Quiz 2 Flashcards
Imaging Techniques for Animals
-Patch Clamp
-Single Unit Recording
-Intracranial Electrodes
Imaging Techniques for Humans preparing for brain surgery
-Single Unit Recording
-Intracranial electrodes
Imaging Techniques for Humans
-Functional Magnetic Resonance Imaging (fMRI)
-Positron Emission Tomography (PET)
-Electroencehpalography (EEG)
-Magnetoencephalography (MEG)
Patch Clamp
-Very good temporal and spatial resolution
-Allows measurement of current through individual channels or whole cells with micropipetts
-Uses neurotransmitter property
Single Unit Recording
-Micropipette is placed near but outside neuron
-Uses property of electricity
-Action potentials can be picked up
-Great temporal resolution
-Spatial resolution worse than patch clamp, but still great
Intracranial electrodes
-Electrodes are inserted into brain via skull for neurosurgery on epilepsy
-Uses electricity property
-Good temporal resolution and spatial resolution
-Spatial resolution worse than Single Unit recording
-Can get info from deeper structures
-Con: Invasive, impaired population only, clinical decision for electrode placement, few locations across patients
fMRI
-Uses blood property
-High spatial resolution but low temporal resolution (hundreds of ms)
-Must avoid ferrous metals (iron-like attracted to magnetic field)
-Very expensive
-Oxygenated and deoxygenated blood have different properties
-Neurons call up oxygenated blood when they fire
-Changes in the magnetic field can be read by the machine
-Uses subtraction to compare activation under different conditions
PET
-Brain consumes 20% of all oxygen
-Oxygen is radioactively marked
-As it decays, neutrons release
-Colliding neutrons form positrons that can be sensed outside body
-Uses blood property
-Lower spatial resolution than fMRI
-Low temporal res.
EEG
-Uses electricity property
-Scalp electrodes pick up and amplify a current
-If the electrical signal is timelocked to a stimulus, the signal is called ERP, Event-related potential
-Spatial res is terrible
-Great temporal res
-Cons: only can get responses from cortex, not deeper structures
-Very noisy
MEG
-Magnetic fields created by firing neurons can be read outside head
-Better spatial resolution than EEG, same temporal
-Uses magnetic property
Techniques that directly manipulate functions of neurons
Electro-Cortical Stimulation (brain surgery humans)
TMS (humans)
Electro Cortical Stimulation
-Neurosurgery patients awake and able to give responses
-Homonculus and motor system discovered with this
-Uses electricity property
-Not normal brain functioning pts
-Processing area vs. part of circuit
TMS
-Magnetic property
-Creates temporary lesions
-Magnetic pulses activate or inhibit brain parts
ERP
P300: New events
boop… boop… boop… beep…
N400: Semantic violations
I like my coffee with cream and dog
P600: Syntactic violations and ambiguities
The horse ran past the barn fell
LAN: Syntactic violations
The goose was in the ran
Trilaminar
Ectoderm (skin and nervous system)
Mesoderm (muscles, skeleton, connective tissue)
Endoderm (digestive and respiratory tract)
Neural tube becomes
brain (rostral 2/3) and spinal cord (caudal 1/3)
Neural tube differentiates into
alar plate and basal plate
Alar plate
Sensory portions of spinal cord (dorsal horn)
basal plate
motor portions of spinal cord (ventral horn)
Prosencephalon
Telencephalon (cerebral hemispheres, basal ganglia, and limbic lobe)
Diencephalon
(thalamus and hypothalamus)
Mesencephalon
Midbrain
Rhombencephalon
Hindbrain (pons, medulla, and cerebellum)
Growth cone
used by neurons to seek appropriate connections through attractive and repulsive chemical cues
Pruning
Decreasing the excess number of neurons and connections
critical for learing
Motor cortex
controls volitional movement
Premotor cortex
Involved in planning of actions and complex movements
Sends most connections to primary motor cortex and some to spinal cord
Mirror neurons
-Neurons that fire when performing and action and watching someone perform same action
-In premotor and somatosensory cortex
-Could be used in speech perception
Primary motor cortex
-Generates actions
-can cause simple movements
-inputs from somatosensory cortex,
-Proprioceptive input in same area as area that controls muscles in one area
Cortical representation
-Motor functions topographically mapped
-Size of cortical area related to precision of control
-Is experienced based, can change
Motor equivlance
similar tasks can be scaled using different muscle groups because planning is an abstract concept
Basal ganglia
-Regulates the motion you want to make through direct pathway
-decreases the undesired motions through indirect pathwAY
-contributes to learned movements
-refines motor actions
nucleus accumbens
critical structure for reward
involved in addiction
Substantia nigra
-Major source of dopaminergic neurons
- inhibits indirect pathway for more excitation and movements
-excites excitatory pathway for more movement and excitiation
-Less dopaminergic neurons in substantia nigra means less movement for parkinsons
Dopamine
-critical for reward and addiction
-loss leads to parkinsons
GABA
Major inhibitory neuron for indirect pathways of basal ganglia
Cerebellum
-10% of brain volume but over half of the brain’s neurons
-Between spinal cord and motor cortex
-Modifies cortically generated motor plan
-corrects on-going movements
-Important for speech production and timing and coordination of articulators
-Has two hemispheres
Vermis (median)
Governs:
-Posture
-Locomotion
-Gaze
Paramedian
Governs:
-Distal muscles of limbs and digits
Lateral hemisphere
-Input only from cerebral cortex
-Involved in planning and mental rehearsal of complex actions
-Involved in conscious monitoring of movements
-Output to motor cortex is mediated by dentate nucleus
-Allows conscious assessment of movement errors
Anterior lobe
-Motor tone
-Walking position
Posterior Lobe
-Cortically directed skilled movements
Flocculonodular lobe
Important for equilibrium and eye movements
Cerebellar peduncles
-connect cerebellum and brainstem
-Inferior, middle, superior
-40:1 afferent to efferent
Vestibulocerebellar
-Inferior peduncle
-Maintain upright posture
Dorsal spinocerebellar
unconscious proprioception
inferior peduncle
Olivocerebellar
inferior peduncle
-information from contralateral motor cortex
Cuneocerebellar
proprioception
-inferior peduncle
Middle cerebellar peduncle
-afferents from motor cortex
-Inputs for visual and auditory info
Efferent pathways
-from deep cerebellar nuclei
-Project to brainstem, thalamus, and motor cortex
-allows cerebellum to mediate motor activity
Corticospinal tract
Controls voluntary movements of skeletal muscles
-projections from pre and primary motor cortices, and sensory cortex
Lateral corticospinal tract
-Contralateral control
-More distal
Ventral corticospinal tract
-bilateral and ipsilateral
-More central trunk muscles
Corticobulbar
-Controls head and facial muscles via cranial nerves
-Upper face uses bilateral connections
-Lower face uses contralateral
Dorsal horn
Sensory fibers
Ventral horn
motor fibers
Dorsal ramus
sensorimotor function in posterior body
Ventral ramus
sensorimotor function in anterior body
Alpha motor neurons
-Major spinal neurons
-9 to 16 micro meters in diameter
-Innervates about 200 muscle fibers each
-rapid impulse conduction
-Involved in involuntary and reflexive movements of head, trunk, and extremities
Gamma neurons
-Smaller diameter
-Slow impulse conduction
-Modulate muscle responses
Neuromuscular junction
-Motor neurons synapse onto muscles
-Motor neurons release acetylcholine
-This causes and action potential in muscle fiber
-Muscle fiber contracts
Interneurons
Integrate both sensory and motor functions
-facilitates and sharpens motor neuron activity
Spinal reflexes
Handled by a sensory motor loop where interneurons connect sensory and motor nerves
