Chapter 1: Nervous System Organization Flashcards
1
Q
Adaptive Trait
A
a characteristic that increases the chances of survival and reproduction.
2
Q
What happens to the frequency of an adaptive trait?
A
the adaptive trait will be selected for and will thus become more common in the population. A change in gene frequency that codes for the adaptation will increase
3
Q
natural selection is a ____ that leads to the improvements of organismal design.
A
natural selection is a process
4
Q
why may the end product of evolution still not be optimal?
A
because an adaptation must strike a balance between optimal design and energy cost.
5
Q
Example of how biological structures reflect design principles
A
biological structures follow physical laws.
ex/ vertebrate eyes follows the laws of optics. The anableb for example spends its time on the water surface, peeking out of the water and looking down into the water at the same time. They only have 2 corneas and retinas, like humans, but each cornea and retina is divided into top and bottom halfs in an OVOID shape in order to follow SNELLS LAW
- the lens is more curved where it passes light coming though the water, nad less curved light passes coming through air in order to compensate for the differences of refractory index of air and water.
6
Q
Neuron noisiness
A
represents a compromise between the need for communication between neurons and the need to conserve energy; the neurons cannot be completely “noise-proof” because that requires the synthesis (energy costly) of myelin to extreme degrees
7
Q
CNS
A
brain and spinal cord
8
Q
any nervous tissue outside the brain and spinal cord belongs to:
A
the PNS
9
Q
ganglia
A
distinct clusters of neurons that typically form a bundle in the PNS
10
Q
the PNS is divided into the ___ and ___ Nervous systems
A
autonomic and somatic nervous systems
11
Q
example of an autonomic nervous system
A
the enteric nervous system; part of the autonomic nervous system that lies in the gut and plays a crucial role in digestion.
12
Q
the CNS neurons are highly centralized by___-
A
accumulating in the brain
13
Q
benefit of centralization and cephalization
A
centralization makes communication faster and more efficient because APS do not need to be propagated as long of a distance. This is more METABOLICALLY COST EFFECTIVE for the cell
14
Q
grey matter and white matter
A
grey matter: cell body, dendrides, unmyelinated neurons
white matter: myelinated axons.
15
Q
Fiber Tract
A
“the ganglia of the CNS”: long axon bundles in the CNS
16
Q
T/F: all lobes in the brain are the same size regardless if one feature is more important than the other
A
false. there are different amounts of brain regions dedicated to each part function depending on importance of use.
17
Q
CNS neurons are clustered into specific brain regions of ____ matter , separated by large ____ (white matter)
A
CNS neurons are clustered into specific brain regions of GREY matter , separated by large FIBER TRACTS(white matter)
18
Q
brain nuclei
A
clusters of cell bodies that execute a similar function and segregate themselves from other cell bodies with different features.
19
Q
On a HUMAN: Label the dorsal ventral inferior and superior sides
A
dorsal: back
superior: top of head
inferior: bum
ventral: belly
20
Q
posterior and anterior sides in humans correspond to ___- and _____ sides
A
posterior: dorsal
anterior: ventral
21
Q
anterior portion of the brain
A
aka the ventral side of the brain because it is on the same side as a persons belly
22
Q
posterior portion of the brain
A
aka the dorsal side of the brain because it is on the same side as a persons back
23
Q
in non humans, where is the dorsal ventral rostral and caudal sides?
A
on an animal that walks on all fours:
dorsal: spine
ventral: underbelly
rostral: tip of snout
caudal: tail.
24
Q
medial
A
towards an organisms midline. Plane that bisects the brain into left and right hemispheres
25
when you cut a brain at the midsaggital plane, where was the cut made? What're you looking at?
the cut was made at the midline. you would be seeing the entire half of the brain from the side
26
lateral
away from the midline. towards the right or left.
27
coronal plane view
cutting the brain in half, separating the anterior and posterior sides. you would see the "front view"
28
a coronal plane view is aka__
a cross section or transverse view
29
horizontal plane
cutting the brain opposite of sagital (separating the superior and inferior portions)
30
ipsilateral
on the same side when referring to 2 different structures
31
contrallateral
on opposite sides when referring to 2 different structures.
32
Nissl stain
stains the endoplasmic reticulum, allowing the visualization of cell bodies
33
Myelinated axons appear ____ when staining brain cells
dark blue typically
34
names for adult structures is based on the ____ nature of brain development
hierarchical nature of brain development.
35
in early development, brain is divided into __ ___ and ____
hind, mid, and forebrain.
36
the thalamic and hypothalamic nuceli aggregates are located in the ___brain
forebrain
37
rhombencephalon
hindbrain
38
3 main structures of the hindbrain
medulla, cerebellum and pons
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function of the pons
connects the cerebellum to various other brain structures
40
mesencephalon
mid brain
41
2 main divisions of the midbrain
1: colliculus: superior and inferior
2: tegmentum
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superior vs inferior colliculus
superior involved in processing visual info
| inferior involved in processing auditory info
43
the midbrain and hindbrain are often combined togetehr to form the __
brain stem
44
3 primary structures of the brain stem
medulla, pons and tegmentum
45
prosencephalon and its 3 main components
forebrain, broken down into 3 parts:
diencephalon: thalamus and hypothalamus
telencephalon: striatum and pallidum
cerebral cortex: typical "brain" broken into 4-5 lobes
46
T/F: cerebral cortex is segregated into brain nuclei
false. unlike the brain stem and the di and telencephalon portions of the forebrain, the cerebral cortex is separated by layers, aka LAMINAE
47
how many layers are typically in the cortex? Where could you find structures that are not as layered? Name "thinner" cortical structures
there are usually 6 layers of cortex.
you can find structures that are 2-3 layers in the most medial and most lateral portions of the brain.
Examples include the hippocampus and piriform cortex.
48
the piriform cortex is more ___ than the hippocampus
more anterior than the hippocampus. If you are looking for the piriform cortex, you must look to region "closer to the face"
49
Gyri
ridges of the neocortex
50
sulcus
valleys in the cortex. Folding enables large surgace area in a confined space
51
fissure
large sulcus.
52
according to the NIssl stain image, where are cell bodies typically lcoated?
cell bodies appear to be concentrated in the outer regions of the cortex, as evidenced by the dark outlining.
53
the human neocortex is divisible into 5 lobes:
1) frontal lobe
2) parietal lobe
3) temporal lobe
4) occipital
5- insula: buried beneath the frontal and temporal lobes
54
what separates the frontal and parietal lobe?
the central sulcus
55
what separates the frontal and temporal lobe?
the sylvian fissure
56
the hippocampal and piriform, as well as the amygdala nuclei of the brain can be found in the ___
temporal lobe.
57
where is the olfactory bulb in humans? in non humanS?
in non humans: protrudes ROSTRALLY from the cerebral hemispheres at the top of the hear
in humans: lies inferior (underneath) the surface of the forbrain.
58
as an embryo, where is the retina located? What does this mean?
during development, the retina is formed as part of the forebrain between the diencephelon and telencephalon. it gradually moves away from other forbrain structures towards the surface of the skin, with an eyeball forming around it.
this means that the retina is a forbrain derivative
59
EPSP
a change in membrane potential that increases the likely hood that the post synaptic neuron will fire an AP
60
IPSP
a change in the membrane potential that decreases the likely hood that the post syn neuron will fire an AP
61
T/F Different neurons do different things
false they all propagate action potentials, but depending on the neurotransmitters they release and the receptors around them, they can exert different effects on surrounding neurons
62
axon collateral
axon branches that reach out into other brain regions.
63
glial cells
non neuronal brain cells
64
4 types of glial cells and their functions
microglia: helps control brain damage by engulfing cellular debris through phagocytosis
astroglia: multiple roles. helps protect the brain, controls blood flow, helps recycle transmitters
oligodendrocytes: form myelin around the axons of neurons in CNS
schwann cells: forms myelin around the axons of neurons in PNS
65
topographic projections
neighboring neurons in one brain region often connect to neighboring neurons in another region. act as PARALLEL connections to ensure that neighboring neurosn process similiar info, allowing for connections between neurons that process similar info to be as short as possible.
66
not all neurons are connected to one another, they are ___
topographic. neighboring neurons in one brain region connect to neighboring neurons in another region that are similar to one another.
67
pathway divergence
one neuron with their terminals on multiple targets. the different targets can use the same info differentially in order to elicit different reactions
68
pathway convergence
allows info from different neurons to be inegrated. multiple neurons terminal bulbs are synpasing onto one neuron.
69
example of pathway convergence
ex/ photoreceptor cells in the retina all converge onto a single ganglion cell, allowing for heightened light sensitivity
70
____ feedback loops regulate excitatory activity and ____ feedback loops can amplify activity.
NEGATIVE feedback loops regulate excitatory activity and POSITIVE feedback loops can amplify activity.
71
Rene Descarte believed that the brain and CNS operated as a ____ ____
hydraulic machine.
72
according to renee descarted, he believed that fluids enter the brain cavity and get reflected off of the ____, and the movements of the ____ changes the direction of the reflected fluid, determining which motor nerves are activated in response to a given stimulus.
according to renee descarted, he believed that fluids enter the brain cavity and get reflected off of the PINEAL GLAND, and the movements of the PINEAL GLAND changes the direction of the reflected fluid (hydraulic system), determining which motor nerves are activated in response to a given stimulus.
73
renee descartes got inspiration for his hydraulic system through:
reflex mechanisms.
74
descartes sight hypothesis:
thought that there were vibrations in the air that would be recognized by the SENSORIUM (retina)
75
the work of luigi galvani
used batteries from volta to conduct a frog experiment, where he realized that muscles could be controlled electrically. concluded that the nervous system operates on electricity, not hydraulics---> his work sparked the beginning of the field of electrophysiology
76
allesandro volta
inveted the Voltaic Pile, the first battery. disagreed with luigi galvani that muscles were controlled electrically, but gave him a battery anyway
77
helmholtz
meausred the speed of neural conduction and concluded that neural conduction was much slower than electricity
78
fritz and hitzig
used electrical current to stimulate the cortex of dogs and noted that there was MOVEMENT on the OPPOSITE sides of the body.
79
Johannes Muller
Doctrine of specific nerve energies. Concluded that impulses are the same in all nerves, but stimulated different nerves produced different actions.
the nature of perception is definied by the pathway that the sensory info is carried in.
- modern AI specialists called this "label-lined" coding
80
Charles Sherrington
proposed that the knee jerk reflex involved electrical signals flowing across a gap to the muscles. Discovered the synapse
81
Camillo Golgi
invented a technique to stain nervous tissue with silver
82
Ramon Cajal
used the golgi stain to visualize individual nerve cells, and coined the neuron hypothesis
also inferred that sensory info that triggers a reflex is sent up to the spinal cord as well as the brain. the reflex can become integrated into an ARC: A complex and intricate reflex pathway.
83
neuron hypothesis:
the smallest unit in the brain is a cell.
84
Otto lewis
used hearts and vagus nerve stimulation and saw that the heart was influenced by epinephrine and acetyl choline. proposed that a chemical mechanism may also influence the nervous system.
85
___ proved the existence of synapses
sherrington
86
Describe Meynert and James Dual Reflex Arc Model. What are association fibers? What does the whole pathway of association fibers form?
they argued that info about sensory and moto reponse is always sent to FROM the subcortical regions (ex/ spinal cord) TO the neocortex: EVEN IF the reflexive behavior is driven mainly through the subcortical, short, reflex arc.
they believed that cortical neurons were connected to each other through ASSOCIATION FIBERS, and the experience modifies and strengthens the association fibers so that the activation of one set of cortical neurons triggers the activation of any other neuron associated with them.
The strengthened association fibers form a TRANSCORTICAL PATHWAY that can help MODULATE the subcortical reflex arc, which can facilitate learning and modulate the reflex: ex/ they can prevent the reflex from occuring, or begin the reflex before stimulus even occurs.
experience of a distress reflex thus connects two simple reflex arcs through a transcortical pathway;
1) one short arc is in the medulla
2) the other arc is in the spinal cord
activation of these 2 arcs activates associated cortical neurons, and the fiber connections between them get strengthened by the experience.
if you try and put your hand to the flame again, the transcortical pathway gets activated, and the association fibers activate the cortical neurons, which can modulate the subcortical reflex arcs in such a way that they can begin the reflex before the stimulus even had occurred/ ie, the transcortical pathway will tell the medulla and spinal cord reflex arcs to pull the hand away before you even put the hand in the flame.
87
what is an association cortex
a term commonly used for cortical regions that are not clearly sensory or motor. Meynert and James believed that the cortex was mainly association cortex with only a small portion having sensory or motor functions, but modern psychology has determined that there are MANY sensory and motor cortices which are commonly divided into primary and higher sensory cortices, meaning that the AREA dedicated to association cortex regions is actually SMALLER than what Meynert and James originally believed.
Meynert and James also thought that the association cortex was the only thing that modulated the sensory-motor reflex arcs was the association cortex/transcortical association fiber complexes, but there is actually many SMALLER HIERARCHICAL LOOPS of communication between the sensory and motor hierarchy in addition to the association cortex.
in addition to the association cortex.
88
the ____ ____ sits at the highest level of both the sensory and motor hierarchies
association cortices
89
compared to Meynerts Model, modern brain circuitry is now thougt to:
1) have much greater varition of sensor-motor pathways with side loops.
2) neural projections are widely divergent and can modulate brain states (ex/ hippocampus and amygdala), thus, reflexes arent the only thing that play a role in learning and memory. Behavioral states can also be modulated by DA neurons, which also plays a role in learning.
3) Reflex arcs are not the only thing that controls behavior!!
- locomotion and breathing can occur without sensory input happening first
- many behaviors are driven by CENTRAL PATTERN GENERATORS: the brain stem and spinal cord. these pattern generators can also be modulated by DESCENDING projections from the neocortex and hypothalamus
90
Marc Dax studied Aphasia and believed that speech loss coincided with damage to the _____. Relating his work to Fritz and Hirtzig; the brain is functionally symetrical in terms of ____, but _____ in language capabilities.
Marc Dax studied Aphasia and believed that speech loss coincided with damage to the LEFT HEMISPHERE. Relating his work to Fritz and Hirtzig; the brain is functionally symetrical in terms of MOVEMENT, but ASYMMETRIC in language capabilities(right side is not involved in language)
91
What is aphasia
the acquired loss of speech and language comprehension and production in a person that was perfectly capable before.
92
Paul Broca studied a man who died after struggling with the aftereffects of a stroke and realized that speech involves the _____, which was later named the ____.
Paul Broca studied a man who died after struggling with the aftereffects of a stroke and realized that speech involves the LEFT INFERIOR FRONTAL LOBE, which was later named the BROCAS AREA
(solidified the findings of Marc Dax, who believed that speech involved the left side of the brain.
93
The study of mental faculties and cerebral organs by studying bumps on the head to determine personality traits.
Phrenology. Mind Mapping coined by Franz Gall. Although incorrect, it did give rise to localization; the idea that cognitive abilities are controlled by regions and centers of the cortex. (just not personality traits)
94
Agnosia
damage to the association cortices
recall: the cortex is organized into areas of sensory and motor systems; stimulation of sensory or motor systems will provide sensation or movement. Association cortices are areas of the brain that are not involved with sensory or motor functions, but they do help facilitate perception
ex/ the visual association cortex stimulation does not cause sight, but it facilitates perceptions of what is being seen.
Damage to an association cortex results in agnosia: you can see fine, but you don't understand what you're seeing.
95
Distributed Processing
many regions contributing to one process. Kind of like the opposite of localization. Evidence sows that a specific brain region can be involvedin multiple cognitive functions
ex/ parietal lobe is involved in mental rotation, mathematical caluclation, eye control movemnet, short term memory etc.
96
what is experimental ablation and who pioneered it?
experimental ablation: damage to different regions and looking atthe produced different symptons. pioneered by pierre fluorens
97
who argued that the brain had front-back distinction? who argued for left-right distinction? who argued for up-down distinction?
who argued that the brain had front-back distinction? BROCA
who argued for left-right distinction? DAX
who argued for up-down distinction? HUGHLINGS JACKSON
98
Microtomes
instruments that allow tissue to be cut into extremely thin peices that allow visualization of brain regions on a microscope
99
immunohistochemistry
uses antibodies to target specific proteins to show where in a tissue the specific protein may be located. Antibodies can be tagged with fluoresence for detection. Allows for the study of proteins, receptors, transmitters and glial cells
100
Golgi Methods
stain that can label individual neurons, INCLUDING THEIR AXONS
101
axon tracer molecules
can trace neural connections by injecting a molecule that is taken up by the nueron and distributed throughout thewhole neuron. Allows you to see axon terminals that are very far away from the start point.
102
Experimental ablation
surgical removal of selected brain regions, followed by the analysis of behavior .Coined by Pierre Fluorens.
103
The recording of the brains' electrical activity
EEG
104
Recording sudies
using small extracellular or intracellular electrodes to record voltage changes in the neuronal membrane.
105
Neuropharmacology
local or systemic administration of neuroactive drugs and seeing their effects
106
Intraoperative surgery stimulation
uses eletrodes to map speech pathwyays and different functions during surgery (asks questions to patients while stimulating brain areas). related to intraoperative recording
107
functional imaging
non-invasive imaging techniques to visualize brain activation related to behavior and cognitive function. can measure blood flow (fMRI) to see which regions of the brain are active
108
Why is fMRI better than MRI
allows for indepth study compared to normal MRI. Many disorders do not present with significant structural changes that would be apparent on an MRI, and will only show acitivty level alterations, which can be picked up by fMRI/
109
_____ is a non-invasive procedure that relies on Faradays Principles. The brain responds to changes in Magnetic Stimulation that induces current in the underlying brain regions, activating/inhibited local regions of the brain.
TMS is a non-invasive procedure that relies on Faradays Principles. The brain responds to changes in Magnetic Stimulation that induces current in the underlying brain regions, activating/inhibited local regions of the brain and influencing behavior.
- possible treatment for depression. allows you to manipulate cortical activity and behavior.
110
DTI
diffusion tensor imaging. Measures water flow in neurons on WHITE MATTER TRACTS. good for visualizing brain images. You cannot use DTI in grey matter systems because the water diffusion is non-directional.
111
Purpose of Immediate Early Genes
can examine neuronal activity because their lvels of expression increase whenever neurons are unusually active.
112
Optogenic techniques
uses light activated ion channels from alagae to alter activity/trigger brain activation in eukaryotes that are ALIVE. allows you to control brain activity just by light, and allows you to observe how specific receptor activation alters behavior.
113
chemogenetic techniques
same as opteogenic techniques, but instead of couple a light sensitive ion channel, uses a modified neurotransmitter receptor to modulate neural activity.
114
Fusiform gyrus
involved in face recognition.
115
How does cortical lamination influence cytoarchitecture?
the neocortex has around 6 layers, and each layer is involved with different output/inputs and connections to other cortical areas.
there are also different CELL DENSITIES depending on the layer. Circuitry changes architecture. The cytoarchitecuture is dependent on different layers because different cell properties exist in each layer
some portions of the neocortex do not have all 6 layers (ex/ hippocampus or Piriform cortex), the most lateral or most medial portions do not have all 6 layers.
116
Broadmans cytoarchitecture regions
divides sections of brain that have the same cytoarchitecture layering. AREAS OF THE BRAIN WITH SIMILAR INPUTS AND OUTPUTS AND FUNCTION ARE FAIRLY CYTOARCHITECTURALLY HOMOGENOUS.
117
what is reverse enginerring
being presented with the full object (brain) and must deduce its functions and interrelationships. `
118
2 main methods of reverse engineering
1) neuropyschology: using experiments and observations to discover functions of hte mind; and then link those mental functions to a neurobiological mechanism
2) neuroethology: identify how animals behave under natural conditions, then link those behaviors to neurobiological mechanisms.
119
horizontal decomposition brain scheme
brain performs multiple functions in order to elicit behvior
120
vertical decomposition brain scheme
brain performs multiple functions in parallel (at the same time) in order to elicit behavior. more complex functions are layered on top of simpler functions.
121
Hybrid approach that encompases both aspects of reverse engineering
evolutionary psychology or cognitive ethology.
