Temporal integration of olfactory perceptual evidence in human orbitofrontal cortex
Nicholas E Bowman1, Konrad P Kording, Jay A Gottfried
1Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA. nickbowman80@gmail.com
Neuron
|September 11, 2012
Summary
Human brains integrate odor information over time to improve smell decisions. The orbitofrontal cortex (OFC) shows a ramp-up in activity, supporting accumulator models of perception and decision-making.
Area of Science:
- Neuroscience
- Cognitive Science
- Sensory Perception
Background:
- The human brain integrates sensory evidence over time for optimal decision-making.
- Mechanisms of sensory evidence accumulation in the human brain, particularly olfaction, are not well understood.
- Previous research documented neurophysiological accumulation in animal visual systems.
Purpose of the Study:
- To investigate how the human olfactory system integrates odor evidence over time.
- To determine the neural basis of odor evidence integration using fMRI.
- To test predictions of accumulator models in human olfactory decision-making.
Main Methods:
- Psychophysical techniques to measure behavioral performance.
- Drift-diffusion modeling to quantify decision processes.
- Functional magnetic resonance imaging (fMRI) to measure brain activity.
- Combined behavioral and neuroimaging data analysis.
Main Results:
- Odor evidence integration enhances discrimination performance in a two-alternative forced-choice task.
- A ramp-like increase in orbitofrontal cortex (OFC) activity was observed, peaking at decision time.
- Decision bounds were found to be dynamic and collapse over time, aiding decisions with low-quality evidence.
Conclusions:
- The orbitofrontal cortex plays a crucial role in resolving sensory uncertainty in olfaction.
- Data support the application of accumulator models to human perceptual decision-making.
- Findings provide insights into the neural mechanisms underlying olfactory evidence integration and decision formation.
Related Concept Videos
01:25Olfaction
The sense of smell is achieved through the activities of the olfactory system. It starts when an airborne odorant enters the nasal cavity and reaches olfactory epithelium (OE). The OE is protected by a thin layer of mucus, which also serves the purpose of dissolving more complex compounds into simpler chemical odorants. The size of the OE and the density of sensory neurons varies among species; in humans, the OE is only about 9-10 cm2.
The olfactory receptors are embedded in the cilia of the...
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01:20Physiology of Smell and Olfactory Pathway
Humans detect odors with the help of specialized cells located in the upper part of the nasal cavity, called olfactory receptor neurons (ORNs). ORNs possess hair-like structures called cilia, which are receptive to sensations from the inhaled air. When an odorant molecule binds to a specific receptor on the cell of the cilia, it leads to a series of events that ultimately cause the ORN to send electrical signals to the olfactory bulb in the brain through the olfactory nerves.
The olfactory...
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01:21Association Areas of the Cortex
Association areas are regions of the cerebral cortex that do not have a specific sensory or motor function. Instead, they integrate and interpret information from various sources to enable higher cognitive processes such as memory, learning, and decision-making. Some key association areas include the following:
Prefrontal Association Area: This area is located in the frontal lobe and is involved in planning, decision-making, and moderating social behavior. It connects with primary motor areas,...
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01:14Motor and Sensory Areas of the Cortex
The cerebral cortex, the brain's outermost layer, is pivotal in processing complex cognitive tasks, emotions, and various sensory inputs and executing voluntary motor activities. This intricate structure is divided into three primary functional areas: the motor areas, sensory areas, and association areas.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
Motor Areas
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01:03Olfactory Receptors: Location and Structure
The process of olfaction, also known as the sense of smell, is a sophisticated chemical response system. The specialized sensory neurons that facilitate this process, known as olfactory receptor neurons, are situated in an upper segment of the nasal cavity, known as the olfactory epithelium. Olfactory sensory neurons are bipolar, with their dendrites extending from the epithelium's apex into the mucus that lines the nasal cavity. Airborne molecules, when inhaled, traverse the olfactory...
01:23Somatosensory, Motor, and Association Cortex
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