Feb 06 (Midterm Review)

• Approaches to study cognition:

  • Cognitive Psychology: Studies behavior to understand the mind
  • Neuroscience: Studies the physical brain and connects it to the mind
  • Computational Modeling: Builds models of the mind-brain relationship
• What can we learn from ancient philosophers:

  • Plato:
  • Rationalism: Knowledge is the result of prior reasoning and observation
  • We use logic and a priori knowledge to interpret what we observe
  • Aristotle:
  • Empiricism: All knowledge comes from experience/observation
  • All thought is based on associations between what we observe
• Origins of Experimental Psychology:

  • Structuralism: Understands the structure of the mind by identifying the basic building blocks to explain how they give rise to more complex cognitive processes (Wilhelm Wundt)
  • Functionalism: Understands the function(s) of the mind. Assumes that the mind is constantly changing and adapting to changing contexts and goals (William James)
  • Behaviorism: Psychology can be objectively studied through observations
  • Focus on stimulus and response
  • Not interested in mental concepts
• Cognitive Revolution:

  • The importance of internal mental states is now recognized, but also acknowledges that rigorous scientific methods must be used to study them
  • Information Processing View: The mind and brain as an information processor (e.g. computer)
  • Processing information takes time and resources
• • Neutral Monism: Reality is neither physical nor mental; Mind and brain are composed of the same neutral substance
• Mind-Body Problem:

  • Dualism views the mind and brain as separate entities
  • Monism views the mind and brain as the same entity
  • Interactionism: The mind and brain are separate substances that interact and influence each other (e.g. bidirectional relationship)
  • Epiphenomenalism: The mind is a by-product of the brain
  • Mental events (mind) are caused by physical events (brain) but not the other way around
  • Physicalism/Materialism: All reality is the result of physical processes
  • Idealism: All reality is a mental construct
• Methods to Study the Link Between Mind and Brain:

  • Behavioral Measurements in Humans:
  • Behavioral experiments to measure voluntary response to a stimulus (E.g.; RT to response to light stimulus)
  • Psychophysiological measurement to measure involuntary response to a stimulus (E.g.; Skin conductance response to fearful stimulus)
  • Behavioral Neuroscience Using Animal Models:
  • Causal link between brain and behavior (E.g; by lesioning brain area)
  • Limited translation to human cognition
  • Cognitive neuroscience:
• • Neuropsychological cases-Studying differences in cognition and behavior by comparing brain-injured patients vs. healthy participants
  • Functional specialization
  • Neuroimaging techniques:
  • EEG
  • MRI
  • Brain stimulation
• Neuroimaging Techniques:

  • EEG:
  • Records electrical activity of the brain via electrodes affixed to the scalp
  • Good temporal but poor spatial resolution
  • MRI:
  • Non-invasive imaging technique that uses a magnetic field and radio waves to create detailed images of the organs and tissues in your body
  • Structural MRI: Images of anatomical brain structures
  • Functional MRI: Images of metabolic activity in the brain by measuring blood flow, which we assume to reflect neural activity
  • Good spatial but poor temporal resolution
  • Brain Stimulation:
• • Non-invasive method of altering brain activity to inhibit or increase behavior or cognitive process
  • Transcranial Magnetic Stimulation (TMS): Focal magnetic field that induces temporary change in brain activity
• Perception - Important Terms:

  • Sensation: Conversion of the physical properties of our environment or body into neural code (by the peripheral nervous system)
  • Transduction
  • Perception: Processing and interpretation of the sensory information into a form that is useful for behavioral decisions/actions
• Sensation Interoceptive vs. Exteroceptive senses:

  • Interoceptive Sensations:
  • Proprioception: sense of where our limbs are in space
  • Nociception: sense of pain due to body damage
  • Equilibrioception: sense of balance
  • Exteroceptive sensations:
  • Vision/Sight: light entering the eye
  • Audition/Hearing: vibrations in the air entering ear canal
  • Touch: pressure, heat, vibrations on skin
  • Gustation/Taste: chemical compounds in mouth
  • Olfaction/Smell: chemical compounds in nose
• • Fovea: Part of the retina with a higher concentration of cone receptors (center of your visual field, most detailed vision)
  • After information leaves the eyes through the optic nerve, it crosses over at the optic chiasm and reaches the LGN of the thalamus
  • Thalamus is important for sensory relay
  • There is contralateral representation in both hemispheres
• The Visual System:

  • The eye is where the transduction of light into neural code occurs
  • Retina: made up of multiple layers of receptors. Final layer consists of light-sensitive receptors called photoreceptors
  • Photoreceptors: convert light energy into neural code
  • Rods: low resolution (low light levels)
  • Cones: high resolution (detailed coloured vision)
  • Optic nerve: axons of ganglion cells leave the eye
  • Blindspot: area with no photoreceptors where the optic nerve is leaving the eye through the retina
• The Visual System - Late Visual Processing:

  • Information is projected from the LGN to the Primary Visual Cortex (area V1) in the occipital lobe
  • Area V1 responds to specific visual attributes such as Edges, Angles, Colour, Light
  • Ventral Pathway (What): Shape, size, details of objects
  • Dorsal Pathway (Where): Location, space, movement information
• Damage to the Visual Cortex - Blindsight & Visual Agnosias:

  • Blindsight: Cortical blindness (no explicit perception of objects) but unconscious (implicit) perception. —> Primary Visual Area (V1)
  • Damage to the dorsal pathway:
  • Akinetopsia: Visual motion blindness; difficulty in perceiving motion
  • Optic Ataxia: Difficulty in reaching for objects (but can name them)
  • Damage to the ventral pathway:
  • Semantic (Visual) Agnosia: Difficulty in recognizing daily objects (Damage to LOC)
  • Prosopagnosia: Difficulty in recognizing individual faces (Damage to FFA)
• The Auditory System:

  • The ear is where the transduction of sound waves into neural code occurs
  • Structures of the ear can amplify sound waves
  • Sound waves are oscillating movement in the air caused by vibrations of objects in the environment
  • Basilar membrane: Strip of tissue inside the cochlea that contains the hair cells that transduce sound
  • Tonotopic map: Special arrangement of neural structures (hair cells) in which locations are organized based on the frequency of sound they encode
• The Chemical Senses:

  • Olfactory system (Smell):
  • Olfactory bulb: Specialized brain structure that filters and relays olfactory signals to other subcortical brain structures (amygdala, hippocampus)
  • Olfactory epithelium: Where the chemical receptors are located
  • Gustatory system (Taste): We have thousands of chemoreceptors in each taste bud on our tongue that all us to taste
  • Signals are sent to the brainstem and then the primary gustatory cortex
  • There are 5 types of taste receptors: Sweet, sour, salty, savory, bitter
• The Somatosensory System:

  • The skin is covered in mechanoreceptors, which respond to different kinds of physical stimuli (touch, pressure)
  • Cortical homunculus: spatially organized map of the human body, contained within the somatosensory cortex
• Receptors respond to different kinds of physical stimuli such as touch and pressure
• Cortical homunculus is a spatially organized map of the human body within the somatosensory cortex that processes touch information
• Different body parts have larger or smaller representations based on the density of tactile sensory receptors within them
• Bottom-up Processing is the influence of information from the external environment on perception (unidirectional)
• Top-down Processing is the influence of knowledge (expectations, context, goals) on perception (bidirectional)
• Constructive Model of Perception: Perceptual processing is the brain's attempt to construct a mental model of the external world based on sensory input using top-down processing
• Our brains use knowledge and expectations to perceive images, relying on relationships between distance and size, the world being lit from above, and the importance of context
• Feature Matching Theory: Visual input is broken down into individual parts and each feature is processed separately
• Template Matching Theory: Matching an incoming stimulus to a stored representation in memory
• Prototype Theory: Matching an incoming stimulus to an average representation stored in memory
• Endogenous/Top-down Attention is voluntary attention that uses the Frontal Eye Fields (FEF), Intraparietal sulcus (IPs, IPL)
• Exogenous/Bottom-up Attention is guided purely by external stimuli and uses the temporoparietal junction & VPS
• Arousal is a measure of how alert you are
• Spatial Neglect is damage to the right hemisphere resulting in the inability to attend to information on the contralateral side (left side)
• Sustained Attention is focusing on something for an extended period of time
• Divided Attention is multitasking
• Selective Attention is ignoring irrelevant information
• Dichotic Listening Task is a way to measure selective attention and provides evidence for early selection model
• The Load Theory states that attentional filtering can occur at different levels of processing and is dependent on how demanding a task is
• Change Blindness is the failure to detect changes in stimuli and is tested using the flicker technique paradigm
• Inattentional Blindness is not noticing something new in your attentional focus