CNS: The Cerebrum Flashcards
1
Q
cerebrum
A
most rostral part of brain
accounts for 83% of brain mass
transverse fissure and longitudinal fissure
2
Q
longitudinal fissure
A
separates cerebral hemispheres
3
Q
transverse fissure
A
separates cerebrum and cerebellum
4
Q
sulci and gyri in cerebrum
A
sulci: shallow grooves on the surface of cerebral hemispheres
gyri: ridges of brain tissue between sulci
5
Q
deep sulci
A
center sulcus
lateral sulcus (fissure)
parieto-occipital sulcus
6
Q
five major lobes of cerebrum
A
frontal lobe temporal lobe parietal lobe occipital lobe insula lobe
7
Q
central sulcus
A
separates frontal lobe and parietal lobe
bordered by precental gyrus anteriorly and postcentral gyrus posteriorly
8
Q
lateral sulcus
A
sometimes called a fissure
separates temporal lobe from parietal and frontal lobes
9
Q
insula lobe
A
positioned deep within the lateral sulcus and forms part of its floor
10
Q
cerebral cortex (gray matter)
A
primary sensory areas sensory association areas multimodal association areas premotor cortex (motor association cortex) primary motor areas
11
Q
cerebrum white matter
A
commissure, projection fibers, association fibers
12
Q
deep cerebral gray matter
A
basal ganglia, basal forebrain nuclei, claustrum
13
Q
the cerebral cortex
A
2-4 mm thick
folds in cortex triple its surface areas
approximately 40% of brain mass
contains billions of neurons arranged in six layers
no fiber tracts
most sensory information is routed through the thalamus to the cerebral cortex
14
Q
functional areas in cerebral cortex
A
primary sensory cortex sensory association areas multimodal association areas premotor cortex (motor association cortex) primary motor cortex
15
Q
primary sensory cortex
A
receives sensory information resulting in awareness of the sensation
16
Q
sensory association areas
A
receive information from the primary sensory cortex and interpret (give meaning to) the sensory input
17
Q
multimodal association areas
A
receive input in parallel from multiple sensory areas and integrate/interpret the information aided by past experiences
develop a motor response
18
Q
premotor cortex
A
motor association cortex
plans and coordinates complex movements and relays the plan to the primary motor cortex for implementation
19
Q
primary motor cortex
A
enacts plan
20
Q
cerebral cortex: primary sensory areas
A
primary somatosensory cortex primary visual cortex primary auditory cortex vestibular (equilibrium) cortex gustatory (taste) cortex primary olfactory (smell) cortex visceral sensory area
21
Q
primary somatosensory cortex
A
located along the postcentral gyrus of the parietal lobe
involved with awareness of general somatic senses:
touch, pressure, vibration, pain, temperature
22
Q
spatial discrimination
A
ability to precisely locate a stimulus
sensory receptors in periphery relay signals through spinal cord, brain stem, thalamus, and up to the primary somatosensory cortex
23
Q
sensory homunculus
A
body map of the sensory cortex in the postcentral gyrus
24
Q
vestibular cortex
A
processes information of the vestibular apparatus
responsible for conscious awareness of sense of balance (position of the head in space)
located in the posterior part of the insular lobe deep to the lateral sulcus
25
gustatory cortex
processes taste stimuli from the tongue
function involved in the conscious awareness of taste stimuli
located in insula on the "roof" of the lateral sulcus
26
primary olfactory cortex
processes smell
lies on the medial aspect of the cerebrum in a small region called the piriform lobe which includes the hooklike uncus
olfactory nerves from the nasal cavity transmit impulses to the olfactory cortex and provides conscious awareness of smells
27
piriform lobe
region of medial cerebrum which houses the primary olfactory cortex
includes the hooklike uncus
28
rhinencephalon
olfactory cortex is in this part of the brain
includes parts of the cerebrum that receive olfactory signals: piriform lobe, olfactory tracts, olfactory bulbs
connects to limbic system in the brain which explains why smells trigger emotions
involved with consciously identifying and recalling specific smells
29
parts of the cerebrum that receive olfactory signals
piriform lobe
olfactory tracts
olfactory bulbs
located in the rhinencephalon
30
visceral sensory areas
located deep within the lateral sulcus of the insula lobe
| receives general sensory input (pain, pressure, hunger) from abdominal and thoracic organs
31
primary visual cortex
located deep within the calcarine sulcus on the posterior and medial part of the occipital lobe
damage to this area can cause blindness
largest of all sensory areas
receives visual information that originates from the retina
exhibits contralateral function
first of a series of areas processing visual input at the level of putting sensory stimuli from the two eyes together and noting object orientation
32
calcarine sulcus
houses primary visual cortex
| posterior and medial part of the occipital lobe
33
primary auditory cortex
sound waves excite receptors in the inner ear cochlea which triggers impulse transmission to primary auditory cortex where conscious awareness of sound including loudness, rhythm, and pitch is detected
located at superior edge of temporal lobe
34
sensory association areas
somatosensory association cortex
visual association areas
auditory association areas
35
somatosensory association cortex
lies posterior to the primary somatosensory cortex
integrates different sensory inputs, eg touch and pressure from somatosensory cortex to understand sensations
draws upon stored memories of past sensory experiences, eg ability to feel and recognize keys or coins in your pocket without looking at them
36
visual association area
surrounds the primary visual area and covers much of the occipital lobe
continues the processing of visual information by analyzing color, form, and movement
about 30 cortical areas for visual processing have been identified
complex visual processing extends into temporal and parietal lobes
visual information proceeds anteriorly through these visual areas into two streams (dorsal and ventral streams)
37
visual association area: dorsal stream
"where" pathway
extends through the posterior parietal cortex to the post-central gyrus
perceives information about spatial relationships about objects
38
visual association area: ventral stream
"what" pathway
passes information into inferior part of the temporal lobe
responsible for recognizing words, objects, faces
39
auditory association area
lies just posterior and lateral to the primary auditory cortex
permits evaluation of different sounds such as a screech, thunder, or music and integrates memories of past sounds
auditory stimuli are processed serially along two pathways from the auditory association area to the multimodal association areas
40
auditory areas: posterolateral pathway
"where" pathway
| through the parietal lobe to the lateral pre-frontal cortex evaluates location of stimulus
41
auditory areas: anterolateral pathway
"what" pathway
from the anterior temporal lobe to the inferior region of the frontal lobe
processes information related to sound identification
42
Wernicke's area
in one hemisphere, the auditory association area overlaps with Wernicke's area
includes superior-posterior temporal lobe and inferior-posterior parietal lobe
functional brain region involved in recognizing and understanding spoken words
43
function of Wernicke's area
involved in recognizing and understanding spoken words
44
Wernicke's aphasia
receptive aphasia
impaired ability to understand spoken words and sentences and comprehend speech
often associated with damage to Wernicke's area
45
multimodal association areas
posterior association area
anterior association area
limbic association area
46
multimodal association areas: function
large association area of the cerebral cortex that receive sensory input from multiple sensory modalities
make associations between various kinds of sensory information
associates sensory inputs with memories of past experiences and plan appropriate motor responses
47
posterior association areas
located at interface of visual, auditory, and somatosensory association areas
unified perception of sensory input --> allows awareness of spatial location of body ("body sense")
related to language comprehension and speech
areas in right cerebral hemisphere: creative interpretation of words, controlling emotional overtones of speech
48
functions of posterior association areas
```
awareness of spatial location of body
language comprehension
speech
creative interpretation of words
controlling emotional overtones of speech
```
49
anterior association areas
large region of frontal lobe: prefrontal cortex
integrates information from all other association areas to plan and initiate motor responses
receives processed sensory information from posterior association area and adjusts motor output to respond appropriately
integrates information with past experience through connection with limbic association area
50
functions of anterior association areas
```
plan and initiate motor responses
working memory for spatial tasks
executive area for task management
working memory for object-recall tasks
solving complex multi-task problems
```
51
other functions of anterior association areas
appreciation of humor, empathy, conscience
impulse control, mental flexibility, social skills
cognitive reasoning, thinking, perceiving
intentional memory and recall
processing of abstract ideas, reasoning, judgment
52
3 types of working memory (anterior association)
visual working memory
auditory working memory
"executive area" which mediates interaction between visual and auditory
53
anterior association area is one of the ____ brain parts to mature
last
| not fully formed until early adulthood
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location of anterior association
prefrontal cortex
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location of limbic association area
medial side of frontal lobe
56
multimodal association areas: limbic association area
medial side of frontal lobe
memory, emotions, motor response
integrates input from other cortical areas to form memory
57
functions of limbic association area
processes emotions in complex personal and social interactions, guides emotional response
memory, emotions, motor response
integrates input from other cortical areas to form memory
integrates sensory and motor behaviors with past experience --> uses past experience to influence future motor response
58
cerebral cortex: motor areas
```
all localized in posterior frontal lobe
frontal eye field
Broca's area
premotor cortex
primary motor cortex
```
59
frontal eye field
lies anterior to premotor cortex
| controls voluntary movement of eyes, especially to follow a moving target
60
location of Broca's area
lies anterior to inferior part of premotor cortex in left hemisphere (language-driven)
61
functions of Broca's area
controls the motor movements necessary for speaking
connected to language comprehension areas in posterior association areas
corresponding region in the right hemisphere controls emotional overtones to spoken words
62
Broca's aphasia
expressive aphasia
| diminished ability to speak and produce language
63
premotor cortex (motor association area)
located anterior to primary motor cortex
plans and coordinates complex movements and relays plan to the primary motor cortex for implementation
receives processed information from sensory and multimodal association areas of the cortex
controls voluntary actions that depend on sensory feedback on spatial relations
involved in planning movements
64
location of premotor cortex
located anterior to primary motor cortex
65
functions of premotor cortex
plans and coordinates complex movements
relays plan to primary motor cortex for . implementation
controls voluntary actions that depend on sensory feedback on spatial relations
involved in planning movements
66
primary motor cortex
located along the precentral gyrus of the frontal lobe, just anterior to the primary sensory cortex
controls motor functions
pyramidal cells
67
location of primary motor cortex
located along precentral gyrus of frontal lobe
| just anterior to the primary sensory cortex
68
pyramidal cells
large neurons of the primary motor cortex
axons of pyramidal cells make up pyramidal (corticospinal) tracts that descend through brainstem and spinal cord
pyramidal axons synapse on motor neurons to generate precise voluntary motor movements
69
how does the primary motor cortex generate precise voluntary motor movements?
pyramidal axons synapse on motor neurons
70
projection of the pyramidal axons is _____
contralateral
71
lateralization of cortical functioning
contralateral: two hemispheres control opposite sides of the body
hemispheres communicate through commissures
72
left hemisphere controls
language abilities
math
logic
73
right hemisphere controls
```
visual-spatial skills
reading facial expressions
intuition
emotion
artistic and musical skills
```
74
cerebral white matter
fibers that make up cerebral white matter allow the different parts of the cerebral cortex to communicate with each other, the brain stem, spinal cord
communicating fibers are usually myelinated and bundled into tracts
commissure fibers, association fibers, projection fibers
75
commissure fibers
horizontal fibers connecting corresponding gray matter areas of right and left hemispheres
corpus callosum - largest commissure, lies superior to the lateral ventricles
76
association fibers
connect different parts of the same hemisphere
short association fibers connect cortical areas
long association fibers connect widely separated cortical lobes
parts of Wernicke's and Broca's areas are connected by association fibers
77
projection fibers
some descend from cerebral cortex to more caudal parts of the CNS
some ascend to the cortex from lower regions
through projection fibers, sensory information reaches the cerebral cortex and motor instructions leave the cerebral cortex
78
internal capsule
compact bundle formed by projection fibers deep to cerebral white matter
passes between thalamus and basal ganglia (deep gray matter)
79
corona radiata
superior to internal capsule
| projection fibers running to and from the cerebral cortex
80
deep cerebral gray matter
basal ganglia: control movements in conjunction with motor cortex
basal forebrain nuclei: major role in arousal, learning, memory, and motor control
claustrum: nucleus of unknown function located internal to the cortex of the insula
81
basal ganglia
group of nuclei embedded deep within the cerebral white matter that control movements in cooperation with motor cortex
striatum: caudate nucleus and putamen
corpus striatum: caudate nucleus, putamen, globus pallidus
82
parts of the basal ganglia
caudate nucleus: arches superiorly over the thalamus and lies medial to the internal capsule
putamen: lateral to internal capsule
globus pallidus: lateral to internal capsule
83
functions of the basal ganglia
start, stop, and regulate intensity of voluntary movements
| select appropriate muscles for a task and inhibit others
84
dyskinesia
motor disorders
| diseases of the basal ganglia can cause dyskinesia which results in abnormal motor function
85
Huntington's disease
there is a corpus striatum pathway that inhibits motor activity
degeneration of this pathway results in an overstimulation of motor activities with uncontrolled jerking of limbs and early death
86
Parkinson's disease
degeneration in the part of the substantia nigra that normally sends inhibitory input to the basal ganglia
lack of inhibitory input results in overactive globus pallidus basal ganglia, which inhibits movements --> causes slow and jerky movements, tremors, eventual muscle rigidity and early death
87
basal forebrain nuclei: structures
septum
horizontal band of Broca
diagonal band of Broca
basal nucleus of Meynert
88
basal forebrain nuclei: location
dorsal to hypothalamus
89
basal forebrain nuclei: functions
arousal, learning, memory, motor control
| part of basal forebrain cholinergic system - neurons synthesize and release an abundance of acetylcholine
90
Alzheimer's disease
degeneration of brain areas involved with memory and thought (basal forebrain nuclei, the hippocampus, and associated areas of the cerebral cortex)
results in a reduction of cholinergic activity
91
functional brain systems
networks of neurons that function together despite spanning large distances in the brain
limbic system: spread widely in the forebrain
reticular formation: spans the brainstem
92
claustrum
nucleus of unknown function located internal to the cortex of the insula
may integrate information from the cerebral cortex and the limbic system
93
the limbic system: location
within the medial aspect of the cerebral hemispheres and also within the diencephalon
94
limbic system: medial aspect of cerebral hemispheres
septal nuclei, cingulate gyrus, dentate gyrus, hippocampus, parahippocampal gyrus
95
limbic system part of____
amygdaloid body
96
limbic system in the diencephalon
anterior thalamic nuclei, hypothalamus, mammillary bodies
97
limbic system linked together by
fornix
| anterior commissure fibers
98
two structures of limbic system especially important in emotion
amygdala
| cingulate gyrus
99
cingulate gyrus
superior to corpus callosum
enables people to shift between thoughts and express emotions through gestures
interprets pain as unpleasant
resolves mental conflict during frustrating tasks
100
amygdala
contains key nuclei for processing fear and triggering appropriate sympathetic response
enables people to recognize menacing facial expressions, detect precise direction of gaze
forms memories of past experiences based on emotional impact, especially when fear-based
101
hippocampal formation
hippocampus and parahippocampal gyrus
encodes, consolidates, later retrieves memories of facts and events
retrieves information to be remembered from the cerebral cortex
processes these data and returns them to the cortex, where they are stored as long term memories
102
the reticular formation
runs through medulla, pons, and the midbrain
forms 3 columns in the medulla
axons have widespread connections ideal for arousal fof the brain as a whole
certain reticular neurons send a continuous stream of impulses to the cerebrum through relays in the thalamus
103
3 columns of the reticular formation
midline raphe nuclei
medial nuclear group
lateral nuclear group
104
reticular activating system (RAS)
part of reticular formation that maintains consciousness and alertness
axons from all the major ascending sensory tracts synapse on RAS neurons
visual, auditory, and touch stimuli help keep people awake and alert
105
ascending pathways
carry sensory information to more rostral areas of the CNS
| 3 main ascending pathways: spinocerebellar, dorsal column, spinothalamic
106
spinocerebellar pathway
conveys information on proprioception from lower limbs and trunk to the cerebellum to coordinate body movements
first and second order neurons
107
dorsal column medial pathways
transmits information on discriminative senses which are senses that can be located very precisely on the body surface
includes fine touch, pressure, and conscious aspects of proprioception
108
spinothalamic pathway
brain usually interprets the information carried by the spinothalamic tract as unpleasant, eg pain, burns, heat, and cold
transmits information on temperature, pain, and deep pressure
transmits information on non-discriminative touch (stimuli we are aware of, but cannot precisely localize ont he body surface)
109
descending pathway
carry motor information to more caudal regions of CNS
divided into two groups: pyramidal (corticospinal) and other
other: rubrospinal tract, reticulospinal tract, tectospinal tracts, vestibulospinal tract
110
descending pyramidal pathway
long axons of pyramidal cells form the pyramidal tracts
pyramidal tracts descend from primary motor cortex through internal capsule
control precise and skilled voluntary movements, such as writing and threading a needle
influence limb muscles, such as muscles that influence hands and fingers
111
Lou Gehrig's disease
amyotropic lateral sclerosis
involves degeneration of the pyramidal tracts with formation of hardened scar tissue in lateral parts of spinal cord
results in wasting and atrophy of skeletal muscles and is fatal
112
extrapyramidal tracts
other type of descending pathway
rubrospinal tract: from red nucleus in midbrain
tectospinal tract: from nuclei in superior colliculus in tectum of midbrain
reticulospinal tract: from reticular formation, median nuclear groups of pons and medulla
vestibulospinal tract: from vestibular nuclei in medulla
113
spinal cord damage
paralysis: loss of motor function
paresthesia: loss of sensation
paraplegia: injury to the spinal cord is between T1 and L2 causing paralysis of the lower limbs
quadriplegia: injury to the spinal cord in the cervical region causing paralysis of all four limbs
114
cerebrovascular accident (stroke)
thrombotic stroke: caused by a clot that blocks blood flow to brain tissue
hemorrhagic stroke: caused by a bleed in the brain that impairs blood flow to brain tissue
