3B: The Brain

EEG Scan

(electroencephalogram) a graphical record of electrical activity of the brain EX. picture

fMRI

(function MRI) provides both the structure and the function of the brain as it measures brain activity using the amount of blood flow in and out of the brain. EX. image

MRI

(magnetic resonance imaging) shows the soft tissue of the brain and can be used for measuring differences between healthy brains and those with disorders such as schizophrenia. EX. image

PET Scan

(positron emission topography) displays the brain's hot spots of action by measuring its consumption of sugar glucose. EX. image

New: Limbic System

- located between the older brain structures and the cerebral hemispheres. -involved in many of our emotions and motivations, particularly those related to survival. (fear, anger, and emotions related to sexual behavior, eating, sex) - The amygdala and hippocampus are involved in memory. EX. The limbic system is responsible for our motivation to get food for ourselves.

New: Frontal Lobe

- positioned at the frontmost region of the cerebral cortex - involved in movement, decision-making, problem solving, and planning. - Divided into prefrontal cortex, the premotor area and the motor area. EX. My frontal lobe helped me stop my impulse to eat all the candy I saw as it aids in impulse control.

New: Hypothalamus

-The main pleasure center of the brain -important in hunger, thirst, body temperature, sexual behavior -emits hormones that affect the pituitary gland EX. When scientists planted an electrode in a rat's hypothalamus, rats would not stop pressing a lever to receive pleasurable stimulation until its brain was exhausted.

New: Prefrontal Cortex

-personality expression -planning of complex cognitive behaviors (executive thought) E.g: My pre-frontal cortex told me to avoid jumping off that cliff

Right Handed vs. Left Handed

96% of right handed people process speech in the left region of the brain, but only 70% of left handed people process speech in the left region. Right and Left handedness seems genetic. Left handers have more reading disabilities, allergies, and migraines but are better at music, art, and math.

Neurogenesis

A process of growing new brain cells as a result of exercise, sleep, and stimulating environments. EX. Neurogenesis can happen in school as well as in your own bed when you're asleep.

Pons

Above the medulla, the pons is a portion of the hindbrain that connects the cerebral cortex with the medulla. It also serves as a communications and coordination center between the two hemispheres of the brain. As a part of the brainstem, the pons helps in the transferring of messages between various parts of the brain and the spinal cord. EX. The Pons helps in functions like sleep and arousal.

Cerebral Cortex

Apart from the older brain parts, the cerebral cortex is a newer brain part which deals with higher functioning activities such as voluntary actions. It is the largest part of the brain and resembles a bark-like texture. It is divided into four lobes: Frontal, parietal, occipital, temporal EX. The cerebral cortex is responsible for perception, thinking, and speaking.

Cerebellum

At the back of the brain, it is small, wrinkled, and split into two separate parts. It coordinates movement, manages emotion, and figures out sounds and textures. EX. The cerebellum helps you distinguish a bumpy surface from a flat one.

Left Hemisphere Vs. Right Hemisphere

LEFT: handles rational, logical thought, speech, and words. Also handles sign language. EX. A person who loves math and science. RIGHT: handles images, emotions, intuition, and drawing inferences. Also handles our sense of self and how we look. EX. A person who loves interpreting literature and drawing art.

"Old brain" functions Vs. Higher Order Brain Functions

Older brain: the survival part of the brain- aids in basic needs to live. EX. simple animals such as sharks only have a brain to carry out these needs (sleeping, eating, resting) Higher Order Brain: the more complex brain actions such as emotion and memory EX. humans can feel happiness, memorize, think critically.

Temporal Lobe

Structures of the limbic system, including the olfactory cortex, amygdala, and the hippocampus are located within the temporal lobes. The temporal lobes play an important role in organizing sensory input, auditory perception, language and speech production, as well as memory association and formation. EX. My temporal lobe is responsible for things such as understanding sounds.

Reticular Formation

Inside the brain stem, it relays messages of stimuli to other areas of the brain. What it aids in: arousal, attention, cardiac reflexes, motor functions, regulates awareness, relays nerve signals to the Cerebral Cortex, and sleep. EX. The reticular formation aids in keeping you attentive in class.

Hippocampus

Inside the limbic system, it processes memory. EX. The hippocampus helps you remember all of these vocab terms.

Parietal Lobe

Involved in: Cognition Information Processing Pain and Touch Sensation Spatial Orientation Speech Visual Perception EX. The parietal lobe helps in feeling the pain of a hot pan.

Limbic System

It is located between the older brain structures and the cerebral hemispheres. Limbic system structures are involved in many of our emotions and motivations, particularly those that are related to survival. Such emotions include fear, anger, and emotions related to sexual behavior. The limbic system is also involved in feelings of pleasure that are related to our survival, such as those experienced from eating and sex. Certain structures of the limbic system are involved in memory as well. Two large limbic system structures, the amygdala and hippocampus play important roles in memory. EX. The limbic system is responsible for our motivation to get food for ourselves.

Corpus Callosum

It links the two hemispheres of the left and right. If one is damaged, the corresponding specialites are damaged as well. EX. If the left hemisphere is damaged, then reading, writing, speaking, math and reasoning were damaged as well.

Sensory Cortex

It receives input from the senses to the brain. The more sensitive an organ is, the larger that area of the sensory cortex. EX. Since the fingers are very sensitive, the sensory cortex is large there.

Amygdala

Made up of two small nerve bundles in a bean shape, the amygdala manages fear, anger, and the basic handling of emotions and memories. EX. The amygdala was responsible for my fear of the rollercoaster when I saw it.

Modern Study of the Brain

Many techniques are used today to study the brain, including: -destruction of animal brains and the results analyzed -the stimulation of brains and results analyzed -EEG -PET -MRI -fMRI

Epileptic Seizures and the Corpus Callosum

Patients with sever epileptic seizures had their corpus callosum cut which stopped the seizures. Many experiments were done seeing how the patient reacts to the left and right side of a screen and how the brain interprets them. EX. Two different images were flashed on opposite sides of a screen. The patient could tell the researchers what he saw on the right side but could only point to the image on the left side.

New: Brain size to body weight ratio

Ratio of brain size to animal's body weight is important to the function of the brain, but is not the only available measure of intelligence. E.g: A human could not survive with a cat-sized brain, and a cat's body could not support (metabolically) a human-sized brain.

Brain Plasticity

The brain has an ability to change after being damaged, and can reassign and reorganize jobs and functions so the organism can still properly function. EX. A blind person who begins to read braille will begin to have more sensitivity in their fingertips.

Hypothalamus

The main pleasure center of the brain. It is below the thalamus and is important in hunger, thirst, body temperature, and sexual behavior. It emits hormones that affect the pituitary gland which then affects other hormones. Therefore, the hypothalamus influences brain activity. --animal research shows that dopamine is released during pleasurable activities such as eating and sex. EX. When scientists planted an electrode in a rat's hypothalamus, rats would not stop pressing a lever to receive pleasurable stimulation until its brain was exhausted.

Medulla

The medulla is a portion of the hindbrain that controls autonomic functions. Motor and sensory neurons from the midbrain and forebrain travel through the medulla. As a part of the brainstem, the medulla helps in the transferring of messages between various parts of the brain and the spinal cord. EX. The medulla is responsible for breathing, digestion, heart and blood vessel function, swallowing and sneezing.

Occipital Lobe

The occipital lobes are involved in several functions of the body including: Visual Perception Color Recognition EX. I know the difference between red and green thanks to my occipital lobe.

New: Premotor and Motor areas

The premotor and motor areas of the frontal lobes contain nerves that control the execution of voluntary muscle movement.

Thalamus

The thalamus is a large, dual lobed mass of grey matter buried under the cerebral cortex. It is involved in sensory perception and regulation of motor functions. It sends incoming sensory impulses, besides smell, to the higher brain parts. As a regulator of sensory information, the thalamus also controls sleep and awake states of consciousness. EX. The thalamus has helped me in my jog today because it's involved with motor functions, and the sensory information it relayed like what roads looked like helped me plan my jog.

Association Areas of the Cerebral Cortex

The well known areas of the cerebral cortex make up only a fourth of the mass of the cortex, while the other areas is generally called the association areas. These areas help us make sense of things and put various parts of information together. EX. The placement of a match and gasoline are not associated with each other until the association areas tell us that they are logically dangerous.

Early Study of the Brain

There were no tools back then to map out the brain so damages to the brain and the resulting symptoms helped researchers figure out certain parts.

Frontal lobe

They are positioned at the frontmost region of the cerebral cortex and are involved in movement, decision-making, problem solving, and planning. There are three main divisions of the frontal lobes. They are the prefrontal cortex, the premotor area and the motor area. The prefrontal cortex is responsible for personality expression and the planning of complex cognitive behaviors. The premotor and motor areas of the frontal lobes contain nerves that control the execution of voluntary muscle movement. EX. My frontal lobe helped me stop my impulse to eat all the candy I saw as it aids in impulse control.

The Relationship Between the Left & Right

Things that happen to the right side of the brain will affect the left side of the person and vice versa. For example, if a patient receives a sedative to the left side of the brain, the right half of the body will feel it.

Motor Cortex

Within the boundaries of the cerebral cortex, it is between the frontal and parietal lobes and it handles movements and motions by sending impulses from the brain to the body. --Researchers have found that people can use their brains to perform actions through the motor cortex (a man could control a TV, draw shapes on a computer, and play video games through a computer chip planted in his cerebral cortex) EX. The motor cortex helps you sit and stand up.

Glial cells

Within the cerebral cortex, glial cells surround the nerve cells as they feed and insulate them. E.g: Glial cells may play a role in Parkinsons' disease. It is believed they break down, and nerves are poorly insulated.

Brain size to Body Weight

an important weight ratio in determining intelligence but is one of many factors of intelligence

Brainstem

the oldest brain region. The brainstem is the region of the brain that connects the cerebrum with the spinal cord. It consists of the midbrain, medulla, and the pons. Motor and sensory neurons travel through the brainstem allowing for the relay of signals between the brain and the spinal cord. The brainstem coordinates motor control signals sent from the brain to the body. The brainstem also controls life supporting autonomic functions of the peripheral nervous system. EX. My brain stem helps me in many functions such as my daily movement and my involuntary functions such as breathing and heartbeat.