CH. 2 CP

Cognitive Neuroscience Overview

Levels of Analysis

  • Importance of understanding brain for cognition.

  • Levels from single neurons to complex networks, showing brain interconnections.

  • Brain functioning is dynamic and changeable along with cognition.

Neural Basis of Cognition

  • Neurons transmit information via electrical and chemical signals.

  • Output can be studied through various methodologies, e.g., brain imaging and recording single neurons.

Key Concepts in Neurons

  • Neuron Structure: Comprises cell body, axon (transmits signals), and dendrites (receive signals).

  • Neural Function: Neurons communicate through synapses; chemical neurotransmitters transmit signals.

Early Concepts in Neuroscience

  • The historical view began with the nerve net theory, where neurons were thought to be interconnected without gaps.

  • Cajal introduced the neuron doctrine: neurons are discrete entities communicating across synapses.

Methods of Study

  • Recording from Neurons: Microelectrodes measure electrical signals; action potentials indicate neural firing.

  • Neuropsychology: Examines effects of brain damage to localize functions.

Information Transmission in Neurons

Action Potentials

  • Resting potential of -70mV; action potential can rise to +40mV.

  • Action potentials represent signals traveling down the axon, critical for communication.

Correlation with Experience

  • Recording reveals that increased stimulus intensity correlates with increased nerve firing rate.

Representation by Neural Firing

  • Each neuron responds to specific stimuli; this principle extends to neural firing patterns across multiple neurons.

  • Feature Detectors: Specific neurons signal particular stimuli features (e.g., orientation of lines).

Distributed Representation

  • Cognitions involve neural firing across multiple regions; perception of complex stimuli is multidimensional.

  • E.g., recognizing faces engages several interconnected neural areas.

Experiments and Findings

  • Huth et al. (2012) analyzed brain activation patterns during viewing films, linking brain areas to processed stimuli.

Structural and Functional Connectivity

  • Structural Connectivity: Refers to physical wiring of brain networks via neuron axons.

  • Functional Connectivity: Measures interactivity between brain regions, indicating how areas work together during tasks.

Connectome

  • New neuroimaging techniques help map the brain's connectome; related to understanding cognitive functions.

Dynamic Nature of Cognition

  • Brain activity fluctuates based on task demands; networks activate and deactivate in response to changing tasks (like picking up a cup).

  • Default Mode Network (DMN): A network that activates during rest; correlated with mind-wandering and introspection.

Implications of Technologies in Cognitive Neuroscience

  • Advances in imaging technology (e.g., fMRI, PET) led to understanding brain organization and connectivity.

  • Techniques enable more complex and realistic studies of neuronal responses to stimuli, beyond basic reflex reactions.