The Brain

Ways we Study the Brain Accidents Lesions CAT Scan PET Scan MRI Functional MRI

Accidents Phineas Gage Story (1848) Personality changed after the accident What does this tell us? Different parts of the brain control different aspects of who we are.

Lesions Cutting into the brain and looking for change Brain tumors and brain tissue lesions Removal or destruction of some part of the brain

Less Invasive Ways to Study the Brain EEG Electroencephalogram Detects brain waves through their electrical output Used mainly in sleep research

Computerized Axial Tomography CAT Scan 3D X-Ray of the brain Good for tumor locating, but tells us nothing about function

Magnetic Resonance Imaging MRI More detailed picture of brain using magnetic field to knock electrons off axis Takes many still pictures and turns images into a movie like production

Positron Emission Tomography PET Scan Measures how much of a chemical the brain is using (usually glucose consumption)

Functional MRI Combination of PET and MRI

The Three Brains 1.Hindbrain 2.Midbrain 3.Forebrain

Hindbrain Structures on top of our spinal cord (rear base of skull) Controls basic biological structures The brain in purple makes up the hindbrain.

Medulla Oblongata Located just above the spinal cord. Involved in control of: blood pressure heart rate breathing

Pons Located just above the medulla Connects hindbrain with midbrain and forebrain Involved in facial expressions and certain respiratory functions

Cerebellum Located in the back of our head- means “little brain” Coordinates voluntary muscle movements, balance, precision, timing, and body positions Like tracking a target

Cerebellum

Midbrain Located at upper end of brainstem Coordinates simple movements with sensory information Most important structure in Midbrain is the Reticular Formation: controls arousal and ability to focus our attention If DestroyedIf stimulated

Forebrain What makes us human Largest part of the brain Made up of the Thalamus, Limbic System and Cerebral Cortex

Thalamus Switchboard of the brain Receives sensory signals from the spinal cord and sends them to other parts of the forebrain Every sense except smell

Limbic System EMOTIONAL CONTROL CENTER of the brain Doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres Made up of Hypothalamus, Amygdala, Hippocampus, and Pituitary Gland

The Limbic System

Hypothalamus Maybe most important structure in the brain Controls and regulates: Body temperature Sexual arousal (libido) Hunger Thirst Endocrine System The most powerful structure in the brain

Hippocampus Involved in the processing and storage of memories Explicit or implicit???

Amygdala Involved in how we process memory More involved in volatile emotions like anger The emotion of anger has not changed much throughout evolution.

The Cerebral Cortex Top layer of our brain Made up of densely packed neurons we call “gray matter” and glial cells Wrinkles are called fissures. The fissures increase surface area of our brain If you lay it out and iron out all the wrinkles, it would be as big as a large pizza.

Cerebral Cortex Hemispheres Divided into a left and right hemisphere Contralateral control- left controls right side of body and vice versa Lefties (stronger right hemisphere) are better at spatial and creative tasks Righties (stronger left hemisphere) are better at logic and sequential tasks

Areas of the Cerebral Cortex Divided into eight lobes, four in each hemisphere (frontal, parietal, occipital and temporal) Any area not dealing with our senses or muscle movements are called association areas

Frontal Lobes Deals with planning, maintaining emotional control and abstract thought. Contains Motor Cortex: sends signals to our body controlling muscle movements. Contains Broca’s Area: responsible for controlling muscles that produce speech. Damage to Broca’s Area is called Broca’s Aphasia: unable to make movements to talk.

Parietal Lobes Located at the top of our head. Contain Somatosensory Cortex: receives incoming touch sensations from rest of the body. Most of the Parietal Lobes are made up of Association Areas

Occipital Lobes Located in the back of our head Contains Visual Cortex: interprets messages from our eyes into images we can understand Right half of each retina sends info to left occipital lobe and vice versa.

Temporal Lobes Process sound sensed by our ears Interpreted in the Auditory Cortex Contains Wernike's Area: interprets written and spoken speech Wernike's Aphasia: unable to understand language: the syntax and grammar jumbled

Split-Brain Patients Corpus Collosum attaches the two hemispheres of cerebral cortex When removed you have a split-brain patient

Right Brain/Left Brain Test

Brain Plasticity The idea that the brain, when damaged, will attempt to find news ways to reroute messages. Children’s brains are more plastic than adults.

Pinky and the Brain

The Endocrine System * The body’s “slow” chemical communication system * A set of glands that secrete hormones into the bloodstream *Similar to nervous system, except hormones work a lot slower than neurotransmitters. Neurotransmitters Hormones

Neural and Hormonal Systems Hormones – chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and effect another. Adrenal (ah-DREEN-al) Glands – a pair of endocrine glands just above the kidneys’ that secrete the hormones epinephrine and norepinephrine, which help to arouse the body in times of stress. Pituitary Gland – under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Genetics Every human cell contains 46 chromosomes (23 pairs) Made up of deoxyribonucleic acid- DNA Made up of Genes Made up of nucleotides

Twins Best way to really study genetics because they come from the same zygote Bouchard Study.69 Correlational coefficient for IQ tests of identical twins raised apart.88 raised together