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Central nervous system (CNS) Brain + Spinal Cord • Forebrain – telencephalon • cortex, basal ganglia – diencephalon • thalamus, hypothalamus • Midbrain • tectum, tegmentum • Hindbrain • cerebellum, pons, medulla brain stem cerebral hemispheres

Basic Neuroanatomy

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Neuroanatomy

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Page 1: Basic Neuroanatomy

Central nervous system (CNS) Brain + Spinal Cord

• Forebrain– telencephalon

• cortex, basal ganglia

– diencephalon• thalamus, hypothalamus

• Midbrain• tectum, tegmentum

• Hindbrain• cerebellum, pons, medulla

brain stem

cerebral hemispheres

Page 2: Basic Neuroanatomy

Cerebral cortex

• Surface is folded to increase area:– Sulcus (pl. sulci) = groove– Gyrus (pl. gyri) = bulge between sulci

• Grey matter = cell bodies• White matter = axons

central sulcuspostcentral gyrus

grey matterwhite matter

Page 3: Basic Neuroanatomy

Cerebral hemispheres

• Left & right hemispheres are connected by white matter tracts called commissures.– These allow communication between lateralized

brain areas.– Largest commisure is the corpus callosum.– In “split brain” patients the corpus callosum is

transected, leading to neuropsychological deficits.

corpus callosum

Page 4: Basic Neuroanatomy

Lobes of the cerebral cortex

frontal lobe-motor-executive functions

parietal lobe -body sense -multimodal integration

occipital lobe -visual

temporal lobe-memory-auditory

Page 5: Basic Neuroanatomy

Primary & association cortex

• Primary cortical areas are most directly linked to the sensory or motor systems in the body.

• These areas project to association cortex, allowing integration of information.

• Association cortex is where sophisticated, higher-level processing takes place, e.g.:– planning of a sequence of movements - motor

association cortex, frontal lobe– perceiving a visual object - visual association

cortex, temporal lobe– making decisions - multimodal association cortex,

frontal lobe

Page 6: Basic Neuroanatomy

Primary cortical areasprimary somatosensory area

medial surface of right hemisphere

lateral surface of left hemisphere

primary motor area

central sulcus

primary visual area

primary auditory area

lateral fissure (Sylvian fissure)

Page 7: Basic Neuroanatomy

Functional Distribution of Cortex1. Primary Cortex (Direct

Projection Areas) • 3 Sensory—Visual,

Auditory, Somatosensory—

• 1 Motor.

2. Secondary Cortex (unimodal)

3. Tertiary Cortex (Association, polymodal)

Page 8: Basic Neuroanatomy

Subcortical structures

• In the forebrain, these are:– in the telencephalon, the basal ganglia

and the limbic system.– in the diencephalon, the thalamus and

hypothalamus.

basal gangliathalamus

hypothalamus

Page 9: Basic Neuroanatomy

Basal ganglia• important in motor control

and cognition.• Damage to the basal ganglia

occurs in Parkinson’s disease and Huntington’s disease.

5 Components:1. Caudate Nucleus2. Putamen3. Globus Pallidus4. Subthalamic Nucleus5. Substantia Nigra

Page 10: Basic Neuroanatomy

Limbic system

• Functions include emotion and memory.• Limbic system includes cortical & subcortical

structures:– Cingulate gyrus (cognitive control).– Hippocampus, fornix & mamillary bodies

(episodic memory).– Amygdala (emotion).

amygdalahippocampus

cingulate gyrus

Page 11: Basic Neuroanatomy

Diencephalon• Thalamus:

– Closely connected with cerebral cortex & its functions.

– Thalamic nuclei have distinct functions, e.g. lateral geniculate nucleus in vision.

• Hypothalamus:– Controls autonomic nervous

system and endocrine system (hormones).

•Last sensory way station on the way to the cortex.

Page 12: Basic Neuroanatomy

• Thalamic nuclei• 1. Ventral Posterior Nuclei: Somatosensory• 2. Lateral Geniculate: Visual• 3. Medial Geniculate: Auditory

Pulvinar connects with parietal lobe and is a major part of an attentional control system.

Page 13: Basic Neuroanatomy

Midbrain

tectum

tegmentum

• Midbrain (and hindbrain) structures perform relatively primitive functions, e.g. reflexes.

• Tectum comprises:– superior colliculi, fish’s visual system– inferior colliculi, fish’s auditory system.

• Tegmentum includes nuclei involved with :– arousal (reticular formation)– species-specific behavior (periaqueductal grey) – motor control (red nucleus, substantia nigra)

Page 14: Basic Neuroanatomy

Hindbrain

• Cerebellum– important for precise movement

control and learning.– also involved in cognition.

• Pons:– nucleus relays info. from cortex to cerebellum.– contains reticular formation - arousal.

• Medulla (oblongata):– necessary for vital functions: breathing, heartbeat.

pons

medulla

cerebellum

Page 15: Basic Neuroanatomy

• BRAINSTEM– Many neurotransmitter systems– Reticular Activating System– Sleep & wakefulness control– Controls respiration and other bodily functions

– Midbrain– Pons– Medulla

Page 16: Basic Neuroanatomy

Brainstem Components

• Midbrain– Superior Colliculus:

Eye movements and visual reflex functions.

– Inferior Colliculus: Auditory reflex functions.

– Pons & Medulla.– Ascending sensory

and descending motor pathways. Bulge of Pons caused by pathways to the cerebellum.

Page 17: Basic Neuroanatomy

Cerebellum

• Inputs from sensory & motor centers and vestibular system.

• Outputs to spinal cord and thalamus (then cortex).

• Functions: – Maintenance of posture, and fine

motor control (timing).– Also involved in higher functions

including language

Page 18: Basic Neuroanatomy