Skirball

Making Sense of the Senses: ‘Context’ Matters When the Brain Interprets Sounds

The brain’s interpretation of sound is influenced by cues from other senses, explaining more precisely how we interpret what we hear at a particular moment, according to a report published online October 31 in Nature Neuroscience.

In the new study in mice, researchers at NYU Langone Medical Center found that nerve cells dedicated to hearing also rely on surrounding context to properly interpret and react to familiar sounds.

“What the brain ‘hears’ depends on what is ‘seen’ in addition to specific sounds, as the brain calculates how to respond,” says study senior investigator and neuroscientist Robert Froemke, PhD, an assistant professor at NYU Langone and its Skirball Institute of Biomolecular Medicine.

Froemke says his team’s latest findings reveal that while mammals recognize sounds in the auditory cortex of their brains, the signaling levels of nerve cells in this brain region are simultaneously being strengthened or weakened in response to surrounding context.

“Our study shows how the same sound can mean different things inside the brain depending on the situation,” says Froemke. “We know, for instance, that people learn to respond without alarm to the honk of a car horn if heard from the safety of their homes, but are startled to hear the same honk while crossing a busy street.”

If further experiments find similar activity in human brains, the researchers say their work may lead to precise explanations of situation-specific behaviors, such as anxiety brought on during math exams; sudden post-traumatic stress among combat veterans hearing a car backfire; and the ability of people with dementia to better remember certain events when they hear a familiar voice or see a friend’s face.

To map how the same sense can be perceived differently in the brain, the NYU Langone team, led by postdoctoral fellow Kishore Kuchibhotla, PhD, monitored nerve circuit activity in mice when the animals expected, and did not expect, to get a water reward through a straw-like tube (that they see) after the ringing of a familiar musical note.

When mice were exposed to specific auditory cues, researchers observed patterns based on a basic divide in the nature of nerve cells. Each nerve cell “decides” whether a message travels onward in a nerve pathway. Nerve cells that emit chemicals which tell the next cell in line to amplify a message are excitatory; those that stop messages are inhibitory. Combinations of the two strike a counterbalance critical to the function of the nervous system, with inhibitory cells sculpting “noise” from excitatory cells into the arrangements behind thought and memory.

Furthermore, the processing of incoming sensory information is achieved in part by adjusting signaling levels through each type of nerve cell. Theories hold that the brain may attach more importance to a given signal by turning up or down excitatory signals, or by doing the same with inhibitory nerve cells.

In the current study, researchers found to their surprise that most of the nerve cells in auditory cortex neurons that stimulate brain activity (excitatory) had signaled less (had “weaker” activity) when the mice expected and got a reward. Meanwhile, and to the contrary, a second set of remaining “excitatory” neurons saw greater signaling activity when mice expected a reward based on exposure to the two sensory cues and got one.

Further tests showed that the activation of specific inhibitory neurons—parvalbumin, somatostatin, and vasoactive intestinal peptide—was responsible for these changes and was in turn controlled by the chemical messenger, or neurotransmitter, acetylcholine. Chemically shutting down acetylcholine activity cut in half the number of times mice successfully went after their water reward when prompted by a ring tone. Some studies in humans have linked acetylcholine depletion to higher rates of Alzheimer’s disease.

Froemke, who is also a faculty scholar at the Howard Hughes Medical Institute, says the team next plans to assess how the hormones noradrenaline and dopamine affect auditory cortex neurons under different situations.

“If we can sort out the many interactions between these chemicals and brain activity based on sensory perception and context, then we can possibly target specific excitatory and inhibitory neurological pathways to rebalance and influence behaviors,” says Froemke.

What was the relationship between Sephardim and Ashkenazim on the West Coast?

By Leora Singer, Former Research Intern

This is my second blog post in a series of three posts in which I discuss the theme of Sephardim in the West Coast in the 19th-20th century. You can see my first post here. In this post, I compare and contrast the relationship between Ashkenazim and Sephardim in Seattle and San Francisco.

Seattle:

When Calvo and Policar (the first two Sephardim in Seattle) first encountered the Orthodox Ashkenazi Jews living in the city, they weren’t exactly welcomed with open arms. These observant Jews didn’t believe that Policar and Calvo were “real Jews” because they spoke Greek instead of Yiddish (Adatto, 56), and their names didn’t “sound Jewish” (Angel, 553). Because they felt ostracized by the Jewish community, Calvo and Policar spent a lot of time with Greek non-Jews living in Seattle (Adatto, 58). Fortunately, the rabbi of Bikur Holim, an Orthodox synagogue, convinced the Orthodox Ashkenazim that the Sephardim were just as observant as they were. The Ashkenazim accepted Calvo and Policar as members of the Jewish people.

The Seattle Sephardic community kept growing as Calvo and Policar brought family members over, and these family members spread the word about the opportunities available in Seattle (Adatto, 60). In 1904, the first Rhodesli Sephardic immigrant came to Seattle (FitzMorris, 29). As the number of Sephardim in Seattle grew, their ties to the overall Jewish community of Seattle grew. Many Sephardim prayed at Bikur Holim. They felt somewhat connected to the Orthodox Ashkenazim because they, like the Sephardim, upheld high religious standards (Adatto, 116). However, the perception was that their cultures were just too different to mix together, so the Sephardim and Orthodox Ashkenazim remained fairly separate. For example, intermarriage between the two groups was highly rare (Adatto, 117).

Despite its rocky nature, the beginning of the relationship between Orthodox Sephardim and Orthodox Ashkenazim was still stronger than the beginning of the relationship between Sephardim and Reform Ashkenazim. The Sephardim distrusted the Reform Ashkenazim because they believed that the Reform Ashkenazim were not following enough of the Jewish traditions. Fortunately, Aubrey Levy from the Reform Temple de Hirsch helped to change this negative view of Reform Judaism by forming a friendship with the Sephardic Jews. As a lawyer, he helped Sephardim with legal work, free of charge. For example, in 1914, he assisted them with the legal logistics in the purchase of the (previously Ashkenazi-owned) Bikur Holim synagogue (Adatto, 118-119). Levy was highly regarded by the Sephardim. By association, his synagogue became highly regarded as well. In fact, many Sephardic children got their Jewish education at the Hebrew School of Temple de Hirsch. However, even after many years, there was still very little intermarriage. The Sephardim still did not feel like a part of Ashkenazi culture.

San Francisco:

There was a temporary Sephardic congregation in the early 1850s (Zerin, 30). The congregation was called Shaar Hashamayim. It was so temporary that it never even had a building because the congregation stopped meeting only a few months after its creation (Zerin, 47). This is likely because the construction of new buildings for two Ashkenazi-run synagogues, Temple Emanu-El and Temple Sherith- Israel, was underway. Since the Sephardim and Ashkenazim in San Francisco were united, (especially in comparison to these sects in other West Coast cities) the Sephardim didn’t want to divide it by having their own synagogue. Also, some members of the Sephardic congregation had been leaders in the other synagogues, because they were so prominent and respected by the Ashkenazim (Stern and Kramer, 47).

Sephardim from San Francisco are sometimes difficult to identify because intermarriage with Ashkenazim and even non-Jews was common (Stern and Kramer, 45). This practice showed a stark difference between the Jews of San Francisco and in other West Coast cities. In the other cities, intermarriage between pretty much anyone that was not a Jew from your home country was frowned upon.

Bibliography:

Adatto, Albert. Sephardim and the Seattle Sephardic Community. Seattle: U of Washington, 1939. Print.

Angel, Marc D., Hasson, Aron, Kramer, William M., Maimon, Isaac, Samuels, Beth, Sidell, Loraine, Stern, Norton B. Sephardic Jews in the West Coast States : An Anthology. 1st ed. Los Angeles: Published for the Skirball Cultural Center, Los Angeles by the Western States Jewish History Association, 1996. Print. Western States Jewish History ; v. 28, No. 1-3.

Stern, Stephen. The Sephardic Jewish Community of Los Angeles. New York: Arno, 1980. Print. Folklore of the World (New York).

Zerin, Edward. Jewish San Francisco. Charleston, SC: Arcadia, 2006. Print. Images of America

hd.hk: Just saw a live script read of Good Will Hunting with a crazy famous cast. Way to start to 5-day weekend right.

Henry was kind enough to say that I could share this. 

Look at D’s face!

P.S. Just…throwing this out there. Someone is very conveniently suddenly in NYC the same day/night a certain someone else happens to be hosting SNL… Hmm…I wonder…