BIO chapter 11 - 1

Auditory Information Processing

• Auditory information is crucial for decision-making in social interactions.

• Volume and clarity of sound help determine whether we continue engaging with a person or move away.

• The temporal lobe processes auditory information, located near brain areas responsible for language comprehension.

• This proximity facilitates our ability to understand complex sounds and language seamlessly.

Brain Lobes and Their Functions

• Frontal Lobe:

  • Responsible for movement and complex thinking.

  • Contains Broca's area, which is essential for speech production.

• Parietal Lobe:

  • Processes somatosensory information, including touch sensations.

• Occipital Lobe:

  • Primarily focused on processing visual information and contributes to language comprehension.

Sensory Deficits

• Genetic Factors:

  • Sensory deficits can be congenital or acquired.

  • Genetic issues during fetal development can lead to conditions like deafness or blindness.

• Acquired Deficits:

  • Trauma, such as traumatic brain injury, drugs, or strokes may result in sensory deficits later in life.

  • Damage can occur at various brain levels, including the peripheral sensory areas.

Neurons and Signal Processing

• Neurons:

  • Fundamental components of the nervous system responsible for transmitting signals.

  • Composed of:

    • Cell Body: Integrates incoming signals.

    • Dendrites: Branch-like structures that receive signals from other neurons, likened to 'listeners.'

    • Axon: Transmits signals away from the cell body.

• Myelin Sheath:

  • Fatty insulation surrounding the axon that increases signal transmission speed.

  • Essential for long-distance signals, such as those from spinal cord to toe.

Synaptic Transmission

• Synapse: Junction where two neurons communicate.

  • Neurotransmitters like serotonin and dopamine cross the synaptic gap to relay messages from one neuron to another.

  • Excitatory Signals: Enhance the likelihood of firing action potentials in the next neuron.

  • Inhibitory Signals: Reduce the likelihood of neuron firing, maintaining balance in brain activity.

Importance of Neurotransmitter Balance

• Imbalance Consequences:

  • Excessive excitatory signals can lead to conditions like seizures or anxiety.

  • Inhibitory signals must also be balanced; too much inhibition can lead to lethargy or cognitive dysfunction.

  • Conditions such as ADHD and anxiety can be linked to neurotransmitter imbalances.

• Drug Treatments:

  • Medications like benzodiazepines enhance inhibitory signals, helping manage anxiety and stress-related disorders.

Resting Membrane Potential

• Neurons maintain a resting membrane potential around -70 millivolts due to different ion distributions.

  • At rest, neurons are negatively charged inside due to high chloride concentrations and negative proteins.

  • Action Potential:

    • When stimulated adequately, neurons can reach a threshold and fire an action potential, temporarily reversing the charge and propagating the signal.

    • Action potentials are essential for effective communication between neurons.

Excitatory vs. Inhibitory Signals

• Excitatory Signals:

  • Occur when sodium ions enter the neuron, making the inside more positive (depolarization).

• Inhibitory Signals:

  • Occur when potassium ions exit the neuron, making the inside more negative (hyperpolarization).

  • These processes help regulate the firing of neurons and maintain overall brain activity balance.