Human middle temporal cortex, perceptual bias, and perceptual memory for ambiguous three-dimensional motion.

Area of Science:

• Neuroscience
• Cognitive Science
• Psychophysics

Background:

• Human perception can be ambiguous, with observers experiencing different interpretations of the same visual input.
• Perceptual memory, influenced by past experiences, plays a role in resolving ambiguous stimuli.
• The middle temporal cortex (hMT+) is a key area for processing visual motion.

Purpose of the Study:

• To investigate the role of the human middle temporal cortex (hMT+) in perceptual memory for ambiguous motion stimuli.
• To determine if transcranial magnetic stimulation (TMS) applied to hMT+ affects short-term and long-term perceptual memory.

Main Methods:

• Transcranial magnetic stimulation (TMS) was applied to the hMT+ region.
• Observers viewed an ambiguous motion stimulus, and their perceptual choices were recorded.
• The influence of TMS on both short-term (trial-to-trial) and long-term (baseline bias) perceptual memory was assessed.

Main Results:

• TMS applied to hMT+ increased the predominance of an observer's preferred percept.
• This effect indicates an impairment in the long-term buildup of perceptual memory traces.
• No significant effect was observed on short-term perceptual memory.

Conclusions:

• The middle temporal cortex (hMT+) is critical for the long-term consolidation of perceptual memory for ambiguous visual motion.
• hMT+ activity influences how past perceptions shape current interpretations, particularly for long-term biases.
• Targeting hMT+ with TMS disrupts the normal mechanism of building perceptual memory, leading to a stronger adherence to prior biases.