NEURO LESIONS IN SPECIFIC PARTS OF THE CEREBRUM Flashcards
There are how many brodmann areas?
47
surface area of the cortex
Unfolded, it has a surface extent of about 4,000 cm2
the allocortex (“other cortex”), is composed of?
hippocampus and olfactory cortex
what are the layers of the cortex from the pial to subcortical
the molecular (or plexiform), external granular, external pyramidal, internal granular, ganglionic (or internal pyramidal), and multiform (or fusiform) layers
cell types of the cortex
types-relatively large
pyramidal cells and smaller, more numerous rounded
(granular) cells-predominate in the neocortex
2 types of neocortex
(1) the homol:tjpical cortex, in which the
six-layered arrangement is readily discerned, and (2) the
heterotypical cortex, in which the layers are less distinct.
The precentral cortex
(Brodmann areas 4 and 6, mainly motor region) is dominated by______________, especially
in layer V
pyramidal rather than granular cells
the primary sensory cortices, postcentral
gyrus (areas 3, 1, 2), banks of the calcarine sulcus
(area 1 7), and the transverse gyri of Heschl (areas 41 and
42), where layers II and IV are strongly developed for the
receipt of afferent impulses, has been termed __________because of the marked predominance of granular cells
granular cortex
Neurons of ___________
send axons to subcortical structures and the spinal cord.
Neurons of layer Vl project mainly to the_______
layer V (projection efferents)
thalamus
Another group of disorders known as __________depend not merely on involvement of certain
cortical regions but more specifically on the interruption
of inter- and intrahemispheric fiber tracts
disconnection
Syndromes
Area _______of the dominant hemisphere
(Broca area) and the contiguous part of ___________ are “centers” of motor speech and related functions of the lips, tongue, larynx, and pharynx
44
area 4
The ________ and anterior parts of the _________, which are the frontal components of the limbic system, take part in the control of respiration, blood pressure, peristalsis, and other autonomic function
medial-orbital gyri
cingulate and insular gyri
The ___________ and more
specifically, pyramidal cells of layer V of the pre- and
postcentral convolutions provide most of the cerebral
efferent motor system that forms the pyramidal, or corticospinal, tract
frontal agranular cortex (areas 4 and 6)
A tract, the ________, connects
the frontal with the occipital lobe and the ____________connects the orbital part of the frontal lobe with the temporal lobe
fronto-occipital fasciculus
uncinate bundle
With regard to behavior and the frontal lobe, the
___________ is in a general sense committed
to the planning, initiation, monitoring, and execution
of all cerebral activity
anterior half of the brain
lesions of the frontal lobes give rise
to:
a loss of drive, impairment of consecutive planning,
an inability to maintain serial relationships of events,
and to shift easily from one mental activity to another
lesions of these parts cause mutism, contralateral motor
neglect, and impairment of bibrachial coordination
Ablation of the right or left supplementan; motor areas
(the parts of area 6 that lie on the medial surfaces of the
cerebral hemispheres)
an important function of the
supplementary motor area is the ________________,
ordering of motor tasks
or the recall of memorized motor sequences
_________________________ the dominant
hemisphere result in a reduction or loss of motor
speech, and of agraphia, and apraxia of the face, lips, and
tongue,
Destruction of the Broca convolution (areas 44 and
45) and the adjacent insular and motor cortex of
they signify a loss of the
ability to use the lower limbs in the act of walking that
cannot be explained by weakness, loss of sensation, or
ataxia from lesions of frontal lobe
gait apraxia
lesions resulting in incontinence
Right- or left-sided lesions involving the posterior
part of the superior frontal gyrus, the anterior cingulate gyrus, and the intervening white matter
speech problems associated with frontal lobe disease
laconic speech,
lack of spontaneity of speech, telegrammatic speech
(agrammatism), loss of fluency, perseveration of speech, a
tendency to whisper instead of speaking aloud, and dysarthria
lesions that lead to abulia
ventromedial
frontal regions or frontal-diencephalic connections
Disinhibition occurs largely
with_________
dorsolateral frontal lesions.
These patients, otherwise displaying mental
clarity and despite negative personal and social consequences,
collect massive amounts of useless items such
as newspapers, junk mail, catalogs, food, clothing, and
appliances, often encompassing several categories
Pathological collecting behavior (hoarding)
lesions associating with hoarding behavior
medial frontal lobe damage, including the cingulate
gyri
In general, the greatest cognitive-intellectual deficits
relate to lesions in the __________
dorsolateral parts of the prefrontal lobes
greatest personality, mood, and behavioral changes stem from lesions of the ____________
medialorbital
parts,
associations:
left dorsal frontal lesions and _______________, and right side orbitofrontal lesions, with___________
anger with hostility
anxiety and depression
Psych tests to check for frontal lobe dysfunction
They include the Wisconsin card-sorting test, the Stroop color-naming test, sequencing of pictures, "trail making test" "go-no-go" test threestep hand posture test of Luria
abnormaility in Luria test results in this:
“kinetic limb apraxia
what is “kinetic limb apraxia
the natural kinetic “melody,” or
smoothness of transition from one hand position to the
next is disrupted and there is a tendency to perseverate
Effects of unilateral frontal disease, either left or right
A. Contralateral spastic hemiplegia
B. Contralateral gaze paresis
C. Apathy and loss of initiative or its opposite,
slight elevation of mood, increased talkativeness,
tendency to joke inappropriately (witzelsucht), lack
of tact, difficulty in adaptation
D. If entirely prefrontal, no hemiplegia; but grasp
and suck reflexes or instinctive grasping may be
released
E. Anosmia with involvement of orbital parts
Effects of right frontal disease
A. Left hemiplegia
B. Changes as in I.B, C, and D
Effects of left frontal disease
Right hemiplegia
B. Broca’s aphasia with agraphia, with or without
apraxia of the lips and tongue (see Chap. 23)
C. Sympathetic apraxia of left hand (see
Effects of bifrontal disease
A. Bilateral hemiparesis
B. Spastic bulbar (pseudobulbar) palsy
C. If prefrontal, abulia or akinetic mutism, lack of
ability to sustain attention and solve complex
problems, rigidity of thinking, bland affect, social
ineptitude, behavioral disinhibition, inability to
anticipate, labile mood, and varying combinations
of grasping, sucking, obligate imitative movements,
utilization behavior
D. Decomposition of gait and sphincter incontinence
The ________________ supplies blood to the convexity of the temporal lobe,
and the _______________________supplies the medial and inferior aspects, including the hippocampus
inferior branch of the middle cerebral
artery
temporal branch of the posterior cerebral artery
The
______________ an integral part of the auditory cortex, lies immediately posterior to the Heschl convolutions, on the superior surface of the temporal lobe
planum temporale (area 22),
The middle and inferior temporal gyri (areas 2 1
and 37) receive a massive contingent o f fibers from
the___________and the______________
striate cortex (area 1 7)
parastriate visual association areas (areas 18 and 1 9 ) .
The superior part of the dominant temporal lobe is
concerned with the ___________
acoustic or receptive aspects of language
The most important functions of the hippocampus
and other structures of the hippocampal formation
(dentate gyrus, subiculum, entorhinal cortex, and parahippocampal
gyrus) are___________
learning and memory
The temporal
lobes are connected to one another through the _____ and _______
anterior
commissure and middle part of the corpus callosum
Physiologically, ________ is an integrator of
“sensations, emotions, and behavior” in so far as it relates
the organism’s sensory experiences to emotional meaning
thought it’s proximity to the limbic system
the temporal lobe
lesions
of the white matter of the central and posterior parts of
the temporal lobe characteristically involve the lower
arching fibers of the _______
geniculocalcarine pathway (Meyer loop).
In ______________, auditory sensations cannot be
distinguished from one another. Such varied sounds as
the tinkling of a bell, the rustling of paper, running water,
and a siren all sound alike
agnosia for sounds
Also, it was observed that lesions of the right auditory
cortex impaired the recognition of __________ (the temporal sequence of pitches) and of ____________ (the sounding of simultaneous pitches)
melody
harmony
it appears that the left inferior
frontal region is activated by tasks that involve the ____________
identification
of familiar music
nondominant hemisphere is important for the _____________________
but that the naming of musical scores and all the semantic
(writing and reading) aspects of music require the integrity
of the ________________
recognition
of harmony and melody (in the absence of words),
dominant temporal and probably the frontal
lobes as wel
___________i s a failure o f the left temporal
lobe function in decoding the acoustic signals of speech
and converting them into understandable words
word deafness
It should also be noted that complex
but unformed auditory hallucinations (e.g., the sound of
an orchestra tuning up), as well as entire strains of music
and singing, also occur, inexplicably, with lesions that
appear to be restricted to the ______
pons (pontine auditory hallucinosis,
Stimulation of this cortical
area for the treatment of intractable tinnitus has elicited
________
autoscopy
What is autoscopy
seeing one’s self from an external
perspective
The central
areas identified physiologically with olfaction are the
____________________, i.e., the areas that mediate numerous
visceral functions
posterior orbitofrontal, subcallosal, anterior temporal,
and insular cortices
Stimulation of the posterior
parts of the___________________of
fully conscious epileptic patients can arouse complex
memories and visual and auditory images, some with
strong emotional content
first and second temporal convolutions
The loss of certain visual integrative abilities, particularly face recognition (prosopagnosia), is usually assigned to lesions of the\_\_\_\_\_\_\_\_\_\_\_\_
inferior occipital lobes
difference in dominant vs non-dominant temporal lobectomy
With the
former, there is dysnomia and impairment in the learning
of material presented through the auditory sense; with
the latter, there is impairment in the learning of visually
presented material
Effects of unilateral disease of the dominant temporal
lobe
A. Homonymous contralateral upper quadrantanopia
B. Wernicke’s aphasia (word deafness; auditory
verbal agnosia)
C. Dysnomia or amnesic aphasia
D. Amusia (some types)
E. Visual agnosia
F. Occasionally, amnesic (Korsakoff ) syndrome
Effects of unilateral disease of the nondominant temporal
lobe
A. Homonymous upper quadrantanopia
B. Inability to judge spatial relationships in some
cases
C. Impairment in tests of visual! y presented nonverbal
material
D. Agnosia for sounds and some qualities of music
Effects of disease of either temporal lobe
A. Auditory, visual, olfactory, and gustatory
hallucinations
B. “Dreamy” states with seizure (focal temporal
lobe seizure)
C. Emotional and behavioral changes
D. Delirium-confusional states (usually nondominant
Effects of bilateral temporal lobe disease
A. Korsakoff amnesic defect (hippocampal
formations)
B. Apathy and placidity
C. Kliiver-Bucy syndrome: compulsion to attend to
all visual stimuli, hyperorality, hypersexuality,
blunted emotional reactivity; the full syndrome
is rarely seen in humans
This sulcus runs anteroposteriorly from the middle
of the posterior central sulcus and separates the mass
of the parietal lobe into superior and inferior lobules
interparietal
sulcus
The inferior parietal lobule is composed
of the ______________(Brodmann area 40) and the
____________(area 39).
supramarginal gyrus
angular gyrus
The architecture
of the postcentral convolution is typical of all primary
receptive areas________________
(homotypical granular cortex).
the anterior parietal cortex contains
the mechanisms for__________.
______, are organized in the more
posterior, secondary sensory areas
tactile percepts
Discriminative tactile
functions
The discomfort involved the entire half of the body or
matched the region of cortical hypesthesia; in a few cases, the symptoms were paroxysmal
pseudothalamic pain st;ndrome
With _______________ there is sometimes
an associated mild hemiparesis, as this portion of
the parietal lobe contributes a considerable number of
fibers to the corticospinal tract
anterior parietal lobe lesions,
In instances of cortical sensory disturbance, the outstretched
hand may display small random “searching”
movements of the fingers that simulate playing a piano
; these are exaggerated when the eyes
are closed. What is this phenomenon called?
(pseudoathetosis)
a patient with
a dense hemiplegia, usually of the left side, may be
indifferent to a paralysis, or is entirely unaware of it
Anosognosia and hemispatial neglect (AntonBabinski
syndrome)
On the other extreme of the conceptual negation
of paralysis are instances of self-mutilation of the
paralyzed limb __________
(apotemnophilia).
Another common group of parietal symptoms consists
of neglect of one side of the body in dressing and
grooming, recognition only on the intact side of bilaterally
and simultaneously presented stimuli_________
(sensory
extinction)
Conventional treatments for hemispatial neglect use
_________ and training in visual exploration of the
left side.
prismatic glasses
what is the use of the mirror in the treatment of hemispatial neglect
With a mirror in the right parasagittal plane, the patient
observes the mirror image of their neglected hand and
space and is induced to use that side more naturally
When
defects of apraxia are intertwined with agnosic defects,
the term ____________ seems appropriate.
apractognosia
A special type
of visuospatial disorder, separable from neglect but also
associated with lesions of the nondominant parietal lobe,
is reflected in the patient’s inability to reproduce geometric
figures __________
(constructional apraxia)
Lesions of Gerstmann
The lesion is in the left inferior
parietal lobule (below the interparietal sulcus), particularly
involving the angular gyrus or subjacent white matter of
the left hemisphere.
Occasionally, severe left-sided visual
neglect results from a lesion in the _________
Visual neglect can also occur after focal
lesions in the __________
right angular gyrus
posterior medial temporal lobe
lesions of what side of the parietal lobe?
R
Effects of unilateral disease of the parietal lobe, right
or left
A. Corticosensory syndrome and sensory extinction
(or total hemianesthesia with large acute lesions
of white matter)
B. Mild hemiparesis or poverty of movement (variable),
poverty of movement, hemiataxia (seen
only occasionally)
C. Homonymous hemianopia or inferior quadrantanopia
(incongruent or congruent) or visual
inattention
D. Abolition of optokinetic nystagmus with target
moving toward side of the lesion
E. Neglect of the opposite side of external space
(more prominent with lesions of the right parietal
lobe; see later)
Effects of unilateral disease of the dominant (left) parietal lobe (in right-handed and most left-handed patients); additional phenomena include
A. Disorders of language (especially alexia)
B. Gerstmann syndrome (dysgraphia, dyscalculia,
finger agnosia, right-left confusion)
C. Tactile agnosia (bimanual astereognosis)
D. Bilateral ideomotor and ideational apraxia
Effects of unilateral disease of the nondominant
(right) parietal lobe
A. Visuospatial disorders
B. Topographic memory loss
C. Anosognosia, dressing, and constructional apraxias
(these disorders may occur with lesions of
either hemisphere but are observed more frequently
and are of greater severity with lesions of
the nondominant one)
D. Confusion
E. Tendency to keep the eyes closed, resist lid opening,
and blepharospasm
Effects of bilateral disease of the parietal lobes
A. Balint syndrome: visual-spatial imperception (simultagnosia), optic apraxia (difficulty directing gaze), and optic ataxia (difficulty reaching for objects)
The large calcarine fissure courses in an
anteroposterior direction from the pole of the occipital
lobe to the _________
splenium of the corpus callosum
Area 17 is a typical homotypical
cortex but is unique in that its fourth receptive layer
is divided into two granular cell laminae by a greatly
thickened band of myelinated fibers,__________
the external band
of Baillarger.
This stripe, also called the line or band of
Gennari, is grossly visible and has given this area its
name, __________
striate cortex
The largest part of area 17 is the
terminus of the _________ that arrive via the
lateral geniculate
retinal macular fibers
The occipital lobes are supplied almost exclusively
by the posterior cerebral arteries and their branches,
either directly in most individuals or through an embryologically
persistent branch of the ____________
(“fetal” posterior cerebral artery)
internal carotid arteries
monkeys with bilateral lesions in the temporal
visual zones lose the ability to _______; with
posterior parietal lesions, there is loss of ability ________
identify objects
to locate
objects.
EEG findings for cortical blindness
With rare exceptions, no cortical
potentials can be evoked in the occipital lobes by light
flashes or pattern changes (visual evoked response),
and the alpha rhythm is lost in the electroencephalogram
(
natural hx for recovery from cortical blindness
from cortical blindness
through visual agnosia and partially impaired perceptual
function to recovery.
Vis u a l A n o so g n os i a (Anto n Syn d ro m e ) lesions
The lesions in cases of negation of
blindness extend beyond the striate cortex to involve the
visual association areas.
What comprises Vis u a l I l l u s i o n s ( M eta m o rp h o ps i a s )
deformation of the image,
change in size, illusion of movement, or a combination
of all three
The illusion of tilting
of the environment or upside-down vision is known to
occur with __________, but occurs more often
with abnormalities of the _________
parietooccipital lesions
vestibular system.
It is usually the case that the lesions responsible for
visual hallucinations are situated in the _______________ and that elementary
hallucinations have their origin in the________
and complex ones in the _______
occipital lobe or posterior part of the temporal lobe
occipital cortex,
temporal cortex
distinct processes of visual recognition
the construction of a perceptual representation from vision (perception)
and the mapping of this perceptual representation onto stored percepts or engrams of the object’s functions and associations (apperception)
In pts with prosopagnosia, how do they identify the person
In identifying
persons, the patient depends on other data, such as the
presence and type of glasses or moustache, the type of
gait, or sound of the voice.
The patient may be able to describe a familiar
environment from memory and locate it on a map, but
he experiences no sense of familiarity and gets lost when
faced with the actual landscape. What is this?
environmental agnosia.
The common
form of retinal color blindness is congenital and is readily
tested by the use of ________
Ishihara plates
___________ is
frequently associated with visual field defects and with
prosopagnosia
Achromatopsia
no
difficulty with color perception (i.e., they can match
seen colors), but they cannot reliably name them or
point out colors in response to their names
color anomia
Occipital lobe lesions:
Effects of unilateral disease, either right or left
A. Contralateral (congruent) homonymous hemianopia,
which may be central (splitting the
macula) or peripheral; also homonymous
hemiachroma topsia
B. Elementary (unformed) hallucinations-usually
because of irritative lesions
Effects of left occipital disease
A. Right homonymous hemianopia
B. If deep white matter and splenium of corpus callosum
is involved, alexia without agraphia
C. Visual object agnosia
Effects of right occipital disease
A. Left homonymous hemianopia
B. With more extensive lesions, visual illusions
(metamorphopsias) and hallucinations (more frequent
with right-sided than left-sided lesions)
C. Loss of topographic memory and visual
orientation
Bilateral occipital disease
A. Cortical blindness bilateral hemianopias,
B. Anton syndrome (visual anosognosia, denial of
cortical blindness)
C. Loss of perception of color (achromatopsia)
D. Prosopagnosia (impaired face recognition,
bilateral temporooccipital including fusiform
gyrus)
E. Balint syndrome (bilateral dorsal parietooccipital)
