HMB200H1 Study Guide - Winter 2018, Comprehensive Midterm Notes - Gamma-Aminobutyric Acid, Amygdala, Synapse
HMB200H1
MIDTERM EXAM
STUDY GUIDE
Fall 2018
HMB: LECTURE ; DOES THE BRAIN CHANGE ITSELF?
Principles of Neurosci 1
The Ns function is to produce movement w/I the perceptual world the brain creates
History
• Rene Descartes believed nerves were hollow tubes filled with liquid
o inspired by mechanical statues and got the idea of reflexive behaviour from them
o Theorized that humans and animals behaved the same way
o Stimuli vibrate spirits (fluid) in our nerves and that is sent to the brain and back down to the muscles
(reflex arc)
• Descartes was a dualist so he believed the mind (spiritualism) and body (materialism) were separate
o Materialism: our body was fixed and we used it to create simple behaviours and reflexes
o Rational soul in penal gland ca modify those movements (spiritualism = change)
Modern Materialism
• Spinal motor neurons send nerve impulses to synapse on muscle cells
• Muscle activation occurs through Ach
o Released at the axon terminal of muscle fibers called muscle end plates
o Muscle generates AP to contract
o Nmj was the first synapse studied
• Spinal motor neurons are activated by cortical neurons whose axons deceased down the anterior spinal tract
• Fibers entering dorsal root carry sensory information from sensory receptors while ventral root carry motor
information to muscles
• Motor cortex: cortical motor neurons that connect to the brainstem or spinal cord
• Brainstem: can execute specific behaviours
• The spinal cord can execute simple reflex motor actions
Spinal cord and Brainstem
• Spinal reflexes can still function even though the spinal cord is severed from the brain
o Paralyzed limbs may spasm also if given postural support people can imitate walking movement
o Brainstem helps to produce complex patterns of behaviour (e.g. walking, breathing)
• Organizes adaptive movements
• Cerebral palsy: voluntary movements become difficult to make whereas conscious
behaviour controlled by the cortex may still remain intact
• Caused by brainstem trauma
Principles of Neurosci 4
• The NS functions on multiple levels
• Each addition of new levels ads new behavioural complexity without discarding the previous levels
o This confers adaptive functions
• Wilder Penefield confirmed the role of the primary motor cortex
o Discovered mid surgery that electrical stimulation causes movement and mapped the brain using this
method
Motor Cortex
• Topographic organization: neural spatial representations of the body parts activated by the brain religion
o There is not a 1:1 correspondence between brain and muscle. But with body parts
• Proportional representation: in the motor cortex the body parts with most dexterity get the most cortical
representations in the brain
• Homoulus: the proportional representations of the human body according to the sensory and motto cortex
o Sensory and motor cortex are not directly connects also the motor cortex is in front of the sensory
cortex
• Motor cortex triggers categories not individual movements
o Activated by the premotor cortex
o Represents a repertoire of fundamental movements (e.g. reaching, jumping, bring arm up)
• Primary motor cortex (M1): encode direction, force, and speed of movement
find more resources at oneclass.com
find more resources at oneclass.com
Principles of Neurosci 6
• Brian systems are organized hierarchically and in parallel
• CNS comprises multiple levels of function and these levels must be extensively interconnected to integrate
their processing and produce unified perception or movements
• All parts of the brain project to the frontal lobe (executive function) and most input comes form association
area (parietal lobe) which in turn gets info from a bunch of regions and projects if forward
• Frontal lobe: executive function
• Partial lobe: sensory integration
• Temporal lobe: A1, T1, O1 and medial temporal lobe
• Occipital: visual processing
• From our retina's our optic nerve can go to two pathways: genicostriate or tectopulvinar
• Hubel and Wiesel said the V1 was a feature detector which means is it sensitive to orientation and position
Principle of Neurosci 1 (con’t)
• The brain produces a reality that is adaptive for the species to survive
• To form a unified perception senses stimuli in all modalities arrives in the brain after 3-4 synapses and info is
added at every step (re-coded)
• Info may interact at each parallel (e.g. McGurk effect results from unified perception of what we see and
hear)
• The brains primary function is to produce movement and to do so it must:
1.
Reactive info from the world (sensation)
2.
Interrelate sensory info to create a subjective experience (perception)
3.
Produce movement
• Reductionist approach: defines variable as specially as
possible but like principle 6 the subsystems of the brain
are organized into multiple parallel levels, your conscious
experience is always unified
• The brain is built by nature but also influenced by nature
Principles of Neurosci 2
• Neuroplasticity: the hallmark of NS functioning
o Necessary for memory and learning
o The potential of the nervous system to physically
or chemically change to enhance the brains
adaptability
o When monkeys motor cortex controlling one of
their hands was destroyed the cortical
representations shirked
o Behaviour + feedback = adaptability
• The brains function is to perceive and act
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The ns function is to produce movement w/i the perceptual world the brain creates. Motor cortex: topographic organization: neural spatial representations of the body parts activated by the brain religion, there is not a 1:1 correspondence between brain and muscle. Hmb200: lecture 2; how does the brain develop and adapt. If those receptor are activated it may trigger further maturation if not that pre or post synaptic neurons may die. Critical period: critical periods are when column formation/change is maximal. Hmb200: lecture 2; how does the brain communicate. The brain like a city: brain/city analogy is meant to describe the brain structures of connectivity drives the function. Thalamus; severs as integrating/relay center while amygdala is like a dispatcher. The thalamus-amygdala connections is almost as fast as spinal reflexes are. Every sensory organ has its own sensory neurons that detects stimulus. Sensory signals activate sensory receptors: within these neurons are specialized proteins called ion channels.