Perceptual decision related activity in the lateral geniculate nucleus

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Understanding the neural basis of perception and decision-making is crucial in neuroscience.
• The lateral geniculate nucleus (LGN) is a key relay station for visual information.
• Previous studies have not directly linked LGN neural activity to perceptual decision-making in animals.

Purpose of the Study:

• To investigate the relationship between individual lateral geniculate nucleus (LGN) neuron activity and perceptual decision-making in macaques.
• To determine if LGN neurons' sensitivity matches behavioral performance during a visual task.
• To explore the role of neural response fluctuations and correlations in perceptual choices.

Main Methods:

• Recorded single-unit activity in the macaque LGN during a two-alternative, forced-choice (2AFC) contrast detection task and a passive fixation task.
• Quantified choice probability to measure the covariation between neural responses and behavioral choices.
• Utilized a bottom-up pooling model to simulate perceptual choices based on sensory neuron responses.

Main Results:

• A small percentage (13.5%) of LGN parvocellular (P) and magnocellular (M) neurons' activity covaried with the monkey's psychophysical performance.
• The majority of recorded LGN neurons showed lower sensitivity compared to the monkey's behavioral performance.
• Choice probability was significantly above chance during active detection, even without external stimuli, suggesting neural fluctuations influence perception.
• Interneuronal correlations and task-related gain modulations were minimal under these conditions.

Conclusions:

• Perceptual decisions may arise from the pooling of activity from multiple sensory neurons in the LGN.
• Fluctuations in the response of individual LGN neurons can significantly influence an animal's perceptual choices.
• A simple pooling model without interneuronal correlations can explain the observed relationship between LGN activity and behavior.