Summary of Huberman Lab Podcast Episode: Neuroscience of Speech, Language & Music with Dr. Erich Jarvis

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Introduction

• Dr. Erich Jarvis (@erichjarvis) is a Professor and the Head of the Laboratory of Neurogenetics of Language at Rockefeller University and an Investigator with the Howard Hughes Medical Institute (HHMI). Dr. Jarvis’ research spans the molecular and genetic mechanisms of vocal communication, comparative genomics of speech and language across species, and the relationship between speech, language, and movement.
• In this episode, Andrew Huberman & Erich Jarvis discuss the unique ability of humans to learn and communicate using complex written and spoken language. They break down the connections between language, song, and dance, underlying biology to speech pathology, what distinguishes one’s ability to learn multiple languages, and more!
• Host: Andrew Huberman (@hubermanlab)

Are Language & Speech Different?

• Speech and language are behavioral, psychological terms that don’t exactly align with brain function
• Speech is the motor patterns and production of sound that combine to have meaning
• There may not be as much distinction between speech and language as you’d think – there is a separate language module in the brain that has the algorithms and computations that influence the speech pathway in how to produce sound, and the auditory pathway in how to interpret that sound
• Speech production pathway: controls larynx and jaw muscles and has built-in all the algorithms for spoken language
• The auditory pathway has the algorithms for understanding speech
• Dogs can understand several hundred human speech words

Modes Of Communication Across Animals

• For spoken language, we use the speech pathway and its algorithms
• The larynx is the fastest firing muscle in the human  body
• There is an evolutionary relationship between the brain pathways that control speech production and gesturing
• The region of the brain that controls hand gestures is next to the region of the brain responsible for spoken language
• “Humans are the most advanced at spoken language but not necessarily at gestural language.” – Dr. Erich Jarvis
• Each language comes with a learned set of gestures that comes with it
• Some species can gesture with hands more than voice and vice versa
• Most vertebrate species vocalize with innate sounds they’re born with – very few have learned vocal communication in which they can imitate other sounds
• Learned behavior uses forebrain circuits
• Primates are the only ones that have advanced vocal ability – it’s likely Neanderthals had spoken language which evolved in the last 500,000-1 million years
• Birds have parallel structures & underlying genes as humans for language
• Hummingbirds hum with their wings and sing with their pharynx in coordination
• Songbirds can learn other birds’ songs but not as well as they can sing their innate language

Plasticity & Ability To Learn Language

• It is easier to learn a language early in life – and – the ability to learn another language later in life is easier if you already speak multiple languages
• Critical period: the brain is designed to solidify circuits learned as a child
• If you learn another language early in life, you develop and maintain the ability to learn and make different sounds (phonemes) as an adult so you can apply those phonons to other languages

The Power Of Music

• Semantic communication: communication that has meaning
• Effective communication: communication that has emotional feelings embedded
• The same circuits are being used in different ways when processing semantic and effective communication
• The context and intent heavily shape the way we perceive what’s being said
• The right brain is artistic, the left brain is for thinking: in birds and humans, there’s left-right dominance for sound communication – the left is more dominant for speech, but the right has more balance for singing and processing musical sounds
• History of songs: the evolution of spoken language evolved for singing and emotional mate attraction then was used for abstract communication

Dance As A Form Of Communication

• Vocal learning brain pathways in songbirds and humans are embedded within circuits that control learning how to move
• Motor theory of vocal learning origin: brain pathways for vocal learning and speech evolve by duplication of surround circuits involved in learning how to move
• Hypothesis: when speech evolved in humans and songbirds, the auditory-motor integration contaminated surrounding brain regions and allowed for coordination of sound and movement
• The body can communicate using movement

Other Forms Of Communication: Facial Expression, Written Language

• Non-human primates have a lot of diversity in facial expressions, like humans
• Non-human primates have strong connections from cortical regions to motor neurons that control facial expressions – but – weak connections to motor neurons that control voice
• There is likely a combination of innate and learned behavior with allows humans to couple uncoupled circuits that control the thousands of facial expressions depending on the context
• We write in complete sentences but don’t often think in simple, declarative sentences (like we speak)
• Thought to language to the written word: your speech pathway speaks what you read, then is sent to auditory pathway – you’re essentially speaking in your own head – then you have a fourth pathway online to write
• We have competing brain circuits for conscience attention – it can be difficult to speak at the same time depending on the complexity of the task
• If the rate of thought and rate of writing are aligned, things tend to go smoothly
• There is not necessarily peer-reviewed support, but anecdotally it does seem writing by hand is different than typing

Speech Pathology

• Stutter does not mean the thinking is slow
• Songbirds also stutter
• Stutter: damage to basal ganglia or disruption to basal ganglia at a young age causes stutter
• Stutter can be overcome with behavioral therapy, learning to speak slower, tapping out a rhythm – basically, sensory-motor integration tools – controlling what you hear with output

Texting & Communication

• Are we getting less proficient at speech because we don’t write and think in complete sentences?
• Texting has allowed for more rapid communication in written form between people – arguably, since we’re using those parts of our brain more, we’re stimulating it
• “With texting, what you’re losing is less so the ability to write but more the ability to interpret what is written.” – Dr. Erich Jarvis

On The Horizon For Speech

• It’s possible we’ll see electrodes implanted in the human brain and electrical outputs translated into human speech which will help us with paralyzed or non-communicative individuals (but could also be frightening to have these signals floating around which could be intercepted)
• Study of genomes & creation of a  database to find genetic associations across species and potentially resurrect extinct species