Brain Regions Associated with Semantic and Perceptual Processes

When people have a vivid memory of an exact statement and the topic of conversation, they are making semantic associations within the memory; if they also remember the speaker’s voice they are using their perceptual associations. These memories are called relational memory. They are connected to the medial temporal lobes and the prefrontal cortex.

This study used a functional magnetic resonance imaging (fMRI) to explore relational memory in the brain. Prince (2005) wanted to find the answers to three questions. First of all, he wanted to know if relational memory encoding and retrieval activations were different in the medial temporal lobes and the prefrontal cortex. Second, he asked does relational memory involve the reactivation during retrieval of process-specific encoding regions? Last, is there a brain region critical to successful relational memory, regardless of memory phase (encoding vs. retrieval) and stimulus content (semantic vs. perceptual)?

Prince wanted to find information leading to the transfer – appropriate processing (TAP) principle by Morris. It proposed a memory overlap between encoding and retrieval. When retrieving information the cognitive function depended on the nature of the information.

The participants used in the study were scanned for semantic and perceptual conditions. Semantic memory was tested while encoding and retrieving words. For example, a pair of words in plain font was displayed. The perceptual processes were tested between the words and different fonts. The font was different for each pair.

The results of the fMRI answered the above questions. First, differences were found in the encoding and retrieval activations in both the medial temporal lobes and the prefrontal cortex. Secondly, several of the same regions were activated in both the encoding and retrieval in a content-specific method. Last, there was one brain region critical to successful relational memory during encoding and retrieval in semantics and perceptual processing, the left hippocampus. This was the first study to prove that a common hippocampal region is activated during encoding and retrieval, and during semantic and perceptual relational memory.


The brain region where semantic memory is located is the Hippocampus which is inside the temporal lobe. The hippocampus encodes memories, or makes it possible for memories to form at all. The temporal lobe stores memories after the initial encoding process is completed. There is a passageway from the structure of the nervous system where semantic memory is located in the temporal lobes to the hippocampus. (Graham et al, 2000)

Brain regions associated with Semantic Memory - Pictures are posted on blog with this title.

The TAP principle confirmed that reactivation during retrieval used the same brain regions that were used previously in the encoding phase. This proved there were overlaps in many regions of the brain during encoding and retrieval that differed between the semantic and perceptual relational memory conditions. Even though semantic processing and episodic encoding were located in the ventrolateral prefrontal cortex, they may also be activated in several subregions of the area. With perceptual relational memory while encoding and retrieving information the areas of the brain that were activated were the left occipitotemporal, bilateral parietal and right parahippocampal regions (Prince, 2005).

References:

Prince, S.E., Daselaar, S.M., & Cabeza, R. (2005). Neural correlates of relational memory: successful encoding and retrieval of semantic and perceptual associations. The Journal of Neuroscience. 25(5), 1203-1210.

Graham, K.S., Simons, J.S., Pratt, K.H., Patterson, K., & Hodges, J.R. (2000). Insights from semantic dementia on the relatinship between episodic and semantic memory. Neuropsychologia. 38, 313-324.