This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
�� longitudinal fissure of the cerebrum:longitudinal fissure of the cerebrum:
� falx cerebri
�corpus callosum
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 3
� Embryonic origin – rostral part of the prosencephalonprosencephalon
� at birth ~ 340 g = 1/10 of the total body weight� up to 9th postnatal month – weight duplication� mid-3 year ~ 1000 g� about 20 years of age – definitive size and weight
Telencephalon Telencephalon –– development development TelencephalonTelencephalon
NB: The human brain contains roughly 90 billion neurons, The human brain contains roughly 90 billion neurons, which transmit information across roughly 150 trillion synapseswhich transmit information across roughly 150 trillion synapses!!
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 10
�� pyramidal cellspyramidal cells – 66% of the total neocortical cell population(glutamate- and aspartatergic)� small-sized (10-15 µm)� medium-sized (20-40 µm)� large-sized (50-80 µm)� giant pyramidal cells of Betz (80-120 µm) – in the precentral gyrus (motor cortex)
�� stellate (granule) cellsstellate (granule) cells – 33% of the total neocortical population (GolgiGolgi type II cellstype II cells)� small in size (8-14 µm) – interneurons
(GABA, VIP, SP, CCK, ENK)�� horizontal cells ofhorizontal cells of CajalCajal – small and fusiform;
in the most superficial cortical layer�� fusiform cellsfusiform cells – “modified pyramidal cells”;
spindle-shaped, in the deepest cortical layer�� cells ofcells of MartinottiMartinotti – small and multipolar;
in practically all cortical layers�� basket cellsbasket cells – horizontally extended�� neurogliaform stellate cellsneurogliaform stellate cells – small in size
�� pleomorphic cells pleomorphic cells – modified pyramidal cells; – large-sized and varying in shape,
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 13
�� heterotypicheterotypicalal cortexcortex (Brodmann):� agranular type – III, V, VI (motor cortexmotor cortex)� granular type (koniocortex) – II, IV layers
(sensory cortexsensory cortex)
�� hhomomotypicotypicalal cortexcortex:� frontal type cortex – premotor cortexpremotor cortex� parietal type – postcentral cortexpostcentral cortex� polar type – visuopsychic cortexvisuopsychic cortex
Variants of neocortical structureVariants of neocortical structure
5 major types of cerebral cortex:5 major types of cerebral cortex:
TelencephalonTelencephalon
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 14
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 21
� Lat. claudereclaudere – barrier�� a thin ((1-2 mm) lamina of grey matter� capsula externa� capsula extrema� part of the lentiform nucleus?� part of the insular cortex?� polysensory integrator
TelencephalonTelencephalon
ClaustrumClaustrum
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 22
� arcuate mass of grey matter� length ~ 7 сm� parts:
� head head ((caput nuclei caudati)� body body
(corpus nuclei caudati)
� tail tail
((caudanuclei caudati)
TelencephalonTelencephalon
Caudate nucleusCaudate nucleus
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 23
�� hhippocampippocampal formation and fornixal formation and fornix�� amygdaloid nuclear complexamygdaloid nuclear complex�� septal nucleiseptal nuclei�� hypothalamus, epithalamushypothalamus, epithalamus�� various thalamic nucleivarious thalamic nuclei�� part of the basal gangliapart of the basal ganglia
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 29
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 39
�� frontal eye fieldfrontal eye field – middle frontal gyrus“center for voluntary eye movements”:� considerable (inferior) part of area 8area 8� area 6 behind and probably area 9 in front
�� second frontal eye field second frontal eye field –– anterior to the aboveanterior to the above�� motor speech areamotor speech area::
� posterior part of the inferior frontal gyrus –areaarea 4444 and part of area 45 (gyrus Brocaegyrus Brocae)
�� motormotor aphasiaaphasia(paralysis of speech in man)(paralysis of speech in man)�� agramatismusagramatismus
Paul Broca, Paul Broca, 1861 speech center
TelencephalonTelencephalon
Somatomotor areasSomatomotor areas
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 40
� I.P. Pavlov – Pavlov's cortical irradiation hypothesis,"cortical representations" of sensory modalities � primary (first-order) areas� associative (second- and third-order) areas –
involved in integration of incoming sensory information
�� primary somatosensory area (Sprimary somatosensory area (S--I) I) ––areas 3, 1 and 2areas 3, 1 and 2:� gyrus postcentralis� part of lobulus paracentralis
�� secondary somatosensory area (Ssecondary somatosensory area (S--II) II) –– area 5area 5� lobulus parietalis superior
�� third somatosensory area third somatosensory area (S(S--III) III) –– area 7area 7
((inability to identify an object by touch without visual inputinability to identify an object by touch without visual input ))
ИИ..ПП. . ПавловПавлов
TelencephalonTelencephalon
Somatosensory areasSomatosensory areas
�� ““sensorysensory homunculushomunculus””ofof Penfield andPenfield and RasmussenRasmussen
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 41
�� primary visual cortex (Vprimary visual cortex (V--I)I) – area 17area 17calcarine sulcus �� optic radiation�granular type cortex (koniocortex)
�� area striataarea striata (striate cortex)(striate cortex)�3% of cerebral surface area�10% of cortical neurons – numerous GABAergic interneurons
�� visual agnosiavisual agnosia –– inability of the inability of the brain brain to make senseto make sense((““mentallymentally blindnessblindness””))
�� secondary visual cortex secondary visual cortex (association areas):(association areas):� in the occipital lobe
��VV--II II –– area 18area 18
��VV--III III –– area 19area 19
TelencephalonTelencephalon
Visual receptive areasVisual receptive areas
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 42
�� primary auditory cortexprimary auditory cortex (A-I) = area area 4411 � acoustic radiation� granular type cortex� upper part of gyrus temporalis superior� gyri temporales transversi (Heschl’s gyrus)
�� secondary auditory cortexsecondary auditory cortex (A-II) = areaarea 4242; belt areas – association (second-order) auditory area:� gyrus temporalis superior
�� acoustic agnosia acoustic agnosia (word (word but not soundbut not sound deafness)deafness)
�� tertiary auditory cortextertiary auditory cortex (A-III) = areaarea 2211; association (third-order) auditory area:� between the first, second acoustic
area and parainsular cortex
TelencephalonTelencephalon
Auditory receptive areasAuditory receptive areas
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 43
�� supramarginal gyrussupramarginal gyrus ((areaarea 40)40) – inferior parietal lobe:� involved in phonological and
articulatory processing of words � agraphia (writing apraxia = inability to write)� astereognosia� apraxia (inability to execute a normal volitional act)
�� angular gyrusangular gyrus ((areaarea 39):39):� written word is translated to