Phineas Gage

The Brain’s Two Hemispheres Language and Special Abilities

Language and the Left Hemisphere In most people, language functions are located primarily in the left hemisphere. Two particularly important language regions of the left hemisphere are Broca’s area and Wernicke’s area

Broca’s Area Broca’s Area is located in the left frontal lobe – directs the muscle movements involved in speech (expressive language). Damage to Broca’s area, which often happens to victims of strokes, results in difficulty with spoken language. The stroke victim can form ideas but cannot turn those ideas into coherent speech

http://www.youtube.com/watch?v=6CJWo5T DHLE http://www.youtube.com/watch?v=12dO78c 6-q8

Wernicke’s Area Wernicke’s Area, located in the left temporal lobe, is involved with your ability to understand what someone else says (receptive language). Damage to Wernicke’s Area might leave a person able to hear words but unable to comprehend the meaning of sentences created with the words. For example: A person with Wernicke’s Area damage would be able to recognize the individual parts of a computer (monitor, mouse, keyboard, etc.) but not understand that these parts, together, create a computer.

Spatial Abilities – Right Hemisphere The right hemisphere houses most of your brain’s spatial abilities. The word spatial relates to your ability to perceive or organize things in a given space, such as judging distance, understanding geometric objects, or parking a car. The right hemisphere also provides the insight to help us make connections among words.

Right Hemisphere Example What word goes with painting, ring, and nail? Our right hemisphere finds the answer: finger. For a small handful of people with surgically severed corpus callosums the differing roles of the two hemispheres are much more dramatic…

The Brain

The Brain The average adult human brain weighs 1.3 to 1.4 kg (approximately 3 pounds). The Brain controls our mental processes and maintains basic life functions Brain is not divided into sections, but certain brain structures are specialized to perform certain tasks, process called localization of function

The Brainstem The brainstem is the oldest part and central core of the brain. It begins where the spinal cord swells as it enters the skull and is responsible for automatic survival functions

Medulla and Reticular Formation Medulla – located at the base of the brainstem, it controls basic life-support functions like heartbeat and breathing Reticular formation – a nerve network in the brainstem that plays an important role in controlling wakefulness and arousal

Brain Stem Thalamus Cerebellum Midbrain Pons Medulla Spinal Cord

The Thalamus Thalamus – the brain’s sensory switchboard, located on top of the brainstem. It directs messages to the sensory receiving areas in the cortex

Brain Stem Thalamus Cerebellum Midbrain Pons Medulla Spinal Cord

The Cerebellum Cerebellum – the “little brain” attached to the rear of the brainstem. It helps coordinate voluntary movements and balance

Brain Stem Thalamus Cerebellum Midbrain Pons Medulla Spinal Cord

The Limbic System Limbic System is a ring of structures at the border of the brainstem and cerebral cortex. It helps regulate important functions such as memory, fear, aggression, hunger and thirst, and it includes the hypothalamus, the hippocampus, and the amygdala.

The Limbic System

Limbic System - Definitions Hypothalamus – a neural structure lying below the thalamus. It helps regulate many of the body’s maintenance activities, such as eating, drinking, and body temperature, and is linked to emotion Hippocampus – a neural center located in the limbic system that wraps around the back of the thalamus. It helps process new memories for permanent storage Amygdala – an almond-shaped neural cluster in the limbic system that controls emotional responses, such as fear and anger.

The Cerebral Cortex The cerebral cortex is the intricate fabric of interconnected neurons that form the body’s ultimate control and information- processing center

The Cerebral Cortex Frontal lobes – the portion of the cerebral cortex lying just behind the forehead that is involved in planning and judgment. It includes the motor cortex Parietal lobes – the portion of the cerebral cortex lying at the top of the head and toward the rear. It is used for processing information Temporal lobes – the portion of the cerebral cortex lying roughly above the ears. It includes the auditory (hearing) areas of the brain Occipital lobes – the portion of the cerebral cortex lying at the back of the head. It includes the primary visual processing areas of the brain

Lobes of the Brain

The cerebral cortex Motor Cortex Sensory Cortex Parietal Lobe Frontal Lobe Occipital (Visual) Lobe Temporal Lobe Cerebellum Medulla Spinal Cord

Corpus Callosum Corpus Callosum is the large band of neural tissue that connects the two brain hemispheres and allows them to communicate with each other

Corpus Callosum

Corpus Callosum From a top view, notice how the brain is divided into two halves, called hemispheres. Each hemisphere communicates with the other through the corpus callosum, a bundle of nerve fibers.

Somato-sensory and Motor Cortex Somato-sensory cortex is a brain area at the front of the parietal lobes that registers and processes body sensations Motor cortex – a strip of brain tissue area at the rear of the frontal lobes that controls voluntary movements Output: Motor Cortex (left-hemisphere section controls the body’s right side) Input: Somatosensory Cortex (left- hemisphere section receives input from the body’s right side) See your textbook on page 71

Motor and Somatosensory Cortex

Your Task Individually answer the following question: “Can you explain why professional boxers frequently develop slurred speech and coordination problems?” Share and discuss your answer with partner Be prepared to present your answers to the class

Brain Size Although larger animals have larger brains, this does not mean that animals with larger brains are smarter than animals with smaller brains For example, a larger brain is necessary to control larger muscles in larger animals and a larger brain is necessary to process more sensory information from the skin in larger animals - this has nothing to do with intelligence.

Brain Size The brain areas that show the most changes, as a result of evolution, are the cerebral hemispheres (the red areas in the drawings). The more recently evolved animals have a larger proportion of the brain taken up by the cerebral cortex. In the "higher" animals (especially the higher mammals), the surface of the cerebral cortex becomes folded. This creates grooves on the surface of the brain called sulci (singular = sulcus). The bumps or ridges on the surface of the brain are called gyri (singular = gyrus).

Mnemonics are devices to help us remember – they are memory aide Mnemonics are devices to help us remember – they are memory aide. They come in many varieties and can aid memorisation of many types of information. For instance, the phrase “King Henry Died Marry Didn’t Care Much” is used to help people remember the units of the metric system… Your task Create mnemonic devices for each term learned in this unit – focus primarily on the parts of the brain and neuron… Example: “Seeing Medusa would turn you to stone and cause your medulla to stop functioning so your vital signs would cease.” The Reticular Activating System (RAS) causes us to ‘rise and shine’ so we can be alert and ready for action.”