Psych Chapter 3 Flashcards

CHAPTER 3 NEUROSCIENCE AND BEHAVIOR

MODULE 7 – Neurons: The Basic Elements of Behavior

• Behavioral neuroscientists (or biopsychologists) are psychologists who explore how biological structures and functions affect behavior.

  • Key Questions:

  • How does the nervous system communicate electrical and chemical messages between its parts?

  • What are the basic elements of the nervous system?

  • Why do psychologists study the brain and the nervous system?

The Structure of the Neuron

• Neurons: Nerve cells that are the fundamental units of the nervous system.

  • Composed of:

  • Cell body: Contains the nucleus and hereditary material that dictates cellular functions.

  • Glial cells: Supportive cells that:

    • Provide nourishment to neurons.

    • Insulate neurons.

    • Help repair damage.

    • Support neural functioning.

Communication within Neurons

• Neurons differ from most other cells in their ability to:

  • Communicate with other cells.

  • Transmit information over long distances.

• Messages or impulses typically flow in one direction within the neuron:

  • Dendrites: Cluster of fibers at one end of a neuron that receive messages from other neurons.

  • Axon: Carries messages from dendrites to other neurons. Action potentials take place.

  • Terminal buttons: The part of the axon that sends messages to other neurons.

Myelin Sheath and Communication Speed

• Myelin sheath: A protective coating made of fat and protein that surrounds the axon, enhancing the speed of electrical impulses.

  • Axons carrying critical information typically have a higher concentration of myelin.

How Neurons Fire

• Neurons operate under the all-or-none law, meaning they are either on or off.

  • Resting state: The state before a neuron is triggered, with a negative electrical charge of approximately −70 millivolts within the neuron.

  • Action potential: The electrical nerve impulse that propagates along the axon when the neuron is activated, transitioning its charge from negative to positive. (about positive 40 milivolts)

  • Action Potential Mechanism

• Movement of an action potential occurs when positively charged ions enter the neuron, creating a temporary positive charge and leading to the propagation of the signal. After completion, positive ions are pumped out, restoring negativity.

• The voltage changes during an action potential can vary from −70 millivolts to about +40 millivolts before dropping again after the action potential passes.

Speed of Transmission

• The speed of an action potential is influenced by:

  • The size of the axon.

  • The thickness of the myelin sheath.

  • Neurons vary in the quickness of impulse transmission and firing rates, influenced by stimulus intensity (how much of a nuerons potentail firing is reached)

Mirror Neurons

• Mirror neurons: Specialized neurons that activate both when an individual performs an action and when they observe someone else performing the same action.

  • Implications:

  • Suggests an inherent capacity for imitation in humans.

  • May explain understanding of others' intentions.

  • Linked to empathy and language development of language in humans

  • Potential therapeutic applications for stroke victims and individuals with emotional issues.

Where Neurons Meet: Bridging the Gap

• Synapse: The junction between two neurons where communication occurs, utilizing chemical messages released by a sending neuron's axon that target a receiving neuron's dendrites.

• Neurotransmitters: Chemicals that transmit messages across the synaptic gap.

Communication Specifics in Synapses

• Not all neurons can receive signals from every neurotransmitter; fit at receptor sites is vital for successful communication.

• Types of messages conveyed by neurotransmitters:

  • Excitatory messages: Increase likelihood of action potentials in receiving neurons.

  • Inhibitory messages: Decrease the likelihood of action potentials.

Reuptake Process

• To prevent constant stimulation or inhibition, neurotransmitters must be deactivated or reabsorbed via reuptake—the process where terminal buttons take back neurotransmitters.

• Understanding reuptake has led to drugs like SSRIs (selective serotonin reuptake inhibitors) which prolong the activity of neurotransmitters at synapses, helping alleviate depression symptoms.

Neurotransmitters: Multitalented Chemical Couriers

• Over 100 known neurotransmitters exist, vital for maintaining brain and body functions.

  • Imbalances can lead to behavioral disorders.

Major Neurotransmitters Overview

MODULE 8 – The Nervous System and the Endocrine System: Communicating Within the Body

• Explores the link between nervous system structures and the influence of the endocrine system on behavior.

The Nervous System: Linking Neurons

• Each neuron connects with many, creating a vast network of communication.

• Comprised of two primary structures:

  • Central nervous system (CNS): Includes the brain and spinal cord.

    • Spinal cord: Transmits messages between the brain and body and can control simple reflexes independently.

  • Peripheral nervous system (PNS): Branches out from CNS to connect all parts of the body.

Reflexes and Neurons Involved

• Reflex: Automatic response to stimuli, involving sensory (afferent) neurons and motor (efferent) neurons.

• Afferent - Transmits information from the perimeter of the body to the nervous system and brain

• Efferent neurons - communicate information from the brain and nervous system to the muscles and glands

Central and Peripheral Nervous Systems

• Peripheral nervous system (PNS): Includes autonomic and somatic divisions.

  • Somatic division: Controls voluntary movements and connects sensory organs.

  • Autonomic division: Governs involuntary functions (e.g., heartbeat).

Autonomic Nervous System Divisions

• Further divided into:

  • Sympathetic division: Activates during stress (fight-or-flight response).

  • Parasympathetic division: Calms the body post-emergency.

The Evolutionary Foundations of the Nervous System

• Evolutionary psychology: Investigates behavior patterns stemming from genetic inheritance.

• Behavioral genetics: Studies how heredity influences behavior.

The Endocrine System: Of Chemicals and Glands

• The endocrine system operates as a chemical communication network via hormones in the bloodstream.

  • Pituitary gland: The “master gland” controlling other glands and regulating growth. The major component of the endocrine system

  • Hormones - Chemicals that circulate through the blood and regulate the functioning of growth

Module 9 - Studying the Brain’s Structure and Functions

• Electroencephalogram (EEG): Measures brain electrical activity via electrodes that are placed outside of the skull

• Functional magnetic resonance imaging (fMRI): Produces 3D images of brain activity and structures using magnetic fields.

• Positron emission tomography (PET) scans: Show brain biochemical activity via injected radioactive liquids.

• Transcranial magnetic stimulation (TMS): Disrupts electrical activity in targeted brain regions to study effects. May be able to treat certain kinds of psychological disorders.

• Optogenetics: Investigates neuronal circuits.

• Hydrogel-embedding methods: Observe individual brain cells and circuitry.

• Neuropixels: Probes that monitor neuron activity across multiple brain areas simultaneously.

The Central Core: Our “Old Brain”

• The central core controls basic life functions and is common across species.

  • Contains hindbrain:

  • Medulla: Regulates breathing and heart rate.

  • Pons: Connects and coordinates motor information between the right and left halves of the body; regulates sleep.

  • Cerebellum: Maintains balance.

Additional Structures of the Central Core

• Reticular formation: Regulates arousal levels. Passes through the midbrain and into the forebrain.

• Thalamus: Relays sensory information. Located in the middle of the central core

• Hypothalamus: Maintains homeostasis and regulates basic survival behaviors (e.g., eating and drinking).

The Limbic System: Beyond the Central Core

• Limbic system: Governs emotions related to self-preservation and integrates memory functions, crucial for survival.

  • Important components: Amygdala (emotion) and Hippocampus (memory).

The Cerebral Cortex: Our “New Brain”

• The cerebral cortex is responsible for advanced information processing, encompassing four lobes:

  • Frontal lobes: Executive functions, decision making.

  • Parietal lobes: Sensation and spatial awareness.

  • Temporal lobes: Auditory processing, language comprehension.

  • Occipital lobes: Visual processing.

Functionality of the Cortex Areas

• Motor area: Controls voluntary movement, with areas correlated to specific body parts.

• Sensory area: Corresponds to sensory perceptions, where sensitivity matches the amount of cortical tissue associated with a body part.

• The somatosenory area in the parietal lobe encompasses specific locations associated with the ability to perceive touch and pressure in a particular area of the body.

• Audiory area located in the temporal lobe is repsonsible for the sense of hearing

• The visual area is located in the occipital bone

• Association areas: Involved in higher mental processes (speech, memory, language).

  • Injuries can result in aphasia:

  • Broca’s aphasia: Impaired speech production.

  • Wernicke’s aphasia: Impaired understanding and language production.

Neuroplasticity and the Brain

• Neuroplasticity: The brain's capacity to reorganize itself and adapt by forming new neuron connections.

• Neurogenesis: The creation of new neurons may occur in adult brains in specific areas.

The Specialization of the Hemispheres: Two Brains or One?

• The brain comprises two hemispheres, each controlling the opposite body side.

  • Lateralization: Refers to the special functions of each hemisphere.

  • Left hemisphere: Sequential processing (especially language).

  • Right hemisphere: Global processing (nonverbal tasks).

The Split Brain: Exploring the Two Hemispheres

• In split-brain patients, the corpus callosum (connection between hemispheres) is severed, demonstrating distinct processing characteristics of each hemisphere, useful in severe epilepsy treatments.