PP 03b-Gross anatomy, in PP 03b-Gross anatomy, in more detailmore detail

Anatomy of the BrainAnatomy of the Brain• Dorsolateral SurfaceDorsolateral Surface

– Central Sulcus (fissure Central Sulcus (fissure of Rolando)of Rolando)

• Separation of Separation of primary motor from primary motor from sensory cortexsensory cortex

– Lateral fissure (Sylvian Lateral fissure (Sylvian fissure)fissure)

• Separation of frontal Separation of frontal from temporal lobefrom temporal lobe

– Parieto-occipital sulcusParieto-occipital sulcus

• Separation of Separation of parietal from parietal from occipital lobeoccipital lobe

• Borders between lobes Borders between lobes convenient convenient approximations, and lobes approximations, and lobes are inter-connectedare inter-connected

Frontal lobeFrontal lobe• Largest of the lobesLargest of the lobes

• Primary motor cortex (Area Primary motor cortex (Area 4)4)– Contralateral Contralateral

sensorimotor sensorimotor organizationorganization

– Topologic Topologic representation of motor representation of motor homunculus here homunculus here

• Premotor cortex (Area 6)Premotor cortex (Area 6)

• Prefrontal cortex (Area 10-Prefrontal cortex (Area 10-12)-cognitive brain12)-cognitive brain– Personality, reasoning, Personality, reasoning,

thinking, executive thinking, executive decisiondecision

• Anterior language cortex Anterior language cortex (Area 44/45) “Broca’s area”(Area 44/45) “Broca’s area”

Frontal lobeFrontal lobe• Clinical InformationClinical Information

– Prefrontal lobe damagePrefrontal lobe damage• Difficulty with planning, problem Difficulty with planning, problem

solving, thinking, reasoning and solving, thinking, reasoning and performing executive functionsperforming executive functions

– Orbital prefrontal damageOrbital prefrontal damage• Personality disorders, emotional Personality disorders, emotional

disintegration & impulsive social disintegration & impulsive social behaviorsbehaviors

– Medial prefrontal damageMedial prefrontal damage• Problems with attention, motivation Problems with attention, motivation

and responsivenessand responsiveness

– Example of Phineas GageExample of Phineas Gage

Parietal LobeParietal Lobe• Primary somatosensory Primary somatosensory

cortex (Area 3,1,2)cortex (Area 3,1,2)– Topologic representation of Topologic representation of

sensory homunculus heresensory homunculus here

• Superior parietal lobule Superior parietal lobule (5/7) (5/7) – Sensory integration, Sensory integration,

visual-spatial and visual-spatial and construction tasksconstruction tasks

• Inferior parietal lobule Inferior parietal lobule (language [dominant], (language [dominant], body schema, & spatial body schema, & spatial orientation [nondominant])orientation [nondominant])

Parietal lobeParietal lobe• Clinical InformationClinical Information

– Contralateral somato- Contralateral somato- sensory losssensory loss

– Perceptual/conceptual Perceptual/conceptual disorders of tactile disorders of tactile recognitionrecognition

– Impaired constructional Impaired constructional (drawing/designing) skills(drawing/designing) skills

– Impaired spatial Impaired spatial orientationorientation

– Visual spatial memory lossVisual spatial memory loss– Tactile agnosiaTactile agnosia

Primary Primary motor motor cortexcortex(posterior (posterior frontal frontal lobe)lobe)

Primary Primary somato-somato-sensory sensory cortexcortex(anterior (anterior parietal parietal lobe)lobe)

Larger size of structure represents greater cortical area

dedicated to that structure

Summary slide: Primary motor cortex and primary somatosensory cortex

Occipital lobeOccipital lobe• Primary Visual Cortex Primary Visual Cortex

(Area 17, medial surface, (Area 17, medial surface, on either side of calcarine on either side of calcarine sulcus)sulcus)– Visual perceptionVisual perception

• Secondary Visual Cortex Secondary Visual Cortex (Area 18)(Area 18)– visual recognitionvisual recognition

• Clinical: Damage here Clinical: Damage here associated with associated with problems with problems with ____________________________

Temporal LobeTemporal Lobe• Superior, Middle, & Superior, Middle, &

Inferior GyriInferior Gyri– Primary auditory cortex Primary auditory cortex

•Heschl gyri (Area 41, Heschl gyri (Area 41, 42)42)

– Association language Association language cortex (Area 22)cortex (Area 22)• Comprehension of spoken Comprehension of spoken

languagelanguage

– Hippocampus- Hippocampus- verbal/nonverbal verbal/nonverbal memory on medial memory on medial surfacesurface

– OlfactionOlfaction

Temporal lobeTemporal lobe• Clinical presentation if Clinical presentation if

damageddamaged– Deficit in auditory Deficit in auditory

perceptual and perceptual and discriminative skillsdiscriminative skills

– Wernicke’s Aphasia Wernicke’s Aphasia (dominant temporal (dominant temporal lobe)lobe)

– Disorders of nonverbal Disorders of nonverbal memory memory •Music (right temporal lobe)Music (right temporal lobe)

– Prone to seizuresProne to seizures

Ventral SurfaceVentral Surface• Frontal, temporal & Frontal, temporal &

occipital lobesoccipital lobes• Major structuresMajor structures

– Orbital cortexOrbital cortex– Olfactory bulbOlfactory bulb– Occipito-temporal Occipito-temporal

gyrus (fusiform)gyrus (fusiform)– Lingual gyrus Lingual gyrus – Parahippocampal Parahippocampal

gyrusgyrus– UncusUncus

Clinical InformationOccipito-temporal region, when damaged, results in:

Impaired object recognition, visual hallucinations, and failure of facial recognition

CNS 3-D detailsCNS 3-D details (W pp. 9-10 & (W pp. 9-10 & 97; W&A pp. 25-44 & 48-54)97; W&A pp. 25-44 & 48-54)

Brain (encephalon)Cerebrum (telencephalon)

2 hemispheres 4 lobes in each hemisphereDeep in each hemisphere: Limbic systemBasal gangliaVentricles

Diencephalon (“between brain”)BrainstemMidbrainPonsMedullaCerebellum

Spinal cord CervicalThoracicLumbarSacralCoccygeal (not shown)

Note: Gradual transitions b/w the

parts

Notice the shaded

structures and

structures drawn with

dashed lines. Why are they

drawn this way?

Of the structures in

the list, which two are not

depicted here?

3-D views of the 3-D views of the rostral spinal cord, brainstem, diencephalon, and basal gangliarostral spinal cord, brainstem, diencephalon, and basal ganglia

Here are 3-D views of the “dashed and shaded” structures in the previous slide’s

illustration

Anterior view Posterior view Lateral view

Basal GangliaBasal Ganglia

• AnatomyAnatomy– Structures: Caudate nucleus, putamen, globus pallidus, Structures: Caudate nucleus, putamen, globus pallidus,

claustrum, & amygdaloid nucleus claustrum, & amygdaloid nucleus – Associated Structures: Substantia nigra and Subthalamic Associated Structures: Substantia nigra and Subthalamic

nucleusnucleus• FunctionFunction

– Regulation of motor cortical output & muscle toneRegulation of motor cortical output & muscle tone– Cognitive functions with multiple projections to prefrontal lobeCognitive functions with multiple projections to prefrontal lobe

• Clinical InformationClinical Information– Structural damage or reduction/overabundance of specific Structural damage or reduction/overabundance of specific

neurotransmittersneurotransmitters– Inappropriate movement patterns i.e. tremor, chorea, Inappropriate movement patterns i.e. tremor, chorea,

athetosis, and myoclonic jerks (hyperkinetic) or difficulty athetosis, and myoclonic jerks (hyperkinetic) or difficulty initiating movements (hypokinetic)initiating movements (hypokinetic)

DiencephalonDiencephalon• Central Core of the BrainCentral Core of the Brain

• StructuresStructures– ThalamusThalamus– HypothalamusHypothalamus

3-D views of the 3-D views of the rostral spinal cord, brainstem, diencephalon, and basal gangliarostral spinal cord, brainstem, diencephalon, and basal ganglia

Anterior view Posterior view Lateral view

ThalamusThalamus• AnatomyAnatomy

– Above the hypothalamus in Above the hypothalamus in the floor of lateral ventriclethe floor of lateral ventricle

• Functions:Functions:– Transmission of Transmission of

sensorimotor information to sensorimotor information to cortexcortex

– Contribution to cortically Contribution to cortically mediated sensorimotor, mediated sensorimotor, speech & language speech & language functions (cortico-thalamo-functions (cortico-thalamo-cortical connectionscortical connections

Coronal section through deep brain structures, to show relative positions of thalamus, basal ganglia, and

internal capsuleWhite spaces containing choroid plexus are ventricles

HypothalamusHypothalamus• Connections to brain, Connections to brain,

brainstem, & spinal cord brainstem, & spinal cord by neural & hormonal by neural & hormonal efferents, provides efferents, provides specialized circuitry for: specialized circuitry for: – Autonomic nervous systemAutonomic nervous system– Body temperature, blood Body temperature, blood

volume, food & water volume, food & water intake, body mass, intake, body mass, reproduction, circadian reproduction, circadian rhythms, drives & rhythms, drives & emotionsemotions