brain

BRAIN BRAIN

ACHMAD AMINUDDINACHMAD AMINUDDIN

MAJOR PARS OF THE BRAINMAJOR PARS OF THE BRAIN

THE BRAIN STEMTHE BRAIN STEM

Consists of the medulla oblongata, pons and Consists of the medulla oblongata, pons and midbrainmidbrain

CREBELLUMCREBELLUM DIENCEPHALONDIENCEPHALON

Consists of the thalamus, hypothalamus and Consists of the thalamus, hypothalamus and epithalamusepithalamus

CEREBRUMCEREBRUM

Fig 14.1Fig 14.1

PROTECTIVE COVERING OF PROTECTIVE COVERING OF THE BRAINTHE BRAIN

The craniumThe cranium The cranial meningesThe cranial meninges - Duramater- Duramater - Falx cerebri- Falx cerebri - Falx cerebelli- Falx cerebelli - Tentorium cerebelli- Tentorium cerebelli - Arachnoid mater- Arachnoid mater - Piamater- Piamater

Fig 14,2Fig 14,2

MEDULLA OBLONGATAMEDULLA OBLONGATA

The medulla begins at the foramen magnum The medulla begins at the foramen magnum and extends to the inferior border of the pons, and extends to the inferior border of the pons, a distance of about 3 cm.a distance of about 3 cm.

The medullaThe medulla‘‘s white matter s white matter

- Sensory tracts.- Sensory tracts.

- Motor tracts.- Motor tracts.

- Pyramids- Pyramids The decussation of pyramidsThe decussation of pyramids


The cardiovascular centerThe cardiovascular center The medullary rhythmicity area of the The medullary rhythmicity area of the

respiratory center adjust the basic rhythm of respiratory center adjust the basic rhythm of breathing.breathing.

Nuclei controls reflexes for fomiting, coughing Nuclei controls reflexes for fomiting, coughing swallowing, hiccuping and sneezing.swallowing, hiccuping and sneezing.

Within the olive is the inferior olivary nucleus. Within the olive is the inferior olivary nucleus. Neuron here relay impulsis from Neuron here relay impulsis from proprioceptors to the cerebellumproprioceptors to the cerebellum

Fig 14.5Fig 14.5

Fig 14.6Fig 14.6


The right and left gracile nucleus and cuneate The right and left gracile nucleus and cuneate nucleus.nucleus.

The medial lemniscusThe medial lemniscus Five pairs of cranial nervesFive pairs of cranial nerves - Vestibulocochlear N.- Vestibulocochlear N. - Glossopharyngeal N.- Glossopharyngeal N. - Vagus N.- Vagus N. - Accessory N ( cranial portion )- Accessory N ( cranial portion ) - Hypoglossal N.- Hypoglossal N.

PONSPONS The pons lies directly superior to the medulla and The pons lies directly superior to the medulla and

anterior to the cerebellum and is about 2,5 cmanterior to the cerebellum and is about 2,5 cm Several pontine nucleiSeveral pontine nuclei The pneumotaxic area.The pneumotaxic area. The apneustic area The apneustic area Four pairs of cranial nervesFour pairs of cranial nerves - Trigeminal n.- Trigeminal n. - Abducents n.- Abducents n. - Facial n.- Facial n. - Vestibulocochlear n.- Vestibulocochlear n.

MIDBRAINMIDBRAIN

Mesencephalon extends from the pons to the Mesencephalon extends from the pons to the diencephalon, is about 2,5 cm.diencephalon, is about 2,5 cm.

The cerebral aqueduct passes through the midbrain.The cerebral aqueduct passes through the midbrain. Cerebral pedunclesCerebral peduncles - Corticospinal tract.- Corticospinal tract. - Corticopontine.- Corticopontine. - Corticobulbar.- Corticobulbar. TectumTectum - The superior colliculi- The superior colliculi

MIDBRAINMIDBRAIN

TECTUMTECTUM

Superior colliculiSuperior colliculi

- Refflex centers for certain visual activity.- Refflex centers for certain visual activity.

- Responsible for reflexes that govern - Responsible for reflexes that govern

movements of the eyes, head and neck in movements of the eyes, head and neck in

response to visual stimuli.response to visual stimuli.

Inferior colliculiInferior colliculi

Fig 14.7 aFig 14.7 a

Fig 14.7 bFig 14.7 b

MIDBRAINMIDBRAIN

TECTUMTECTUM

Inferior colliculiInferior colliculi

- Part of the auditory pathway, relaying impul - Part of the auditory pathway, relaying impul

from the receptors for hearing in the ear to from the receptors for hearing in the ear to

the thalamus.the thalamus.

- Reflex centers for the startle reflex.- Reflex centers for the startle reflex.

MIDBRAINMIDBRAIN

Substantia nigraSubstantia nigra

- Release dopamine.- Release dopamine.

- Extending from the substantia nigra to the - Extending from the substantia nigra to the

basal ganglia, help control suconscious basal ganglia, help control suconscious

muscle activity.muscle activity.

- Loss of these nurons is associated with - Loss of these nurons is associated with

Parkinson disease.Parkinson disease.

MIDBRAINMIDBRAIN

Red nucleiRed nuclei - Axon from the cerebellum and cerebral - Axon from the cerebellum and cerebral cortex form synapses in the red nuclei, which cortex form synapses in the red nuclei, which function with the cerebellum tocoordinate function with the cerebellum tocoordinate muscular movementsmuscular movements Cranial nerveCranial nerve - Oculomotor n.- Oculomotor n. - Trochlear n.- Trochlear n.

RETICULAR FORMATIONRETICULAR FORMATION The broad region where white matter and gray matter exhibit The broad region where white matter and gray matter exhibit

netlike arrangement .netlike arrangement . Extends from the upper part of the spinal cord , throughout the Extends from the upper part of the spinal cord , throughout the

brain stem, and into the lower part of the diencephalon.brain stem, and into the lower part of the diencephalon. Have ascending and descending neurons.Have ascending and descending neurons. The reticular activating system ( RAS )The reticular activating system ( RAS ) - Consists of sensory axons that project to the - Consists of sensory axons that project to the cerebral cortex .cerebral cortex . - Help maitain consciousness and is activate during - Help maitain consciousness and is activate during awakening from sleep.awakening from sleep. - Help regulate muscle tone .- Help regulate muscle tone .

Fig 16.10Fig 16.10

THE CEREBELLUMTHE CEREBELLUM

Fig 14.8 aFig 14.8 a

Fig 14.8 cFig 14.8 c

THE CEREBELLUMTHE CEREBELLUM

The anterior and posterior lobes govern The anterior and posterior lobes govern subconscious aspects of skeletal muscle subconscious aspects of skeletal muscle movements.movements.

The flocculonodular lobe contributes to The flocculonodular lobe contributes to equilibrium and balance.equilibrium and balance.

Cerebellar nuclei, within the white matter, are Cerebellar nuclei, within the white matter, are the region of gray matter that give rise to axon the region of gray matter that give rise to axon carrying impulses from the cerebellum to other carrying impulses from the cerebellum to other brain centers and the spinal cord.brain centers and the spinal cord.

CEREBELLAR PEDUNCLESCEREBELLAR PEDUNCLES

The inferior cerebellar pedunclesThe inferior cerebellar peduncles - Carry sensory information from the vestibular - Carry sensory information from the vestibular apparatus of the inner ear and from proprio- apparatus of the inner ear and from proprioceptors throughout the body into the cerebe-ceptors throughout the body into the cerebellum; their axons extend from the inferior llum; their axons extend from the inferior olivary nucleus of the medulla and from the olivary nucleus of the medulla and from the spinocerebellar tracts of the spinal cord into the spinocerebellar tracts of the spinal cord into the cerebellumcerebellum The middle cerebellar pedunclesThe middle cerebellar peduncles

CEREBELLAR PEDUNCLESCEREBELLAR PEDUNCLES

The middle cerebellar pedunclesThe middle cerebellar peduncles - Their axons carry commands for voluntary - Their axons carry commands for voluntary movements ( those that originate in motor movements ( those that originate in motor area of the cerebral cortex ) from the pontine area of the cerebral cortex ) from the pontine nuclei into the cerebellum.nuclei into the cerebellum. The superior cerebellar pedunclesThe superior cerebellar peduncles - Contain axons that extend from the cerebe – - Contain axons that extend from the cerebe – llum to the red nuclei of the midbrain and to llum to the red nuclei of the midbrain and to several nuclei of the thalamus.several nuclei of the thalamus.

THE DIENCEPHALONTHE DIENCEPHALON

Extends from the brain stem to the cerebrum Extends from the brain stem to the cerebrum and surounds the third ventricle.and surounds the third ventricle.

Includes Includes

- Thalamus.- Thalamus.

- Hypothalamus.- Hypothalamus.

- Epithalamus.- Epithalamus.

THALAMUSTHALAMUS

3cm in length and make up 80% of the 3cm in length and make up 80% of the diencephalon.diencephalon.

Consist of paired oval masses of gray matter Consist of paired oval masses of gray matter organized into nuclei with interspersed tract of organized into nuclei with interspersed tract of white matter.white matter.

The intermediate mass joints the right and left The intermediate mass joints the right and left halves of the thalamus in about 70 %halves of the thalamus in about 70 %

Fig 14.9Fig 14.9

THALAMUS THALAMUS

The thalamus is the major relay station for The thalamus is the major relay station for most sensory impulses that that reach the most sensory impulses that that reach the primary sensory areas of the cerebral cortex primary sensory areas of the cerebral cortex from the spinal cod and brain stem. Although from the spinal cod and brain stem. Although crude perseption of pain ful, thermal and crude perseption of pain ful, thermal and pressure sensations arise at the level of the pressure sensations arise at the level of the thalamus , precise localization of these thalamus , precise localization of these senasations depends on nerve impulses ariving senasations depends on nerve impulses ariving at the cerebral cortexat the cerebral cortex

THALAMUSTHALAMUS

The thalamus contributes to motor functions The thalamus contributes to motor functions by transmitting information from the by transmitting information from the cerebellum and basal ganglia to the primary cerebellum and basal ganglia to the primary motor area of the cerebral cortex. It also relays motor area of the cerebral cortex. It also relays nerve impulses between different area of the nerve impulses between different area of the cerebrum, and plays arole in the regulation of cerebrum, and plays arole in the regulation of autonomic activities and the maintenance of autonomic activities and the maintenance of consciousness. Axon that connect the thalamus consciousness. Axon that connect the thalamus and cerebral cortex pass through the internal and cerebral cortex pass through the internal capsule capsule

THALAMUSTHALAMUS

The internal medullary lamina, devides the The internal medullary lamina, devides the gray matter of the right and left of the gray matter of the right and left of the thalamus. It consist of myelinated axons that thalamus. It consist of myelinated axons that enter and leave the various thalamic nuclei.enter and leave the various thalamic nuclei.

Seven major groups of nucleiSeven major groups of nuclei 1. The anterior nucleus, connect to the 1. The anterior nucleus, connect to the hypothalamus and limbic system. It function hypothalamus and limbic system. It function in emotions, regulation of alertness, and in emotions, regulation of alertness, and memory.memory.

SEVEN MAJOR GROUP OF SEVEN MAJOR GROUP OF NUCLEINUCLEI

The anterior nucleus.The anterior nucleus. The medial nuclei, connect to the cerebral cortex, The medial nuclei, connect to the cerebral cortex,

limbic system and basal ganglia. They function in limbic system and basal ganglia. They function in emotions, learning, memory, awareness and cognitionemotions, learning, memory, awareness and cognition

Nuclei in the lateral group connect to the superior Nuclei in the lateral group connect to the superior colliculi, limbic system, and cortex in all lobes of the colliculi, limbic system, and cortex in all lobes of the cerebrum.cerebrum.

The lateral dorsal nucleus functions in the expression The lateral dorsal nucleus functions in the expression of emotionsof emotions


The lateral posterior nucleus and pulvinar The lateral posterior nucleus and pulvinar nucleus help integrate sensory information.nucleus help integrate sensory information.

Five nuclei are part of the ventral group. The Five nuclei are part of the ventral group. The ventral anterior nucleus contribute to motor ventral anterior nucleus contribute to motor functions, possibly movement planning. The functions, possibly movement planning. The ventral lateral nucleus, connect to the ventral lateral nucleus, connect to the cerebellum and motor parts of the of the cerebellum and motor parts of the of the cerebral cortex. It neurons are active during cerebral cortex. It neurons are active during movements on the opposite side of the body. movements on the opposite side of the body.


The ventral posterior nucleus,relays impulses for The ventral posterior nucleus,relays impulses for somatic sensations such as touch, pressure, somatic sensations such as touch, pressure, proprioception, vibration, heat cold, and pain from proprioception, vibration, heat cold, and pain from the face and body to the cerebral cortex.the face and body to the cerebral cortex.

The lateral feniculate nucleus, relays visual impulses The lateral feniculate nucleus, relays visual impulses for sight from the retina to the primary visual area of for sight from the retina to the primary visual area of the cerebral cortex.the cerebral cortex.

The medial geniculate nucleus, relays auditory The medial geniculate nucleus, relays auditory impulses for hearing from the ear to the primary impulses for hearing from the ear to the primary auditory area of the cerebral cortex.auditory area of the cerebral cortex.


Intralaminar nuclei, lie within the internal medullary lamina Intralaminar nuclei, lie within the internal medullary lamina and make connection with the reticular formation, cerebellum, and make connection with the reticular formation, cerebellum, basal ganglia and wide areas of the cerebral cortex.They basal ganglia and wide areas of the cerebral cortex.They funcion in pain peception, integration of sensory and motor funcion in pain peception, integration of sensory and motor information and aurosal.information and aurosal.

Themidline nucleus form a thin band adjacent to the third Themidline nucleus form a thin band adjacent to the third ventricle and has a presumed functin in memory and olfaction.ventricle and has a presumed functin in memory and olfaction.

The reticular nucleus, surround the lateral aspect of the The reticular nucleus, surround the lateral aspect of the thalamus, nect to the internal capsule. This nuclei monitors, thalamus, nect to the internal capsule. This nuclei monitors, filters and integrate activities of othe thalamic nuclei.filters and integrate activities of othe thalamic nuclei.

HYPOTHALAMUSHYPOTHALAMUS

The mammilary region, includes mammilary The mammilary region, includes mammilary bodies and posterior hypothalamic nuclei. The bodies and posterior hypothalamic nuclei. The mammilary bodies serve as relay stations for mammilary bodies serve as relay stations for reflexes related to the sense of smell.reflexes related to the sense of smell.

The tuberal region includes the dorsomedial The tuberal region includes the dorsomedial nucleus, ventromedial nucleus and arcuate nucleus, ventromedial nucleus and arcuate nucleus, plus the infundibulum. The median nucleus, plus the infundibulum. The median eminence encircle infundibulum.eminence encircle infundibulum.

Fig 14.10Fig 14.10


The supraoptic region, contains the paraventri cular The supraoptic region, contains the paraventri cular nucleus, supraoptic nucleus, anterior hypothalamic nucleus, supraoptic nucleus, anterior hypothalamic nucleus and suprachiasmatic nucleus. Axon from the nucleus and suprachiasmatic nucleus. Axon from the paraventricular and supraoptic nuclei form the paraventricular and supraoptic nuclei form the hypothalamohypo physeal tract, which extends hypothalamohypo physeal tract, which extends through the infundibulum to theposterior lobe of the through the infundibulum to theposterior lobe of the pituitary.pituitary.

Preoptic region, participates with the hypothalamus in Preoptic region, participates with the hypothalamus in regulating certain autonomic activities.Preoptic regulating certain autonomic activities.Preoptic region contains the medial and lateral preoptic nuclei.region contains the medial and lateral preoptic nuclei.


Control of the ANS. Axon extend from the Control of the ANS. Axon extend from the hypothalamus to sympathetic and parasympathetic hypothalamus to sympathetic and parasympathetic nuclei in the brain stem and spinal cord.nuclei in the brain stem and spinal cord.

Production of hormones Production of hormones Regulation of emotional and bihavioral patterns. Regulation of emotional and bihavioral patterns.

together with the limbic system.together with the limbic system. Regulation of eating and drinking. Regulation of eating and drinking.

Through the arcuate and paraventricular nuclei. Through the arcuate and paraventricular nuclei. Thirst center.Thirst center.


Control of body temperature. Control of body temperature. Directs the autonomic nervous system.Directs the autonomic nervous system.

Regulation of circadian rhythmsa nd states of Regulation of circadian rhythmsa nd states of consciousness. consciousness. The suprachiasmatic nucleus , this nucleus The suprachiasmatic nucleus , this nucleus receives input from the eyes ( retina ) and receives input from the eyes ( retina ) and sends output to other hypothalamic nuclei, the sends output to other hypothalamic nuclei, the reticular formation, and the pineal glandreticular formation, and the pineal gland

EPITHALAMUSEPITHALAMUS

Consists of the pineal gland and habenulare Consists of the pineal gland and habenulare nuclei.nuclei.

Pineal gland, it secretes the hormone Pineal gland, it secretes the hormone melatonin. As more melatonin is liberated melatonin. As more melatonin is liberated during darkness than in light. Melatonin also during darkness than in light. Melatonin also appears to contribute to the setting of the appears to contribute to the setting of the bodybody`̀s biological clock.s biological clock.

The habenular nuclei, are involved in olfaction The habenular nuclei, are involved in olfaction especially emotional responses to odorsespecially emotional responses to odors

CIRCUM VENTRICULAR CIRCUM VENTRICULAR ORGANORGAN

Can monitor chemical changes in the blood Can monitor chemical changes in the blood CVOs include part of hypothalamus, the pineal CVOs include part of hypothalamus, the pineal

gland, the pituitary gland, and a few other gland, the pituitary gland, and a few other nearby structures.nearby structures.

CVOs , coordinate homeostatik activities of CVOs , coordinate homeostatik activities of the endocrine and nervous systems, such as the the endocrine and nervous systems, such as the regulation of blood pressure, fluid balance, regulation of blood pressure, fluid balance, hunger and thirsthunger and thirst

THE CEREBRUMTHE CEREBRUM

Fig 14.11Fig 14.11

THE INTERNAL CAPSULETHE INTERNAL CAPSULE

Anterior limb.Anterior limb. Genu.Genu. Posterior limb.Posterior limb. Retrolentiform part.Retrolentiform part. Sublentiform part.Sublentiform part.

CEREBRAL WHITE MATTERCEREBRAL WHITE MATTER

ASSOCIATION TRACTS, contain axons that ASSOCIATION TRACTS, contain axons that conduct nerve impulses between gyri in the same conduct nerve impulses between gyri in the same hemisphere.hemisphere.

COMMISSURAL TRACTS, contain axons that COMMISSURAL TRACTS, contain axons that conduct nerve impulses from gyri in one cerebral conduct nerve impulses from gyri in one cerebral hemosphere to corresponding gyri in the other hemosphere to corresponding gyri in the other cerebral hemisphere. Three commissural tracts are cerebral hemisphere. Three commissural tracts are corpus callosum, anterior commissure and posterior corpus callosum, anterior commissure and posterior commissure.commissure.

PROJECTION TRACTS , contain axon that conduct PROJECTION TRACTS , contain axon that conduct nerve impul from the cerebrum to lower parts of the nerve impul from the cerebrum to lower parts of the CNS, an example is the internal capsule.CNS, an example is the internal capsule.

BASAL GANGLIABASAL GANGLIA

CORPUS STRIATUMCORPUS STRIATUM

- Lentiform nucleus- Lentiform nucleus

- Globus pallidus.- Globus pallidus.

- Putamen.- Putamen.

- Caudate nuclei- Caudate nuclei Nearby structures that are functionally linked Nearby structures that are functionally linked

to the basal ganglia are the substantia nigra of to the basal ganglia are the substantia nigra of the midbrain and the subthalamic nucleithe midbrain and the subthalamic nuclei


The basal ganglia receive impul from the cerebral The basal ganglia receive impul from the cerebral cortex and provide output back to motor part of the cortex and provide output back to motor part of the cortex via medial and ventral group nuclei of the cortex via medial and ventral group nuclei of the thalamusthalamus

Help regulate initiation and termination of movement.Help regulate initiation and termination of movement. Activity of neuronsin the putamen precedes or Activity of neuronsin the putamen precedes or

anticipates body movement, and activity of neurons anticipates body movement, and activity of neurons in the caudate nucleus occur prior to eye movementsin the caudate nucleus occur prior to eye movements


The globus pallidus helps regulate the muscle The globus pallidus helps regulate the muscle tone required for specific body movement.tone required for specific body movement.

Control subconscious contraction of skeletal Control subconscious contraction of skeletal muscles.muscles.

Help initiate and terminate some cognitive Help initiate and terminate some cognitive processes.processes.

Act with the limbic system to regulate Act with the limbic system to regulate emotional bihaviors.emotional bihaviors.

CLINICAL CORRELATIONSCLINICAL CORRELATIONS

Damage to the basal ganglia, result in uncontrollable Damage to the basal ganglia, result in uncontrollable shaking ( tremor ) , muscular regidity, and shaking ( tremor ) , muscular regidity, and involuntary muscle movement.involuntary muscle movement.

Movement disruptions such as these are a hallmark of Movement disruptions such as these are a hallmark of disorder like Parkinson disease. In this disorder , disorder like Parkinson disease. In this disorder , neuron that extend from the substantia nigra to the neuron that extend from the substantia nigra to the putamen and caudate nucleus degenerate, causing putamen and caudate nucleus degenerate, causing disruption.disruption.

Some psychiatric disorders, are thought to involve Some psychiatric disorders, are thought to involve dysfunction of circuit between the basal ganglia and dysfunction of circuit between the basal ganglia and the limbic system.the limbic system.

THE LIMBIC SYSTEMTHE LIMBIC SYSTEM

The limbic lobe, it includes the cingulate gyrus The limbic lobe, it includes the cingulate gyrus , parahippocampal gyrus. The hippocampus, is , parahippocampal gyrus. The hippocampus, is portion of the parahippocampus.portion of the parahippocampus.

Dentate gyrusDentate gyrus Amygdala.Amygdala. Septal nuclei.Septal nuclei. The mammillary bodies of the hipothalamusThe mammillary bodies of the hipothalamus

THE LIMBIC SYSTEMTHE LIMBIC SYSTEM

The anterior nucleus and the medial nucleus of the The anterior nucleus and the medial nucleus of the thalamus.thalamus.

The olfactory bulbs.The olfactory bulbs. The fornix, stria terminalis, stria medullaris, medial The fornix, stria terminalis, stria medullaris, medial

forebrain bundle and mammilothalamic tractforebrain bundle and mammilothalamic tract

The emotional brain plays a primary role in a The emotional brain plays a primary role in a

range of emotions.range of emotions.

The hippocampus, togetrher with other part of the The hippocampus, togetrher with other part of the

cerebrum, functions in memorycerebrum, functions in memory

CEREBRAL CORTEXCEREBRAL CORTEX

Specific types of sensory,motor, and integrative Specific types of sensory,motor, and integrative signals are processed in certain regions of the cerebral signals are processed in certain regions of the cerebral cortex.cortex.

Generally, sensory area receive sensory information Generally, sensory area receive sensory information and are involved in perception, the conscious and are involved in perception, the conscious awareness of sensation.awareness of sensation.

Motor area, initiate movement.Motor area, initiate movement. Association area, deal with more complex integrative Association area, deal with more complex integrative

functions such as memory,emotions,reasoning, will, functions such as memory,emotions,reasoning, will, judgement, personality traits, and intelligence.judgement, personality traits, and intelligence.

SENSORY AREASENSORY AREA

The primary somatosensory area ( areas 1, 2 The primary somatosensory area ( areas 1, 2 and 3 ). Receives nerve impulses for touch, and 3 ). Receives nerve impulses for touch, proprioception, pain, tickle and temperature.proprioception, pain, tickle and temperature.

The primary visual area ( area 17 ). Receives The primary visual area ( area 17 ). Receives visual information and involved in visual visual information and involved in visual perception.perception.

The primary auditory area ( area 41 and 42 ) . The primary auditory area ( area 41 and 42 ) . Receives information for sound and is Receives information for sound and is involved in auditory perception.involved in auditory perception.

SENSORY AREASENSORY AREA

The primary gustatory area ( area 43 ). The primary gustatory area ( area 43 ). Receives impulses for taste and is involved in Receives impulses for taste and is involved in gustatory perception.gustatory perception.

The primary olfactory area ( area 28 ). The primary olfactory area ( area 28 ). Receives impulses for smell and is involved in Receives impulses for smell and is involved in olfactory perception.olfactory perception.

SOMATIC SENSORY PATHWAYSSOMATIC SENSORY PATHWAYS

Three neuronsThree neurons - First-order neurons- First-order neurons - Second-order neurons- Second-order neurons -Third-order neuron.-Third-order neuron. Ascend to the cerebral cortex via two general Ascend to the cerebral cortex via two general

pathwayspathways - The posterior column-medial - The posterior column-medial lemniscus pathways.lemniscus pathways. - The anterolateral ( spinothalamic ) pathways- The anterolateral ( spinothalamic ) pathways

SOMATIC SENSORY PATHWAYSSOMATIC SENSORY PATHWAYS The posterior column-medial lemniscus pathwayThe posterior column-medial lemniscus pathway - Fine touch.- Fine touch. - Stereognosis.- Stereognosis. - Proprioception, kinesthesia and - Proprioception, kinesthesia and weight discrimination.weight discrimination. - Vibratory sensations- Vibratory sensations The anterolateral pathwaThe anterolateral pathwa - The lateral spinothalamic tract conveys sensory- The lateral spinothalamic tract conveys sensory impuls for pain and temperature.impuls for pain and temperature. - The anteruior spinothalamic tract convets impules - The anteruior spinothalamic tract convets impules for tickle, itch, crude touch, and pressure.for tickle, itch, crude touch, and pressure.

Fig. 16.5 p 557Fig. 16.5 p 557

MOTOR AREASMOTOR AREAS

Primary motor area ( area 4 ),controls voluntary Primary motor area ( area 4 ),controls voluntary contractions of specific muscles or group of muscles.contractions of specific muscles or group of muscles.

BrocaBroca‘‘s speech area ( area 44 and 45 ), involved in s speech area ( area 44 and 45 ), involved in the articulation of speech. In most people, Brocathe articulation of speech. In most people, Broca‘‘s s speech area is localized in the left cerebral speech area is localized in the left cerebral hemisphere. Neural circuit established between hemisphere. Neural circuit established between BrocaBroca‘‘s speech area, the premotor area, and primary s speech area, the premotor area, and primary motor area avtivate muscles of the larynx, pharynx motor area avtivate muscles of the larynx, pharynx and mouth and breathing musclesand mouth and breathing muscles

ASSOCIATION AREAASSOCIATION AREA

The somatosensory association area ( area 5 The somatosensory association area ( area 5 and 7 ). This area permits to determine the and 7 ). This area permits to determine the exact shape and texture of an object without exact shape and texture of an object without looking at it, to determine the orientation of looking at it, to determine the orientation of one object with respect to another as they are one object with respect to another as they are felt, and to sense the relationship of one body felt, and to sense the relationship of one body part to another. The storage of memories of part to another. The storage of memories of past sensory experiences, enabling to compare past sensory experiences, enabling to compare current sensations with previous experiencescurrent sensations with previous experiences


The prefrontal cortex ( frontal asociation area ) The prefrontal cortex ( frontal asociation area ) area 9, 10, 11 and 12. area 9, 10, 11 and 12. Concerned with the makeup of personConcerned with the makeup of person‘‘ss personality, intellect, complex learning personality, intellect, complex learning abilities, recall of information, initiative, abilities, recall of information, initiative, judgement, foresight, reasoning, conscience, judgement, foresight, reasoning, conscience, intuition, mood, planning for the future and intuition, mood, planning for the future and development of abstract ideas.development of abstract ideas.


The visual association area ( area 18 and 19 ) The visual association area ( area 18 and 19 ) It relates present and past visual experiences It relates present and past visual experiences and is essential for recognizing and evaluating and is essential for recognizing and evaluating what is seen.what is seen.

The auditory association area ( area 22 ). The auditory association area ( area 22 ). Allow to recognize a particular sound.Allow to recognize a particular sound.

WernickeWernicke‘‘s ( posterior language ) . ( area 22 s ( posterior language ) . ( area 22 and possibly area 39 and 40 )and possibly area 39 and 40 )


WernickeWernicke‘‘s ( posterior labnguage ) area, ( area s ( posterior labnguage ) area, ( area 22 and possibility area 39 and 40 ). A broad 22 and possibility area 39 and 40 ). A broad region in the left temporal and parietal lobes, region in the left temporal and parietal lobes, interprets the meaning of speech by interprets the meaning of speech by recognizing spoken words. It is active as you recognizing spoken words. It is active as you translate words into thoughts. The region in translate words into thoughts. The region in the right hemosphere that correspod to Brocathe right hemosphere that correspod to Broca‘‘s s and Wernickeand Wernicke‘‘s area in the left hemisphere s area in the left hemisphere also contribute toverbal communication by also contribute toverbal communication by adding emotional contentadding emotional content


The common integrative area ( area 5, 7, 39 The common integrative area ( area 5, 7, 39 and 40 ). This area integrates sensory and 40 ). This area integrates sensory interpretations from the association area and interpretations from the association area and impulses from other area, allowing the impulses from other area, allowing the formation of thoughts based on a variety of formation of thoughts based on a variety of sensory input. It the transmits signals to other sensory input. It the transmits signals to other parts of the brain for the appropriate response parts of the brain for the appropriate response to the sensory signals it has interpreted.to the sensory signals it has interpreted.


The premotor area ( area 6 ) The premotor area ( area 6 ) Premotor area deals with learned motor activities of Premotor area deals with learned motor activities of complex and sequensial nature. It generates nerve complex and sequensial nature. It generates nerve impul that cause specific group of muscles to contract impul that cause specific group of muscles to contract in a specific sequence, as when you write your name. in a specific sequence, as when you write your name. The premotor area also serves as a memory bank for The premotor area also serves as a memory bank for such movements.such movements.

The frontal eye field area ( area 8 ). It controls The frontal eye field area ( area 8 ). It controls voluntary scanning movement of the eyes.voluntary scanning movement of the eyes.

APHASIAAPHASIA

FLUENT APHASIFLUENT APHASI Damage to WernickeDamage to Wernicke‘‘s area , the common integrative s area , the common integrative

area, or auditory association, chracterized by faulty area, or auditory association, chracterized by faulty understanding of spoken or writen words. People may understanding of spoken or writen words. People may fluently produce strings of words that have no fluently produce strings of words that have no meaning.meaning.

NONFLUENT APHASIANONFLUENT APHASIA Damage to BrocaDamage to Broca‘‘s speech area, an inability to s speech area, an inability to

properly articulate or form words.People know what properly articulate or form words.People know what they wish to say, but cannot speak.they wish to say, but cannot speak.

SOMATIC SENSORY PATHWAYS SOMATIC SENSORY PATHWAYS TO THE CEREBELLUMTO THE CEREBELLUM

Anterior and posterior cerebellar : convey Anterior and posterior cerebellar : convey nerve impulses from proprioceptors in the nerve impulses from proprioceptors in the trunk and lower limb of one side of the body to trunk and lower limb of one side of the body to the same side of the cerebellum. the same side of the cerebellum. The proprioceptive input informs the The proprioceptive input informs the cerebellum of actual movements, allowing it to cerebellum of actual movements, allowing it to coordinate, smooth, and refine skilled coordinate, smooth, and refine skilled movements and maintain posture and balance.movements and maintain posture and balance.

Fig 16.7Fig 16.7

Fig 16.8Fig 16.8

Table 16.4 aTable 16.4 a

INDIRECT MOTOR PATHWAYINDIRECT MOTOR PATHWAY

TABLE 16.4 BTABLE 16.4 B

brain

Documents

medulla oblongatathe

vestibulocochlear n

inferior olivary nucleus

trochlear n

cerebellar nuclei

inferior colliculifig

ponsthe pons

inferior border