1.3 Structure and function: Brain Structure

What are the planes of dissection?

Horizontal, Sagittal, Coronal

Medial/Lateral

Toward Middle / Toward Side

Ipsilateral / Contralateral

Same / Opposite Side

Proximal / Distal

Near / Far

Superior / Inferior

Up / Down

Anterior / Posterior

Front / Back

Rostral / Caudal

Beak / Tail

Dorsal / Ventral

Back / Belly

Cerebral Cortex

Outermost layer of the brain; has gyri and sulci

Gyri

In the cerebral cortex, ridged or raised portions

Sulci

In the cerebral cortex, furrows

Lobes in Cerebral Cortex

Frontal, Parietal, Occipital, Temporal

Frontal Lobe

Attention, planning, motor

Parietal Lobe

Touch, other

Occipital Lobe

Visual processing

Temporal Lobe

Auditory Processing, memory

List of Boundaries between lobes

Longitudinal fissure, sulvian fissure, central sulcus

Longitudinal Fissure

Separates Left/Right Hemispheres

Sylvian Fissure

Boundary of temporal lobe

Central Sulcus

Divides frontal/parietal lobes

Precentral Gyrus

In frontal lobe, for motor control

Postcentral gyrus,

In parietal lobe, for touch

Gray Matter

Cell bodies and dendrites (lack myelin), Nuclei (collections of neurons)

White matter

Axons with white myelin sheaths (fatty), tracts (bundles of axons)

Tracts

Bundles of axons

Embryonic Development

Begins with neural tube; divided by into forebrain, midbrain, and hindbrain

What does the forebrain develop into?

Telencephalon and diencephalon

What does the midbrain develop into?

Remains as midbrain

What does the hindbrian develop into?

Cerebellum, pons, and medulla

List of inside the telencephalon

Cerebral Cortex, Basal Ganglia, Hippocampus Amygdala, Cingulate Gyrus, Olfactory bulb

Cerebral Cortex

Sensory, motor, associative, cognitive, six layers, pyramidal cells

Basal Ganglia

Control of movement and actions

Hippocampus and Fornix

Learning

Amygdala

Emotional Regulation and Perception of Odor

Cingulate Gyrus

Attention

Olfactory bulb

Sense of Smell

List inside the Diencephalon

Thalamus, Hypothalamus

Thalamus

Cluster of Nuclei that relay all sensory information to cortex

Hypothalamus

Motivated behavior, homeostasis, regulating autonomic nervous system, control pituitary gland

List inside the Midbrain

Tectum, Tegmentum, Reticular Formation, Periaqueductal Gray

Tectum

Superior colliculi (visual) and Inferior colliculi (auditory)

Tegmentum

Sustantia nigra (source of dopamine to basal ganglia)

Periaqueductal Gray

Pain Perception

Reticular Formation

Sleep and arousal

List of Structures in Hindbrain

Pons, Medulla, Cerebellum

Pons

Sensory and motor nuclei

Medulla

Transition from brain to spinal cord; essential process such as respiration and heart rate

Cerebellum

Attached to brain stem, function in motor cooridination/control

Meninges

Protective membranes that surround the brain and spinal cord; Dura mater, arachnoid membrane, pia mater

Dura mater

tough outermost layer

Arachnoid membrane

between other two, filled with cerebrospinal fluid (CSF)

Pia Mater

Delicate innermost layer

Ventricular system

Series of chambers filled with CSF

Lateral Ventricle

Extend into all four lobes and lined with choroid plexus

Choroid Plexus

Membrane that produces CSF

How does the CSF flow?

From the lateral ventricles, into third ventricle at midline, into fourth ventricle, exits to circulate over the brain and spinal cord

What does CSF provide?

Buoyancy, protection, exchange of nutrients/waste between blood and brain

What does the brain depend on besides CSF?

Oxygenated blood from the cerebral arteries

Cerebral Arteries

Branch from the carotid and vertebral arteries

Stroke

Caused by the rupture of blockage of blood vessels

Blood Brain Barrier

Filters blood before it enters brain tissue; selectively permeable

Structural Imaging

Computerized Axial Tomography (CAT or CT), Magnetic Resonance Imaging (MRI), Diffusion Tensor Imaging

Computerized Axial Tomography (CAT or CT)

Map based on tissue density and X-ray absorption, best for strokes and tumors

Magnetic Resonance Imaging (MRI)

Magnetic fields and radio waves to map tissue density, best for high resolution images

Diffusion Tensor Imaging

Visualize axon fiber tracts

Functional Brain Imaging

Functional MRI (fMRI), Positron Emission Tomography (PET), Transcranial Magnetic Stimulation (TMS), Magnetoencephalography (MEG)

Functional MRI (fMRI)

detect small changes in brain metabolism (ex. oxygen use)

Positron Emission Tomography (PET)

gives images of brain activity using radioactive chemicals in blood stream

Transcranial Magnetic Stimulation (TMS)

Stimulates discrete cortical regions through magnetism

Magnetoencephalography (MEG)

Measures tiny magnetic fields given off by active neurons through magnetism