1.3: Organization of the Brain

Meninges

A thick, three-layered sheath of connective tissue that covers the brain. These help to protect the brain by keeping it anchored within the skull

Dura Mater

Outer layer of connective tissue (meninges) and is directly connected to the skull

Arachnoid Mater

The middle layer of the meninges and is a fibrous, web-like structure

Pia Mater

The inner layer of the meninges which is connected directly to the brain

Cerebrospinal Fluid

The aqueous solution that nourishes the brain and spinal cord and provides a protective cushion. The meninges resort this.

Ventricles

Cerebrospinal fluid is produced by specialized cells that line the _________ (internal cavities) of the brain

Hindbrain, Midbrain, Forebrain

Three basic parts of the human brain

Lower

The brain structures associated with basic survival are located ________ in the brain

Higher

The brain structures associated with more complex functions are located ________ in the brain

Brainstem

The most primitive region of the brain and composed of the hindbrain and midbrain

Last

The forebrain developed _______ compared to the other brain regions

Limbic System

A group of neural structures primarily associated with emotion and memory. Aggression, fear, pleasure, and pain are all related to this

Cerebral Cortex

The most recent evolutionary development of the human brain and is the outer covering of the cerebral hemispheres. In humans, it is associated with everything from language processing to problem solving, and from impulse control to long-term planning

Forebrain

Composed of:

• Cerebral cortex

• Basal ganglia

• Limbic system

• Thalamus

• Hypothalamus

Midbrain

Composed of:

• Inferior and superior colliculi

Hindbrain

Composed of:

• Cerebellum

• Medulla oblongata

• Reticular formation

• Pons

Cerebral Cortex

Complex perceptual, cognitive, and behavioral processes

Basal ganglia

Movement

Limbic System

Emotion and memory

Thalamus

Sensory relay station

Hypothalamus

Hunger and thirst; emotion

Inferior and Superior Colliculi

Sensorimotor reflexes

Cerebellum

Refined motor movements

Medulla Oblongata

Heart, vital reflexes (vomiting coughing)

Reticular Formation

Arousal and alertness

Pons

Communication within the brain, breathing

Neural Tube

In prenatal life, the brain develops from the _______

Rhombencephalon

Hindbrain; located where the brain meets the spinal cord. It controls balance, motor coordination, breathing, digestion, and general arousal processes such as sleeping and waking. It manages vital functions necessary for survival.

Myelencephalon

One half of what the rhombencephalon divides into during embryonic development. It becomes the medulla oblongata

Metencephalon

One half of what the rhombencephalon divides into during embryonic development. It becomes the pons and cerebellum

Medulla Oblongata

In the developed brain, this is a lower brain structure that is responsible for regulating vital functions such as breathing, heart rate, and digestion

Pons

Lies above the medulla and contains sensory and motor pathways between the cortex and the medulla

Cerebellum

At the top of the hindbrain, this mushrooms out of the back of the pons. It is a structure that helps maintain posture and balance and coordinates body movements. Damage to this causes clumsiness, slurred speech, and loss of balance. Alcohol impairs the functioning of this and consequently affects speech and balance.

Mesencephalon

Midbrain; just above the hindbrain which receives sensory and motor information from the rest of the body. It is associated with involuntary reflex responses triggered by visual or auditory stimuli

Colliculi

Two prominent nuclei in the midbrain

Superior Colliculis

Receives visual sensory input

Inferior Colliculis

Receives sensory information from the auditory system. It has a role in reflexive reactions to sudden loud noises

Prosencephalon

Forebrain; Located above the midbrain and is associated with complex perceptual, cognitive, behavioral processes. It is also associated with emotion and memory and it has the greatest influence on human behavior. It’s functions are not absolutely necessary for survival, but are associated instead with the intellectual and emotional capacities most characteristic of humans.

Telencephalon

One of the parts that the forebrain (prosencephalon) divides into during prenatal development. This forms the cerebral cortex, basal ganglia, and Limbic system.

Diencephalon

One of the parts that the forebrain (prosencephalon) divides into during prenatal development. This forms the thalamus, hypothalamus, posterior pituitary gland, and pineal gland.

Neuropsychology

Refers to the study of functions and behaviors associated with specific regions of the brain. It is most often applied in research settings, where researchers attempt to associate very specific areas in the brain to behavior. It is also applied in clinical settings with evaluations of patient cognitive and behavioral functioning, as well as the diagnosis and treatment of brain disorders. This has its own experimental methodology and technology.

Cortical Maps

Created by neurosurgeons using electrical stimulation on the brain. This relies on the assistance of the patient who is awake and alert. Because there are no pain receptors in the brain, only local anesthesia is required.

Electroencephalogram (EEG)

Electrical activity generated by larger groups of neurons can be studied using this. It involves placing several electrodes on the scalp. Broad patterns of electrical activity can thus be detected and recorded. Because this procedure is noninvasive (it does not cause any damage), these are commonly used with human subjects.

Regional Cerebral Blood Flow (rCBF)

A noninvasive mapping procedure which detects broad patterns of neural activity based on increased blood flow to different parts of the brain. It relies on the assumption that blood flow increases to regions of the brain that are engaged in cognitive function. To measure blood flow, the patient inhales a harmless radioactive gas; a special device that can detect radioactivity in the bloodstream can then correlate radioactivity levels with regional cerebral blood flow. This research method used noninvasive computerized scanning devices.

Computer Axial Tomography (CAT or CT) Scan

Multiple x-rays are taken at different angles and processed by a computer to produce cross-sectional images of the tissue

Positron Emission Tomography (PET) Scan

A radioactive sugar is injected and absorbed into the body, and its dispersion and uptake throughout the target tissue is imaged

Magnetic Resonance Imaging (MRI)

A magnetic field that interacts with hydrogen atoms is used to map out hydrogen dense regions of the body

Functional Magnetic Resonance Imaging (fMRI)

A magnetic field that interacts with hydrogen atoms is used to map out hydrogen dense regions of the body to specifically measure changes associated with blood flow. It is especially useful for monitoring neural activity, since increased blood flow to a region of the brain is typically coupled with its neuronal activation