Watson and Breedlove Chapter 2

INTRODUCTION TO BRAIN & BEHAVIOR

  • Overview of the study of brain function and behavior in "The Mind's Machine" by Watson & Breedlove.

THE NERVOUS SYSTEM

  • Composed of cells that facilitate communication between organs and muscles.

Neurons

  • Definition: Basic units of the nervous system known as nerve cells.

  • Each neuron consists of:

    • Dendrites: Receptive extensions for input.

    • Cell Body (Soma): Integrates inputs.

    • Axon: Conducts signals away from the cell body.

    • Axon Terminal: Transmits signals to other cells.

Functions of Neurons

  • Neurons receive inputs from multiple sources.

  • They integrate these signals and distribute processed information to other neurons.

  • The human brain has approximately 100 billion neurons, which work collectively to process vast information.

PARTS OF THE NEURON

Functional Zones of a Neuron

  • Input Zone: Dendrites collect and process information from the environment or other cells.

  • Integration Zone: The cell body processes received information and decides whether to send a signal.

  • Conduction Zone: The axon transmits electrical signals over distances.

  • Output Zone: Axon terminals transmit signals to other neurons.

Dendrites

  • Act as the input zone, intricately branched to receive signals from multiple neurons.

Cell Body (Soma)

  • Integrates synaptic inputs to determine if a neural signal should be produced.

Axon

  • A singular extension that conducts output signals away from the neuron.

Axon Terminals

  • Specialized structures that release neurotransmitters to transmit signals to neighboring neurons.

SYNAPSES

Transmission of Information via Synapses

  • Information is received at dendrites through synapses.

  • Presynaptic Neuron: Releases neurotransmitters at its axon terminals.

  • Postsynaptic Neuron: Receives information at its membrane, responding to neurotransmitters.

Synaptic Membranes

  • Presynaptic Membrane: Transmits information by releasing neurotransmitters.

  • Postsynaptic Membrane: Receives neurotransmitters and starts a new signal in the postsynaptic neuron.

Synaptic Cleft

  • The gap between presynaptic and postsynaptic neurons where neurotransmitter release occurs.

Synaptic Vesicles

  • Small structures that store neurotransmitters for release into the synaptic cleft.

Neurotransmitters

  • Chemicals released from presynaptic terminals for neuron communication.

  • Receptors on the postsynaptic neuron respond to neurotransmitters, influencing its activity.

THE NERVOUS SYSTEM STRUCTURE

Central Nervous System (CNS)

  • Comprises the brain and spinal cord.

  • The spinal cord extends downward and splits into the cauda equina.

Peripheral Nervous System

  • Composed of nerves that link the body to the CNS.

  • Includes somatic and autonomic divisions.

Somatic Nervous System

  • Connects the brain to major muscles and senses, controlling movement and sensory information.

  • Comprised of cranial and spinal nerves.

Autonomic Nervous System

  • Manages organ functions with two divisions:

    • Sympathetic Division: Prepares the body for 'fight or flight.'

    • Parasympathetic Division: Manages 'rest and digest' functions, supporting recovery and energy conservation.

THE HUMAN BRAIN

Brain Lobes

  • Divided into four distinct lobes:

    • Frontal Lobe

    • Temporal Lobe

    • Occipital Lobe

    • Parietal Lobe

Brain Structure

  • Various parts include:

    • Olfactory bulb

    • Brainstem

    • Cerebellum and various gyri and sulci.

Development of the Brain

  • Development illustrated through neural tube and stages from 25 to 100 days gestation.

    • Parts of the brain develop into the hindbrain, midbrain, and forebrain.

Limbic System

  • Includes essential areas such as the amygdala, hypothalamus, and hippocampus, vital for emotion and memory.