cognition test 1

• Cognitive Neuroscience


  The study of the physiological basis of cognition
• Cognitive Neuroscience


  • It is a combination of cognition and neuroscience
  • Involves an understanding of both the nervous system and the individual units that comprise that system
• Levels of Analysis


  We do not examine topics of interest from a single perspective; we look at them from multiple angles and different points of view. We do not examine topics of interest from a single perspective; we look at them from multiple angles and different points of view.
• Levels of Analysis


  Each "viewpoint" can add small amounts of information that, when considered together, lead to greater understanding
• Nerve Nets


  • Early concept of interconnected neurons creating a nerve net, similar to a highway network. This allows for almost nonstop, continuous communication of signals throughout the network
• Neuron Doctrine


  Individual nerve cells transmit signals, and are not continuously linked with other cells
• Building Blocks of the Nervous System

  • Neurons: cells specialized to create, receive, and transmit information in the nervous system
  • Cell body: contains mechanisms to keep cell alive
  • Dendrites: multiple branches reaching from the cell body, which receive information from other neurons
  • Axon: tube filled with fluid that transmits electrical signal to other neurons
• How Neurons Communicate


  1. Neuron receives signal from environment

  2. Information travels down the axon of that neuron to the dendrites of another neuron

  3. Microelectrodes pick up electrical signal

  4. Placed near axon
• Action Potential


  Electrical signal transmitted by neurons
• Measuring Action Potentials


  • Size is not measured; it remains consistent
  • The rate of firing is measured (Rate Coding)
  • Low-intensity stimulus: slow firing
  • High-intensity stimulus: fast firing
• Synapse


  • Space between axon of one neuron and dendrite or cell body of another
  • When the action potential reaches the end of the axon, synaptic vesicles open and release chemical neurotransmitters
  • Neurotransmitters, chemicals that affect the electrical signal of the receiving neuron, cross the synapse and bind with the receiving dendrites
• Principle of Neural Representation


  Everything a person experiences is based on representations in the person's nervous system
• Feature Detectors


  Neurons that respond best to a specific stimulus
• Feature Detectors


  • Experience-dependent plasticity: the structure of the brain changes with experience
  • Kittens exposed to vertical-only stimuli over time could only perceive verticals in normal stimuli
  • Demonstrated that perception is determined by neurons that fire to specific qualities of a stimulus
• Hierarchical Processing


  • When we perceive different objects, we do so in a specific order that moves from lower to higher areas of the brain
  • The ascension from lower to higher areas of the brain corresponds to perceiving objects that range from lower (simple) to higher levels of complexity
• Sensory Coding


  • Specificity coding: representation of a stimulus by the firing of specifically tuned neurons specialized to respond only to a specific stimulus
  • Population coding: representation of a stimulus by the pattern of firing of a large number of neurons
  • Sparse coding: representation of a stimulus by a pattern of firing of only a small group of neurons, with the majority of neurons remaining silent
• Localization of Function


  • Specific functions are served by specific areas of the brain
  • Cognitive functioning declines in specific ways when certain areas of the brain are damaged
  • Cerebral cortex (3-mm-thick layer covering the brain) contains mechanisms responsible for most cognitive functions
• Localization of Function: Language


  • Language production is impaired by damage to Broca's area (Frontal lobe)
  • Language comprehension is impaired by damage to Wernicke's area (Temporal lobe)
• Localization of Function: Perception


  • Primary receiving areas for the senses:
  • Occipital lobe: vision
  • Parietal lobe: touch, temperature, and pain
  • Temporal lobe: hearing, taste, and smell
  • Coordination of information received from all senses: Frontal lobe
• Single Dissociation


  Lesion to brain structure A disrupts function X but not Y
• Double Dissociation


  Damage to one part of the brain causes function A to be absent while function B is present, and damage to another area causes function B to be absent while function A is present
• Localization Demonstrated by Brain Imaging


  • Functional magnetic resonance imaging (fMRI) measures neural activity by identifying highly oxygenated hemoglobin molecules
  • Activity recorded in voxels (3-D pixels)
• Localization Demonstrated by Brain Imaging


  • Fusiform face area (FFA) responds specifically to faces
  • Parahippocampal place area (PPA) responds specifically to places (indoor/outdoor scenes)
  • Extrastriate body area (EBA) responds specifically to pictures of bodies and parts of bodies
• Distributed Representation in the Brain


  • Most of our experience is multidimensional
  • In addition to localization of function, specific functions are processed by many different areas of the brain
• Neural Networks


  • Interconnected areas of the brain that communicate with each other
  • Connectome: structural description of the network of elements and connections forming the human brain
• Structural Connectivity


  The brain's "wiring diagram" created by axons that connect brain areas, as unique to individuals as fingerprints
• Functional Connectivity


  How groups of neurons within the connectome function in relation to types of cognition, determined by the amount of correlated neural activity in two brain areas
• Dynamics of Cognition


  • The flow and activity within and across the brain's functional networks change based on conditions
  • Change within and across networks is constant
• Default Mode Network


  Mode of brain function that occurs when it is at rest, one of the brain's largest networks
• Perception


  Experience resulting from stimulation of the senses
• Perception


  • Basic concepts
  • Perceptions can change based on added information
  • Involves a process similar to reasoning or problem solving
  • Perceptions occur in conjunction with actions
• Attempts to create artificial forms of perception (machines) have been met with limited success and each time have had problems that could not be solved
• Inverse Projection Problem


  The task of determining the object responsible for a particular image on the retina
• Inverse Projection Problem


  • Involves starting with the retinal image and then extending outward to the source of that image
  • Objects can be hidden or blurred
  • People can often identify objects that are obscured and therefore incomplete, or in some cases objects that are blurry
• Perception


  • Objects look different from different viewpoints
  • Scenes contain high-level information
  • Scenes are more complex
• Information Used in Human Perception


  • Environmental energy stimulating the receptors
  • Knowledge and expectations the observer brings to the situation
• Direct perception theories


  Bottom-up processing, perception comes from stimuli in the environment, parts are identified and put together, and then recognition occurs
• Constructive perception theories


  Top-down processing, people actively construct perceptions using information based on expectations
• Approaches to Understand Perception


  • Direct perception theories
  • Constructive perception theories
• Bottom-up processing


  • Perception may start with the senses, incoming raw data, energy registering on receptors