Cognitive Neuroscience Quiz

Brain Structure-Function relationship

• Dissociation logic lesion studies are used to study the relationship between cognitive processes and specific brain areas.
• Lesion studies involve individuals with brain damage.
• Single dissociation shows that one function is affected but a related function is not.
• Double dissociation confirms that two functions are independent.
• Lesions in specific brain areas help understand how cognitive processes are organized and aid in developing targeted treatments.

Different brain regions and their functions

• Cerebellum ("little brain"): contains more than half of the brain's neurons, essential for smooth and precise motor control, coordinating and regulating various functions related to balance and movement.
• Brainstem: composed of the midbrain, pons, and medulla.
  • Midbrain: involved in pain modulation and plays a role in processing auditory and visual information.
  • Pons: the main connection between the brain and cerebellum, and is important for some eye movements and facial movements. It also modulates arousal and pain responses
  • Medulla: vital for life functions such as heart rate, blood pressure, breathing and arousal. It houses cell bodies of many cranial nerves.

The 4 Lobes

• Frontal Lobe:
  • Prefrontal Cortex: executive functions, decision-making, and emotional regulation.
  • Primary Motor Cortex: voluntary movement control.
  • Premotor Cortex: movement planning and coordination.
  • Broca's Area: language production
  • Supplementary Motor Area: movement initiation and coordination.
  • Orbitofrontal Cortex: risk assessment, decision-making, and social behavior.
  • Frontal Eye Fields: eye movement control and visual attention.
• Parietal Lobe:
  • Primary Somatosensory Cortex: touch, temperature, and pain.
  • Somatosensory Association Cortex: interpretation of sensory input and hand-eye coordination.
  • Superior Parietal Lobule: spatial awareness and body position.
  • Inferior Parietal Lobule: integrates sensory information for complex language and math tasks.
• Temporal Lobe:
  • Primary Auditory Cortex: sound processing.
  • Wernicke's Area: language comprehension.
  • Hippocampus: memory formation.
  • Amygdala: emotional processing.
  • Fusiform Gyrus: facial and object recognition.
• Occipital Lobe:
  • Primary Visual Cortex (V1): basic visual processing.
  • Visual Association Areas: complex visual interpretation.
  • Dorsal/Ventral Pathways: location/motion (dorsal), and object recognition (ventral).
  • Multisensory Cortex

Diencephalon

• Thalamus: Divided into two parts, one on each hemisphere. It's connected by a bridge of gray matter (massa intermedia). It receives sensory information from the body and directs it to the appropriate regions of the cerebral cortex. Plays a role in coordinating motor signals between cerebral cortex and other parts of the brain, and involved in regulating sleep-wake cycle and levels of consciousness. Helps modulate alertness and attention.
• Hypothalamus: Maintains internal balance, regulates body temperature, hunger, thirst, and fluid balance. Monitors blood parameters. Through its connection to the pituitary gland it releases and regulates hormones that influence growth, stress responses, reproduction, and metabolism. Plays a role in emotional responses.

Brain Damage and Effects

• Lobotomy: a now-obsolete surgical procedure aimed at severing connections between the prefrontal cortex and deeper brain areas. The goal was to reduce symptoms of mental illnesses like extreme mood swings, hallucinations, and aggression, The procedure involves drilling holes into the skull.
• Prefrontal lobotomy: a standard lobotomy involving surgical tools to cut brain tissue.
• Transorbital Lobotomies (Ice-Pick Lobotomy): A surgical procedure involving inserting a thin instrument through an eye socket into the frontal lobe to damage neural pathways.

Split Brain

• Corpus Callosotomy: Severing connections between the brain's two hemispheres by separating the corpus callosum.
• Effects of a Split Brain:
  • Isolates the two hemispheres preventing communication between them
  • One hemisphere can only process information from the side of the body or one visual field they control directly.
  • The left hemisphere can express information verbally.

Memory I

• Working memory is a subset of short-term memory in which information is actively manipulated.
• Phonological Loop: deals with spoken and written material, stores spoken words for 1-2 seconds, and processes speech productions.
• Visuospatial Sketchpad: stores and processes visual and spatial information (used for navigation); combining information from the two systems, while also drawing information from the long-term memory.
• Executive Control: manages attention and coordinates phonological loop and visuospatial sketch.

Memory II

• Medial Temporal Lobe Memory System: Hippocampus, plays a critical role in linking relationships between different types of information, essential for forming episodic memories. Perirhinal cortex is involved in familiarity-based recognition while hippocampus, and posterior parahippocampal cortex support source-based recognition (episodic). Studies show medial temporal lobe is needed for forming new long-term memories.
• Neocortex: the brain's outer layer, where long-term memories are ultimately stored.
• Frontal Lobe: involved in working memory, encoding episodic information, and organizing the retrieval of information; involved in various aspects of memory.
• Parietal Lobe: involved in encoding and retrieving memories, especially episodic and context-rich memories.

Cognitive Control

• Refers to a set of psychological processes for goal oriented behavior.
• Allows individuals to use their knowledge, perception, and objectives to influence their actions effectively.
• The key characteristics and capabilities are goal-oriented behavior, focusing on the relevant information, inhibiting distractions or irrelevant stimuli, and monitoring progress toward goals.
• The neurological basis is the prefrontal cortex (particularly dorsolateral prefrontal cortex) and anterior cingulate cortex
• The prefrontal cortex implements top-down control.
• The anterior cingulate cortex acts as a monitoring system by detecting conflicts or errors.

Memory I

• Working memory is a subset of short-term memory in which information is actively manipulated.
• Phonological Loop: deals with spoken and written material, stores spoken words for 1-2 seconds, and processes speech productions.
• Visuospatial Sketchpad: stores and processes visual and spatial information (used for navigation); combining information from the two systems, while also drawing information from the long-term memory.
• Executive Control: manages attention and coordinates phonological loop and visuospatial sketch.

Neurons

• Neuron (nerve cell): basic unit of the nervous system.
• Dendrites: cellular extensions that receive information, forming a multitude of branches on which synapses are located.
• Cell body (soma): the main body of the neuron and responsible for processing and integrating incoming information.
• Axons: bundles of axons that carry information over long distances from one part of a neuron to another.
• Anterograde transport: the movement of materials from the cell body towards axon terminals.
• Retrograde transport: the movement of used materials back to the cell body.
• Axon terminals: transmit information to the next cell in the chain.

Action Potential

• Rapid electrical impulse traveling along the neuron's membrane.
• Action potential either happens fully or doesn't happen at all.
• All-or-none principle applies to action potentials.
• Electrical gradient and chemical gradient contribute to action potentials.
• Ion channels (proteins) are crucial for the action potential.
• Includes depolarization, repolarization, and hyperpolarization.
• Absolute and relative refractory periods determine the one-way travel of action potentials.

Neurotransmitters

• Chemical messengers facilitating communication between neurons and other cells at synapses.
• Synapses are specialized junctions for communication.
• Synaptic vesicles contain neurotransmitter molecules.
• Presynaptic membrane, synaptic cleft, and postsynaptic membrane are key structural elements.
• Receptors: protein molecules in postsynaptic membranes, bind to specific neurotransmitters to trigger changes in postsynaptic neurons.
• Ionotropic receptors are directly coupled to ion channels.
• Metabotropic receptors are linked to G protein-coupled receptors, triggering slower, indirect effects.

Vision I

• Cornea: clear covering, crucial for refracting light for focusing.
• Pupil: dark opening in iris, regulates light entering the eye.
• Iris: colored part, controls pupil size.
• Lens: focuses light onto the retina.
• Ciliary muscle: changes lens shape for near/far vision.
• Retina: captures light, converts it to signals, and relays them to the brain.
• Photoreceptors: Specialized cells in retina; rods (low light), and cones (color vision).
• Macula: central part of retina, for high-resolution vision (with fovea).
• Optic Nerve: carries visual signals to the brain.
• Optic Disk: where optic nerve exits eye.
• Vitreous Humor: clear gel-like substance filling the space behind the lens; maintains eye shape.
• Aqueous Humor: fluid between cornea and lens; nourishes the lens and cornea.
• Sclera (white of the eye): tough outer layer of the eye, protecting inner components.
• Suspensory ligaments: connect iris to the lens, controlling lens shape.
• Choroid: vascular tissue nourishing retina.

Vision II

• LGN (Lateral Geniculate Nucleus): a relay station in the thalamus for visual information from the optic nerve to the primary visual cortex (V1).
• Feedback processing means information travels both ways, from visual cortex to LGN, guiding subsequent visual processing.
• Receptive fields, On-center cells, and Off-center cells are key elements for visual processing and contrast detection.
• P and M cells (Parvocellular and Magnocellular cells) help with colour and motion detection.
• Visual cortex processes the signals further and combines the data with information from memory and previous experiences for a complete interpretation.

Vision III

• The primary visual cortex (V1 or Striate cortex) is visually organized
• The primary visual cortex is organized into:
  • Location columns: neurons in these areas are organised to deal with different locations on the retina.
  • Orientation columns: neurons in these areas respond best to stimuli with specific angles.
  • Ocular dominance columns: neurons are organized based on which eye is creating the stimulus.
  • Colour columns: these structures are responsible for processing colours.