Chapter 2 Cognitive Neuroscience PDF - Syracuse University Spring 2025

Chapter 2 Cognitive Neuroscience Spring 2025  Some Questions to Consider What is cognitive neuroscience, and why is it necessary? How is information transmitted from one place to another in the nervous system? How are things in the environment, such as faces and trees, represented in the...

Chapter 2 Cognitive Neuroscience Spring 2025  Some Questions to Consider What is cognitive neuroscience, and why is it necessary? How is information transmitted from one place to another in the nervous system? How are things in the environment, such as faces and trees, represented in the brain? What are neural networks, and what is their role in cognition? Is it possible to read a person’s mind by measuring the activity of the person’s brain? Syracuse University 2  Cognitive Neuroscience The study of the physiological basis of cognition Involves an understanding of both the nervous system and the individual units that comprise that system Syracuse University 3 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 Each “viewpoint” can add small amounts of information that, when considered together, lead to greater understanding Figure 2.1 Physiological levels of analysis. (a) Gil perceives Mary and their surroundings as he talks with her. The physiological processes involved in Gil’s perception can be described at levels ranging from chemical reactions to single neurons, to structures in the brain, to groups of structures in the brain. (b) Later, Gil remembers his meeting with Mary. The physiological processes involved in remembering can also be described at different levels of analysis. Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 4 duplicated, or posted to a publicly accessible website, in whole or in part. Levels of Analysis Syracuse University 5  Building Blocks of the Nervous System Neurons: cells specialized to create, receive, and transmit information in the nervous system Each neuron has a cell body, an axon, and dendrites Syracuse University 6  Building Blocks of 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 Syracuse University 7 Building Blocks of the Nervous System Figure 2.3 (a) Basic components of a neuron in the cortex. (b) A neuron with a specialized receptor in place of the cell body. This receptor responds to pressure on the skin. Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 8 duplicated, or posted to a publicly accessible website, in whole or in part.  How Neurons Communicate (1 of 6) Action potential – Neuron receives signal from environment – Information travels down the axon of that neuron to the dendrites of another neuron Measuring action potentials – Microelectrodes pick up electrical signal – Placed near axon – Active for 1 second Syracuse University 9 How Neurons Communicate (2 of 6) Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 10 duplicated, or posted to a publicly accessible website, in whole or in part.  How Neurons Communicate (3 of 6) 1In practice, most recordings are achieved with the tip of the electrode positioned just outside the neuron because it is technically difficult to insert electrodes into the neuron, especially if it is small. However, if the electrode tip is close enough to the neuron, the electrode can pick up the signals generated by the neuron. Figure 2.5 Recording an action potential as it travels down an axon. (a) When the nerve is at rest, there is a difference in charge, called the resting potential, of −70 millivolts (mV) between the inside and outside of the axon. The difference in charge between the recording and reference electrodes is fed into a computer and displayed on a computer monitor. This difference in charge is displayed on the right. (b) As the nerve impulse, indicated by the red band, passes the electrode, the inside of the fiber near the electrode becomes more positive. (c) As the nerve impulse moves past the electrode, the charge in the fiber becomes more negative. (d) Eventually the neuron returns to its resting state. Syracuse University 11  How Neurons Communicate (4 of 6) Measuring action potentials – Size is not measured; it remains consistent – The rate of firing is measured ▪ Low-intensity stimulus: slow firing ▪ High-intensity stimulus: fast firing Syracuse University 12 How Neurons Communicate (5 of 6) Figure 2.7 Action potentials recorded from an axon in response to three levels of pressure stimulation on the skin: (a) light, (b) medium, and (c) strong. Increasing stimulus intensity causes an increase in the rate of nerve firing. Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 13 duplicated, or posted to a publicly accessible website, in whole or in part.  How Neurons Communicate (6 of 6) 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 Electricity Chemicals Electricity Syracuse University 14  How Neurons Communicate Neurotransmitters: chemicals that affect the electrical signal of the receiving neuron – Excitatory: increases chance neuron will fire – Inhibitory: decreases chance neuron will fire Syracuse University 15  How Neurons Process Information Not all signals received lead to action potential The cell membrane processes the number of impulses received An action potential results only if the threshold level is reached – Interaction of excitation and inhibition Syracuse University 16  Principle of Neural Representation Definition of the mind: – a system that creates representations of the world, so we can act on it to achieve goals Principle of neural representation: – Everything a person experiences is based on representations in the person’s nervous system. Syracuse University 17 Feature Detectors (1 of 2) Hubel & Wiesel (1960s) research with visual stimuli in cats Feature detectors: – neurons that respond best to a specific stimulus Figure 2.9 (a) An experiment in which electrical signals are recorded from the visual system of an anesthetized cat that is viewing stimuli presented on the screen. The lens in front of the cat’s eye ensures that the images on the screen are focused on the cat’s retina. The recording electrode is not shown. (b) A few of the types of stimuli that cause neurons in the cat’s visual cortex to fire. Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 18 duplicated, or posted to a publicly accessible website, in whole or in part. Feature Detectors (2 of 2) 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 Syracuse University 19  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 Syracuse University 20  Sensory Coding (1 of 2) 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 Syracuse University 21 Sensory Coding (2 of 2) Figure 2.14 Three types of coding: (a) Specificity coding. The response of 10 different neurons to each face on the left is shown. Each face causes a different neuron to fire. (b) Population coding. The face’s identity is indicated by the pattern of firing of a large number of neurons. (c) Sparse coding. The face’s identity is indicated by the pattern of firing of a small group of neurons. Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 22 duplicated, or posted to a publicly accessible website, in whole or in part.  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 Syracuse University 23  Localization of Function Frontal lobe: Parietal lobe: Coordination of sensations information touch, received from all pressure, pain senses. language, thinking, problem solving and motor functioning Occipital lobe: vision (lower level) Temporal lobe: Language, memory, hearing and vision (higher level) Syracuse University 24 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 Figure 2.16 Broca’s area, in the frontal lobe, and Wernicke’s area, in the temporal lobe, were identified in early research as being specialized for language production and comprehension, respectively. Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 25 duplicated, or posted to a publicly accessible website, in whole or in part.  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 Syracuse University 26 Localization Demonstrated by Brain Imaging (1 of 2) Functional magnetic resonance imaging (fMRI) Measures neural activity by identifying highly oxygenated hemoglobin molecules – Activity recorded in voxels (3-D pixels) Figure 2.17 (a) Person in a brain scanner. (b) fMRI record. Colors indicate locations of increases and decreases in brain activity. Red and yellow indicate increases in brain activity; blue and green indicate decreases. Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 27 duplicated, or posted to a publicly accessible website, in whole or in part.  Localization Demonstrated by Brain Imaging (2 of 2) Fusiform face area (FFA) responds specifically to faces – Damage to this area causes prosopagnosia (inability to recognize 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 Syracuse University 28 Evidence for Localization of Function Figure 2.18 (a) The parahippocampal place area (PPA) is activated by places (top row) but not by other stimuli (bottom row). (b) The extrastriate body area (EBA) is activated by bodies (top) but not by other stimuli (bottom). Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 29 duplicated, or posted to a publicly accessible website, in whole or in part.  Distributed Representation in the Brain Central principle of cognition: – Most of our experience is multidimensional. In addition to localization of function, specific functions are processed by many different areas of the brain May seem to contradict the notion of localization of function, but the concepts are complementary Syracuse University 30  Caption: As this person watches the red ball roll by, different properties of the ball activate different areas of his cortex. These areas are in separate locations, although there is communication between them. Syracuse University 31  Distributed representation Evaluating a face Occurs when a specific cognition – Emotional aspects activates many areas of the brain. – Attractiveness Syracuse University 32 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 Figure 2.24 The connectome. Nerve tracts in the human brain determined by track- weighted imaging. Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 33 duplicated, or posted to a publicly accessible website, in whole or in part.  Structural and Functional Connectivity 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 Syracuse University 34 Six Common Functions Determined by Resting-State fMRI Network Function Visual Vision; visual perception Somato-motor Movement and touch Dorsal Attention Attention to visual stimuli and spatial locations Executive Control Higher-level cognitive tasks involved in working memory (see Chapter 5) and directing attention during tasks Salience Attending to survival-relevant events in the environment Default mode Mind wandering, and cognitive activity related to personal life-story, social functions, and monitoring internal emotional states Goldstein, Cognitive Psychology, 5th Edition. © 2019 Cengage. All Rights Reserved. May not be scanned, copied or Syracuse University 35 duplicated, or posted to a publicly accessible website, in whole or in part. Syracuse University 36  Dynamics of Cognition and Default Mode Network 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 Syracuse University 37