Function of Brain in Communication (Language) Lec:13 Dr. Farah Nabil Abbas

Language or communication is composed of 2 aspects: 1 Language or communication is composed of 2 aspects: 1. Sensory Aspect (Language Input): The input is either through the eyes by reading a question or staring or through the ears by hearing a conversation. -Any destruction to the auditory association areas leads to inability to understand spoken words (Auditory Receptive Aphasia or Word Deafness) in which there is impaired comprehension and impaired repetition of spoken language only, preserved naming and fluency. While in Wernicke’s Aphasia where there is destruction to the Wernicke’s Area in the Superior Temporal Gyrus, there will be impaired comprehension and impaired repetition of both spoken and written language, as well as impaired naming but the fluency is reserved also. Wernicke’s Aphasia is also called Receptive Aphasia. Destruction to the Visual Association Areas or the Angular Gyrus leads to inability to understand written words (Visual Receptive Aphasia or Word Blindness or Dyslexia). Global Aphasia destruction to W. area , angular gyrus, lower area of temporal and superior border of sylvian fissure ( dementia for language understanding and unability to communicate).

2. Motor Aspect (Language Output) (Answering): Either by: A 2. Motor Aspect (Language Output) (Answering): Either by: A. Verbal: By movement of the muscles of larynx, lips, tongue, soft palate  so we answer by understandable words that we call Vocalization. When the muscles of articulation are impaired as in cerebellar or basal ganglia lesion  will have Dysarthria. In cerebellar Dysarthria  there will be a monotonus, low volume speech as in Parkinson’s Disease.

B. Writing: By the movement of the upper limb (hands) and the answer is by the motor system of the body [The Pyramidal and Extra Pyramidal (Basal Ganglia) system].

C. Visual: If the answer is yes  you will move your eyebrows and if no  you will close your eyes. Any damage to the Broca’s Area in the Inferior Frontal Gyrus will lead to Broca’s or Expressive Aphasia  Good comprehension, impaired repetition, impaired naming and fluency. When there is damage to the Arcuate Fasiculus which lies between both the Broca’s and Wernicke Areas  there will be impaired repetition only. Global Aphasia means both Broca’s and Wernicke’s Aphasia with destruction to both areas.

Principle Pathways For Communication 1. Hearing & Speaking: The reception is in the primary Auditory Area (in the temporal lobe) of sound signals, then interpretation of words and determination of thoughts and words to be spoken in the Wernicke Area. Signals are transmitted from the Wernicke area to the Brocas area in order to activate skilled motor programs for control of word formation, and then signals are transmitted to the motor cortex to control the speech muscles. 2. Reading & Speaking: The reception is in the primary Visual Area in the occipital lobe, which is connected to the angular gyrus for interpretation, then to the Wernicke area in order to reach a full level of recognition  then it goes to the Broca’s Area and then to the motor cortex.

Functions of Corpus Callosum and Anterior Commissure   Corpus Callosum provides abundant bidirectional neural connections to transfer thought, memories, training and other information between the two hemispheres. The Anterior Commissure is responsible for transfer of emotions between the anterior part of the temporal lobes.

(Memory)   It is the ability to register (receive information), store and ultimately retrieve information. It is caused by changes in the synaptic transmission from one neuron to the next as a result of previous neural activity. Negative Memory: The brain will ignore any information that has no consequences. Positive Memory: The brain has the capacity of enhancing and storing the memories that cause important consequences as pain, pleasure, …etc

Clinical Classification of Memory   Immediate Memory Recent Memory Remote Memory When we want to convert the short term memory into a long term one  we keep on repeating the information many times (Rehearsal). This process is called Consolidation of the memory.