Lecture 1 Flashcards
Neuroscience is an integrative discipline
- Questions about how nervous systems of humans and animals are organized, develop, and how they function to generate behaviour
- Use tools from many disciplines to answer these questions
- eg. genetics/genomics, molecular and cell bio, psyc, physiology, anatomy, computer science
Neural systems serve three basic purposes (3 subcategories)
- Sensory systems: report info about the state of the organism and its environment
- Motor systems: organize and generate actions
- Associational systems: provide ‘higher-order’ brain functions such as perception, attention, memory, emotions, language, thinking
Sensory systems (5)
- somatic sensory system
- auditory system
- vestibular system
- vision
- chemical senses (optional)
Organization of the Human NS
- CNS: brain + spinal cord
-
PNS: anywhere else
- sensory neurons
- somatic motor division
- visceral/autonomic motor division
Cells in the NS
- Early 19th century: cell recognized as fundamental units of living organisms, but not recognized as central to nervous tissue until the 20th century
- Camillo Golgi discovered that by soaking a brain in silver chromate solution, a small number of cells became fully-filled with dark color
Neuron Doctrine <3 vs Reticular Theory :(
- Golgi: ** Reticular Theory**: all neurons form a single continuously connected network
- Ramon y Cajal: Neuron doctrine: neurons communicate at contact points rather than through physical continuity, neuron = individual cell of the NS
Neuron doctrine- Synapses
- Charles Sherrington (early 1900s) identified synapses aka points of communication between neurons
- Ultimate proof of the neuron doctrine required development of electron microscopy (1950s) to visualize synapses and confirm that neurons are discrete entities
Two basic cell types in the brain
Neurons
- process into, sense envt changes, communicates changes to other neurons via APs, control bodily responses
Glia❤️🔥
- support the signalling functions of neurons
- insulate, nourish, repair
Dendrites
Primary target for synaptic input
-extensive branching that diggers greatly between neuron types
- complexity of arbour depend on the number of inputs a neuron receives and dictates capacity to integrate info from many sources (vs just relay)
Axon
Signal transduction from cell body, reads out info
- most neurons have only one that extends for a long distance
- vary in length
- some branching
- site of output to other neurons
action potential
electrical event that carries signal to other neurons
Two ways to increase speed of transmission down axon
- increase diameter
- myelination
Glia
- also have complex processes extending from cell bodies but serve different functions:
- maintaining ionic milieu of neurons
- modulating rate of AP propagation
- NT uptake at cleft
- regulate recovery from neural injury
- interface between brain and immune system
- facilitating flow of interstitial fluid through the brain during sleep
Classes of glia
- Astrocytes (CNS)
- Olygodendrocytes (CNS)
- Schwann cells (PNS)
- Microglia
- Radial glia aka glia stem cells
Astrocytes
