Neuroscience and Psychophysics

CHAPTER 3: Neuroanatomy and Neurotransmitters

  • Synaptic cleft

    • Definition: A tiny gap between the sending axon and the receiving dendrites.

  • Dendritic spines

    • Function: Locations where excitatory synapses are formed, playing a crucial role in learning and memory.

  • Types of glial cells:

    • Astrocytes

    • Functions: Involved in the development of the nervous system, thought processes, memory formation, and immune responses in the brain.

    • Oligodendrocytes

    • Function: Speeds up electrical message transmission along axons by forming the myelin sheath.

  • Neurotransmitters:

    • Glutamate

    • Type: Excitatory neurotransmitter in the brain.

    • Roles: Involved in learning, control mechanisms, and memory processes.

    • GABA (Gamma-Aminobutyric Acid)

    • Type: Inhibitory neurotransmitter in the brain.

    • Acetylcholine

    • Type: Neuromodulator, a type of chemical messenger involved in various functions.

    • Monoamines

    • Is defined by the suffix “ine” in their names, including neurotransmitters like serotonin.

    • Serotonin

    • Functions: Regulates mood, sleep patterns, and digestive processes.

  • Brain Structures and Functions:

    • Frontal lobe

    • Functions: Responsible for planning, decision-making, and language processing.

    • Parietal lobe

    • Functions: Processes tactile information and integrates sensory inputs.

    • Temporal lobe

    • Functions: Processes auditory information, language comprehension, and plays a role in long-term memory formation.

    • Occipital lobe

    • Functions: Responsible for processing visual information.

    • Basal Ganglia

    • Functions: Controls movement, motor planning, and habit learning.

CHAPTER 4: Sensory Perception and Psychophysics

  • Transduction

    • Definition: The process of converting neural activity into sensory experiences.

  • Psychophysics

    • Definition: The study of how sensory information is perceived by organisms.

    • Just Noticeable Difference (JND)

    • Definition: The smallest detectable difference between two stimuli.

    • Weber’s Law

    • Formula: JND is directly proportional to the intensity of the stimulus. This implies that the perceived difference depends on the original stimulus level.

    • Absolute threshold

    • Definition: The lowest level of stimulus intensity that an individual can detect 50% of the time.

  • Signal detection theory

    • Definition: A framework for understanding how people detect signals under varying conditions of uncertainty. It emphasizes decision-making processes.

  • Multisensory Perception:

    • McGurk effect

    • Phenomenon where visual and auditory information converge during speech perception, leading to a mismatch between what is heard and seen.

    • Synesthesia

    • Definition: A condition where stimulation of one sensory modality leads to involuntary experiences in another; for instance, seeing colors upon hearing sounds.

  • Visual System Structures:

    • Retina

    • Function: Converts light into neural impulses for processing by the brain.

    • Iris

    • Function: Controls the size of the pupil and, consequently, the amount of light entering the eye.

    • Cornea

    • Function: Bends incoming light waves to focus images on the retina.

    • Fovea

    • Function: Area of sharpest vision due to a high concentration of cone cells.

  • Pathway of light entering the eye:

    • Order of structures: Cornea → Pupil → Iris → Lens → Retina.

  • Visual agnosia

    • Definition: A recognition deficit arising from damage to higher visual cortical areas, affecting the ability to interpret visual stimuli.

CHAPTER 5: Biological Rhythms and Consciousness

  • Circadian rhythm

    • Definition: Cyclical biological changes that occur on a roughly 24-hour basis, influenced by external cues.

    • Factors regulated: Hormone release, body temperature, and various bodily functions.

    • Mechanism: Regulated by the suprachiasmatic nucleus (SCN), referred to as the biological clock located in the hypothalamus.

  • Neurological Conditions:

    • Lock-in syndrome

    • Description: A condition where an individual is fully conscious but unable to move or respond.

  • Mystical experiences

    • Definition: Deep encounters characterized by a transcendent state of being that exceeds ordinary sensory perception and rational thought.

  • Dependence Types:

    • Physical dependence

    • Definition: Relates to withdrawal symptoms when the substance is discontinued, indicating physiological adaptation.

    • Psychological dependence

    • Definition: Relates to cravings or a compulsion to use the substance, often without physical withdrawal symptoms.