Brain Structure and Function

“If the human brain were so simple that we could understand it, we would be so simple that we couldn’t” -Emerson Pugh, The Biological Origin of Human Values (1977)

Parts of the Brain BRAINSTEM  Heart rate and breathing THALAMUS  Relays messages amygdala hippocampus pituitary CEREBELLUM  Coordination and balance BRAINSTEM  Heart rate and breathing

The Brain Brainstem Medulla responsible for automatic survival functions Medulla controls heartbeat and breathing Brainstem the central core of the brain, beginning where the spinal cord swells as it enters the skull responsible for automatic survival functions Medulla [muh-DUL-uh] base of the brainstem controls heartbeat and breathing Brainstem, controls for heartbeat and breathing—swell is called the medulla. Vital Functions : Breathing Blood circulation Swallowing Urination

Reticular Formation Widespread connections Arousal of the brain as a whole Reticular activating system (RAS) Maintains consciousness and alertness Functions in sleep and arousal from sleep Reticular formation The brainstem also contains networks of neurons, known collectively as the reticular formation, that project up into the cerebral cortex and basal ganglia and affect general arousal. The reticular formation is also involved in inducing and terminating the different stages of sleep. The autonomy of the brain stem can be dramatically illustrated by severing an animal’s brain stem from the entire brain above it, including its entire cerebral cortex. Cats that receive this treatment can still walk around and direct attacks at noises; if they then find themselves holding on to food, they will eat it. Some cases have been reported of humans born without cerebral cortices, and their behaviors are extremely basic and reflexive. Such infants tend not to develop normally and also do not tend to survive

The Cerebellum helps coordinate voluntary movement and balance the “little brain” attached to the rear of the brainstem, cerebellum actually means little brain. Also helps involved in nonverbal learning and memory (will discuss in later chapters), if you injured your cerebellum you would have difficulty walking, keeping your balance, shaking hands. Note: these lower brain functions occur without any conscious effort.

The Limbic System Hypothalamus, pituitary, amygdala, and hippocampus all deal with basic drives, emotions, and memory Hippocampus  Memory processing Amygdala  Aggression (fight) and fear (flight) Hypothalamus  Hunger, thirst, body temperature, pleasure; regulates pituitary gland (hormones) The limbic system is an older term for a group of subcortical structures dealing with basic drives, emotions and memory The diencefpahlon (or between brain) the hypothalamus and thalamus The hippocampus and amygdala The basal ganglia The dreebral cortex

The Limbic System Hypothalamus neural structure lying below (hypo) the thalamus; directs several maintenance activities eating drinking body temperature helps govern the endocrine system via the pituitary gland linked to emotion (show video)

The Limbic System Amygdala two almond-shaped neural clusters that are components of the limbic system and are linked to emotion and fear Researchers began to find evidence that the amygdala was involved in the emotion of fear in the late 1930s. Monkeys with damage to the brain cluster and surrounding areas had a dramatic drop of fearfulness. Later, studies showed that rats with targeted amygdala damage would snuggle up to cats. But if you electrically stimulate the amygdala in a normally placid domestic animal such as a cat, the cat prepares to attach by hissing, arching its back, pupils dilate, and its hair stands up on end. Accumulating revelations about this fear system led researchers recently to examine the human brain's response to fear with imaging studies. One study showed that pictures of frightening faces initiate a quick rise and fall of activity in the amygdala. In the future, scientists believe imaging techniques may help determine the course of treatment for disorders involving a malfunction in fear processing. For example, a person with an extreme fear of germs who continuously washes, known as an obsessive-compulsive disorder,

The Brain Thalamus the brain’s sensory switchboard, located on top of the brainstem it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla Thalamus- located on top of the brainstem, a joined pair of egg-shaped structures, Receives sensory info, routes it to higher brain regions that deal with seeing, tasting, touching etc. directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

The Cerebral Cortex Cerebral Cortex the body’s ultimate control and information processing center the intricate fabric of interconnected neural cells that covers the cerebral hemispheres

The lobes of the cerebral hemispheres Figure 4.14 page 110 The lobes of the cerebral hemispheres: parietal, occipital, temporal, and frontal.

The lobes of the cerebral hemispheres Planning, decision making speech Sensory Figure 4.14 page 110 The lobes of the cerebral hemispheres: parietal, occipital, temporal, and frontal. Vision Auditory

The Cerebral Cortex Frontal Lobes Parietal Lobes involved in speaking and muscle movements and in making plans and judgments the “executive” Parietal Lobes include the sensory cortex The cerebral cortex is organized or divided into 4 regions or lobes. frontal lobe- behind your forehead, executive functions. -parietal lobe- at the top and to the rear of the head

The Cerebral Cortex Occipital Lobes Temporal Lobes include the visual areas, which receive visual information from the opposite visual field Temporal Lobes include the auditory areas, each of which receives auditory information primarily from the opposite ear Occipital lobe- at the back of your head -Temporal lobe- just above your ears; receives auditory info primarily from the opposite ear. The lobes are separated by prominent fissures or folds. Important to note that although each lobe carries out different functions, many of our functions require the interplay or involvement of several lobes. Temporal lobes -- each of which receives auditory information primarily from the opposite ear

The Cerebral Cortex Frontal (Forehead to top)  Motor Cortex Parietal (Top to rear)  Sensory Cortex Occipital (Back)  Visual Cortex Temporal (Above ears)  Auditory Cortex

Brain Lateralization

Our Divided Brains Corpus collosum – large bundle of neural fibers (myelinated axons, or white matter) connecting the two hemispheres

Hemispheric Specialization LEFT Symbolic thinking (Language) Detail Literal meaning RIGHT Spatial perception Overall picture Context, metaphor

Contra-lateral division of labor Right hemisphere controls left side of body and visual field Left hemisphere controls right side of body and visual field

Split Brain Patients Epileptic patients had corpus callosum cut to reduce seizures in the brain Lives largely unaffected, seizures reduced Affected abilities related to naming objects in the left visual field left and right brain differences in learning.m4v http://www.youtube.com/watch?v=4Qi5_dANWYo

Brain Plasticity

Brain Plasticity The ability of the brain to reorganize neural pathways based on new experiences Persistent functional changes in the brain represent new knowledge Age dependent component Brain injuries

Environmental influences on neuroplasticity Impoverished environment Enriched environment

Phineas Gage September 13th, 1848 Phineas 25 years old Rutland & Burlington Railroad, Cavendish, VT Paving the way for new RR tracks “Tamping Iron” 1.25in x 3ft

Phineas Gage Accident Months later: “No longer Gage” Quick Recovery Months later: “No longer Gage” Before: capable, efficient, best foreman, well-balanced mind After: extravagant, anti-social, liar, grossly profane Stint with P.T Barnum Died 12 years later Watch Clip: http://www.youtube.com/watch?v=c6kRP41ygrI

The Nervous System The nervous system is made up of neurons, nerve cells that transmit signals or “messages” throughout the body. Dendrites – The rootlike structures at the ends of neurons that receive messages from other neurons. Axon – The long, thin part of a neuron along which nerve impulses travel. © 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.

© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved. The Nervous System Terminals – The small branching structures at the tips of axons. Neurotransmitters – Chemical substances that transmit messages from one neuron to another. Synapse – The junction between one neuron and another across which neurotransmitters pass. Receptor site – A part of a dendrite on a receiving neuron that is structured to receive a neurotransmitter. © 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.

© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved. The Anatomy of a Neuron © 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.

Transmission of Neural Impulses © 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.

Neurotransmitter Functions and Relationships © 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.

The Brain's Inner Workings - Part 1 - Structure and Function Neural Transmission The Brain's Inner Workings - Part 1 - Structure and Function http://www.youtube.com/watch?v=C13OVRguQrQ&feature=relmfu The Brain's Inner Workings - Part 2 – Cognition http://www.youtube.com/watch?v=1NixAppWWec&NR=1&feature=endscreen Neurons and how they work http://www.youtube.com/watch?v=FR4S1BqdFG4&feature=related

Steps in Neural Transmission Class Challenge Goal: gain a hands-on idea of how electrical information is passed along an axon for neural transmission to occur. 1 Facilitator and 12 students. Facilitator- Assign the following roles to each student in your group: electrical stimulus, dendrite, cell body, axon, myelin sheath (use four students for this one), positive ion, negative ion, terminal button, and neighboring neuron. (use the text to help you understand what each role does) Group – Students line up in the correct order of neural transmission. Facilitator – Orchestrate the group to ‘act out’ each of the steps and have each student act out their parts as you are going through the steps. Do this a couple of times until you think they have the hang of it. Next, allow the students to run through the steps by themselves. (Extra points for creativity)

Neural Transmission Act 1 electrical stimulus dendrite cell body axon myelin sheath (use four students for this one) positive ion negative ion terminal button neighboring neuron.

The Brain – History Channel http://www.youtube.com/watch?v=iE3MgMFfI6U

Introductory Psychology Concepts The Brain - Major Structures and Their Function Amygdala Hippocampus Cerebrum Thalamus Corpus callosum Hypothalamus Pituitary gland Pons Cerebellum Medulla Brain stem Reticular formation Spinal cord