Chapter 2  Neural Communication & The Brain  Psychology 101  Sara J. Buhl

Phrenology (1800s)

Neural Communication  Biological Psychology  branch of psychology concerned with the links between biology and behavior  Neuron  a nerve cell  the basic building block of the nervous system

Neural Communication

 Dendrite  the branching extensions of a neuron that receive messages and conduct impulses toward the cell body  Axon  the extension of a neuron, through which messages are sent to other neurons or to muscles or glands  Myelin Sheath  a layer of fatty cells covering the axon of some neurons  greatly increases the speed of neural impulses

How do neurons communicate?  Synapse  junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron  tiny gap at this junction is called the synaptic gap or cleft  Neurotransmitters  chemical messengers that cross the synaptic gaps between neurons  when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse

Neurotransmission

Neurotransmitters  Acetylcholine – Enables muscle action, learning, and memory  Dopamine – Influences movement, learning, attention, and emotion  Serotonin – Affects mood, hunger, sleep, and arousal  Endorphins – opiatelike neurotransmitters linked to pain control and to pleasure

Neural Communication

Serotonin pathways

The Nervous System  Central Nervous System (CNS)  the brain and spinal cord  Peripheral Nervous System (PNS)  the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

Peripheral Nervous System  Autonomic Nervous System  the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (e.g., heart)  Two Parts:  Sympathetic Nervous System  part of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations  Parasympathetic Nervous System  Part of the autonomic nervous system that calms the body, conserving its energy

Central Nervous System  Spinal Cord – information highway; connects the peripheral nervous system to the brain  The Brain – enables the mind – seeing, hearing, smelling, feeling, remembering, thinking, speaking, dreaming.

Reflex  a simple, automatic, inborn response to a sensory stimulus

The Brain  Brainstem  the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull  responsible for automatic survival functions  Medulla  base of the brainstem  controls heartbeat and breathing

The Brainstem and Thalamus

The Brain  Thalamus  on top of brainstem  the brain’s sensory switchboard  Reticular Formation  a nerve network in the brainstem  plays an important role in controlling arousal

Electroencephalogram (EEG)  an amplified recording of the waves of electrical activity that sweep across the brain’s surface  these waves are measured by electrodes placed on the scalp

MRI Scan

The Brain  Cerebellum  the “little brain” attached to the rear of the brainstem  it helps coordinate voluntary movement and balance  injury results in difficulty walking and keeping balance; movements would be jerky and exaggerated

The Brain  Limbic System  a doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres  associated with emotions such as fear and aggression and drives such as those for food and sex  includes the hippocampus (ch. 8), amygdala, and hypothalamus.

The Limbic System

 Amygdala  two almond-shaped neural clusters that are part of the limbic system  linked to emotion  influence aggression and fear

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

The Limbic System  Electrode implanted in reward center of hypothalamus

The Cerebral Cortex  Cerebral Cortex (Cerebrum)  the intricate fabric of interconnected neural cells that covers the cerebral hemispheres  the body’s ultimate control and information processing center  Left & Right Hemispheres of the Cerebrum  Left hemisphere receives input from & controls the right side of the body  Right hemisphere receives input from & controls the left side of the body

The Cerebral Cortex

 Frontal Lobes  Involved in speaking & muscle movements  Important for planning and making judgments  Damage can alter personality (e.g., Phineas Gage)  Parietal Lobes  Receives sensory input for touch and body position

The Cerebral Cortex  Occipital Lobes  include the visual areas, each of which receives visual information from the opposite visual field  Temporal Lobes  include the auditory areas, each receives auditory information primarily from the opposite ear

The Cerebral Cortex  Functional MRI scan of the visual cortex activated by looking at faces

Brain Reorganization  Plasticity  the brain’s capability to reorganize following damage (especially in children) and in experiments on the effects of experience on brain development

Brain Reorganization zCorpus Callosum ylarge bundle of neural fibers connecting the two brain hemispheres and carrying messages between the hemispheres zSplit Brain ya condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them

Brain Reorganization

Left visual field  Right visual  field

Testing the divided brain: