Cerebrum and Limbic System Flashcards
What separates the two hemispheres of the Cerebrum?
Longitudinal Fissure
Layers of the cerebrum and their corresponding cells?
1.Molecular layer ( plexiform)
2.External Granular layer –
3.External Pyramidal layer –
4.Internal Granular layer -
5.Internal Pyramidal layer
6.Multiform / Polymorphic/ Fusiformlayer –
Horizontal cells of Cajal–spindle shape
small pyramidal cells, stellate& granule cells
medium size
large pyramidal cells , Band of Ballerger
inverted cells of Martinotti
Different Cerebral Lobes?
- Frontal
- Parietal
- Occipital
- Temporal
- Insular
- Limbic
Largest lobe, 1/3 of hemispheric’s surface,
Lies rostral to the central sulcus and superior to the lateral fissure?
Frontal Lobe
Functional Divisions of Frontal Lobe?
Primary motor area Pre-motor / supplemental motor area Prefrontal area Broca’s motor speech area Frontal eyefield
Primary motor area, Brodmann area 4, 1/3 of cortico-spinal tract arises from here?
Precentral Gyrus
Which lies rostral to precentral gyrus, brodmann area 6, and 1/3 of the cortico-spinal fibers originates here?
Supplemental Motor Area
From which lobe comes from these manifestation of lesions:
–Monoplegia or hemiplegia
–Initial flaccid paralysis
–[+] Babinski reflex
Precentral Gyrus
From which lobe comes from these manifestation of lesions:
–Paralysis of the head and eye movements to the opposite side (head and eyes turn “toward” the diseased hemisphere)
–Spasticity
–Increased tendon reflex added to primary motor lesion
Supplemental Motor Area
Functions of Supplemental Motor Area?
Contralateral head and eye turning
Assumption of posture
Complex patterned movements infrequent rapid incoordinate movements
Function of Precentral Gyrus?
contralateral movements of face, arm, leg and trunk
Located in the caudal zone of middle frontal gyrus, Brodmann area 8 and it stimulation leads to conjugate deviation of the eyes to the other side?
Frontal Eyefield
Lesions from this lobe results in difficulty in voluntarily moving the eyes to the opposite side?
Frontal Eyefield
What are the other Frontal Lobe Gyri?
Superior Frontal Gyrus
Middle Frontal Gyrus
Inferior Frontal Gyrus
What are the Inferior Frontal Gyrus Structures?
Pars orbitale -Anterior limb of lateral fissure Pars triangularis -Ascending limb of lateral fissure Pars opercularis
What part of the frontal lobe has the components pars opercularis and pars triangularis?
Broca’s Speech Area
Has connections with the dorsomedial nucleus of the thalamus, hypothalamus, limbic lobe, anterior temporal area, and association areas of the parietal and occipital lobes?
Prefrontal Area
What are the functions of Prefrontal Area?
Personality Abstract thinking Mature judgement Foresight Tactfulness Self-control Initiative “Socialization” of certain autonomic functions and emotions Monitor cortical plan of behavior
What Lesion shows inappropriate jocularity?
Witzelsucht
What Lesion shows severe loss of initiative with disinterest and unconcern?
Akinetic mutism
What lesion shows grasping and pouting?
Primitive reflexes
What lesion shows disturbance of gait?
Frontal ataxia
What lesion shows resistance to passive movements of limbs?
Paratonia
What lobule is anteriorly bounded by the paracentral sulcus and posteriorly bounded by the marginal branch of the cingulate sulcus?
Paracentral Lobule
What is the function of the Paracenral Lobule?
cortical inhibition of bladder and bowel voiding
What are the manifestations of lesions in the Paracentral Lobule?
Incontinence of urine and feces
Atrophy that lacks general sense of responsibility, sloppiness in habits, vulgar speech and clownfish behavior?
Neurosyphilitic Frontal Atrohpy
Posterior to central sulcus and anterior to parieto-occipital sulcus?
Parietal Lobe
Parietal Lobe Structures?
Postcentral gyrus Postcentral sulcus Superior parietal lobule Intraparietal sulcus Inferior parietal lobule -Angular gyrus -Supramarginal gyrus
Granular cortex / sensory cortex, Brodmann areas 3,1,2, and Cortical regions where impulses concerned with tactile and kinesthetic sense from superficial and deep receptors and converge and are somatopically represented?
Postcentral Gyrus
Functions of Postcentral Gyrus?
Receives afferent pathways for appreciation of posture, touch and passive movements
Manifestations of lesions in Postcentral Gyrus?
Contralateral impairment of touch, pressure and proprioception
Disturbed postural and passive movement sensation
Disturbed localization of touch with loss of two point discrimination
Astereognosis (impaired appreciation of size, shape, texture and weight)
Perceptual rivalry (sensory inattention)
Posterior to Brodmann area 3,1,2 which is along the superior border of the Sylvian fissure and its lesions results in impaired pain sensation?
Secondary Somesthetic Area
What are the other Parietal Structures?
Superior Parietal Lobule (Brodmann areas 5 + 7), Intraparietal Sulcus and Inferior Parietal Lobule (Supramarginal gyrus, Angular gyrus)
Cortical association areas and mnemonic constellations for understanding and interpreting sensory signals?
Inferior Parietal Lobule
Function of the Supramarginal Gyrus?
Understanding and interpreting sensory signals
Manifestations of lesions in Supramarginal Gyrus?
Dominant hemisphere (Tactile and propioceptive agnosia) and Non-dominant hemisphere (Confusion in left-right discrimination, Body image disturbance, Apraxia)
Surrounds the ascending terminal part of the superior temporal sulcus, Brodmann area 39?
Angular Gyrus
Functions of Angular Gyrus?
Association cortex which has connections with somesthetic, visual and auditory associations areas
Manifestations of lesions in Angular Gyrus?
Dominant hemisphere
- Alexia and Agraphia
Located in the roof of the lateral fissure
•Brodmann area 43
•Primary gustatory area
Parietal Operculum
Confusion of right and left limbs
Finger agnosia (difficulty in distinguishing finger from hand)
Acalculia
Agraphia
Gertsmann’s syndrome
Auditory cortex and Wernicke’s speech area is located in the
Superior temporal gyrus
Dizziness with sensations of turning movement of the body)
Vertigo
Located on trasverse gyri of Heschl
Brodmann areas 41 + 42
Auditory Cortex
A non-dominant hemispher problem where there is difficulty appreciating sound, rhythm and music
Amusia
T or F:
Unilateral lesions have little effect on hearing
True
Auditory associational area
•Brodmann area 22
•It functions in language comprehension
Wernicke’s Area
Hears but does not understands
Wernicke’s or Receptive dysphasia
Most medial protrusion of the parahippocampal gyrus
Uncus
Results from extensive damage of the striate cortex
Anton’s syndrome
Located on the banks of the calcarine sulcus
Brodmann area 17
Primary Visual Cortex
Cortical blindness in the contralateral visual field is a manifestation of lesion in the
Primary Visual Cortex
Brodmann areas 18 + 19
Secondary Visual Area
Divides frontal and parietal lobes
Central sulcus
Separates lateral orbital gyri and medial gyrus rectus
Olfactory sulcus
A triangular cortical area with the apex directed forward and downward to open into the lateral fissure
Insula
Opening leading to insular region
Limen insula
Forms the central core of the hemispheres
Contains both myelinated and unmyelinated fibers
Cerebral White Matter
Three groups of white matter fibers:
–Projection fibers
–Association fibers
–Commisural fibers
Carry afferent and efferent information between hemispheric structures and other parts of the CNS
Projection Fibers
Interconnect different cortical areas within the same hemisphere
Associations Fibers
Interconnect corresponding areas of each hemispheric cortex
Commisural Fibers
The Visceral Brain
Limbic System
Derived from the corpus callosum to the induseum griseum (above) and the hippocampus and dentate gyrus (below)
Hippocampal Formation
An almond shaped nuclear mass located in the deep medial part of the temporal lobe
Amygdala
Lesions produce docility
Stimulation produces rage reaction
Amygdala
Concerned with emotion
Parts of the limbic lobe and diencephalon
Papez Circuit
Bilateral lesions destroying the amygdala and hippocampus in male monkeys manifestations include hypersexuality, marked absence of emotional response etc
Kluver–Bucy Syndrome
Profound loss of the ability to acquire new information
Seen in bilateral damage of the medial temporal lobe
Anterograde Amnesia
