Objectives include naming three techniques for studying the brain, defining the motor cortex, discussing somatotopic motor cortex organization, listing evidence that motor cortex represents movements and not muscles, listing evidence showing plasticity of motor cortex organization, listing motor cortex output pathways, discussing the corticospinal tract, describing the effects of lesions, and naming findings from monkey experiments about pyramidal tract neuron discharge, and listing factors delaying movement onset.

Neuro XI: Cerebellum

• Objectives include diagramming and explaining the cerebellum's structure, origin of the name, neuronal types, function of the cerebellum, effects of medial and lateral lesions, overall function and four specific functions.

Neuro XII: Basal Ganglia

• Objectives: Name brain areas that interact with motor cortex, name the nuclei, draw a connection diagram and describe features; describe motor, oculomotor, limbic, and cognitive circuits; describe a possible function in motor loops; describe two classic diseases (Parkinson's and Huntington's), describe the MPTP incident and explain its importance to scientific understanding, and explain the factors for time delay between cortical discharge and movement.