jmu neuroscience (chap 1-4)

• The brain is the "nerve center" of the body, containing billions of neurons that transmit information from the body and the outside world, and then program our responses, including conscious and unconscious movements, thoughts, emotions, and memories.
• The brain can perform these tasks simultaneously: You can throw a ball while talking to a friend, plan dinner while you're shopping, or daydream about a balloon ride as you drive to work.
• The brain is split into many distinct regions specialized for specific tasks and abilities.
• The largest part of the human brain is the cerebrum, which is divided into two large, separate hemispheres, one on the left side, the other on the right.
• The hemispheres are connected by bundles of nerve fibers that carry information from one side of your brain to the other.
• The axon terminals of a neuron release chemical messengers called neurotransmitters.
• The cell body of a neuron contains structures such as the nucleus.
• The neuron sends signals via the axon, a long cable that ends with the axon terminals.
• Neurons are the building blocks of the nervous system.
• Dendrites, the arms extending from the cell body, receive signals from other neurons at junctions called synapses.
• Neurons come in many shapes and sizes, but most have some basic features.
• The largest of these bundles forms a bridge between the cerebral hemispheres and is called the corpus callosum.
• This image of a mouse dentate gyrus shows newborn cells, labeled in blue, along with the support cells called glia, labeled in red, that will help them migrate to their final destinations.
• Some of these new cells will mature to become different types of neurons in the dentate gyrus, where they will play important roles in learning and memory.
• The dentate gyrus, a portion of the hippocampus responsible for memories of events, is one of the few areas of the adult brain where neurogenesis takes place.
• The surface of the cerebrum is a deeply folded layer of nerve tissue called the cerebral cortex.
• The cerebral cortex has deep folds that increase the area of the surface layer, creating space for more neurons, which increase the brain’s processing power.
• Neuroscientists use the deepest divisions of the cerebrum to identify regions of each hemisphere as separate lobes, distinct regions that have characteristic functions.
• The frontal lobes are at the front of the brain, immediately above the eyes, and parts of these lobes coordinate voluntary movements and speech, memory and emotion, higher cognitive skills like planning and problem-solving, and many aspects of personality.
• The parietal lobes are located at the top of the brain, immediately behind the frontal lobes, and they integrate sensory signals from the skin, process taste, and process some types of visual information.
• The occipital lobes process visual information and are responsible for recognizing colors and shapes and integrating them into complex visual understanding.
• The temporal lobes lie on the sides of the brain, at and below the level of the eyes, and carry out some visual processing and interpret auditory information.
• The tips of olfactory cells are equipped with several hair-like cilia that are receptive to a number of different odor molecules, and many cells respond to the same molecules.
• A specific smell will therefore stimulate a unique combination of olfactory cells, creating a distinct activity pattern.
• This “signature” pattern of activity is then transmitted to the olfactory bulb and on to the primary olfactory cortex located on the anterior surface of the temporal lobe.
• The hippocampus and amygdala are part of the limbic system, a group of structures deep within the brain that help regulate our emotion and motivation.
• Neurons are able to process harmony, rhythm, and melody, and combine the types of auditory information into a voice or instrument that you can recognize.
• Smell is the only sensory system that sends sensory information directly to the cerebral cortex without first passing through the thalamus.
• Other neurons are selective for complex sounds, while still others specialize in various combinations of tones.
• The left side of the brain is typically responsible for understanding and producing speech.
• The brainstem and thalamus use the information from both ears to compute a sound’s direction and location.
• The senses of taste (gustation) and smell (olfaction) are closely linked and help you navigate the chemical world.
• Loss of hair cells is responsible for the majority of cases of hearing loss.
• Hair cells don’t regrow once they die, leaving current research focusing on how inner ear structures like hair cells develop and function, exploring new avenues for treatment that could eventually involve neurogenesis with the goal of replacing damaged hair cells.
• We have around 1,000 different types of olfactory cells, but can identify about 20 times as many smells.
• The frequency map of the basilar membrane is maintained throughout, even in the primary auditory cortex in the temporal lobe, where different auditory neurons respond to different frequencies.
• Some cortical neurons respond to sound qualities such as intensity, duration, or a change in frequency.
• Someone with damage to the left auditory cortex, particularly a region called Wernicke’s area, is able to hear a person speak but no longer understands what is being said.
• The hippocampus, parahippocampal region, and areas of the cerebral cortex work in tandem to produce memories of facts and events.
• Following a childhood blow to the head, Henry Molaison developed severe seizures and underwent an experimental procedure that removed sections of his medial temporal lobes, including most of his two hippocampi.