Exam 2 Flashcards
nervous system as a box-and-arrow diagram
hierarchy
-shows up in both perception and action
-perception is built from simple features that get put together, a homonculus decides what to do, then tells a motor system to do it
-pandemonium model
population density
Records spike trains of multiple neurons over the same trials
primary motor cortex
represents movement tactics
spike count rate
spikes/time of a single neuron, measured in Hz
spike density
Firing rate of one neuron over multiple trials; time bins are used to obtain temporal information
Premotor (PMA) & Supplementary Motor cortex (SMA)
master strategist
motor cortex
-motor cortex and other cortical ares support motor planning oin the brain and allow excecution and planning of movement
central sulcus
divides motor from somatosensory cortex
cerebellum
assist in primary motor cortex’s tactics, smoothing out movements and doing constant error correction
basal ganglia
-involved in rewarding aspect of movement and in help cortex sequence and choose movements (strategy)
-A group of nuclei lying deep in the subcortical white matter of the frontal lobes that organize motor behavior.
M1
-primary motor cortex
-has somatotopic map of muscles
-more neurons for parts that have lots of control (tongue, hands)
motor neurons in the motor cortex
synapse on motor neurons in the spinal cord
activated by sensory input
Prefrontal cortex
decides what movements to make + more
motor neurons in the spinal cord
-synapse on muscle cells and use firing rate code to determine strength of muscle contraction
ventral stream
object identity is detected and processed
dorsal stream
object position
synapses in spinal cord
immediate reflexes
synapses in parietal cortex
planned behavior
Bob Wurtz
-monkey get juice for good performance
-saw spike rates increase when a monkey is developing its intention to make a movement
-spike counting is a way to explain what we saw
-the relationship between speed and accuracy is usually observed
population coding
-the idea that there is not a single neuron for any given action or sensation
-whole population acts collectively to encode information
-each neuron “votes” for a given movement
-tuning curves define which movement the neuron votes most strongly for
-think of vectors being added to decide a final movement
Superior Colliculus
-vector representations of space are topographically organized in the superior colliculus
combination of microstim & evidence
-eye movements reflect vector sum of evidence and microstim
-shows how evidence for a bigger choice has a bigger behavioral effect
-brain uses vectors to code movements
-uses populations to represent those vectors