Lecture Notes: Perception and Neuroanatomy

Key Concepts of Motion Perception

• Importance of Motion
  • Understanding animal motion for safety (avoid predators) or hunting (catching prey).
  • Unique human ability: Precision throwing.
  • Visual motion detection shared across many animal species.

Challenges in Motion Perception

• Difficulty discerning emotions from static faces.
• Facial expressions have subtle micro-expressions that can be missed without motion cues.
• Importance of motion information in daily life and survival.
• Speculation on whether specialized brain mechanisms exist for processing motion.

Motion and the Brain

• Neuroanatomy Overview
  • The human brain contains approximately 100 billion neurons.
  • Neurons consist of cell bodies, dendrites, and axons.
  • Myelin sheath speeds up neural signal transmission.

Major Brain Components

• Cortex: Outer layer, involved in higher cognitive functions.
• Brain Stem: Primitive structure crucial for survival (breathing, consciousness).
• Cerebellum: Motor coordination; potential role in cognition debated.
• Limbic System: Involved in emotion and memory (includes thalamus, hippocampus, amygdala).

Subcortical Structures

• Thalamus: Relay station for sensory information, plays a role in consciousness and high-level cognitive processing.
• Hippocampus: Key for episodic memory and navigation; case studies highlight its importance.
  • Example: Patient H.M. lost ability to form new memories after hippocampus removal.
• Amygdala: Processes emotions, especially fear; damage leads to inability to recognize fear in others.

White Matter

• Composed of myelinated axons that connect different brain regions.
• Essential for understanding how cortex regions communicate and function together.

Cortex Overview

• The cortex is divided into primary sensory regions (visual, auditory, somatosensory, etc.) which receive direct information from the thalamus.
• Each sensory area has a map (e.g., retinotopic map in visual cortex) which corresponds to sensory input.

Receptive Fields in Visual Cortex

• Neurons have specific receptive fields that respond to particular areas in the visual field.
• Nearby neurons have similar receptive fields, creating a systematic organization in the cortex.
• Retinotopy: Organization of visual information in the brain resembling the layout of the retina.

Area MT

• A specific region in the visual cortex known for processing motion.
• Evidence for its distinct function includes:
  • Neurons sensitive to direction of motion.
  • Connectivity patterns unique to area MT.
  • Akinetopsia: Condition where individuals cannot perceive motion, highlights importance of area MT.

Conclusion and Takeaways

• Understanding the brain's structure and function helps us comprehend perception processes.
• The interplay between different brain areas is crucial for interpreting sensory information and forming memories.
• The importance of specialized areas, such as area MT, in understanding how we perceive motion and other sensory modalities.