Exam 5: Sensation and Perception

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The plasticity of the somatosensory cortex has been demonstrated through various experimental studies. One method used to investigate this plasticity is through the use of sensory deprivation or enrichment. For example, in a classic experiment by Merzenich et al. (1984), adult monkeys were trained to use only one finger for a tactile discrimination task while the other fingers were immobilized. The researchers found that the somatosensory cortex reorganized in response to this manipulation, with the cortical representation of the finger used for the task expanding at the expense of the immobilized fingers. This demonstrated that the somatosensory cortex is capable of reorganizing its neural connections in response to changes in sensory input.

Another method used to study somatosensory cortex plasticity is through the use of neuroimaging techniques such as functional magnetic resonance imaging (fMRI). In a study by Pascual-Leone et al. (1995), participants underwent a period of tactile stimulation using a Braille reading task. The researchers found that after just 2 weeks of training, there was an increase in the cortical representation of the stimulated fingers in the somatosensory cortex, providing evidence of neuroplastic changes in response to sensory input.

Overall, these experiments provide strong evidence that the somatosensory cortex is plastic, meaning it has the ability to reorganize and adapt in response to changes in sensory input. This plasticity has important implications for understanding how the brain processes sensory information and for developing interventions to rehabilitate sensory function following injury or disease.