Midterm 1 Flashcards
What is systems neuroscience?
;ooking at all the parts of the brain that move together
What is the key to understanding the brain?
look at the functional anatomy
What are the two principles of brain potentials?
The Neuron Doctrine and the Law of Dynamic Polarization
Who created the neuron doctrine and the law of dynamic polarization?
Ramon y Cajal
How did Cajal come to the neuron doctrine and the law of dynamic polarization?
golgi staining approach
What is the law of dynamic polarization?
information goes in one direction in the form of electric potentials that travel down the axon and release NT
dendrite/soma –> axon –> axon terminal
What is Nitz’s favorite brain region? (Extra Credit!!!)
somatosensory cortex
What two systems are involved in the Pinocchio Effect?
- somatosensory
2. proprioceptive
What is proprioception?
proprioception orients all the joints and limbs in space, the status of the muscles, allowing the animal to dissipate falling energy over time
It is your sense of self
What is the Pinocchio effect?
A person holds his nose with hand, then scientists put vibration on arm tendon with the person’s eyes closed. This signals the muscle spindle afferent, giving the information to the brain that the arm is elongating, giving the illusion that the nose is extending.
Which of the receptor neurons activate in response to Glutamate?
Bipolar neurons
Name some functions of proprioception.
- joint protecting reflexes (knee jerk)
- adjustment of muscle contraction/recruitment
- kinesthesia-detection of body position and movement
- coordination of motor commands
- possibly a sense of self, as distinct from everything else
Working hard is equivalent to greater electrical activity. (T/F)
False
brain is first and foremost an ________ system
electrical
Synaptic and action potentials are the same thing. (T/F)
FALSE
What is the structure of the brain? (layers)
(micro) synapses => neurons => nuclei (all cells contribute to produce some function) -> regions (macro)
What is the difference between synaptic and action potentials?
Synaptic potentials have to do with amplitudes and durations and are continuous
Action potentials are an all or nothing event, binary.
Define membrane potential.
The voltage difference between the intracellular space of a neuron and the surrounding extracellular space (includes resting, synaptic, and action potentials)
What is the equilibrium potentials?
The membrane potential at which the net flux of ions across the membrane is 0 given the overall concentration of that ion on either side of the membrane.
What are the properties of ion channels?
Properties of ion channels:
- Ion selectivity
- gating, e.g. voltage, ligand
- Kinetics e.g. open-time
- state-e.g. activated, inactivated, deenactivated, persistent
- distribution-e.g., in dendrites at the axon hillock
What does the Nernst equation do?
- used to determine the equilibrium potential
- relates ion concentration gradients to electrical charge gradients
Action potential conduction speed is a function of ____ and ____
axon length, myelination
Neurotransmitters exist within what type of potential?
synaptic
What are the three basic types of neurotransmitters?
- excitatory
- inhibitiory
- neuromodulatory
What is topographic representation?
-neurons in the brain are anatomically arranged in a systematic fashion that those responding to similar features of a single sensory modality are grouped into the same area of the brain
Which of the mechanoreceptors are slow adapting/sustained?
Merkel disks, SA2’s
Which of the mechanoreceptors are rapidly adapting/transient?
Meissner corpuscles, Pacinian corpuscles
What is the sequence of dynamics within the brain?
synaptic and action potentials (micro) –> field potentials/EEG -> fMRI (macro)
What are the functions of the dorsal root ganglion cell?
- receiving and transducing external energy
2. sending that activity to the brain
The dorsal root ganglion cell types are:
- mechanoreception and proprioception
2. thermoreception and nociceptors
What are Dorsal Root Ganglion Cells?
- group on either side of the spine
- takes information from the body to the spinal cord
- splits at spine and goes to brain
What is a muscle spindle afferent?
- proprioceptive receptor
- sense movement in joints
- gamma motor fiber -> contractile -> sensory fiber (non-contractile) -> contractile
What are sensory organ receptors?
Across sensory modalities, anatomical features of sensory organ receptors determine the dynamic activity and within a modality, the type of sensory information they convey
What is the golgi tendon organ?
-registers tendon stretch = muscle contraction
What did they find in the Hubel and Wiesel experiment?
left and right eye organizes visual input from the lateral geniculate nucleus and that hte other dominance column is layered over the retinotopic map
What did they do in the Hubel and Wiesel experiment?
- Kittens either had one of their eyes sewn shut or had one of their eyes taken out
- kittens were allowed to dvelop and then sacrificed
- V1 cortex was taken out and stained
What enzyme did they use to to stain the V1/second egocentric map in the Hubel and Wiesel experiment?
cytochrome oxidase
What is the first egocentric map and what does it tell us?
- retinotopic map
2. organization of neighboring cells in the retina projecting to respective neighboring cells in the LGN and V1
What is the third egocentric map?
- refers to the orientation tuning “pinwheels”
- pinwheels tell which orientation of a bar or light or stimuli the neurons like
Why is the intersection in the third egocentric map important?
-tells us that neurons that respond to different orientations are adjacent to one another and grouped together
What are the main properties of the retinotopic map?
- space on the visual field yields responses to space in the retina (space in the LGN)
- everything in the visual field projects to the opposite direction in V1
Parvocellular cells are in layers ____ - ____ of the LGN
3 - 6
Magnocellular cells are in layers ___ - ____ of the LGN
1 - 2
Where are the koniocellular layers located in LGN?
-between the X and Y layers
Color input is distributed homogeneously. (True/False)
False
All regions of V1 get output from the koniocellular layers. (True/False)
False
Where do the koniocellular layers project to in the striate cortex?
Layers 2-3
What are the main properties of the Ocular Dominance Columns map?
- cytochrome oxidase in the normal eye picks up the stain and turns black
- information from the left and right eye is mapped to the LGN and V1
What are the main properties of the Orientation Tuning Wheels map?
- Different neurons like different orientation sof bars of light or stimuli
- adjacent neurons in V1 fire to adjacent degrees of bars, showing pinwheels
- pinwheels are in the center of ODC
What are the main properties of the color map?
- koniocellular cells responds to color in blob like fashion
- only layers 2 and 3 of V1 receive this input
- blobs are in the center of the ODC
As you move further from the V1 and closer to the “what pathway”…retinotopy begins to _____.
decline
As you move further from the V1 and closer to the “what pathway”…receptive field begins to _____.
increase
As you move further from the V1 and closer to the “what pathway”…generalization of stimulus features like color and shape begins to _____.
increase
What are the functions of V5/MT? What pathway is it in?
- movement and direction 2
2. where pathway
What are the functions of MT/MST (medial superior temporal? What pathway is it in?
- optic/depth, vestibular flow, and trajectories
2. Where pathway
What are the functions of the VIP (ventral intraparietal)? What pathway is it in?
- brings visual and somatosensory systems together in the parietal lobe
- neurons fire to a stimulus in the visual field corresponding to the sensory body map of the head
What are the functions of the V4 ? What pathway is it in?
- distinguishes if something is part of a figure or background
- depends if parts move in synchrony - what pathway
What are the functions of the IT (inferior temporal)? What pathway is it in?
- recognizing objects, including faces
- TE and TEO refer to the anterior and posterior region ss of IT, respectively
- damage leads to prosopagnosia - what pathway
Merkl disks produce _______ responses and best process _______ and ______,
sustained; fine touch and edges
Meissner corpuscles produce ______ responses and best process ______ and ________ vibrations
transient; slip and low frequency vibrations
Where do we get convergence of sensory information from different mechanoreceptors?
-directs the sensory information to the primary somatosensory cortex to be processed and coverge with one another
Excitatory and inhibitory inputs from one neuron (axon terminal) onto the other (dendrite) generate ___________ .
synaptic potential
When the temporal and spatial integration of synaptic potentials on a neuron exceeds a certain threshold, it generates ________.
action potential
Action potential conduction speed is a function of _______ and ________.
myelination and axon length
________ potential is a special case of ________ potential which occurs when the net influx of ions across the neuron membrane is 0.
Equilibrium, membrane
Information exchange between neurons through generation of synaptic potentials is mediated by _______.
neurotransmitters
In terms of their functionality (effect on the post-synaptic cell) , they can be divided into three types: ______, _____, and ______.
excitatory, inhibitory, and neuromodulatory
The neurotransmitter GABA (2 things)
is inhibitory and opens Cl- channels
Generator potentials are analogous to [synaptic]/[action] potentials
synaptic
they result in action potentials if they achieve a certain threshold
Vestibular system has two functionally different structures that register the movement and static position of the head. ______________ registers rotational velocity of the head, where as _______ registers the linear translation and static head position.
Semicircular canals, otolith organs
The two mechanoreceptors Pacinian cells and Meissner cells are both sensitive to vibration. However, they differ in terms of the _____ they are sensitive to. Pacinian cells are sensitive to _____ _____ vibrations, whereas Meissner cells are sensitive to _____ ______ vibration.
frequency, high frequency, low frequency
The fine texture discrimination during tactile sensation is mediated by _______, which have ______ -adapting responses to stimulus.
Merkel disks, slowly
To which layers of the cortex does the information from the mechanoreceptors arrive?
Merkel: layer 2 (slowly adapting)
Meissner and Pacinian: layer 4 (rapidly adapting)
Microslip events are best detected by the _______ ________ of touch receptors
Meissner corpuscle
Photo-receptors -> ______ -> ______ -> Optic Nerve
—-> bipolar —-> ganglion —–>
How do ON-bipolar cells respond to glutamate and release light?
Glutamate release - hyperpolarize; light - depolarize
Light causes photoreceptors to ______ and release ______ glutamate
hyperpolarize, less
How does an off bipolar cell work?
reduced glutamate when exposed to light release onto the OFF bipolar is, effecetively, the removal of an excitatory (Depolarizing influence), bipolar cell hyperpolarizes
How do OFF-bipolar cells respond to
Glutamate release - depolarize ; light - hyperpolarize
Ganglion cells of which type have responses to light that are analogous to Pacinian corpuscle responses to touch?
Magnocellular (Y-type) which ha transient responses to light
Recordings of neurons along ______ trajectories through visual cortex yield neurons with different directional tuning preferences.
oblique
On an otherwise dark field of view, light in the form of a plus sign in the upper left field of view will excite neurons in the _________
right-lower V1
Damage to the dorsal pathway impairs ________
visual spatial abilities
Damage to the ventral pathway impairs
object identification
